Anatomy of the Midcontinent Rift beneath Lake Superior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, M.D.; McGinnis, L.D.; Ervin, C.P.

1994-09-01

The structure and geometry of the 1.1-b.y.-old Midcontinent Rift system under Lake Superior is interpreted from 20 seismic reflection profiles recorded during the early and mid-1980s. The seismic data reveal that rift basins under Lake Superior are variable in depth and are partially filled with Keweenawan age sediments to depths of 7 km or more and volcanic flows to depths of 36 km. These rift basins form a continuous and sinuous feature that widens in the Allouez Basin and Marquette Basin in the western and central lake and narrows between White Ridge and the Porcupine Mountains. The rift basin bendsmore » southeast around the Keweenaw Peninsula, widens to about 100 km as it extends into the eastern half of Lake Superior, and exists the lake with its axis in the vicinity of Au Sable Point in Pictured Rocks National Lake Shore, about 50 km northeast of Munising, Michigan. The axis of the rift may exit the western end of the lake near Chequamegon Bay in Wisconsin. However, lack of data in that area limits interpretation at this time. Prior to late-stage reverse-faulting, a continuous basin of more uniform thickness was present beneath the lake. Crustal extension during rifting of approximately 50 km was followed by plate convergence and crustal shortening of approximately 30 km, with the major component of thrust from the southeast. Crustal shortening occurred after development of rift grabens and their filling with lava flows, but before deposition of the final sag basin sediments. Integration of information obtained from outcrops with data reported here indicates that the Lake Superior section of the rift is associated with as many as three major boundary faults.« less

Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

EPA Science Inventory

The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

77 FR 37321 - Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

... 1625-AA00 Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN AGENCY: Coast Guard, DHS. ACTION... suspected to contain munitions waste materials which were dumped in the 1960's in a portion of Lake Superior... offshore in a portion of Lake Superior approximately 50 years ago. C. Discussion of the Final Rule The...

Evaluation of methods to estimate lake herring spawner abundance in Lake Superior

USGS Publications Warehouse

Yule, D.L.; Stockwell, J.D.; Cholwek, G.A.; Evrard, L.M.; Schram, S.; Seider, M.; Symbal, M.

2006-01-01

Historically, commercial fishers harvested Lake Superior lake herring Coregonus artedi for their flesh, but recently operators have targeted lake herring for roe. Because no surveys have estimated spawning female abundance, direct estimates of fishing mortality are lacking. The primary objective of this study was to determine the feasibility of using acoustic techniques in combination with midwater trawling to estimate spawning female lake herring densities in a Lake Superior statistical grid (i.e., a 10′ latitude × 10′ longitude area over which annual commercial harvest statistics are compiled). Midwater trawling showed that mature female lake herring were largely pelagic during the night in late November, accounting for 94.5% of all fish caught exceeding 250 mm total length. When calculating acoustic estimates of mature female lake herring, we excluded backscattering from smaller pelagic fishes like immature lake herring and rainbow smelt Osmerus mordax by applying an empirically derived threshold of −35.6 dB. We estimated the average density of mature females in statistical grid 1409 at 13.3 fish/ha and the total number of spawning females at 227,600 (95% confidence interval = 172,500–282,700). Using information on mature female densities, size structure, and fecundity, we estimate that females deposited 3.027 billion (109) eggs in grid 1409 (95% confidence interval = 2.356–3.778 billion). The relative estimation error of the mature female density estimate derived using a geostatistical model—based approach was low (12.3%), suggesting that the employed method was robust. Fishing mortality rates of all mature females and their eggs were estimated at 2.3% and 3.8%, respectively. The techniques described for enumerating spawning female lake herring could be used to develop a more accurate stock–recruitment model for Lake Superior lake herring.

CONTOURITES IN LAKE SUPERIOR

EPA Science Inventory

Contour currents influence sedimentation in an area 15 km wide and 65 km long at the base of the slope off the Keweenaw Peninsula in Lake Superior, northwestern Michigan. Seismic-reflection profiles (3.5 kHz) from this area show distinct wavy reflectors in a scoured trough at a d...

Trophic connections in Lake Superior Part II: the nearshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Yule, D.L.; Stockwell, J.D.

2011-01-01

We use detailed diet analyses of the predominant planktivorous, benthivorous and piscivorous fish species from Lake Superior to create a nearshore (bathymetric depths Mysis diluviana and Diporeia spp). Although the piscivorous fishes like lean lake trout (Salvelinus namaycush) fed to a lesser extent on Diporeia and Mysis, they were still strongly connected to these macroinvertebrates, which were consumed by their primary prey species (sculpin spp., rainbow smelt Osmerus mordax, and coregonines). The addition of Bythotrephes to summer/fall cisco and lake whitefish diets, and the decrease in rainbow smelt in lean lake trout diets (replaced by coregonines) were the largest observed differences relative to historic Lake Superior diet studies. Although the offshore food web of Lake Superior was simpler than nearshore in terms of number of fish species present, the two areas had remarkably similar food web structures, and both fish communities were primarily supported by Mysis and Diporeia. We conclude that declines in Mysis or Diporeia populations would have a significant impact on energy flow in Lake Superior. The food web information we generated can be used to better identify management strategies for Lake Superior.

INFLUENCES OF HYDROLOGY ON NUTRIENT DYNAMICS IN LAKE SUPERIOR COASTAL WETLANDS

EPA Science Inventory

Little is known about the role of the coastal wetlands (CWs) of Lake Superior in modifying or contributing to nutrient fluxes from watersheds to the lake. We are studying factors controlling nutrient retention and transformation of CWs in Western Lake Superior. CWs may be unique ...

Genetic diversity of Diporeia in the Great Lakes: comparison of Lake Superior to the other Great Lakes

EPA Science Inventory

Abundances of Diporeia have dropped drastically in the Great Lakes, except in Lake Superior, where data suggest that population counts actually have risen. Various ecological, environmental, or geographic hypotheses have been proposed to explain the greater abundance of Lake Supe...

Winter diet of lake herring (Coregonus artedi) in western Lake Superior

USGS Publications Warehouse

Link, Jason; Selgeby, James H.; Hoff, Michael H.; Haskell, Craig

1995-01-01

Lake herring (Coregonus artedi) and zooplankton samples were simultaneously collected through the ice in the Apostle Islands region of western Lake Superior to provide information on the winter feeding ecology of lake herring. Zooplankton constituted the entire diet of the 38 lake herring collected for this study. We found no evidence of piscivory, although it has been reported by anglers. Diet selectivities were calculated using a Wilcoxon signed-ranks test and showed a preference of lake herring for larger zooplankton, especially Diaptomus sicilis, whereas the smaller copepod,Cyclops bicuspidatus thomasi, and immature copepod stages were selected against. These data document that overwintering copepods are food for a broad size range of lake herring in winter.

FORAGE FISH AND ZOOPLANKTON COMMUNITY COMPOSITION IN WESTERN LAKE SUPERIOR

EPA Science Inventory

We assessed the abundance, size, and species composition of the fish and zooplankton communities of western Lake Superior during 1996 and 1997. Data were analyzed for 3 ecoregions (Duluth-Superior (1), Apostle Islands (2), Minnesota coast (3) differing in lake bathymetry, phsiodo...

Spawning Cisco investigations in Canada waters of Lake Superior during 2007

USGS Publications Warehouse

Yule, Daniel L.; Evrard, Lori M.; Cholwek, Gary A.; Addison, Peter A.; Cullis, Ken I.

2008-01-01

Cisco Coregonus artedi form pre-spawning aggregations in Lake Superior during November with the bulk of spawning occurring during late November through early December (Dryer and Beil 1964). Eggs are broadcast into open water (Smith 1956) with fertilized eggs settling to the lakebed (Dryer and Beil 1964). Peak hatching occurs the following May (United States Geological Survey – Great Lakes Science Center, GLSC, unpublished data). Interannual variability in year class strength is high, but tends to be synchronous across different regions of Lake Superior (Bronte et al. 2003). November 2005 sampling of Thunder Bay showed 14 year-classes were present with the oldest fish being from the 1984 year-class (Yule et al. 2008). The ciscoes sampled were predominantly from five year classes that hatched during 1988, 1989, 1990, 1998, and 2003. These same strong year-classes were found in the western arm of Lake Superior during November 2006 (GLSC, unpublished data). Growth is rapid in the first few years of life with minimal growth after age-8 (Yule et al. 2008). Ciscoes exceeding 250 mm total length (TL) are typically sexually mature (Yule et al. 2006b, 2008). Thunder Bay ciscoes have high annual survival with rates for females and males averaging 0.80 and 0.75, respectively; females have higher rates of fishing-induced mortality compared to males but lower rates of natural mortality (Yule et al. 2008). Some Lake Superior stocks are currently commercially fished with the bulk of harvest occurring during November when fishers target females for their roe. The bulk of fish are harvested from Thunder Bay using suspended gillnets with mesh sizes ranging from 79-89 mm stretch measure. Ciscoes younger then age-5 make up a very small proportion (<0.1%) of the harvest (Yule, et al. 2008).

WATER QUALITY AND BIOLOGICAL CONDITIONS OF GREAT LAKES COASTAL WETLANDS, WITH AN EMPHASIS ON LAKE SUPERIOR

EPA Science Inventory

This presentation will focus on MED's past and ongoing research in Lake Superior wetlands, and will include data on habitat, water quality, and biological condition of these systems. Comparisons of the condition of Lake Superior wetlands relative to those found around the Great ...

Fat content of the flesh of siscowets and lake trout from Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.; Phillips, Arthur M.

1965-01-01

Samples of flesh were excised from the middorsal region of 67 siscowets (Salvelinus namaycush siscowet) and 46 lake trout (Salvelinus n. namaycush) collected from Lake Superior. Chemical analysis of the samples revealed a range in fat content (dry weight) of 32.5 to 88.8 per cent in siscowets and 6.6 to 52.3 per cent in lake trout. Percentage fat increased progressively with increase in length of fish in both forms, but the average rate of increase was far greater for siscowets than for lake trout at lengths between 12 and 20 inches. Despite substantial individual variation, the percentage fat in the two forms was widely different and without overlap at all comparable lengths. The range in iodine number of the fat was 100 to 160 for siscowets and 103 to 161 for lake trout; average values were generally lower for siscowets than for lake trout among fish of comparable length. Percentage fat and relative weight were not correlated significantly in either subspecies. The fat content of flesh samples from a distinctive subpopulation of Lake Superior lake trout known as 'humpers' was more closely similar to that of typical lean lake trout than to siscowets, but the rate of increase in fat with increasing length was greater than for lean lake trout. Flesh samples from hatchery-reared stocks of lake trout, hybrid lake trout X siscowets, and siscowets tended to support the view that the wide difference in fat content between siscowets and lake trout is genetically determined.

Spatial and temporal distribution of singlet oxygen in Lake Superior.

PubMed

Peterson, Britt M; McNally, Ann M; Cory, Rose M; Thoemke, John D; Cotner, James B; McNeill, Kristopher

2012-07-03

A multiyear field study was undertaken on Lake Superior to investigate singlet oxygen ((1)O(2)) photoproduction. Specifically, trends within the lake were examined, along with an assessment of whether correlations existed between chromophoric dissolved organic matter (CDOM) characteristics and (1)O(2) production rates and quantum yields. Quantum yield values were determined and used to estimate noontime surface (1)O(2) steady-state concentrations ([(1)O(2)](ss)). Samples were subdivided into three categories based on their absorbance properties (a300): riverine, river-impacted, or open lake sites. Using calculated surface [(1)O(2)](ss), photochemical half-lives under continuous summer sunlight were calculated for cimetidine, a pharmaceutical whose reaction with (1)O(2) has been established, to be on the order of hours, days, and a week for the riverine, river-impacted, and open lake waters, respectively. Of the CDOM properties investigated, it was found that dissolved organic carbon (DOC) and a300 were the best parameters for predicting production rates of [(1)O(2)](ss). For example, given the correlations found, one could predict [(1)O(2)](ss) within a factor of 4 using a300 alone. Changes in the quantum efficiency of (1)O(2) production upon dilution of river water samples with lake water samples demonstrated that the CDOM found in the open lake is not simply diluted riverine organic matter. The open lake pool was characterized by low absorption coefficient, low fluorescence, and low DOC, but more highly efficient (1)O(2) production and predominates the Lake Superior system spatially. This study establishes that parameters that reflect the quantity of CDOM (e.g., a300 and DOC) correlate with (1)O(2) production rates, while parameters that characterize the absorbance spectrum (e.g., spectral slope coefficient and E2:E3) correlate with (1)O(2) production quantum yields.

Prey selection by the Lake Superior fish community

USGS Publications Warehouse

Isaac, Edmund J.; Hrabik, Thomas R.; Stockwell, Jason D.; Gamble, Allison E.

2012-01-01

Mysis diluviana is an important prey item to the Lake Superior fish community as found through a recent diet study. We further evaluated this by relating the quantity of prey found in fish diets to the quantity of prey available to fish, providing insight into feeding behavior and prey preferences. We describe the seasonal prey selection of major fish species collected across 18 stations in Lake Superior in spring, summer, and fall of 2005. Of the major nearshore fish species, bloater (Coregonus hoyi), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis) consumed Mysis, and strongly selected Mysis over other prey items each season. However, lake whitefish also selected Bythotrephes in the fall when Bythotrephes were numerous. Cisco (Coregonus artedi), a major nearshore and offshore species, fed largely on calanoid copepods, and selected calanoid copepods (spring) and Bythotrephes (summer and fall). Cisco also targeted prey similarly across bathymetric depths. Other major offshore fish species such as kiyi (Coregonus kiyi) and deepwater sculpin (Myoxocephalus thompsoni) fed largely on Mysis, with kiyi targeting Mysis exclusively while deepwater sculpin did not prefer any single prey organism. The major offshore predator siscowet lake trout (Salvelinus namaycush siscowet) consumed deepwater sculpin and coregonines, but selected deepwater sculpin and Mysis each season, with juveniles having a higher selection for Mysis than adults. Our results suggest that Mysis is not only a commonly consumed prey item, but a highly preferred prey item for pelagic, benthic, and piscivorous fishes in nearshore and offshore waters of Lake Superior.

Early detection of invasive fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as "high risk" for new introductions: St. Louis River near Duluth, MN, Upper St. Marys River near S...

Movements of hatchery-reared lake trout in Lake Superior

USGS Publications Warehouse

Pycha, Richard L.; Dryer, William R.; King, George R.

1965-01-01

The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed. The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets. Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in 3A? hr. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2-4 miles (3.2-6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated. Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

Observations of the Winter Thermal Structure of Lake Superior

NASA Astrophysics Data System (ADS)

Titze, Daniel James

Moored thermistor strings that span the water column have been deployed at up to seven locations throughout Lake Superior from 2005 through present, producing a unique year-round record of the thermal structure of a large lake. This extensive temperature record reveals significant interannual and spatial variability in Lake Superior's winter heat content, thermocline depth, and phenology. Of particular mention is a stark contrast in thermal structure between the cold, icy winter of 2009 and the much warmer winter of 2012, during which especially strong and weak negative stratification was observed, respectively. Significant interannual and spatial variability was also observed in Lake Superior ice cover, as shown through data extracted from Ice Mapping System satellite imagery (NOAA/NESDIS 2004). When water column heat content was estimated from temperature data and analyzed in concert with lake ice-cover data, it was found that ice cover can inhibit heat flux between the lake and the atmosphere, and that spatial variability in ice cover can translate into spatial variability in end-of-winter heat content. Such variability in end-of-winter heat content is found to be preserved through the spring warming season, and is strongly correlated with variability in the timing of the onset of summer stratification, with regions that have warmer end-of-winter water columns stratifying earlier than regions with colder end-of-winter water-columns.

Sea lamprey abundance and management in Lake Superior 1957-1999

USGS Publications Warehouse

Heinrich, John W.; Mullett, Katherine M.; Hansen, Michael J.; Adams, Jean V.; Klar, Gerald T.; Johnson, David A.; Christie, Gavin C.; Young, Robert J.

2003-01-01

The international sea lamprey (Petromyzon marinus) control program successfully laid the foundation for rehabilitation of lake trout (Salvelinus namaycush) in Lake Superior and was well coordinated among management agencies during 1957–1999. The lampricide TFM was the primary control tool, with recurring treatments in 52 larval-producing streams. Barriers and sterile-male-release, as alternative control technologies, were significant elements of the program. Barriers blocked spawning sea lampreys from substantial areas of habitat for sea lamprey larvae during 1966–1999, and the sterile-male-release technique was used to reduce larval production during 1991–1996. Sea lamprey control resulted in the suppression of sea lamprey populations in Lake Superior, as evidenced by the linear decline in spawner abundance during 1962–1999. However, sea lamprey abundance was not as low as the targets specified in the fish community objectives. Most of the parasitic sea lampreys in Lake Superior probably originated from survivors of lampricide treatments. Self-sustaining populations of lake trout were restored in most of the lake by 1996, although many were killed annually by sea lampreys. Economic injury levels for damage to fish populations by sea lampreys are being developed and will be used to distribute sea lamprey control resources among the Great Lakes.

LAKE HERRING (COREGONUS ARTEDI) AND RAINBOW SMELT (OSMERUS MORDAX) DIETS IN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the diets of lake herring and rainbow smelt, currently the two dominant forage fish species (fish that are food for game fishes) in western Lake Superior. Despite the pelagic nature of both these species, they have substantially different diets and henc...

Status of the shortjaw cisco (Coregonus zenithicus) in Lake Superior

USGS Publications Warehouse

Hoff, Michael H.; Todd, Thomas N.

2004-01-01

The shortjaw cisco (Coregonus zenithicus) was historically found in Lakes Huron, Michigan, and Superior, but has been extirpated in Lakes Huron and Michigan apparently as the result of commercial overharvest. During 1999-2001, we conducted an assessment of shortjaw cisco abundance in five areas, spanning the U.S. waters of Lake Superior, and compared our results with the abundance measured at those areas in 1921-1922. The shortjaw cisco was found at four of the five areas sampled, but abundances were so low that they were not significantly different from zero. In the four areas where shortjaw ciscoes were found, abundance declined significantly by 99% from the 1920s to the present. To increase populations of this once economically and ecologically important species in Lake Superior, an interagency rehabilitation effort is needed. Population monitoring is recommended to assess population trends and to evaluate success of rehabilitation efforts.

77 FR 35857 - Safety Zone, Fireworks Display, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-15

... 1625-AA00 Safety Zone, Fireworks Display, Lake Superior; Duluth, MN AGENCY: Coast Guard, DHS. ACTION... of Lake Superior during the Duluth Fourth Fest fireworks display. This temporary safety zone is necessary to protect spectators and vessels from the hazards associated with fireworks displays. DATES: This...

Discrimination among spawning aggregations of lake herring from Lake Superior using whole-body morphometric characters

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

The lake herring (Coregonus artedi) was one of the most commercially and ecologically valuable Lake Superior fishes, but declined in the second half of the 20th century as the result of overharvest of putatively discrete stocks. No tools were previously available that described lake herring stock structure and accurately classified lake herring to their spawning stocks. The accuracy of discriminating among spawning aggregations was evaluated using whole-body morphometrics based on a truss network. Lake herring were collected from 11 spawning aggregations in Lake Superior and two inland Wisconsin lakes to evaluate morphometrics as a stock discrimination tool. Discriminant function analysis correctly classified 53% of all fish from all spawning aggregations, and fish from all but one aggregation were classified at greater rates than were possible by chance. Discriminant analysis also correctly classified 66% of fish to nearest neighbor groups, which were groups that accounted for the possibility of mixing among the aggregations. Stepwise discriminant analysis showed that posterior body length and depth measurements were among the best discriminators of spawning aggregations. These findings support other evidence that discrete stocks of lake herring exist in Lake Superior, and fishery managers should consider all but one of the spawning aggregations as discrete stocks. Abundance, annual harvest, total annual mortality rate, and exploitation data should be collected from each stock, and surplus production of each stock should be estimated. Prudent management of stock surplus production and exploitation rates will aid in restoration of stocks and will prevent a repeat of the stock collapses that occurred in the middle of the 20th century, when the species was nearly extirpated from the lake.

Delineation of sympatric morphotypes of lake trout in Lake Superior

USGS Publications Warehouse

Moore, Seth A.; Bronte, Charles R.

2001-01-01

Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

Causes of declining survival of lake trout stocked in U.S. waters of Lake Superior in 1963-1986

USGS Publications Warehouse

Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H.; Taylor, William W.

1996-01-01

Survival of the 1963-1982 year-classes of stocked yearling lake trout Salvelinus namaycush declined significantly over time in Lake Superior. To investigate possible causes of this decline, a Ricker model of stock-recruitment was used to describe the catch per effort (CPE) of age-7 stocked lake trout in the Michigan, Minnesota, and Wisconsin waters of Lake Superior as functions of the numbers of yearlings stocked 6 years earlier (an index of density dependence), the density (CPE) of wild adult lake trout (an index of predation), and large-mesh (a?Y 114-mm stretch-measure) gill-net fishing effort (an index of fishing mortality). Declining CPE of stocked lake trout in Michigan and Wisconsin was significantly associated with increasing large-mesh gillnet fishing effort. Declining CPE of stocked lake trout in Minnesota was significantly associated with increasing density of wild lake trout. Declining survival of stocked lake trout may therefore have been caused by increased mortality in large-mesh gill-net fisheries in Michigan and Wisconsin, and by predation by wild lake trout that recently recolonized the Minnesota area. We recommend that experimental management be pursued to determine the relative importance of large-mesh gillnet fishing effort and of predation by wild lake trout on the survival of stocked lake trout in U.S. waters of Lake Superior.

Ups and Downs of Burbot and their predator Lake Trout in Lake Superior, 1953-2011

USGS Publications Warehouse

Gorman, Owen T.; Sitar, Shawn P.

2013-01-01

The fish community of Lake Superior has undergone a spectacular cycle of decline and recovery over the past 60 years. A combination of Sea Lamprey Petromyzon marinus depredation and commercial overfishing resulted in severe declines in Lake Trout Salvelinus namaycush, which served as the primary top predator of the community. Burbot Lota lota populations also declined as a result of Sea Lamprey depredation, largely owing to the loss of adult fish. After Sea Lamprey control measures were instituted in the early 1960s, Burbot populations rebounded rapidly but Lake Trout populations recovered more slowly and recovery was not fully evident until the mid-1980s. As Lake Trout populations recovered, Burbot populations began to decline, and predation on small Burbot was identified as the most likely cause. By 2000, Burbot densities had dropped below their nadir in the early 1960s and have continued to decline, with the densities of juveniles and small adults falling below that of large adults. Although Burbot populations are at record lows in Lake Superior, the density of large reproductive adults remains stable and a large reserve of adult Burbot is present in deep offshore waters. The combination of the Burbot's early maturation, long life span, and high fecundity provides the species with the resiliency to remain a viable member of the Lake Superior fish community into the foreseeable future.

Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

USGS Publications Warehouse

Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

2016-01-01

Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

The pygmy whitefish, Coregonus coulteri, in Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.; Bailey, Reeve M.

1955-01-01

Other cold-water fishes–cottids, ninespine sticklebacks, smelt, and four species of coregonines–were the most frequent associates of the pygmy whitefish. Lake trout and trout-perch were also taken with it at the same stations or in the same trawl hauls. Its closest relative in Lake Superior, the round whitefish, was not an ecological associate.

Early detection of non-indigenous fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the ecological stability of the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as “high risk” for new introductions: St. Louis River near Duluth, M...

High levels of MHC class II allelic diversity in lake trout from Lake Superior

USGS Publications Warehouse

Dorschner, M.O.; Duris, T.; Bronte, C.R.; Burnham-Curtis, M. K.; Phillips, R.B.

2000-01-01

Sequence variation in a 216 bp portion of the major histocompatibility complex (MHC) II B1 domain was examined in 74 individual lake trout (Salvelinus namaycush) from different locations in Lake Superior. Forty-three alleles were obtained which encoded 71-72 amino acids of the mature protein. These sequences were compared with previous data obtained from five Pacific salmon species and Atlantic salmon using the same primers. Although all of the lake trout alleles clustered together in the neighbor-joining analysis of amino acid sequences, one amino acid allelic lineage was shared with Atlantic salmon (Salmo salar), a species in another genus which probably diverged from Salvelinus more than 10-20 million years ago. As shown previously in other salmonids, the level of nonsynonymous nucleotide substitution (d(N)) exceeded the level of synonymous substitution (d(S)). The level of nucleotide diversity at the MHC class II B1 locus was considerably higher in lake trout than in the Pacific salmon (genus Oncorhynchus). These results are consistent with the hypothesis that lake trout colonized Lake Superior from more than one refuge following the Wisconsin glaciation. Recent population bottlenecks may have reduced nucleotide diversity in Pacific salmon populations.

NEW RECORDS AND RANGE EXTENSIONS FOR SEVERAL CHIRONOMID GENERA IN LAKE SUPERIOR

EPA Science Inventory

Recent USEPA investigations of Lake Superior benthos in Minnesota, Wisconsin, and Michigan waters have resulted in the discovery of six uncommon genera of Chironomidae. Five new records of genera for Lake Superior and five significant Nearctic range extensions are reported. New r...

Lake trout (Salvelinus namaycush) populations in Lake Superior and their restoration in 1959-1993

USGS Publications Warehouse

Hansen, Michael J.; Peck, James W.; Schorfhaar, Richard G.; Selgeby, James H.; Schreiner, Donald R.; Schram, Stephen T.; Swanson, Bruce L.; MacCallum, Wayne R.; Burnham-Curtis, Mary K.; Curtis, Gary L.; Heinrich, John W.; Young, Robert J.

1995-01-01

Naturally-reproducing populations of lake trout (Salvelinus namaycush) have been reestablished in most of Lake Superior, but have not been restored to 1929-1943 average abundance. Progress toward lake trout restoration in Lake Superior is described, management actions are reviewed, and the effectiveness of those actions is evaluated; especially stocking lake trout as a tool for building spawning stocks, and subsequently, populations of wild recruits. Widespread destruction of lake trout stocks in the 1950s due to an intense fishery and sea lamprey (Petromyzon marinus) predation resulted in lower overall phenotypic diversity than was previously present. Stocking of yearling lake trout, begun in the 1950s, produced high densities of spawners that reproduced wherever inshore spawning habitat was widespread. Sea lampreys were greatly reduced, beginning in 1961, using selective chemical toxicants and barrier dams, but continue to exert substantial mortality. Fishery regulation was least effective in Wisconsin, where excessive gillnet effort caused high by-catch of lake trout until 1991, and in eastern Michigan, where lake trout restoration was deferred in favor of a tribal fishery for lake whitefish (Coregonus clupeaformis) in 1985. Restoration of stocks was quicker in offshore areas where remnant wild lake trout survived and fishing intensity was low, and was slower in inshore areas where stocked lake trout reproduced successfully and fishing intensity was high. Inshore stocks of wild lake trout are currently about 61 % of historic abundance in Michigan and 53% in Wisconsin. Direct comparison of modern and historic abundances of inshore lake trout stocks in Minnesota and Ontario is impossible due to lack of historic stock assessment data. Stocks in Minnesota are less abundant at present than in Michigan or Wisconsin, and stocks in Ontario are similar to those in Michigan. Further progress in stock recovery can only be achieved if sea lampreys are depressed and if

Wisconsin's Lake Superior Basin Water Quality Study. Supplement. Technical Report No. 2.

ERIC Educational Resources Information Center

Whisnant, David M., Ed.

During the period extending from May 1972 through April 1973, an investigation of the overall water quality conditions of streams flowing into Lake Superior from the entire state of Wisconsin was conducted. The goal of this publication was to provide much needed regional information on water quality, drainage basins, pollution sources and loads,…

Water quality of streams tributary to Lakes Superior and Michigan

USGS Publications Warehouse

Zimmerman, Jerome W.

1968-01-01

Water quality of streams tributary to Lakes Superior and Michigan was analyzed for 142 stations on 99 streams tributary to Lake Superior and 83 stations on 56 streams tributary to Lake Michigan during 1962-65. Concentrations of aluminum, copper, and iron were not affected greatly by flow or season. Magnesium, calcium, chlorides, total alkalinity, total hardness, and conductivity varied with the flow, temperature, and season; the lowest values were during the spring runoff and heavy rains, and the highest were during low water in late summer and the colder periods of winter. Concentrations of nitrate, silica, and sulfates were lowest in the spring and summer. Concentrations of tanninlike and ligninlike compounds were highest during the spring runoff and other high-water periods, and were lowest during freezeup when surface runoff was minimal. The pH values were highest from June to September and lowest during the spring runoff. Phenolphthalein alkalinity was detected primarily in the summer and coincided occasionally with low flows just before the spring thaw. Total hardness usually was lower in streams tributary to Lake Superior than in streams tributary to Lake Michigan. The total hardness was higher in the streams in Wisconsin than in the streams in Michigan along the west shore of Lake Michigan. It was lowest in the northernmost streams. The water quality of the streams in an area was related to the geological characteristics of the land.

Recoveries of tagged, hatchery-reared lake trout from Lake Superior

USGS Publications Warehouse

Buettner, Howard J.

1961-01-01

Plantings that totaled 13,384 tagged, hatchery-reared lake trout (Salvelinus namaycush)—18, 25, 30, or 37 months old—were made at four Lake Superior localities in 1955-57 to: measure possible increases of return from rearing to greater size and age; study the effect of season of planting on the rate of return; compare returns from different types of tags; and follow the movements of hatchery-reared fish. The great advantage of spring over fall planting, demonstrated for fingerling lake trout in earlier experiments, did not hold for fish planted at ages of 18 to 37 months. The improvement of recovery rates with increase of age over the same 18- to 37-month interval appears to be too small to justify the cost of rearing to the higher ages. The recovery rates were closely similar (3.9 to 4.8 percent) for lower-jaw tags and two types of nylon-streamer tags but were much lower than the rate for Petersen tags (12.4 percent). The pins of Petersen tags render the fish highly vulnerable to entanglement in the webbing of gill nets, the principal gear in Lake Superior. Recoveries of Petersen tags also came earlier after planting than did those of other tags. The time between planting and recovery and the distance traveled by the fish were clearly but not closely correlated. Mean distance between points of planting and recovery increased with time out, and average time out increased with the number of miles traveled. More than half of the recoveries of fish that had been at liberty over 2 years were made within 25 miles of the point of release.

Life history variation among four lake trout morphs at Isle Royale, Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.; Muir, Andrew M.; Bronte, Charles R.; Zimmerman, Mara S.; Krueger, Charles C.

2016-01-01

Life history traits were compared among four morphs of lake trout at Isle Royale, Lake Superior. Of 738 lake trout caught at Isle Royale, 701 were assigned to a morph (119 humpers, 160 leans, 85 redfins, and 337 siscowets) using a combination of statistical analysis of head and body shape and visual assignment. On average, redfins were longer (544 mm), heavier (1,481 g), heavier at length (Wr = 94), more buoyant, and older (22 years) than siscowets (519 mm; 1,221 g; 90; 19 years), leans (479 mm; 854 g; 82; 13 years), and humpers (443 mm; 697 g; 87; 17 years). On average, leans grew from a younger age at length = 0 and shorter length at age = 0, at a faster early growth rate to a longer asymptotic length than the other three morphs, while redfins grew at a slower instantaneous rate and humpers grew to a shorter asymptotic length than other morphs. On average, leans were longer (562 mm) and older (15 years) at 50% maturity than redfins (427 mm, 12 years), siscowets (401 mm, 11 years), or humpers (394 mm, 13 years). Life history parameters did not differ between males and females within each morph. We conclude that differences in life history attributes of lean, humper, redfin, and siscowet morphs of lake trout are consistent with differential habitat use in waters around Isle Royale, Lake Superior.

Declining survival of lake trout stocked during 1963-1986 in U.S. waters of Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H.

1994-01-01

The average catch per effort (CPE) values for the 1963–1982 year-classes of stocked lake trout Salvelinus namaycush caught at age 7 in gill nets and for the 1976–1986 year-classes caught at ages 2–4 in trawls declined significantly in U.S. waters of Lake Superior. The declines in CPE were not explained by reduced stocking, but rather by significant declines in survival indices of the year-classes of stocked lake trout. Increases in mortality occurred in year-classes before the fish reached ages 2–4, before they were recruited into the sport and commercial fisheries, and before they reached sizes vulnerable to sea lamprey predation. We conclude that declining abundance of stocked lake trout resulted from increased mortality, which may have been caused by competition, predation, or by a combination of these and other factors. Restoration of lake trout in Lake Superior may now depend on prudent management of naturally reproducing stocks rather than on stocking of hatchery-reared fish.

Benthic and Pelagic Contributions to Mysis Nutrition across Lake Superior

EPA Science Inventory

Quantification of the sources of nutrition to Mysis diluviana is needed to better understand the basis for production in Mysis lakes and to improve models of migration-driven nutrient and contaminant transport. We collected Mysis, plankton, and benthos across Lake Superior using ...

Geomorphic and sedimentologic evidence for the separation of Lake Superior from Lake Michigan and Huron

USGS Publications Warehouse

Johnston, J.W.; Thompson, T.A.; Wilcox, D.A.; Baedke, S.J.

2007-01-01

A common break was recognized in four Lake Superior strandplain sequences using geomorphic and sedimentologic characteristics. Strandplains were divided into lakeward and landward sets of beach ridges using aerial photographs and topographic surveys to identify similar surficial features and core data to identify similar subsurface features. Cross-strandplain, elevation-trend changes from a lowering towards the lake in the landward set of beach ridges to a rise or reduction of slope towards the lake in the lakeward set of beach ridges indicates that the break is associated with an outlet change for Lake Superior. Correlation of this break between study sites and age model results for the strandplain sequences suggest that the outlet change occurred sometime after about 2,400 calendar years ago (after the Algoma phase). Age model results from one site (Grand Traverse Bay) suggest an alternate age closer to about 1,200 calendar years ago but age models need to be investigated further. The landward part of the strandplain was deposited when water levels were common in all three upper Great Lakes basins (Superior, Huron, and Michigan) and drained through the Port Huron/Sarnia outlet. The lakeward part was deposited after the Sault outlet started to help regulate water levels in the Lake Superior basin. The landward beach ridges are commonly better defined and continuous across the embayments, more numerous, larger in relief, wider, have greater vegetation density, and intervening swales contain more standing water and peat than the lakeward set. Changes in drainage patterns, foreshore sediment thickness and grain size help in identifying the break between sets in the strandplain sequences. Investigation of these breaks may help identify possible gaps in the record or missing ridges in strandplain sequences that may not be apparent when viewing age distributions and may justify the need for multiple age and glacial isostatic adjustment models. ?? 2006 Springer Science

ANTHROPOGENIC COPPER INVENTORIES AND MERCURY PROFILES FROM LAKE SUPERIOR: EVIDENCE FOR MINING IMPACTS

EPA Science Inventory

During the past 150 years, the mining indstry discharged more than a billion tons of tailings along Lake Superior shorelines and constructed numerous smelters in the watershed. Given the vast size of Lake Superior, were sediment profiles at locations far offshore impacted by near...

Otoliths reveal a diverse age structure for humper lake trout in Lake Superior

USGS Publications Warehouse

Burnham-Curtis, Mary K.; Bronte, Charles R.

1996-01-01

Humpers are one of at least three morphological variants of wild lake trout Salvelinus namaycush that maintain self-sustaining populations in Lake Superior. In an early study, bumpers from Isle Royale were shown to have a sharply truncated age distribution that was attributed to high mortality after age 11, but we suspected that these fish were underaged. In August of 1989 and 1992 we collected spawning humper lake trout from the same area and estimated their ages using both scales and sagittal otoliths. Humpers in our sample ranged from 5 to 13 years, based on scale annuli, but counts of sagitta annuli revealed ages of 8 to 28 years. Individual discrepancies between ages from scales and sagittae varied from –2 to 20 years, but differences between scale and otolith ages did not increase with individual age. We applied the von Bertalanffy growth model to the humper length-at-age data to indirectly assess the accuracy of aging estimates. The model significantly overestimated mean asymptotic length when scale ages were used, but the mean asymptotic length estimate was more similar to observed lengths when sagitta ages were used. Our results corroborate evidence that bumpers in Lake Superior grow more slowly and mature at a smaller size than lean lake trout; however, the age composition of bumpers is more diverse than previously thought. This particular population experiences little or no exploitation; the presence of older fish provides one standard by which the success of lake trout rehabilitation programs can be evaluated and emphasizes the need for accurate aging techniques.

Ecology of Lake Superior: Preface and Prospectus

EPA Science Inventory

This Special Issue of Aquatic Ecosystem Health and Management (AEHM) is the first of a two-volume set based on papers presented at a three-day International Conference in Duluth MN held in June 2010, and titled “Ecology of Lake Superior: Integrated Approaches and Challenges for t...

A Holocene history of dune-mediated landscape change along the southeastern shore of Lake Superior

USGS Publications Warehouse

Loope, Walter L.; Fisher, Timothy G.; Jol, Harry M.; Anderton, John B.; Blewett, William L.

2004-01-01

Causal links that connect Holocene high stands of Lake Superior with dune building, stream damming and diversion and reservoir impoundment and infilling are inferred from a multidisciplinary investigation of a small watershed along the SE shore of Lake Superior. Radiocarbon ages of wood fragments from in-place stumps and soil O horizons, recovered from the bottom of 300-ha Grand Sable Lake, suggest that the near-shore inland lake was formed during multiple episodes of late Holocene dune damming of ancestral Sable Creek. Forest drownings at ~3000, 1530, and 300 cal. years BP are highly correlated with local soil burial events that occurred during high stands of Lake Superior. During these and earlier events, Sable Creek was diverted onto eastward-graded late Pleistocene meltwater terraces. Ground penetrating radar (GPR) reveals the early Holocene valley of Sable Creek (now filled) and its constituent sedimentary structures. Near-planar paleosols, identified with GPR, suggest two repeating modes of landscape evolution mediated by levels of Lake Superior. High lake stands drove stream damming, reservoir impoundment, and eolian infilling of impoundments. Falling Lake Superior levels brought decreased sand supply to dune dams and lowered stream base level. These latter factors promoted stream piracy, breaching of dune dams, and aerial exposure and forestation of infilled lakebeds. The bathymetry of Grand Sable Lake suggests that its shoreline configuration and depth varied in response to events of dune damming and subsequent dam breaching. The interrelated late Holocene events apparent in this study area suggest that variations in lake level have imposed complex hydrologic and geomorphic signatures on upper Great Lakes coasts.

Expanding understanding of optical variability in Lake Superior with a 4-year dataset

NASA Astrophysics Data System (ADS)

Mouw, Colleen B.; Ciochetto, Audrey B.; Grunert, Brice; Yu, Angela

2017-07-01

Lake Superior is one of the largest freshwater lakes on our planet, but few optical observations have been made to allow for the development and validation of visible spectral satellite remote sensing products. The dataset described here focuses on coincidently observing inherent and apparent optical properties along with biogeochemical parameters. Specifically, we observe remote sensing reflectance, absorption, scattering, backscattering, attenuation, chlorophyll concentration, and suspended particulate matter over the ice-free months of 2013-2016. The dataset substantially increases the optical knowledge of the lake. In addition to visible spectral satellite algorithm development, the dataset is valuable for characterizing the variable light field, particle, phytoplankton, and colored dissolved organic matter distributions, and helpful in food web and carbon cycle investigations. The compiled data can be freely accessed at LakeSuperior/" target="_blank">https://seabass.gsfc.nasa.gov/archive/URI/Mouw/LakeSuperior/.

Evaluating the behavior of polychlorinated biphenyl compounds in Lake Superior using a dynamic multimedia model

NASA Astrophysics Data System (ADS)

Khan, T.; Perlinger, J. A.; Urban, N. R.

2017-12-01

Certain toxic, persistent, bioaccumulative, and semivolatile compounds known as atmosphere-surface exchangeable pollutants or ASEPs are emitted into the environment by primary sources, are transported, deposited to water surfaces, and can be later re-emitted causing the water to act as a secondary source. Polychlorinated biphenyl (PCB) compounds, a class of ASEPs, are of major concern in the Laurentian Great Lakes because of their historical use primarily as additives to oils and industrial fluids, and discharge from industrial sources. Following the ban on production in the U.S. in 1979, atmospheric concentrations of PCBs in the Lake Superior region decreased rapidly. Subsequently, PCB concentrations in the lake surface water also reached near equilibrium as the atmospheric levels of PCBs declined. However, previous studies on long-term PCB levels and trends in lake trout and walleye suggested that the initial rate of decline of PCB concentrations in fish has leveled off in Lake Superior. In this study, a dynamic multimedia flux model was developed with the objective to investigate the observed levelling off of PCB concentrations in Lake Superior fish. The model structure consists of two water layers (the epilimnion and the hypolimnion), and the surface mixed sediment layer, while atmospheric deposition is the primary external pathway of PCB inputs to the lake. The model was applied for different PCB congeners having a range of hydrophobicity and volatility. Using this model, we compare the long-term trends in predicted PCB concentrations in different environmental media with relevant available measurements for Lake Superior. We examine the seasonal depositional and exchange patterns, the relative importance of different process terms, and provide the most probable source of the current observed PCB levels in Lake Superior fish. In addition, we evaluate the role of current atmospheric PCB levels in sustaining the observed fish concentrations and appraise the need

Evaluating the growth potential of sea lampreys (Petromyzon marinus) feeding on siscowet lake trout (Salvelinus namaycush) in Lake Superior

USGS Publications Warehouse

Moody, E.K.; Weidel, B.C.; Ahrenstorff, T.D.; Mattes, W.P.; Kitchell, J.F.

2011-01-01

Differences in the preferred thermal habitat of Lake Superior lake trout morphotypes create alternative growth scenarios for parasitic sea lamprey (Petromyzon marinus) attached to lake trout hosts. Siscowet lake trout (Salvelinus namaycush) inhabit deep, consistently cold water (4–6 °C) and are more abundant than lean lake trout (Salvelinus namaycush) which occupy temperatures between 8 and 12 °C during summer thermal stratification. Using bioenergetics models we contrasted the growth potential of sea lampreys attached to siscowet and lean lake trout to determine how host temperature influences the growth and ultimate size of adult sea lamprey. Sea lampreys simulated under the thermal regime of siscowets are capable of reaching sizes within the range of adult sea lamprey sizes observed in Lake Superior tributaries. High lamprey wounding rates on siscowets suggest siscowets are important lamprey hosts. In addition, siscowets have higher survival rates from lamprey attacks than those observed for lean lake trout which raises the prospect that siscowets serve as a buffer to predation on more commercially desirable hosts such as lean lake trout, and could serve to subsidize lamprey growth.

RELEASE OF MERCURY FROM MINE RESIDUES INTO LAKE SUPERIOR

EPA Science Inventory

Using recent compilations of mine production and discharge rates, we will demonstrate that the cumulative Hg inputs to Lake Superior from mining activities are much higher than from atmosphereic deposition.

Climate Factors Contributing to Streamflow Inputs and Extreme Water-level Deviations from Long-term Averages for Lakes Superior and Michigan-Huron

NASA Astrophysics Data System (ADS)

Anderson, M. T.; Stamm, J. F.

2014-12-01

The Great Lakes are a highly valued freshwater resource of the United States and Canada. The Lakes are the focus of a science-based restoration program, known as the Great Lakes Restoration Initiative (GLRI). Physical and chemical factors, such as inflows and nutrient loads to the Great Lakes can affect ecosystem function, contribute to the spread of invasive species and increase the occurrence of harmful algal blooms. Since about 1999, water levels in Lakes Superior and Michigan-Huron have been at or below the long-term average (1918 to present). Analyses of streamflow trends for the period 1960 to 2012 in watersheds draining into Lakes Superior and Michigan-Huron showed a long-term decline in average inflows, which helps to explain the persistently below-average lake levels. Recent climatic conditions of October 2013 to August 2014 have contributed to a rapid rise in lake levels, most notably in Lake Superior. Lake Superior recently reached an elevation of 602.56 feet above sea level in August 2014, which is the highest level in 17 years. Coincident with this recovery was the development of a large algal bloom in Lake Erie in August of 2014 that shut down the Toledo, Ohio municipal water supply. These anomalous, extreme deviations from long-term average lake levels will be examined to better understand the forcing factors that contributed to changes in inflow volumes and lake-levels. Particular focus will be given to the climatology of years when changes in lake levels are most pronounced, such as; the measured lake-level declines during 1964-1965 and 1998-2000; and lake-level rises during 1973-1974, 1987-1989, and 2013-2014. The climatology of years with periods of algal blooms will also be examined such as, 2003, 2008, 2011 and 2014.

Spatial patterns in assemblage structures of pelagic forage fish and zooplankton in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Hoff, Michael H.; Trebitz, Anett S.; Bronte, Charles R.; Corry, Timothy D.; Kitchell, James F.; Lozano, Stephen J.; Mason, Doran M.; Scharold, Jill V.; Schram, Stephen T.; Schreiner, Donald R.

2004-01-01

We assessed abundance, size, and species composition of forage fish and zooplankton communities of western Lake Superior during August 1996 and July 1997. Data were analyzed for three ecoregions (Duluth-Superior, Apostle Islands, and the open lake) differing in bathymetry and limnological and biological patterns. Zooplankton abundance was three times higher in the Duluth-Superior and Apostle Islands regions than in the open lake due to the large numbers of rotifers. Copepods were far more abundant than Cladocera in all ecoregions. Mean zooplankton size was larger in the open lake due to dominance by large calanoid copepods although size of individual taxa was similar among ecoregions. Forage fish abundance and biomass was highest in the Apostle Islands region and lowest in the open lake ecoregion. Lake herring (Coregonus artedi), rainbow smelt (Osmerus mordax) and deepwater ciscoes (Coregonus spp.) comprised over 90% of the abundance and biomass of fishes caught in midwater trawls and recorded with hydroacoustics. Growth and condition of fish was good, suggesting they were not resource limited. Fish and zooplankton assemblages differed among the three ecoregions of western Lake Superior, due to a combination of physical and limnological factors related to bathymetry and landscape position.

Denitrification Rates in a Lake Superior Coastal Wetland

EPA Science Inventory

Inputs of anthropogenic nitrogen to the Nation’s aquatic ecosystems have increased substantially over the past several decades. Nitrogen inputs to Lake Superior since about 1900 have increased at a rate of about 2% per year, doubling about every 35 years (Bennett, 1986), althoug...

Development of a new Lake-wide Multiple Gear Survey to Assess Status and Trends of the Lake Superior Fish Community and Lower Trophic Levels

EPA Science Inventory

The U.S. Geological Survey Great Lakes Science Center has developed a plan to implement revision of its annual fish community survey of Lake Superior. The primary objective of the revision is improvement of the sampling design to be more representative of the Lake Superior fish c...

Allelic variability in species and stocks of Lake Superior ciscoes (Coregoninae)

USGS Publications Warehouse

Todd, Thomas N.

1981-01-01

Starch gel electrophoresis was used as a means of recognizing species and stocks in Lake Superior Coregonus. Allelic variability at isocitrate dehydrogenase and glycerol-3-phosphate dehydrogenase loci was recorded for samples of lake herring (Coregonus artedii), bloater (C. hoyi), kiyi (C. kiyi), and shortjaw cisco (C. zenithicus) from five Lake Superior localities. The observed frequencies of genotypes within each subsample did not differ significantly from those expected on the basis of random mating, and suggested that each subsample represented either a random sample from a larger randomly mating population or an independent and isolated subpopulation within which mating was random. Significant contingency X2 values for comparisons between both localities and species suggested that more than one randomly mating population occurred among the Lake Superior ciscoes, but did not reveal how many such populations there were. In contrast to the genetic results of this study, morphology seems to be a better descriptor of cisco stocks, and identification of cisco stocks and species will still have to be based on morphological criteria until more data are forthcoming. Where several species are sympatric, management should strive to preserve the least abundant. Failure to do so could result in the extinction or depletion of the rarer forms.

Visual Sensitivity of Deepwater Fishes in Lake Superior

PubMed Central

Harrington, Kelly A.; Hrabik, Thomas R.; Mensinger, Allen F.

2015-01-01

The predator-prey interactions in the offshore food web of Lake Superior have been well documented, but the sensory systems mediating these interactions remain unknown. The deepwater sculpin, (Myoxocephalus thompsoni), siscowet (Salvelinus namaycush siscowet), and kiyi (Coregonus kiyi) inhabit low light level environments. To investigate the potential role of vision in predator-prey interactions, electroretinography was used to determine visual sensitivity for each species. Spectral sensitivity curves revealed peak sensitivity at 525 nm for each species which closely corresponds to the prevalent downwelling light spectrum at depth. To determine if sufficient light was available to mediate predator-prey interactions, visual sensitivity was correlated with the intensity of downwelling light in Lake Superior to construct visual depth profiles for each species. Sufficient daytime irradiance exists for visual interactions to approximately 325 m for siscowet and kiyi and 355 m for the deepwater sculpin during summer months. Under full moon conditions, sufficient irradiance exists to elicit ERG response to light available at approximately 30 m for the siscowet and kiyi and 45 m for the deepwater sculpin. Visual interactions are therefore possible at the depths and times when these organisms overlap in the water column indicating that vision may play a far greater role at depth in deep freshwater lakes than had been previously documented. PMID:25646781

Food of salmonine predators in Lake Superior, 1981-87

USGS Publications Warehouse

Conner, David J.; Bronte, Charles R.; Selgeby, James H.; Collins, Hollie L.

1993-01-01

Diets of ten species of Lake Superior salmonines are described. Rainbow smelt (Osmerus mordax) were the primary prey during all seasons and years for inshore lake trout (Salvelinus namaycush), Pacific salmon (Oncorhynchus spp.), Atlantic salmon (Salmo salar), brown trout (S. trutta), brook trout (Salvelinus fontinalis), and splake (lake trout x brook trout hybrid). Coregonines were the second most-important prey for chinook salmon (O. tshawytscha), siscowet trout (S. namaycush siscowet), and splake. Invertebrates were important to rainbow trout (O. mykiss), coho salmon (O. kisutch), and pink salmon (O. gorbuscha), especially during the summer. Diets of lake trout from inshore and offshore locations differed markedly. Rainbow smelt were the primary food of inshore lake trout, and coregonines were the main food of offshore lake trout. Chinook salmon and inshore lake trout had the most similar diets because they ate similar proportions of rainbow smelt and coregonines. Salmonines generally ate more rainbow smelt and less coregonines in proportion to the abundance of these prey in the lake. If rainbow smelt populations collapse, the ability of salmonines to convert to a diet based on lake herring (Coregonus artedi) could be important to the stability of predator populations.

The spatial scale for cisco recruitment dynamics in Lake Superior during 1978-2007

USGS Publications Warehouse

Rook, Benjamin J.; Hansen, Michael J.; Gorman, Owen T.

2012-01-01

The cisco Coregonus artedi was once the most abundant fish species in the Great Lakes, but currently cisco populations are greatly reduced and management agencies are attempting to restore the species throughout the basin. To increase understanding of the spatial scale at which density‐independent and density‐dependent factors influence cisco recruitment dynamics in the Great Lakes, we used a Ricker stock–recruitment model to identify and quantify the appropriate spatial scale for modeling age‐1 cisco recruitment dynamics in Lake Superior. We found that the recruitment variation of ciscoes in Lake Superior was best described by a five‐parameter regional model with separate stock–recruitment relationships for the western, southern, eastern, and northern regions. The spatial scale for modeling was about 260 km (range = 230–290 km). We also found that the density‐independent recruitment rate and the rate of compensatory density dependence varied among regions at different rates. The density‐independent recruitment rate was constant among regions (3.6 age‐1 recruits/spawner), whereas the rate of compensatory density dependence varied 16‐fold among regions (range = −0.2 to −2.9/spawner). Finally, we found that peak recruitment and the spawning stock size that produced peak recruitment varied among regions. Both peak recruitment (0.5–7.1 age‐1 recruits/ha) and the spawning stock size that produced peak recruitment (0.3–5.3 spawners/ha) varied 16‐fold among regions. Our findings support the hypothesis that the factors driving cisco recruitment operate within four different regions of Lake Superior, suggest that large‐scale abiotic factors are more important than small‐scale biotic factors in influencing cisco recruitment, and suggest that fishery managers throughout Lake Superior and the entire Great Lakes basin should address cisco restoration and management efforts on a regional scale in each lake.

Lake Superior Coastal Wetland Fish Assemblages and ...

EPA Pesticide Factsheets

The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

USGS Publications Warehouse

Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, Michael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

2005-01-01

Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

Biotic and abiotic factors related to lake herring recruitment in the Wisconsin waters of Lake Superior, 1984-1998

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

Lake Superior lake herring (Coregonus artedi) recruitment to 13-14 months of age in the Wisconsin waters of Lake Superior varied by a factor of 5,233 during 1984-1998. Management agencies have sought models that accurately predict recruitment, but no satisfactory model had previously been developed. Lake herring recruitment was modeled to determine which factors most explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data explained 35% of the variability in the recruitment data. The functional relationship that explained the greatest amount of recruitment variation (93%) included lake herring stock size, lake trout (Salvelinus namaycush) population size, slimy sculpin (Cottus cognatus) biomass, the interaction of mean daily wind speed in April (month of hatch) and lake herring stock size, and mean air temperature in April (when lake herring are 12-months old). Model results were interpreted to mean that lake herring recruitment was affected negatively by: slimy sculpin predation on lake herring ova; predation on age-0 lake herring by lake trout; and adult cannibalism on lake herring larvae, which was reduced by increased wind speed. April temperature was the variable that explained the least amount of variability in recruitment, but lake herring recruitment was positively affected by a warm April, which shortened winter and apparently reduced first-winter mortality. Stock size caused compensatory, density-dependent mortality on lake herring recruits. Management efforts appear best targeted at stock size protection, and empirical data implies that stock size in the Wisconsin waters of the lake should be maintained at 2.1-15.0 adults/ha in spring, bottom-trawl surveys.

MERCURY IN METAL ORE DEPOSITS: AN UNRECOGNIZED, WIDESPREAD SOURCE TO LAKE SUPERIOR SEDIMENTS, CONTRIBUTION #1072

EPA Science Inventory

Mining operations have worked the rich mineral resources of the Lake Superior Basin for over 150 years, leaving industrially impacted regions with tailing piles and smelters. In Lake Superior sediments, mercury and copper inventories increase towards shorelines and are highly cor...

Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

USGS Publications Warehouse

Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

2015-01-01

Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

Changing climate in the Lake Superior region: a case study of the June 2012 flood and its effects on the western-lake water column

NASA Astrophysics Data System (ADS)

Minor, E. C.; Forsman, B.; Guildford, S. J.

2013-12-01

In Lake Superior, the world's largest freshwater lake by area, we are seeing annual surface-water temperature increases outpacing those of the overlying atmosphere. We are also seeing ever earlier onsets of water-column stratification (in data sets from the mid-1980s to the present). In Minnesota, including the Lake Superior watershed, precipitation patterns are also shifting toward fewer and more extreme storm events, such as the June 2012 solstice flood, which impacted the western Lake Superior basin. We are interested in how such climatological changes will affect nutrient and carbon biogeochemistry in Lake Superior. The lake is currently an oligotrophic system exhibiting light limitation of primary production in winter and spring, with summer primary production generally limited by phosphorus and sometimes co-limited by iron. Analyses in the western arm of Lake Superior showed that the June 2012 flood brought large amounts of sediment and colored dissolved organic matter (CDOM) from the watershed into the lake. There was initially a ~50-fold spike in the total phosphorus concentrations (and a 5 fold spike in soluble reactive phosphorus) in flood-impacted waters. This disappeared rapidly, in large part due to sediment settling and did not lead to an increase in chlorophyll concentrations at monitored sampling sites. Instead, lake phytoplankton appeared light limited by a surface lens of warm water enriched in CDOM that persisted for over a month after the flood event itself. Our observations highlight the need for continuing research on these complex in-lake processes in order to make accurate predictions about longer term impacts of these large episodic inputs in CDOM, sediment, and nutrient loading.

Stable isotope ratios in swale sequences of Lake Superior as indicators of climate and lake level fluctuations during the Late Holocene

USGS Publications Warehouse

Sharma, Shruti; Mora, G.; Johnston, J.W.; Thompson, T.A.

2005-01-01

Beach ridges along the coastline of Lake Superior provide a long-term and detailed record of lake level fluctuations for the past 4000 cal BP. Although climate change has been invoked to explain these fluctuations, its role is still in debate. Here, we reconstruct water balance by employing peat samples collected from swale deposits present between beach ridge sequences at two locations along the coastline of Lake Superior. Carbon isotope ratios for Sphagnum remains from these peat deposits are used as a proxy for water balance because the presence or absence of water films on Sphagnum controls the overall isotope discrimination effects. Consequently, increased average water content in Sphagnum produces elevated ??13C values. Two maxima of Sphagnum ??13C values interpreted to reflect wetter conditions prevailed from 3400 to 2400 cal BP and from about 1900 to 1400 cal BP. There are two relatively short drier periods as inferred from low Sphagnum ??13C values: one is centered at about 2300 cal BP, and one begins at 1400 cal BP. A good covariance was found between Sphagnum ??13C values and reconstructed lake-levels for Lake Michigan in which elevated carbon isotope values correlate well with higher lake levels. Based on this covariance, we conclude that climate exerts a strong influence on lake levels in Lake Superior for the past 4000 cal BP. ?? 2005 Elsevier Ltd. All rights reserved.

Anthropogenic climate change has driven Lake Superior productivity beyond the range of Holocene variability

NASA Astrophysics Data System (ADS)

OBeirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.

2013-12-01

Recent studies have noted that changes in Lake Superior's physical, chemical and biological processes are apparent - including a warming of the surface waters at a rate twice as great as the surrounding airshed in the last 20 years. These changes are often difficult to perceive as cause for concern when not placed within a historical context. In this study, bulk C and N abundance and stable isotope composition was determined on sediments from three piston and corresponding gravity cores, representing a record of lake-wide paleoproductivity trends spanning the Holocene. These data are compared with the same measurements on eight multi-cores sampled at high resolution spanning the past ~200 years, which allows for the historical comparison with recent (1800 A.D. to present) productivity trends. Throughout the Holocene, Lake Superior experienced a slow, steady increase in productivity consistent with conventional lake ontogeny. During the last 200 years, however, the Lake Superior basin has undergone biogeochemical changes that are unique in the context of the Holocene. Lake-wide sedimentary bulk organic carbon data indicate increasing primary production between 1900 and present, as indicated by a ~2‰ increase in δ13Corg. In contrast,δ15Norg values, which increased throughout the Holocene, become progressively 15N-depleted after 1900, likely due to atmospheric deposition of NOx from fossil fuel combustion. The most recent increases in primary productivity are likely a response to increasing water temperatures, leading to longer ice-free periods as previously documented in Lake Superior.

Evaluating Lake Superior nearshore offshore gradients using autonomous gliders

EPA Science Inventory

Slocum electric gliders are autonomous vehicles capable of continuously mapping subsurface conditions at high resolution for months at a time. During the 2016 CSMI in Lake Superior, seven glider deployments were undertaken through a partnership between University of Minnesota Dul...

Depth-specific Analyses of the Lake Superior Food Web

EPA Science Inventory

Characteristics of large, deep aquatic systems include depth gradients in community composition, in the quality and distribution of food resources, and in the strategies that organisms use to obtain their nutrition. In Lake Superior, nearshore communities that rely upon a combina...

Density-independent survival of wild lake trout in the Apostle Islands area of Lake Superior

USGS Publications Warehouse

Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

1995-01-01

The lake trout (Salvelinus namaycush) stock at Gull Island Shoal in western Lake Superior was one of only a few stocks of lean lake trout in the Great Lakes that survived overfishing and predation by the sea lamprey (Petromyzon marinus). Since the mid 1960s, the abundance of wild recruits measured at age 0 and the number of age-7 to -11 wild fish recruited to the fishable stock have increased. We used the Varley-Gradwell method to test for density-dependent survival between these life stages. Survival from age-0 to ages 7–11 was not affected by increasing density, which suggests that further increases in recruitment and stock size are still possible. We suggest that testing for the existence of density-dependent survival can be used to indicate when lake trout populations are rehabilitated.

Age, growth, and size of Lake Superior Pygmy Whitefish (Prosopium coulterii)

USGS Publications Warehouse

Stewart, Taylor; Derek Ogle,; Gorman, Owen T.; Vinson, Mark

2016-01-01

Pygmy Whitefish (Prosopium coulterii) are a small, glacial relict species with a disjunct distribution in North America and Siberia. In 2013 we collected Pygmy Whitefish at 28 stations from throughout Lake Superior. Total length was recorded for all fish and weight and sex were recorded and scales and otoliths were collected from a subsample. We compared the precision of estimated ages between readers and between scales and otoliths, estimated von Bertalanffy growth parameters for male and female Pygmy Whitefish, and reported the first weight-length relationship for Pygmy Whitefish. Age estimates between scales and otoliths differed significantly with otolith ages significantly greater for most ages after age-3. Maximum otolith age was nine for females and seven for males, which is older than previously reported for Pygmy Whitefish from Lake Superior. Growth was initially fast but slowed considerably after age-3 for males and age-4 for females, falling to 3–4 mm per year at maximum estimated ages. Females were longer than males after age-3. Our results suggest the size, age, and growth of Pygmy Whitefish in Lake Superior have not changed appreciably since 1953.

Successional change in the Lake Superior fish community: population trends in ciscoes, rainbow smelt, and lake trout, 1958-2008

USGS Publications Warehouse

Gorman, Owen T.

2012-01-01

responses to conditions of low and high predator levels, i.e., late 1950s–early 1960s vs. post 1980. Bloaters are most likely to become the predominant cisco in the absence of strong predation and the least abundant under prolonged predation; smelt share this pattern. Conversely, the lake cisco and shortjaw cisco fare better when predator abundance is high. The recovery of lake trout in Lake Superior reestablished a strong top-down influence on the fish community and its present structure and organization appears to be approaching an equilibrium that reflects a more natural state. If lake trout recovery is sustained, shortjaw cisco abundance is expected to increase and join lake cisco and kiyi as dominant cisco species, and bloater and smelt will oscillate at lower abundances.

Historic and modern abundance of wild lean lake trout in Michigan waters of Lake Superior: Implications for restoration goals

USGS Publications Warehouse

Wilberg, Michael J.; Hansen, Michael J.; Bronte, Charles R.

2003-01-01

Populations of lake trout Salvelinus namaycush in Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreys Petromyzon marinus. A binational effort to restore the lean morphotype of lake trout began with the stocking of hatchery-reared fish followed by the chemical control of sea lampreys and closure of the commercial fishery. Previous comparisons of the contemporary abundance of wild lean lake trout with that from historic commercial fishery statistics indicate that abundance was higher historically. However, this conclusion may be biased because several factors—the inclusion of siscowet (the “fat” morphotype of lake trout) in the catch statistics, the soak time of nets, seasonal effects on catch per effort, and the confounding effects of effort targeted at lake whitefish Coregonus clupeaformis—were not accounted for. We developed new indices of historic lean lake trout abundance that correct for these biases and compared them with the assessment data from 1984 to 1998 in Michigan waters of Lake Superior. The modern (1984–1998) abundance of wild lean lake trout is at least as high as that during 1929–1943 in six of eight management areas but lower in one area. Measures to promote and protect naturally reproducing populations have been more successful than previously realized.

Distribution, abundance, and biology of the alewife in U.S. waters of Lake Superior

USGS Publications Warehouse

Bronte, Charles R.; Selgeby, James H.; Curtis, Gary L.

1991-01-01

Alewives (Alosa pseudoharengus) were first reported in Lake Superior in 1954 and gradually increased in abundance in the late 1950s. In the 1960s and early 1970s, the fish were widespread in the lake but scarce. We determined the more recent abundance and distribution of alewives by cross-contour trawling in the spring in 1978–1988. Alewives were scarce lake-wide; the mean catch rate was only 23 fish per 100 h of trawling and represented a density of 0.003 kg per hectare in the area swept by the trawls. Fish of six age groups were caught in trawls in spring and gill nets in fall in 1983–1987. Total annual mortality was 64%, a high natural rate in the absence of fishing. Alewives in Lake Superior were small at the end of their first growing season but later grew faster than those in the other Great Lakes. Fecundity, estimated to be 64,000 eggs (mean total length = 187 mm) was higher than in other freshwater stocks. Zooplankton was the major food of alewives < 100 mm long and Mysis was the main food of larger fish. Exposure to water temperatures below lethal minimums for overwintering fish and for developing eggs limits the success of this species in Lake Superior.

46 CFR 401.410 - Basic rates and charges on Lakes Huron, Michigan and Superior and the St. Mary's River.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Superior and the St. Mary's River. 401.410 Section 401.410 Shipping COAST GUARD (GREAT LAKES PILOTAGE... Services § 401.410 Basic rates and charges on Lakes Huron, Michigan and Superior and the St. Mary's River... performed by U.S. registered pilots on Lakes Huron, Michigan, and Superior and the St. Mary's River. (a...

Modeling nearshore-offshore exchange in Lake Superior

PubMed Central

Tokos, Kathy S.; Matsumoto, Katsumi

2018-01-01

Lake Superior′s ecosystem includes distinct nearshore and offshore food webs linked by hydrodynamic processes that transport water and tracers along and across shore. The scales over which these processes occur and their sensitivity to increasing summer surface temperatures are not well understood. This study investigated horizontal mixing between nearshore and offshore areas of Lake Superior over the 10-year period from 2003 to 2012 using a realistically forced three-dimensional numerical model and virtual tracers. An age tracer was used to characterize the time scales of horizontal mixing between nearshore areas of the lake where water depth is less than 100 m and deeper areas. The age of water in nearshore areas increased and decreased in an annual cycle corresponding to the lake′s dimictic cycle of vertical mixing and stratification. Interannual variability of mixing in the isothermal period was significantly correlated to average springtime wind speed, whereas variability during the stratified season was correlated to the average summer surface temperature. Dispersal of a passive tracer released from nine locations around the model lake’s perimeter was more extensive in late summer when stratification was established lakewide than in early summer. The distribution of eddies resolved in the model reflected differences between the early and late summer dispersal patterns. In the eastern part of the lake dispersal was primarily alongshore, reflecting counterclockwise coastal circulation. In the western part of the lake, cross-shore mixing was enhanced by cross-basin currents. PMID:29447286

Osteological evidence of genetic divergence of lake trout (Salvelinus namaycush) in Lake Superior

USGS Publications Warehouse

Burnham-Curtis, Mary K.; Smith, Gerald R.

1994-01-01

Three phenotypes of Salvelinus namaycush in Lake Superior, the lean, siscowet, and bumper, are traditionally identified primarily by fat content and body shape. Their taxonomic status is in question because of intermediates as well as the possibility that the diagnostic characters are ecophenotypic. Two osteological characters, the dorsal opercular notch (first recorded by Agassiz in his description of the siscowet) and radii on the anterodorsal part of the supraethmoid, differ between most leans and siscowets. The notch in the opercle near its articulation with the hyomandibular bone is present in humpers, usually present in siscowets, and usually absent in leans. Radii on the anterodorsal surface of the supraethmoid bone usually are found in siscowets and humpers but usually are absent in leans. The correlations among these characters and other features of the phenotype indicate a significant level of differentiation between the three phenotypes. Available evidence suggests that the differentiation is genetic. The frequency of mixed phenotypes is evidence of limited gene flow among the phenotypes. The siscowet and humper phenotypes apparently originated in Lake Superior in postglacial time.

FISH ASSEMBLAGES AS INDICATORS OF LAKE SUPERIOR COASTAL WETLAND CONDITION

EPA Science Inventory

Fish assemblages associated with coastal wetlands in Lake Superior are poorly described. Understanding the environmental factors structuring the biota in these habitats is essential to developing robust indicators of their condition. To identify key environmental influences struc...

The contamination of Lake Superior with amphibole gangue minerals.

PubMed

Langer, A M; Maggiore, C M; Nicholson, W J; Rohl, A N; Rubin, I B; Selikoff, I J

1979-01-01

Iron ore called taconite is mined in the Biwabik Iron Formation in the Eastern Mesabi region of the Mesabi Range, in eastern Minnesota. After mining, ore is shipped to Silver Bay, Minnnesota for processing and wet magnetic extraction. Tailings from the process are dumped, as a slurry, into a man-made containment delta constructed in Lake Superior. Submicroscopic amphibole fibers and/or cleavage fragments, a component of the gangue, apparently escape from the delta at Silver Bay, and enter Lake Superior. These particles contaiminate the potable water supplies of municipalities drawing directly from the lake. One of the gangue minerals is the amphibole grunerite, whose asbestiform variety is called amosite. Major emphasis of this study was directed at identification of submicroscopic particle pollutants, based on morphology, structure and chemical composition. Quantitative determination of fibrous amphibole phases, present in a range of water samples, was undertaken. Transmission electron microscopy, selected area electron diffraction, and an electron microprobe technique was used for identification and enumeration and this information was compared with data sets determined from standards. Grunerite fiber and/or acicular cleavage fragments, in some instances indistinguishable from asbestiform grunerite, are present in the tailings, lake water and drinking water of a number of municipalities, a result of contamination of the lake at the Silver Bay milling operation. This amphibole is found in drinking water in concentrations which range from 0.6 to 2.8 X 10(6) fiber/liter. The risk to health, associated with direct ingestion of grunerite fiber is unknown and is extrapolated from the asbestiform grunerite (amosite) data base. The biological activity of other fibrous amphiboles observed, unrelated to any asbestiform silicate variety, is presently unknown and warrants investigation.

Decline of lake herring (Coregonus artedii) in Lake Superior: an analysis of the Wisconsin herring fishery, 1936-78

USGS Publications Warehouse

Selgeby, James H.

1982-01-01

Annual harvests of lake herring (Coregonus artedii) in American waters of Lake Superior declined from an average of 2 million kg in 1936–62 to less than 25 000 kg in 1978. Analysis of commercial fishing records revealed that the sequential overexploitation of discrete unit stocks caused the collapse of the herring population in Wisconsin waters. In each of six major spawning areas, catch exceeded the productive capacity of the stock and the stock failed. Because stocks in the six areas were exploited sequentially, mostly in groups of two or three simultaneously, the demise of the stocks was not readily apparent until the last two failed in the early 1960s. After the collapse of the last major spawning stock, the fishery dwindled but may have continued to overexploit the remaining small stocks. The residual populations were apparently able only to replace themselves. Some form of density-independent mortality was apparently operating to prevent their recovery during the 1960s and 1970s.Key words: lake herring, overfishing, Lake Superior

Physiological modifications of seston in response to physicochemical gradients within Lake Superior (presentation)

EPA Science Inventory

We show for the first time the importance of plankton producing non-phosphorus lipids as a strategy for reducing cellular P inventories in Lake Superior. In September 2011, we investigated the distribution of dissolved and particulate phosphorus (PP) pools throughout the lake. Av...

Trophic connections in Lake Superior Part I: the offshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Stockwell, J.D.; Yule, D.L.

2011-01-01

Detailed diet linkages within the offshore (> 80 m bathymetric depth) food web of Lake Superior are currently not well identified. We used analyses of fish stomach contents to create an empirically based food web model of the Lake Superior offshore fish community. Stomachs were collected seasonally (spring, summer, and fall) from nine offshore locations in 2005, using bottom and midwater trawls. In total, 2643 stomachs representing 12 fish species were examined. The predominant fish species collected were deepwater sculpin (Myoxocephalus thompsonii), siscowet (Salvelinus namaycush siscowet), kiyi (Coregonus kiyi), and cisco (Coregonus artedi). Mysis diluviana was the most common prey item, indicating that changes in Mysis abundance could have a profound impact on the entire offshore food web. Mysis was the primary diet item of deepwater sculpin (≥ 53% by mass) and kiyi (≥ 96% by mass) regardless of depth or season. The invasive Bythotrephes was an important diet component of the pelagic cisco in summer and fall. Deepwater sculpin were the primary diet item of siscowet (≥ 52% by mass), with coregonines appearing in the diet of larger (> 400 mm) siscowet. Non-metric multidimensional scaling analysis indicated that there were no statistically significant seasonal or site-specific differences in diets of deepwater sculpin, cisco, or kiyi. Site was the primary structuring factor in siscowet diets. Generally, in Lake Superior, the diet items of the dominant offshore species did not appear to be in danger from those types of major ecological shifts occurring in the lower Laurentian Great Lakes.

Wave Action and Breakwater Location, Taconite Harbor (Two Islands), Lake Superior, Minnesota: Hydraulic Model Investigation

DTIC Science & Technology

1955-05-01

president, Taconite Contractors, Erie. Mining Company, Duluth, Minnesota The model study was conducted in the Hydraulics Division of the Waterways...CORPS OF ENGINEERS. U. S. ARMY WAVE ACTION AND BREAKWATER LOCATION TACONITE HARBOR (TWO ISLANDS) LAKE SUPERIOR, MINNESOTA ARIIIY-MRC VICKSBURG...Breakwater Location, Taconite Harbor (Two Islands), Lake Superior, Minnesota : Hydraulic Model Investigation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

The Quagga mussel invades the Lake Superior basin - journal article

EPA Science Inventory

Prior studies recognized the presence of a single dreissenid species in Lake Superior--the zebra mussel Dreissena polymorpha. However, taxonomic keys based on traditional shell morphology are not always able to differentiate dreissenid species with confidence. We thus employed ge...

Ontonagon Harbor Operation and Maintenance Activities. Lake Superior.

DTIC Science & Technology

1975-08-01

St. Paul, Minnesota 55101 August 1975 FINAL ENVIRONMENTAL IMPACT STATEMENT OPERATION AND MAINTENAN4CE ACTIVITIES ONTONAGON HARBDOR, MICHIGAN LAKE...SUPERIOR Responsible Office: St. Paul District, Corps of Engineers, 1135 U.S. Post Office and Custom House, St. Paul, Minnesota 55101 Telephone Number 612...Nonesuch shale is a finer siltstone containing recoverable copper deposits. Active mining is present at White Pine, 12 air miles southwest of Ontonagon

Effects of spatial allocation and parameter variability on lakewide estimates from surveys of Lake Superior, North America’s largest lake

EPA Science Inventory

Lake Superior was sampled in 2011 using a Generalized Random Tessellation Stratified design (n=54 sites) to characterize biological and chemical properties of this huge aquatic resource, with statistical confidence. The lake was divided into two strata (inshore <100m and offsh...

Quaternary geologic map of the Lake Superior 4 degrees x 6 degrees quadrangle, United States and Canada

USGS Publications Warehouse

Richmond, Gerald M.; Fullerton, David S.; state compilations by Farrand, William R.; Mickelson, D.M.; Cowan, W.R.; Goebel, J.E.; edited and integrated by Richmond, Gerald Martin

1984-01-01

The Quaternary Geologic Map of the Lake Superior 4? x 6? Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as an effort to depict the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the earth. They make up the 'ground' on which we walk, the 'dirt' in which we dig foundations, and the 'soil' in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The maps were compiled at 1:1,000,000 scale.

A new look at the Lake Superior biomass size-spectrum

EPA Science Inventory

We combined data from multiple sampling programs to describe the Lake Superior pelagic biomass size structure. The data represented phytoplankton, zooplankton and prey-fish that spanned over 10 orders of magnitude in size and two time periods separated by five years. The biomas...

The non-native faucet snail (Bithynia tentaculata) makes the leap to Lake Superior

EPA Science Inventory

The European-origin faucet snail (Bithynia tentaculata) has been present in the lower Great Lakes since the late 1800s but only very recently reached Lake Superior. Surveys from 2011 through 2013 found faucet snail to be abundant and wide-spread in the St. Louis River Estuary wi...

Habitat coupling in a large lake system: delivery of an energy subsidy by an offshore planktivore to the nearshore zone of Lake Superior

USGS Publications Warehouse

Stockwell, Jason D.; Yule, Daniel L.; Hrabik, Thomas R.; Sierszen, Michael E.; Isaac, Edmund J.

2014-01-01

1. We hypothesised that the autumn spawning migration of Lake Superior cisco (Coregonus artedi) provides a resource subsidy, in the form of energy-rich cisco eggs, from the offshore pelagic to the nearshore benthic community over winter, when alternate prey production is likely to be low. 2. We tested this hypothesis using fish and macroinvertebrate surveys, fish population demographics, diet and stable isotope analyses, and bioenergetics modelling. 3. The benthic, congeneric lake whitefish (C. clupeaformis) was a clear beneficiary of cisco spawning. Cisco eggs represented 16% of lake whitefish annual consumption in terms of biomass, but 34% of energy (because of their high energy density: >10 kJ g wet mass−1). Stable isotope analyses were consistent with these results and suggest that other nearshore fish species may also rely on cisco eggs. 4. The lipid content of lake whitefish liver almost doubled from 26 to 49% between November and March, while that of muscle increased from 14 to 26% over the same period, suggesting lake whitefish were building, rather than depleting, lipid reserves during winter. 5. In the other Laurentian Great Lakes, where cisco populations remain very low and rehabilitation efforts are underway, the offshore-to-nearshore ecological link apparent in Lake Superior has been replaced by non-native planktivorous species. These non-native species spawn in spring have smaller eggs and shorter incubation periods. The rehabilitation of cisco in these systems should reinstate the onshore subsidy as it has in Lake Superior.

Coastal geology and recent origins for Sand Point, Lake Superior

USGS Publications Warehouse

Fisher, Timothy G.; Krantz, David E.; Castaneda, Mario R.; Loope, Walter L.; Jol, Harry M.; Goble, Ronald J.; Higley, Melinda C.; DeWald, Samantha; Hansen, Paul

2014-01-01

Sand Point is a small cuspate foreland located along the southeastern shore of Lake Superior within Pictured Rocks National Lakeshore near Munising, Michigan. Park managers’ concerns for the integrity of historic buildings at the northern periphery of the point during the rising lake levels in the mid-1980s greatly elevated the priority of research into the geomorphic history and age of Sand Point. To pursue this priority, we recovered sediment cores from four ponds on Sand Point, assessed subsurface stratigraphy onshore and offshore using geophysical techniques, and interpreted the chronology of events using radiocarbon and luminescence dating. Sand Point formed at the southwest edge of a subaqueous platform whose base is probably constructed of glacial diamicton and outwash. During the post-glacial Nipissing Transgression, the base was mantled with sand derived from erosion of adjacent sandstone cliffs. An aerial photograph time sequence, 1939–present, shows that the periphery of the platform has evolved considerably during historical time, infl uenced by transport of sediment into adjacent South Bay. Shallow seismic refl ections suggest slump blocks along the leading edge of the platform. Light detection and ranging (LiDAR) and shallow seismic refl ections to the northwest of the platform reveal large sand waves within a deep (12 m) channel produced by currents fl owing episodically to the northeast into Lake Superior. Ground-penetrating radar profi les show transport and deposition of sand across the upper surface of the platform. Basal radiocarbon dates from ponds between subaerial beach ridges range in age from 540 to 910 cal yr B.P., suggesting that Sand Point became emergent during the last ~1000 years, upon the separation of Lake Superior from Lakes Huron and Michigan. However, optically stimulated luminescence (OSL) ages from the beach ridges were two to three times as old as the radiocarbon ages, implying that emergence of Sand Point may have begun

Big Numbers for the Big Lake: A Lower Food Web Assessment of Lake Superior (2004-2006)

EPA Science Inventory

Our collaborative binational studies focused on lower trophic levels (plankton, mysids, benthos) of Lake Superior based on comprehensive sampling (2004 to 2006). Information is integrated for a lakewide summary, but also to display patterns among lower food web components by dept...

Seasonal bathymetric distributions of 16 fishes in Lake Superior, 1958-75

USGS Publications Warehouse

Selgeby, James H.; Hoff, Michael H.

1996-01-01

The bathymetric distributions of fishes in Lake Superior, which is one of the largest and deepest lakes in the world, has not been studied on a lakewide scale. Knowledge about the bathymetric distributions will aid in designing fish sampling programs, estimating absolute abundances, and modeling energy flow in the lake. Seasonal bathymetric distributions were determined , by 10-m depth intervals, for 16 fishes collected with bottom trawls and bottom-set gill nets within the upper 150 m of Lake Superior during 1958-75. In spring trawl catches, maximum abundance occurred at these depths: 15 m for round whitefish (Prosopium cylindraceum); 25m for longnose sucker (Catostomus catostomus); 35 m for lake whitefish (Coregonus clupeaformis) and rainbow smelt (Osmerus mordax); 45 m for lake trout (Salvelinus namaycush); 65 m for pygmy whitefish (Prospoium coulteri) and bloater (Coregonus hoyi); 75 m for trout- perch (Percopsis omiscomaycus); 105 m for shortjaw cisco (Coregonus zenithicus); and 115 m for ninespine stickleback (Pungitius pungitius), burbot (Lota lota), slimy sculpin (Cottus cogantus), spoonhead sculpin (Cottus ricei), and deepwater sculpin (Myoxcephalus thompsoni). Bathymetric distributions in spring gill nets were similar to those in trawls, except that depths of maximum abundances in gill nets were shallower than those in trawls for lake trout, rainbow smelt, longnose sucker, and burbot. Lake herring (Coregonus artedi) and kiyi (Coregonus kiyi) were rarely caught in trawls, and their maximum abundances in spring gill net collections were at depths of 25 and 145 m, respectively. In summer, pygmy whitefish, shortjaw cisco, lake herring, kiyi, longnose sucker, burbot, ninespine stickleback, trout-perch, slimy sculpin, and spponhead sculpin were at shallower depths than in spring, whereas rainbow smelt were found in deeper water; there was no change for other species. In fall, shortjaw cisco was at shallower depths than in summer, whereas the remaining species

Reestablishing a spawning population of lake trout in Lake Superior with fertilized eggs in artificial turf incubators

USGS Publications Warehouse

Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

2002-01-01

Fertilized eggs from lake trout Salvelinus namaycush were placed in artificial turf incubators and deployed on Devils Island Shoal, Lake Superior, in an attempt to reestablish a spawning population on this once important spawning area. Efficacy was measured by the changes in catch rates, age composition, and origin of adult lake trout returning to the shoal in the fall in subsequent years. The abundance of lake trout spawners without fin clips, which implies that these fish hatched in the lake, increased throughout the sampling period, whereas the abundance of hatchery-reared fish (indicated by one or more fin clips) stocked for restoration purposes remained low. Year-class-specific stock-recruitment analysis suggested that the recruitment of unclipped spawners was related to the number of eggs planted in previous years rather than to spawning by the few adult lake trout visiting the reef. Increases in adult fish at Devils Island Shoal were independent of trends at adjacent sites, where unclipped spawner abundances remained low. Enhanced survival to hatch and apparent site imprinting of young lake trout make this technique a viable alternative to stocking fingerling and yearling lake trout to reestablish spawning populations on specific sites in the Great Lakes.

A new look at the Lake Superior biomass size spectrum

EPA Science Inventory

We synthesized data from multiple sampling programs and years to describe the Lake Superior pelagic biomass size structure for two time periods separated by 5 years. The data consisted of water analyzed on a Coulter counter for algae, in situ measurements with a laser optical pl...

Lake Superior Phytoplankton Characterization from the 2006 Probability Based Survey

EPA Science Inventory

We conducted a late summer probability based survey of Lake Superior in 2006 which consisted of 52 sites stratified across 3 depth zones. As part of this effort, we collected composite phytoplankton samples from the epilimnion and the fluorescence maxima (Fmax) at 29 of the site...

Burrowing mayflies as indicators of ecosystem health: Status of populations in two western Lake Superior embayments

USGS Publications Warehouse

Edsall, Thomas A.; Gorman, Owen T.; Evrard, Lori M.

2004-01-01

The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development for Great Lakes mesotrophic environments is based on burrowing mayflies (Hexagenia: Ephemeroptera: Ephemeridae). In this paper, we report the results of a benthic survey in spring 2002 to determine the status of nymphal populations of Hexagenia in two western Lake Superior embayments, the St. Louis River estuary, an area with significant water-use impairments, and Chequamegon Bay, an area with no known water-use impairments. Ponar grab samples collected throughout these embayments showed nymphs were generally abundant in finely particulate, cohesive substrate (clay or mixtures of clay and sand) in both embayments. However, in the St. Louis River estuary nymphs were absent in those preferred substrates at 11 stations in the eastern portion of St. Louis Bay and the adjoining northwestern portion of the Duluth-Superior Harbor, where the sediments were variously contaminated with visible amounts of taconite pellets, paint chips, oil, or combusted coal waste (clinkers). Our results suggest that human activities have rendered those portions of the St. Louis River estuary unsuitable for habitation by Hexagenia nymphs and we recommend that trend monitoring of the nymphal population there be conducted to permit reporting on progress in restoring and maintaining the health and integrity of this Great Lakes ecosystem embayment, consistent with the intent of the Great Lakes Water Quality Agreement.

Biological and ecological science for Wisconsin—A Great Lakes and Rivers State

USGS Publications Warehouse

,

2018-03-06

Wisconsin and natural resources go hand-in-hand. Tourism, which generates $19 billion annually and sustains about 200,000 jobs, depends on an abundance of lakes, rivers, shorelines, and woodlands for fishing, hunting, boating, and other outdoor recreation. Rivers and floodplains in the Upper Mississippi Basin, including the Mississippi River, are part of a five-State corridor that generates more than $300 billion annually and sustains millions of manufacturing, tourism, transportation, and agricultural jobs. Wisconsin also is a Great Lakes State with more than 800 miles of shoreline, and the fisheries of lakes Superior and Michigan deliver $185 million annually and provide thousands of jobs.

DYNAMICS OF NUTRIENTS AND HYDROLOGY IN A LAKE SUPERIOR COASTAL WETLAND

EPA Science Inventory

Coastal wetlands are hydrologically complex ecosystems situated at the interface of upland catchments and oligotrophic Lake Superior. Little is known about nutrient dynamics within coastal wetlands or their role in modifying or contributing to nutrient fluxes from watersheds to ...

The Penokean orogeny in the Lake Superior region

USGS Publications Warehouse

Schulz, K.J.; Cannon, W.F.

2007-01-01

The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine-Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of volcanogenic massive sulfide deposits formed in the extending back-arc rift within the arc. Synchronous extension and subsidence of the Superior craton resulted in a broad shallow sea characterized by volcanic grabens (Menominee Group in northern Michigan). The classic Lake Superior banded iron-formations, including those in the Marquette, Gogebic, Mesabi and Gunflint Iron Ranges, formed in that sea. The newly established subduction zone caused continued arc volcanism until about 1850 Ma when a fragment of Archean crust, now the basement of the Marshfield terrane, arrived at the subduction zone. The convergence of Archean blocks of the Superior and Marshfield cratons resulted in the major contractional phase of the Penokean orogeny. Rocks of the Pembine-Wausau arc were thrust northward onto the Superior craton causing subsidence of a foreland basin in which sedimentation began at about 1850 Ma in the south (Baraga Group rocks) and 1835 Ma in the north (Rove and Virginia Formations). A thick succession of arc-derived turbidites constitutes most of the foreland basin-fill along with lesser volcanic rocks. In the southern fold and thrust belt tectonic thickening resulted in high-grade metamorphism of the sediments by 1830 Ma. At this same time, a suite of post-tectonic plutons intruded the deformed sedimentary sequence and accreted arc terranes marking the end of the Penokean orogeny. The Penokean orogen was strongly overprinted by younger tectonic and thermal events, some of which were previously ascribed to the Penokean. Principal among these was a

Sanctuaries for lake trout in the Great Lakes

USGS Publications Warehouse

Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

1987-01-01

Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

Depth-specific Analyses of the Lake Superior Food Web, oral presentation

EPA Science Inventory

Characteristics of large, deep aquatic systems include depth gradients in community composition, in the quality and distribution of food resources, and in the strategies that organisms use to obtain their nutrition. In Lake Superior, nearshore communities that rely upon a combina...

Estimation of invertebrate production from patterns of fish predation in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Mason, Doran M.; Bronte, Charles R.; Kitchell, James F.

1998-01-01

We used bioenergetic models for lake herring Coregonus artedi, bloater Coregonus hoyi, and rainbow smelt Osmerus mordax to estimate consumption of zooplankton,Mysis, andDiporeia in western Lake Superior for selected years between 1978 and 1995. Total invertebrate biomass consumed yearly ranged from 2.5 to 38 g/m2 with nearly 40% consumed between August and October in all years. Copepod zooplankton represented the largest proportion of biomass collectively consumed by the three species (81%), although rainbow smelt consumed almost twice as much Mysis as zooplankton. Growth efficiency was highest for rainbow smelt (3.84–16.64%) and lower for the coregonids (1.91–12.26%). In the absence of quantitative secondary production values, we suggest our estimates of predatory demand provide a conservative range of the minimum invertebrate production in western Lake Superior during the past 20 years.

Late Holocene lake-level variation in southeastern Lake Superior: Tahquamenon Bay, Michigan

USGS Publications Warehouse

Johnston, John W.; Baedke, Steve J.; Booth, Robert K.; Thompson, Todd A.; Wilcox, Douglas A.

2004-01-01

Internal architecture and ages of 71 beach ridges in the Tahquamenon Bay embayment along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan were studied to generate a late Holocene relative lake-level curve. Establishing a long-term framework is important to examine the context of historic events and help predict potential future changes critical for effective water resource management. Ridges in the embayment formed between about 4,200 and 2,100 calendar years before 1950 (cal. yrs. B.P.) and were created and preserved every 28 A? 4.8 years on average. Groups of three to six beach ridges coupled with inflections in the lake-level curve indicate a history of lake levels fluctuations and outlet changes. A rapid lake-level drop (approximately 4 m) from about 4,100 to 3,800 cal. yrs. B.P. was associated with a fall from the Nipissing II high-water-level phase. A change from a gradual fall to a slight rise was associated with an outlet change from Port Huron, Michigan/Sarnia, Ontario to Sault Ste. Marie, Michigan/Ontario. A complete outlet change occurred after the Algoma high-water-level phase (ca. 2,400 cal. yrs. B.P.). Preliminary rates of vertical ground movement calculated from the strandplain are much greater than rates calculated from historical and geologic data. High rates of vertical ground movement could have caused tectonism in the Whitefish Bay area, modifying the strandplain during the past 2,400 years. A tectonic event at or near the Sault outlet also may have been a factor in the outlet change from Port Huron/Sarnia to Sault Ste. Marie.

Life histories and abundance of crustacean zooplankton in the outlet of Lake Superior, 1971-72

USGS Publications Warehouse

Selgeby, James H.

1975-01-01

In sampling throughout a year, at about 3-wk intervals, of the crustacean zooplankton discharged from Lake Superior through the St. Marys River, 30 species were collected, including three not previously recorded for the lake: the copepod Cyclops strenuus, and the cladocerans Alona costata and Alonella acutirostris. Five copepods, Cyclops bicuspidatus thomasi, Diaptomus ashlandi, D. sicilis, Limnocalanus macrurus, and Senecella calanoides were present in the plankton throughout the year while three other copepods, Diaptomus minutus, Epischura lacustris, and Mesocyclops edax, along with all cladocerans, were present only during summer and fall. Five species of copepods, Diaptomus sicilis, D. minutus, Limnocalanus macrurus, Senecella calanoides, and Epischura lacustris produced a single generation annually; three other copepods and all cladocerans produced two or more generations. All species breed 1-3 mo later in Lake Superior than in lakes Michigan and Erie.

Benthic versus Planktonic Foundations of Three Lake Superior Coastal Food Webs

EPA Science Inventory

The structure of aquatic food webs can provide information on system function, trophic dynamics and, potentially, responses to anthropogenic stressors. Stable isotope analyses in a Lake Superior coastal wetland (Allouez Bay, WI, USA) revealed that the food web was based upon carb...

SPATIAL PATTERNS IN ASSEMBLAGE STRUCTURES OF PELAGIC FORAGE FISH AND ZOOPLANKTON IN WESTERN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the spatial distribution of zooplankton and forage fish in western Lake Superior. Fish and zooplankton assemblages are shown to differ substantially in abundance and size structure both between the open lake and nearshore regions and between two differe...

Age, growth, maturity, and fecundity of 'humper' lake trout, Isle Royale, Lake Superior

USGS Publications Warehouse

Rahrer, Jerold F.

1965-01-01

Humper lake trout are one of the several races or subpopulations of lake trout in Lake Superior. This study is based on 3,705 fish collected on a reef south of Isle Royale near the eastern end. The mean lengths of humper trout from commercial gill nets were smaller than those of lean lake trout. Members of age-groups VII, VIII, and IX represented 81.5 per cent of the commercial humper catch. The body-scale relation was described by two intersecting straight lines. The weight of humper trout increased as the 3.282 power of the length. Growth in length was slow and ranged from 1.6 to 3.5 inches per year. Annual increments were greatest in the first, sixth, and seventh years. Growth in weight was also slow but increased each year. Humper trout became legal (1 1/2 pounds) in the eighth year of life and reached 5 pounds in 11 years. All fish longer than 19.1 inches and older than age-group VIII were mature; the shortest mature fish were: males, 12.7 inches; females, 14.7 inches. At minimum legal size, 98 per cent of the males and 56 per cent of the females were mature. Humper trout produced an average of 1,351 eggs per fish or 516 per pound.

Organochlorine compounds in Lake Superior: Chiral polychlorinated biphenyls and biotransformation in the aquatic food web

USGS Publications Warehouse

Wong, Charles S.; Mabury, Scott A.; Whittle, D. Michael; Backus, Sean M.; Teixeira, Camilla; DeVault, David S.; Bronte, Charles R.; Muir, Derek C.G.

2004-01-01

The enantiomeric composition of seven chiral PCB congeners was measured in the Lake Superior aquatic food web sampled in 1998, to determine the extent of enantioselective biotransformation in aquatic biota. All chiral PCB congeners studied (CBs 91, 95, 136, 149, 174, 176, and 183) biomagnified in the Lake Superior aquatic food web, based on biomagnification and food web magnification factors greater than unity. PCB atropisomers were racemic in phytoplankton and zooplankton, suggesting no biotransformation potential toward PCBs for these low trophic level organisms. However, Diporeia and mysids had significantly nonracemic residues for most chiral congeners studied. This observation suggests that these macrozooplankton can stereoselectively metabolize chiral congeners. Alternatively, macrozooplankton obtained nonracemic residues from feeding on organic-rich suspended particles and sediments, which would imply that stereoselective microbial PCB biotransformation may be occurring in Lake Superior sediments at PCB concentrations far lower than that previously associated with such activity. Widely nonracemic PCB residues in forage fish (lake herring, rainbow smelt, and slimy sculpin) and lake trout suggest a combination of both in vivo biotransformation and uptake of nonracemic residues from prey for these species. Minimum biotransformation rates, calculated from enantiomer mass balances between predators and prey, suggest metabolic half-lives on the order of 8 yr for CB 136 in lake trout and 2.6 yr for CB 95 in sculpins. This result suggests that significant biotransformation may occur for metaboliz able PCB congeners over the lifespan of these biota. This study highlights the potential of chiral analysis to study biotransformation processes in food webs.

MERCURY IN STAMP SAND DISCHARGES: IMPLICATIONS FOR LAKE SUPERIOR MERCURY CYCLING

EPA Science Inventory

Approximately a half billion tons of waste rock from the extraction of native copper and silver ores was discharged into the Lake Superior basin. Stamping was the method of choice to recover these metals from the surrounding poor rock. This process created large amounts of extre...

Lakewide monitoring of suspended solids using satellite data. [Lake Superior water reclamation

NASA Technical Reports Server (NTRS)

Sydor, M. (Principal Investigator)

1981-01-01

In anticipation of using LANDSAT and Nimbus 7 coastal zone color scanner data to observe the decrease in suspended solids in Lake Superior following cessation of the dumping of taconite tailings, a series of lakewide sampling cruises was conducted to make radiometric measurements at a lake level. A means for identifying particulates and measuring their concentration from LANDSAT data was developed. The initial distribution of chemical parameters in the extreme western arm of the lake, where the concentration gradients are high, is to be based on the LANDSAT data. Subsequent lakewide dispersal and distribution is to be based on the coastal zone color scanner data.

Food of young-of-the-year lake trout (Salvelinus namaycush) in Presque Isle Harbor, Lake Superior

USGS Publications Warehouse

Swedberg, Donald V.; Peck, James W.

1984-01-01

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.

The biological pump and lower trophic level controls on carbon cycling in Lake Superior: Insights from a multi-pronged study

NASA Astrophysics Data System (ADS)

Schreiner, K. M.; Bramburger, A.; Ozersky, T.; Sheik, C.; Steinman, B. A.

2016-02-01

Lake Superior is the largest freshwater lake in the world, supporting economically important fisheries and providing drinking water to hundreds of thousands of people. In recent decades, summer surface water temperature and the intensity and duration of water column stratification in the lake has increased steadily. These physical changes have resulted in significant perturbations to lower trophic level ecosystem characteristics. Recent observations of Great Lakes plankton assemblages have revealed multi-decadal patterns of community reorganization, with increased relative abundance of taxa characteristic of warmer waters. These changes, coupled with changing nutrient concentrations and colonization by non-native taxa, threaten to shift trophic structure and carbon dynamics at the bottom of the food web. To this end, this study seeks to quantify the impacts of this ecosystem shift on carbon fixation, the biological pump, and organic carbon cycling in Lake Superior. Utilizing a combined sampling approach, in the summer of 2015 we collected water, sediment, and biological samples across a nearshore-to-offshore gradient in the western arm of Lake Superior. Analyses included the community composition of bacteria, archaea, phytoplankton, and zooplankton; water column carbon and nutrient speciation; algal pigments and pigment degradation products; and net primary productivity. The collection of surface sediments allowed for additional assessment of benthic-pelagic coupling. The novel combination of this wide-ranging set of analyses to a locally and globally important water body like Lake Superior allowed us to fully assess the interactions between lower trophic level biology and carbon and nutrient cycling throughout the water column. Preliminary data indicates that microbial community composition was variable across the western arm of Lake Superior and showed signs of stratification at individual stations (>100 m deep). Sample collection occurred soon after lake

Sustainability of the Lake Superior fish community: Interactions in a food web context

USGS Publications Warehouse

Kitchell, James F.; Cox, Sean P.; Harvey, Chris J.; Johnson, Timothy B.; Mason, Doran M.; Schoen, Kurt K.; Aydin, Kerim; Bronte, Charles; Ebener, Mark; Hansen, Michael; Hoff, Michael; Schram, Steve; Schreiner, Don; Walters, Carl J.

2000-01-01

The restoration and rehabilitation of the native fish communities is a long-term goal for the Laurentian Great Lakes. In Lake Superior, the ongoing restoration of the native lake trout populations is now regarded as one of the major success stories in fisheries management. However, populations of the deepwater morphotype (siscowet lake trout) have increased much more substantially than those of the nearshore morphotype (lean lake trout), and the ecosystem now contains an assemblage of exotic species such as sea lamprey, rainbow smelt, and Pacific salmon (chinook, coho, and steelhead). Those species play an important role in defining the constraints and opportunities for ecosystem management. We combined an equilibrium mass balance model (Ecopath) with a dynamic food web model (Ecosim) to evaluate the ecological consequences of future alternative management strategies and the interaction of two different sets of life history characteristics for fishes at the top of the food web. Relatively rapid turnover rates occur among the exotic forage fish, rainbow smelt, and its primary predators, exotic Pacific salmonids. Slower turnover rates occur among the native lake trout and burbot and their primary prey—lake herring, smelt, deepwater cisco, and sculpins. The abundance of forage fish is a key constraint for all salmonids in Lake Superior. Smelt and Mysis play a prominent role in sustaining the current trophic structure. Competition between the native lake trout and the exotic salmonids is asymmetric. Reductions in the salmon population yield only a modest benefit for the stocks of lake trout, whereas increased fishing of lake trout produces substantial potential increases in the yields of Pacific salmon to recreational fisheries. The deepwater or siscowet morphotype of lake trout has become very abundant. Although it plays a major role in the structure of the food web it offers little potential for the restoration of a valuable commercial or recreational fishery

Fleet dynamics of the commercial lake trout fishery in Michigan waters of Lake Superior during 1929-1961

USGS Publications Warehouse

Wilberg, Michael J.; Bronte, Charles R.; Hansen, Michael J.

2004-01-01

Understanding fishing fleet dynamics is important when using fishery dependent data to infer the status of fish stocks. We analyzed data from mandatory catch reports from the commercial lake trout (Salvelinus namaycush) fishery in Michigan waters of Lake Superior during 1929-1961, a period when lake trout populations collapsed through the combined effects of overfishing and sea lamprey (Petromyzon marinus) predation. The number of full-time fishermen increased during 1933-1943 and then decreased during 1943-1957. Addition of new fishermen was related to past yield, market prices, World War II draft exemptions, and lost fishing opportunities in Lake Huron and Lake Michigan. Loss of existing fishermen was related to declining lake trout density. Large mesh (a?Y 114-mm stretch-measure) gill net effort increased during 1929-1951 because fishermen fished more net inshore as lake trout density declined, even though catch per effort (CPE) was often higher in deeper waters. The most common gill net mesh size increased from 114-mm to 120-mm stretch-measure during 1929-1957, as lake trout growth increased. More effort was fished inshore than offshore and the amount of inshore effort was less variable over time than offshore effort. Relatively stable yield was maintained by increasing gill net effort and by moving some effort to better grounds. Because fishing-up caused yield and CPE to remain high despite declining lake trout abundance, caution must be used when basing goals for lake trout restoration on historical fishery indices.

Status and trends in the fish community of Lake Superior, 2012

USGS Publications Warehouse

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Vinson, Mark

2012-01-01

Due to ship mechanical failures, nearshore sampling was delayed from mid-May to mid-June to mid-June to late August. The shift to summer sampling when the lake was stratified may have affected our estimates, thus our estimates of status and trends for the nearshore fish community in 2012 are tentative, pending results of future surveys. However, the results of the 2012 survey are comparable with those during 2009 and 2010 when lake-wide fish biomass declined to < 1.40 kg/ha. Declines in prey fish biomass since the late 1990s can be attributed to a combination of increased predation by recovered lake trout populations and infrequent and weak recruitment by the principal prey fishes, cisco and bloater. In turn declines in lake trout biomass since the mid-2000s are likely linked to declines in prey fish biomass. If lean and siscowet lake trout populations in nearshore waters continue to remain at current levels, predation mortality will likely maintain the relatively low prey fish biomass observed in recent years. Alternatively, if lake trout populations show a substantial decline in abundance in upcoming years, prey fish populations may rebound in a fashion reminiscent to what occurred in the late 1970s to mid-1980s. However, this scenario depends on substantial increases in harvest of lake trout, which seems unlikely given that levels of lake trout harvest have been flat or declining in many regions of Lake Superior since 2000.

Decline of shortjaw cisco in Lake Superior: the role of overfishing and risk of extinction

USGS Publications Warehouse

Bronte, Charles R.; Hoff, Michael H.; Gorman, Owen T.; Thogmartin, Wayne E.; Schneeberger, Philip J.; Todd, Thomas N.

2010-01-01

Recent reviews have further documented the decline of the shortjaw cisco Coregonus zenithicus in Lake Superior. This fish was the most abundant deepwater cisco species in Lake Superior in the early 1920s but presently makes up less than 1% of all deepwater ciscoes (i.e., including shortjaw cisco, bloater C. hoyi, and kiyi C. kiyi) captured in biological surveys. Directed overfishing of deepwater cisco species during the 1930s and again during the mid-1960s and 1970s has been suggested as the cause of the shortjaw cisco's demise. In this paper, we re-examined the overfishing hypothesis by using historical and recent survey data to estimate the proportion of the historical commercial fishery landings that comprised shortjaw ciscoes. We developed time series of estimated harvest and relative abundance for all statistical districts in Michigan waters of Lake Superior during 1929–1996, for which aggregate catch and effort data were available but not previously examined. The spatial distribution of the fishery and the relationships of catch to fishing effort were examined for evidence of overfishing. Our analysis suggested that directed overfishing was probably not the cause of shortjaw cisco demise, as this species appeared to be declining in all statistical districts regardless of the intensity of the fishery. A count-based population viability analysis indicated that quasi-extinction of the shortjaw cisco is highly probable in the near future. We propose an alternative hypothesis based on the decline of Lake Superior's keystone predator, the lake trout Salvelinus namaycush, which resulted in an expansion of the population of its principal prey, the cisco C. artedi, due to release from predation pressure. Competitive or predation interactions between the cisco and shortjaw cisco may be more likely explanations for the demise of the latter species.

A new look at the Lake Superior biomass size spectrum

USGS Publications Warehouse

Yurista, Peder M.; Yule, Daniel L.; Balge, Matt; VanAlstine, Jon D.; Thompson, Jo A.; Gamble, Allison E.; Hrabik, Thomas R.; Kelly, John R.; Stockwell, Jason D.; Vinson, Mark

2014-01-01

We synthesized data from multiple sampling programs and years to describe the Lake Superior pelagic biomass size structure. Data consisted of Coulter counts for phytoplankton, optical plankton counts for zooplankton, and acoustic surveys for pelagic prey fish. The size spectrum was stable across two time periods separated by 5 years. The primary scaling or overall slope of the normalized biomass size spectra for the combined years was −1.113, consistent with a previous estimate for Lake Superior (−1.10). Periodic dome structures within the overall biomass size structure were fit to polynomial regressions based on the observed sub-domes within the classical taxonomic positions (algae, zooplankton, and fish). This interpretation of periodic dome delineation was aligned more closely with predator–prey size relationships that exist within the zooplankton (herbivorous, predacious) and fish (planktivorous, piscivorous) taxonomic positions. Domes were spaced approximately every 3.78 log10 units along the axis and with a decreasing peak magnitude of −4.1 log10 units. The relative position of the algal and herbivorous zooplankton domes predicted well the subsequent biomass domes for larger predatory zooplankton and planktivorous prey fish.

77 FR 45490 - Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-01

... suspected to contain munitions waste materials which were dumped in the 1960's in a portion of Lake Superior... recreational vessels and marine traffic from any unknown hazards as well as provide a safe work zone for... Waterways Management, U.S. Coast Guard Marine Safety Unit Duluth; telephone number (218) 720- 5286...

Wisconsin's Lake Superior Basin Water Quality Study. Technical Report No. 1.

ERIC Educational Resources Information Center

Dickas, Albert B., Ed.

This hydrologic study focuses on Wisconsin's Lake Superior Basin. Water is the most important natural resource in this area which includes Douglass, Bayfield, Ashland, and Iron counties. This study was undertaken to determine the character of this hydrologic base and to determine the effects and extent of man-influenced disturbances. It includes…

Experiencing the changing climate on the shores of Lake Superior

NASA Astrophysics Data System (ADS)

Akerlof, K.; Maibach, E.

2011-12-01

The Great Lakes of the United States - the largest freshwater system in the world - have been termed "the canary in the coal mine" of environmental change. To assess if and how residents of Alger County, Michigan are experiencing changes in climate on the shores of Lake Superior, during the summer of 2010 we conducted a representative household mail survey in collaboration with a national lakeshore and watershed partnership. A total of 765 adult residents (18 years or older) responded to the survey; a 57% survey completion rate. We content analyzed respondents' open-ended characterizations of how they have personally experienced global warming, and compared the results with land surface and storm data for the same geographic region to see whether public perceptions of local changes match trends in National Climatic Data Center data. Just over a quarter of residents (27%) indicated that they had personally experienced global warming. Those who had were most likely to say that they had experienced global warming locally (as opposed to in other locations of the country or globally), and most frequently cited changes in seasons, weather, lake levels, and animals or plant species. However, some local public perceptions appeared to conflict with weather records. For example, residents were more likely to say that they had been experiencing less snow in the winters, while NCDC data suggests the reverse is true. As climate changes differentially in regions across the United States, the public will in turn experience its physical impacts in distinct ways that are unique to each landscape. This may be counter-intuitive to a public that increasingly experiences the world, and issues such as climate change, through sources of information such as national news media that operate at much larger geographic scales. Understanding where these forms of cognitive dissonance may arise may assist researchers, educators, and communicators in furthering discourses with the public about

Microplastic Abundance and Composition in Western Lake Superior As Determined via Microscopy, Pyr-GC/MS, and FTIR.

PubMed

Hendrickson, Erik; Minor, Elizabeth C; Schreiner, Kathryn

2018-02-20

While plastic pollution in marine and freshwater systems is an active area of research, there is not yet an in-depth understanding of the distributions, chemical compositions, and fates of plastics in aquatic environments. In this study, the magnitude, distribution, and common polymers of microplastic pollution in surface waters in western Lake Superior are determined. Analytical methodology, including estimates of ambient contamination during sample collection and processing, are described and employed. Microscopy, pyrolysis-gas chromatography/mass spectrometry (Pyr-GC/MS), and Fourier transform infrared spectroscopy (FTIR) were used to quantify and identify microplastic particles. In surface waters, fibers were the most frequently observed morphology, and, based upon PyGC/MS analysis,  polyvinyl chloride was the most frequently observed polymer, followed by polypropylene and polyethylene. The most common polymer identified by FTIR was polyethylene. Despite the low human population in Lake Superior's watershed, microplastic particles (particularly fibers, fragments, and films) were identified in western-lake surface waters at levels comparable to average values reported in studies within Lake Michigan, the North Atlantic Ocean, and the South Pacific Ocean. This study provides insight into the magnitude of microplastic pollution in western Lake Superior, and describes in detail methodology to improve future microplastics studies in aquatic systems.

Cross shore transport by wind-driven turbidity plumes in western Lake Superior*

EPA Science Inventory

Turbidity plumes frequently occur in the western arm of Lake Superior and may represent a significant cross shelf transport mechanism for sediment, nutrient and biota. We characterize a plume that formed in late April 2016 using observations from in situ sensors and remote sensin...

New Records and Range Extensions for Several Chironomid Genera from Lake Superior

EPA Science Inventory

Five genera of chironomids have been reported for the first time in Lake Superior. Chironomids are small flying insects with a sediment-dwelling aquatic larval stage. The chironomids were collected by scientists at the Mid-Continent Ecology Division as part of a research program ...

Multi-Objective Lake Superior Regulation

NASA Astrophysics Data System (ADS)

Asadzadeh, M.; Razavi, S.; Tolson, B.

2011-12-01

At the direction of the International Joint Commission (IJC) the International Upper Great Lakes Study (IUGLS) Board is investigating possible changes to the present method of regulating the outflows of Lake Superior (SUP) to better meet the contemporary needs of the stakeholders. In this study, a new plan in the form of a rule curve that is directly interpretable for regulation of SUP is proposed. The proposed rule curve has 18 parameters that should be optimized. The IUGLS Board is also interested in a regulation strategy that considers potential effects of climate uncertainty. Therefore, the quality of the rule curve is assessed simultaneously for multiple supply sequences that represent various future climate scenarios. The rule curve parameters are obtained by solving a computationally intensive bi-objective simulation-optimization problem that maximizes the total increase in navigation and hydropower benefits of the new regulation plan and minimizes the sum of all normalized constraint violations. The objective and constraint values are obtained from a Microsoft Excel based Shared Vision Model (SVM) that compares any new SUP regulation plan with the current regulation policy. The underlying optimization problem is solved by a recently developed, highly efficient multi-objective optimization algorithm called Pareto Archived Dynamically Dimensioned Search (PA-DDS). To further improve the computational efficiency of the simulation-optimization problem, the model pre-emption strategy is used in a novel way to avoid the complete evaluation of regulation plans with low quality in both objectives. Results show that the generated rule curve is robust and typically more reliable when facing unpredictable climate conditions compared to other SUP regulation plans.

Changes in a population of exotic rainbow smelt in Lake Superior: Boom to bust, 1974-2005

USGS Publications Warehouse

Gorman, O.T.

2007-01-01

Changes in a population of rainbow smelt (Osmerus mordax) in the Apostle Islands region of Lake Superior were chronicled over a 32-yr time series, 1974–2005. At the beginning of the time series, rainbow smelt was the predominant prey species, abundance of lake herring (Coregonis artedi) was very low, and the dominant predator was stocked lake trout (Salvelinus namaycush). Following a period of successful lake trout stocking in the 1970s, the rainbow smelt population declined sharply in 1980, largely through mortality of adult fish and subsequent poor recruitment. In the succeeding 4 years, rainbow smelt populations reached historic low levels, resulting in reduced food resources for both wild and stocked lake trout. During 1985–1990 lake herring stocks began a spectacular recovery following the appearance of a very strong 1984 year class and subsequent 1988, 1989, and 1990 year classes. Rainbow smelt benefited from the high abundance of young lake herring as an alternate prey source for lake trout and showed a partial recovery in the late 1980s. However, a growing lake trout population coupled with an 8-yr period of low herring reproduction after 1990 resulted in a diminished rainbow smelt population dominated by age-1 and 2 fish and showing a pattern of alternating recruitment attributed to cannibalism. Low productivity of rainbow smelt and intermittent production of herring over the past decade has left lake trout populations with a diminished prey base. Although lake trout recovery benefited from the presence of rainbow smelt as a prey resource, the Lake Superior fish community was fundamentally altered by the introduction of rainbow smelt.

Distribution of fishes in U. S. streams tributary to Lake Superior

USGS Publications Warehouse

Moore, Harry H.; Braem, Robert A.

1965-01-01

Experimental sea lamprey control by the Bureau of Commercial Fisheries on Lake Superior streams provided many new distributional records of the fish fauna. Seventy-one species were recorded from 175 streams. Specimens were collected at the electromechanical barriers, with electric shockers, with fyke nets, and during chemical treatment of streams. Maps showing stream records of each species are presented.

Lake Superior Harbors of Refuge at Lutsen and Beaver Bay Cook and Lake Counties Minnesota.

DTIC Science & Technology

1977-12-01

attributed to the daily dumping into Lake Superior of 67,000 tons of taconite tailings by the Reserve Mining Cormpany. Reserve Mining will be totally...Reserve Mining must be given a reasonable period of time within which to change its operation to on-land disposal of taconite tailings. 2.33 While...shoreline, the city came into existence. The Reserve Mining Company began its construction of the taconite processing plant in 1951, and it went into

Michigan: The Great Lakes State

ERIC Educational Resources Information Center

McKay, Sandra Lee; La Luzerne-Oi, Sally

2009-01-01

Although Michigan is often called the "Wolverine State," its more common nickname is the "Great Lakes State." This name comes from the fact that Michigan is the only state in the United States that borders four of the five Great Lakes. Also referred to as the "Water Wonderland," Michigan has 11,000 additional lakes,…

The relative efficiency of nylon and cotton gill nets for taking lake trout in Lake Superior

USGS Publications Warehouse

Pycha, Richard L.

1962-01-01

The change from cotton to nylon twine for gill nets in 1949–52 resulted in a sharp increase in the efficiency of the most important gear used for taking lake trout in Lake Superior, and, consequently, biased estimates of fishing intensity and abundance severely.From early May to the end of September 1961, short gangs (2000 or 4000 linear feet) of cotton and nylon nets were fished in parallel sets for lake trout. A total of 343,000 feet of gill netting was lifted. Nylon nets were 2.25 times as efficient as cotton nets for taking legal-sized fish and 2.8 times as efficient for undersized lake trout. The average lengths of legal, undersized, and all lake trout taken in nets of the two materials did not differ greatly. The percentage of the catch which was undersized (less than 1.25 lb, dressed weight) was 20.8 in nylon nets and 17.7 in cotton. The relative efficiency of cotton and nylon nets showed no trend during the season. The efficiency ratio determined in this study was closely similar to that obtained by earlier workers.Correction of estimates of fishing intensity and abundance for the greater efficiency of the nylon nets used since 1951 has not been attempted. The drastic decline of the lake trout fishery has forced fishermen to make changes in fishing practices in the past few years that cause new bias of an unknown extent to estimates of fishing intensity.

Predicting geomorphic stability in low-order streams of the western Lake Superior basin

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second and third order stream reaches in the western Lake Superior basin, and stream reaches were assigned a Rosgen geomorphic classification. Over 700 measurements ...

Genetic structure of the benthic amphipod Diporeia (Amphipoda: Pontoporeiidae) and its relationship to abundance in Lake Superior

EPA Science Inventory

The freshwater amphipod Diporeia is a crucial part of the food web in the Laurentian Great Lakes, but has faced serious declines correlated with the invasion of zebra mussels (Dreissena polymorpha), except in Lake Superior, which has seen an increase in Diporeia abundance. Specul...

A rehabilitation plan for walleye populations and habitats in Lake Superior

USGS Publications Warehouse

Hoff, Michael H.

2003-01-01

The walleye (Stizostedion vitreum vitreum) has been historically important in regional fisheries and fish communities in large bays, estuaries, and rivers of Lake Superior. Significant negative impacts on the species caused by overharvesting, habitat degradation, and pollution during the late 1800s and early 1900s have led to the preparation of a strategic rehabilitation plan. The lakewide goal is to maintain, enhance, and rehabilitate habitat for walleye and to establish self-sustaining populations in areas where walleyes historically lived. Population objectives that support the goal are to increase the abundance of juvenile and adult walleyes in selected areas. Habitat objectives that support the goal include increasing spawning and nursery habitat in four areas: enhancing fish passage, reducing sedimentation, increasing water quality, and reducing contaminants in walleyes. Progress toward achieving the habitat objectives should be measured by documenting increases in spawning and nursery habitats, resolving fish-passage issues, reducing sediments in rivers, and reducing contaminant levels in walleyes. Stocking various life stages of walleye should be considered to rehabilitate certain degraded populations. Total annual mortality of walleye populations should be less than 45% to allow populations to either increase or be maintained at target levels of abundance. Routine assessments should focus on gathering the data necessary to evaluate abundance and mortality and on taking inventories of spawning and nursery habitats. Research should be conducted to understand the specific habitat requirements for Lake Superior walleye populations and the habitat-abundance relationships for populations and for the lake as a whole.

Buried soils in a perched dunefield as indicators of late holecene lake-level change in the Lake Superior basin

USGS Publications Warehouse

Anderton, John B.; Loope, Walter L.

1995-01-01

A stratigraphic analysis of buried soils within the Grand Sable Dunes, a dune field perched 90 m above the southern shore of Lake Superior, reveals a history of eolian activity apparently linked with lake-level fluctuations over the last 5500 yr. A relative rise in the water plane of the Nipissing Great Lakes initially destabilized the lakeward bluff face of the Grand Sable plateau between 5400 and 4600 14C yr B.P. This led to the burial of the Sable Creek soil by eolian sediments derived from the bluff face. Subsequent episodes of eolian activity appear to be tied to similar destabilizing events; high lake levels may have initiated at least four and perhaps eleven episodes of dune building as expressed by soil burials within the dunes. Intervening low lake levels probably correlate with soil profile development, which varies from the well-developed Sable Creek Spodosol catena to thin organic layers containing in-place stumps and tree trunks. Paleoecological reconstructions available for the area do not imply enough climatic change to account for the episodic dune activity. Burial of soils by fine-fraction sediments links dune-building episodes with destabilization of the lower lake-facing bluff, which is rich in fines.

Remote Sensing and Underwater Glider Observations of a Springtime Plume in Western Lake Superior

EPA Science Inventory

Plumes are commonly observed in satellite imagery of western Lake Superior following storm events, and represent a significant cross-shelf pathway for sediment and other constituents. However, their subsurface extent is poorly understood. This study reports results from plume ob...

Reassessment of the predatory effects of rainbow smelt on ciscoes in Lake Superior

USGS Publications Warehouse

Myers, Jared T.; Jones, Michael L.; Stockwell, Jason D.; Yule, Daniel L.

2009-01-01

Evidence from small lakes suggests that predation on larval ciscoes Coregonus artedi by nonnative rainbow smelt Osmerus mordax can lead to cisco suppression or extirpation. However, evidence from larger lakes has led to equivocal conclusions. In this study, we examine the potential predation effects of rainbow smelt in two adjacent but contrasting embayments in Lake Superior (Thunder and Black bays, Ontario). During May 2006, we sampled the ichthyoplankton, pelagic fish communities, and diet composition of rainbow smelt in both bays. Using acoustics and midwater trawling, we estimated rainbow smelt densities to be 476 ± 34/ha (mean ± SE) in Thunder Bay and 3,435 ± 460/ha in Black Bay. We used a bioenergetics model to estimate the proportion of cisco larvae consumed by rainbow smelt. Our results suggest that predation by rainbow smelt accounts for 15–52% and 37–100% of the mortality of larval ciscoes in Thunder and Black bays, respectively, depending on the predator feeding rate and the scale of predator–prey overlap. We also examined the sensitivity of past conclusions (based on 1974 field collections) to assumptions of temporal overlap between rainbow smelt and larval ciscoes and estimates of rainbow smelt abundance derived from bottom trawl samples. After adjusting these parameters to reflect current understanding, we found that the previous predation estimates may have been conservative. We conclude that rainbow smelt may have been a more important contributor to the demise and slow recovery of ciscoes in Lake Superior than previously thought.

Empirical evaluation of predator-driven diel vertical migration in Lake Superior

USGS Publications Warehouse

Stockwell, J.D.; Hrabik, T.R.; Jensen, O.P.; Yule, D.L.; Balge, M.

2010-01-01

Recent studies on Lake Superior suggest that diel vertical migration (DVM) of prey (generalized Coregonus spp.) may be influenced by the density of predatory siscowet (Salvelinus namaycush). We empirically evaluated this hypothesis using data from acoustic, midwater trawl, and bottom trawl sampling at eight Lake Superior sites during three seasons in 2005 and a subset of sites in 2006. We expected the larger-bodied cisco (Coregonus artedi) to exhibit a shallower DVM compared with the smaller-bodied kiyi (Coregonus kiyi). Although DVM of kiyi and cisco were consistent with expectations of DVM as a size-dependent, predator-mediated process, we found no relationship between siscowet density and the magnitude of DVM of either coregonid. Cisco appear to have a size refuge from siscowet predation. Kiyi and siscowet co-occur in demersal habitat > 150 m during the day, where visual predation is unlikely, suggesting predator avoidance is not a factor in the daytime distribution of kiyi. Seasonal patterns of kiyi DVM were consistent with reported DVM of their primary prey Mysis relicta. Our results suggest that consideration of nonvisual foraging, rather than lightbased foraging theory (i.e., the antipredation window), is necessary to understand the processes driving DVM in deepwater systems.

Periphyton accumulation at remote reefs and shoals in Lake Superior

USGS Publications Warehouse

Edsall, Thomas A.; Stoermer, Eugene F.; Kociolek, John P.

1991-01-01

Observations made from a submarine showed that the bed-rock surfaces at water depths of about 5 to 14 m on Stannard Rock and Superior Shoal in Lake Superior were covered with a dense, fleece-like blanket of periphyton. Examination of the periphyton revealed it consisted primarily of structurally complex, diverse, diatom communities, but occasional small thalli of the green algae Cladophora andStigeoclonium were also noted. Extensive windrows of detritus-like material, apparently derived from the local periphyton community, were seen on soft bottoms at depths of about 20 to 60 m near the reefs. Our observations suggested that these periphyton communities may be locally important to the food web at these remote and oligotrophic sites, which are 22 to 77 km from the nearest mainland shore and are surrounded by water at least 140 m deep.

Predicting geomorphic stability in low-order streams of the western Lake Superior basin - Poster

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second- and third-order stream reaches in the western Lake Superior basin in 1997-1998. More than 700 measurements of suspended sediment concentration during snowmel...

Altitudes between Lake Superior and the Rocky Mountains

USGS Publications Warehouse

Upham, Warren

1891-01-01

In the survey of Lake Agassiz, a preliminary report of which forms Bulletin No. 39, it was found necessary to ascertain the altitudes determined within its area by railroad surveys as the basis for leveling along the shore lines of that glacial lake, and learning their relations in height to each other, to the great lakes of the St. Lawrence and Nelson Rivers, and to the ocean. From the time of the first observations and description of the upper beaches of Lake Agassiz by the author in 1879 and 1881, for the Geological Survey of Minnesota, and especially since the work was extended in 1885, under the U. S. Geological Survey, to include both sides of this lacustrine area in Minnesota and North Dakota now drained by the Red River of the North, much attention has been given to this collection of altitudes, and to the means of referring them to the sea level. The greater part of Lake Agassiz, however, was in Manitoba and adjacent British Territory, stretching north to the Saskatchewan; and in 1887, jointly for the Geological Surveys of the United States and of Canada, the author continued his examination of the beaches and deltas on the west side of the lake along a distance of a hundred miles north from the international boundary, across the prairie region of southwestern Manitoba, the leveling in this work being based on the altitudes of the Canadian Pacific Railway and its branches and connecting railways.

Principles in sampling design, lessons, and recommendations from a multi-year, multi-port surveillance program in Lake Superior

EPA Science Inventory

We evaluated a pilot aquatic invasive species (AIS) early detection monitoring program in Lake Superior that was designed to detect newly-introduced fishes. We established survey protocols for three major ports (Duluth-Superior, Sault Ste. Marie, Thunder Bay), and designed an ada...

Climate Change Expands the Spatial Extent and Duration of Preferred Thermal Habitat for Lake Superior Fishes

PubMed Central

Cline, Timothy J.; Bennington, Val; Kitchell, James F.

2013-01-01

Climate change is expected to alter species distributions and habitat suitability across the globe. Understanding these shifting distributions is critical for adaptive resource management. The role of temperature in fish habitat and energetics is well established and can be used to evaluate climate change effects on habitat distributions and food web interactions. Lake Superior water temperatures are rising rapidly in response to climate change and this is likely influencing species distributions and interactions. We use a three-dimensional hydrodynamic model that captures temperature changes in Lake Superior over the last 3 decades to investigate shifts in habitat size and duration of preferred temperatures for four different fishes. We evaluated habitat changes in two native lake trout (Salvelinus namaycush) ecotypes, siscowet and lean lake trout, Chinook salmon (Oncorhynchus tshawytscha), and walleye (Sander vitreus). Between 1979 and 2006, days with available preferred thermal habitat increased at a mean rate of 6, 7, and 5 days per decade for lean lake trout, Chinook salmon, and walleye, respectively. Siscowet lake trout lost 3 days per decade. Consequently, preferred habitat spatial extents increased at a rate of 579, 495 and 419 km2 per year for the lean lake trout, Chinook salmon, and walleye while siscowet lost 161 km2 per year during the modeled period. Habitat increases could lead to increased growth and production for three of the four fishes. Consequently, greater habitat overlap may intensify interguild competition and food web interactions. Loss of cold-water habitat for siscowet, having the coldest thermal preference, could forecast potential changes from continued warming. Additionally, continued warming may render more suitable conditions for some invasive species. PMID:23638023

Detection of Viral Hemorrhagic Septicemia Virus by Quantitative Reverse Transcription Polymerase Chain Reaction from Two Fish Species at Two Sites in Lake Superior

USGS Publications Warehouse

Cornwell, Emily R.; Eckerlin, Geofrey E.; Getchell, Rodman G.; Groocock, Geoffrey H.; Thompson, Tarin M.; Batts, William N.; Casey, Rufina N.; Kurath, Gael; Winton, James R.; Bowser, Paul R.; Bain, Mark B.; Casey, James W.

2011-01-01

Viral hemorrhagic septicemia virus (VHSV) was first detected in the Laurentian Great Lakes in 2005 during a mortality event in the Bay of Quinte, Lake Ontario. Subsequent analysis of archived samples determined that the first known isolation of VHSV in the Laurentian Great Lakes was from a muskellunge Esox masquinongy collected in Lake St. Clair in 2003. By the end of 2008, mortality events and viral isolations had occurred in all of the Laurentian Great Lakes except Lake Superior. In 2009, a focused disease surveillance program was designed to determine whether VHSV was also present in Lake Superior. In this survey, 874 fish from 7 sites along the U.S. shoreline of Lake Superior were collected during June 2009. Collections were focused on nearshore species known to be susceptible to VHSV. All fish were dissected individually by using aseptic techniques and were tested for the presence of VHSV genetic material by use of a quantitative reverse transcription (qRT) polymerase chain reaction (PCR) targeting the viral nucleoprotein gene. Seventeen fish from two host species at two different sites tested positive at low levels for VHSV. All attempts to isolate virus in cell culture were unsuccessful. However, the presence of viral RNA was confirmed independently in five fish by using a nested PCR that targeted the glycoprotein (G) gene. Partial G gene sequences obtained from three fish were identical to the corresponding sequence from the original 2003 VHSV isolate (MI03) from muskellunge. These detections represent the earliest evidence for the presence of VHSV in Lake Superior and illustrate the utility of the highly sensitive qRT-PCR assay for disease surveillance in aquatic animals.

Lake states management differs from northeast

Treesearch

Richard M. Godman

1992-01-01

There are "northern hardwoods" in the Lake States and "northern hardwoods" in the Northeast. The term is the same but the forest cover types, stand, and site conditions can be very different. The silvicultural treatments that work in the Northeast may not work at all in the Lake States. And what works in the Lake States will work - but not the best...

Production of sea lamprey larvae from nests in two Lake Superior streams

USGS Publications Warehouse

Manion, Patrick J.

1968-01-01

The life history of the landlocked sea lamprey, Petromyzon marinus, has been described by several authors, the two most recent of which are Applegate and Wigley. The only information on the production of larvae from nests of the sea lamprey was reported by Applegate, who counted the larvae from three nests in the Ocqueoc River, a tributary of Lake Huron. The present report presents data on the hatching success of sea lamprey larvae from 19 nests in two small tributaries of southern Lake Superior and indicates greater production per nest than that recorded by Applegate. Studies were conducted by personnel of the U.S. Bureau of Commercial Fisheries on the Little Garlic River, Marquette County, Michigan, and on the Traverse River, Keweenaw County, Michigan.

THE INFLUENCE OF FOREST FRAGMENTATION AND OTHER ENVIRONMENTAL FACTORS ON LAKE SUPERIOR STREAM FISH ASSEMBLAGE

EPA Science Inventory

As part of a comparative watershed project investigating land cover/land use disturbance gradients for streams in the western Lake Superior region, we wanted to determine the relative influence of hydrogeomorphic region, forest fragmentation, watershed storage, and in-stream habi...

THE INFLUENCE OF FOREST FRAGMENTATION AND OTHER ENVIRONMENTAL FACTORS ON LAKE SUPERIOR STREAM FISH ASSEMBLAGES

EPA Science Inventory

As part of a comparative watershed project investigation land cover/land use disturbance gradients for streams in the western Lake Superior region, we wanted to determine the relative influence of hydrogeomorphic region, forest fragmentation, watershed storage and in-stream habit...

Does Terrestrial Carbon Explain Lake Superior Model-Data pCO2 Discrepancy?

NASA Astrophysics Data System (ADS)

Bennington, V.; McKinley, G. A.; Atilla, N.; Kimura, N.; Urban, N.; Wu, C.; Desai, A.

2008-12-01

As part of the CyCLeS project, a three-dimensional hydrodynamic model (MITgcm) was coupled to a medium- complexity ecosystem model and applied to Lake Superior in order to constrain the seasonal cycle of lake pCO2 and air-lake fluxes of CO2. Previous estimates of CO2 emissions from the lake, while very large, were based on field measurements of very limited spatial and temporal extent. The model allows a more realistic extrapolation from the limited data by incorporation of lake-wide circulation and food web dynamics. A large discrepancy (200 uatm) between observations and model-predicted pCO2 during spring suggests a significant input of terrestrial carbon into the lake. The physical model has 10-km horizontal resolution with 29 vertical layers, ten of which are in the top 50 m of the water column. The model is forced by interpolated meteorological data obtained from land-based weather stations, buoys, and other measurements. Modeled surface temperatures compare well to satellite- based surface water temperature images derived from NOAA AVHRR (Advanced Very High Resolution Radiometer), though there are regional patterns of bias that suggest errors in the heat flux forcing. Growth of two classes of phytoplankton is modeled as a function of temperature, light, and nutrients. One grazer preys upon all phytoplankton. The cycles of carbon and phosphorous are explicitly modeled throughout the water column. The model is able to replicate the observed seasonal cycle of lake chlorophyll and the deep chlorophyll maximum. The model is unable to capture the magnitude of observed CO2 super-saturation during spring without considering external carbon inputs to the lake. Simple box model results suggest that the estimated pool of terrestrial carbon in the lake (17 TgC) must remineralize with a timescale of months during spring in order to account for the model/data pCO2 difference. River inputs and enhanced remineralization in spring due to photo-oxidation are other mechanisms

Effectiveness of a refuge for lake trout in western Lake Superior I: Empirical analysis of past performance

USGS Publications Warehouse

Johnson, Melissa J.; Hansen, Michael J.; Seider, Michael J.

2015-01-01

The Gull Island Shoal Refuge was created in 1976 in response to overfishing of the Lake Trout Salvelinus namaycush population in the Apostle Islands region of western Lake Superior. Our objective was to evaluate effectiveness of the refuge by determining whether Lake Trout abundance, growth, maturity, and mortality differed inside and outside the refuge. We compared abundance of wild and stocked fish captured inside and outside the refuge during spring large-mesh gill-net and summer graded-mesh gill-net surveys. We compared growth and mortality during four periods corresponding to four generations of wild Lake Trout, including the last generation that hatched before the refuge was instituted (sampled in 1981–1984) and three generations that were protected by the refuge (sampled in 1985–1992, 1993–2000, and 2001–2010). Maturity of wild fish inside and outside the refuge was compared only for the latter period (2001–2010) because maturity was not assessed earlier. After the refuge was created, wild Lake Trout abundance increased and stocked Lake Trout abundance decreased. Wild adults and juveniles were more abundant inside than outside the refuge, and stocked adults were less abundant inside than outside the refuge. Growth of wild fish did not differ inside versus outside the refuge before 2001, but wild fish grew faster to a shorter asymptotic length inside than outside the refuge during 2001–2010. Wild fish matured at a similar length but an older age inside than outside the refuge during 2001–2010. Survival of wild fish did not differ inside versus outside the refuge before 1993, but mortality was lower inside than outside the refuge during later periods (1993–2000 and 2001–2010). We conclude that the Gull Island Shoal Refuge enhanced the population growth of wild Lake Trout in the Apostle Islands region and should be retained in the future to sustain conditions that favor population growth.

Optically stimulated luminescence dating of late Holocene raised strandplain sequences adjacent to Lakes Michigan and Superior, Upper Peninsula, Michigan, USA

USGS Publications Warehouse

Argyilan, Erin P.; Forman, Steven L.; Johnston, John W.; Wilcox, Douglas A.

2005-01-01

This study evaluates the accuracy of optically stimulated luminescence to date well-preserved strandline sequences at Manistique/Thompson bay (Lake Michigan), and Tahquamenon and Grand Traverse Bays (Lake Superior) that span the past ∼4500 yr. The single aliquot regeneration (SAR) method is applied to produce absolute ages for littoral and eolian sediments. SAR ages are compared against AMS and conventional 14C ages on swale organics. Modern littoral and eolian sediments yield SAR ages 14C ages on swale organics. Significant variability in 14C ages >2000 cal yr B.P. complicates comparison to SAR ages at all sites. However, a SAR age of 4280 ± 390 yr (UIC913) on ridge77 at Tahquamenon Bay is consistent with regional regression from the high lake level of the Nipissing II phase ca. 4500 cal yr B.P. SAR ages indicate a decrease in ridge formation rate after ∼1500 yr ago, likely reflecting separation of Lake Superior from lakes Huron and Michigan. This study shows that SAR is a credible alternative to 14C methods for dating littoral and eolian landforms in Great Lakes and other coastal strandplains where 14C methods prove problematic.

Radiocarbon and stable-isotope geochemistry of organic and inorganic carbon in Lake Superior

NASA Astrophysics Data System (ADS)

Zigah, Prosper K.; Minor, Elizabeth C.; Werne, Josef P.

2012-03-01

We present a lake-wide investigation of Lake Superior carbon and organic matter biogeochemistry using radiocarbon, stable isotope, and carbon concentrations. Dissolved inorganic carbon (DIC) abundance in the lake was 121-122 Tg C, with offshore concentration andδ13C values being laterally homogenous and tightly coupled to the physical and thermal regime and biochemical processes. Offshore Δ14C of DIC (50-65‰) exhibited lateral homogeneity and was more 14C enriched than co-occurring atmospheric CO2 (˜38‰); nearshore Δ14C of DIC (36-38‰) was similar to atmospheric CO2. Dissolved organic carbon (DOC) abundance was 14.2-16.4 Tg C. DOC's concentration and δ13C were homogenous in June (mixed lake), but varied laterally during August (stratification) possibly due to spatial differences in lake productivity. Throughout sampling, DOC had modern radiocarbon values (14-58‰) indicating a semilabile nature with a turnover time of ≤60 years. Lake particulate organic carbon (POC, 0.9-1.3 Tg C) was consistently 13C depleted relative to DOC. The δ15N of epilimnetic particulate organic nitrogen shifted to more negative values during stratification possibly indicating greater use of nitrate (rather than ammonium) by phytoplankton in August. POC's radiocarbon was spatially heterogeneous (Δ14C range: 58‰ to -303‰), and generally 14C depleted relative to DOC and DIC. POC 14C depletion could not be accounted for by black carbon in the lake but, because of its spatial and temporal distribution, is attributed to sediment resuspension. The presence of old POC within the epilimnion of the open lake indicates possible benthic-pelagic coupling in the lake's organic carbon cycle; the ultimate fate of this old POC bears further investigation.

Conservation genetics of Lake Superior brook trout: Issues, questions, and directions

USGS Publications Warehouse

Wilson, C.C.; Stott, W.; Miller, L.; D'Amelio, S.; Jennings, Martin J.; Cooper, A.M.

2008-01-01

Parallel efforts by several genetic research groups have tackled common themes relating to management concerns about and recent rehabilitation opportunities for coaster brook trout Salvelinus fontinalis in Lake Superior. The questions that have been addressed include the evolutionary and genetic status of coaster brook trout, the degree of relatedness among coaster populations and their relationship to riverine tributary brook trout populations, and the role and effectiveness of stocking in maintaining and restoring coasters to Lake Superior. Congruent genetic results indicate that coasters are an ecotype (life history variant) rather than an evolutionarily significant unit or genetically distinct strain. Regional structure exists among brook trout stocks, coasters being produced from local populations. Introgression of hatchery genes into wild populations appears to vary regionally and may relate to local population size, habitat integrity, and anthropogenic pressures. Tracking the genetic diversity and integrity associated with captive breeding programs is helping to ensure that the fish used for stocking are representative of their source populations and appropriate for rehabilitation efforts. Comparative analysis of shared samples among collaborating laboratories is enabling standardization of genotype scoring and interpretation as well as the development of a common toolkit for assessing genetic structure and diversity. Incorporation of genetic data into rehabilitation projects will facilitate monitoring efforts and subsequent adaptive management. Together, these multifaceted efforts provide comprehensive insights into the biology of coaster brook trout and enhance restoration options. ?? Copyright by the American Fisheries Society 2008.

2008 Spawning Cisco Investigations in the Canadian Waters of Lake Superior

USGS Publications Warehouse

Yule, Daniel; Addison, Peter A.; Evrard, Lori M.; Cullis, Ken I.; Cholwek, Gary A.

2009-01-01

The Great Lakes Science Center of the United States Geological Survey (USGS) is working cooperatively with the Ontario Ministry of Natural Resources (OMNR) on a threeyear study to develop standard procedures for acoustic and midwater trawl (AC-MT) assessments of spawning cisco Coregonus artedi that the OMNR can carry forward as a management activity. In year two (2008), we conducted an AC-MT survey of the northern shore from Nipigon Bay to Thunder Bay. Spawning-cisco (> 250 mm total length) densities were lowest near Nipigon Bay (<10/ha), moderate in and around Black Bay (15- 30/ha), and highest in Thunder Bay (118/ha). Rainbow smelt Osmerus mordax densities were highest in Nipigon (2,179/ha) and Black (3,219/ha) bays, and lowest in Thunder Bay (961/ha). We combined our AC-MT survey results with commercial catch records to estimate exploitation fractions of female cisco in Thunder Bay during the 2008 fishery at 4% for ages 1-5, 8.7% for ages 6-12, and 4.4% for ages ≥ 13. Lake Superior fishery managers recently recommended that annual exploitation of adult female lake cisco be kept below 10-15%. Recruitment of cisco since 2003 has been low and there is a strong probability the Thunder Bay stock will decline into the future. Using a simple population dynamics approach we estimated that if the current total allowable catch (TAC) quota is held constant, exploitation fractions could exceed 10% by 2010 and 15% by 2011. Our 2008 collections suggested the survey of Black Bay was likely conducted before all spawners had returned there to spawn. Our data also suggested that cisco collected in Black Bay and east of this site in mid-November may be from the same stock. During November 2009 we will attempt to get better definition of the area occupied by cisco around Black Bay and also determine when surveys should be conducted at this location.

Current and historical concentrations of poly and perfluorinated compounds in sediments of the northern Great Lakes - Superior, Huron, and Michigan.

PubMed

Codling, Garry; Hosseini, Soheil; Corcoran, Margaret B; Bonina, Solidea; Lin, Tian; Li, An; Sturchio, Neil C; Rockne, Karl J; Ji, Kyunghee; Peng, Hui; Giesy, John P

2018-05-01

Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g -1 dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from lakes with concentrations typically increasing with time. Distributions of PFASs within dated cores largely corresponded with increase in use of PFASs, but with physiochemical characteristics also affecting distribution. Perfluoroalkyl sulfonates (PFSAs) with chain lengths >7 that include perfluoro-n-octane sulfonate (PFOS) bind more strongly to sediment, which resulted in more accurate analyses of temporal trends. Shorter-chain PFASs, such as perfluoro-n-butanoic acid which is the primary replacement for C8 PFASs that have been phased out, are more soluble and were identified in some core layers at depths corresponding to pre-production periods. Thus, analyses of temporal trends of these more soluble compounds in cores of sediments were less accurate. Total elemental fluorine (TF) and extractable organic fluorine (EOF) indicated that identified PFASs were not a significant fraction of fluorine containing compounds in sediment (<0.01% in EOF). Copyright © 2018 Elsevier Ltd. All rights reserved.

Challenges to Lake Superior's Condition, Assessment, and Management: A Few Observations Across a Generation of Change

EPA Science Inventory

Selected comparisons of water quality and biological properties in lakewide samplings of 1970s and 2005/2006 provide a simple illustration of significant changes within Lake Superior in the last three decades. Observations of warmed surface layers, increased nitrate and increase...

Nearshore habitat and fish community associations of coaster brook trout in Isle Royale, Lake Superior

USGS Publications Warehouse

Gorman, O.T.; Moore, S.A.; Carlson, A.J.; Quinlan, H.R.

2008-01-01

We characterized the nearshore habitat and fish community composition of approximately 300 km of shoreline within and adjacent to the major embayments of Isle Royale, Lake Superior. Sampling yielded 17 species, of which 12 were widespread and represented a common element of the Lake Superior fish community, including cisco Coregonus artedi, lake whitefish C. clupeaformis, round whitefish Prosopium cylindraceum, lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, lake chub Couesius plumbeus, longnose sucker Catostomus catostomus, white sucker C. commersonii, trout-perch Percopsis omiscomaycus, ninespine stickleback Pungitius pungitius, burbot Lota lota, and slimy sculpin Cottus cognatus. The presence of brook trout S. fontinalis in an embayment was associated with the common species of the Isle Royale nearshore fish community, particularly cisco, longnose sucker, and round whitefish. However, brook trout were present in only five embayments and were common only in Tobin Harbor. Most Isle Royale embayments had broadly overlapping ranges of nearshore habitats. Within embayments, fish were distributed along a habitat gradient from less-protected rocky habitat near the mouth to highly protected habitat with mixed and finer substrates at the head. Embayments with brook trout had greater mean protection from the open lake, greater variation in depth, greater mean cover, and higher mean frequencies of large substrates (cobble, boulder, and bedrock). Within those embayments, brook trout were associated with habitat patches with higher mean frequencies of small substrates (particularly sand and coarse gravel). Within Tobin Harbor, brook trout were associated with midembayment habitat and species assemblages, especially those locations with a mixture of sand, gravel, and cobble substrates, an absence of bedrock, and the presence of round whitefish, white sucker, and trout-perch. Comparison of embayments with the model, Tobin Harbor, showed that six embayments

Age, growth and sex composition of the American smelt Osmerus mordax(Mitchill), of western Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1964-01-01

This study is based on 4,561 smelt collected in Chequamegon Bay, the Apostle Islands, the Brule River, and Superior Harbor, all in western Lake Superior. Commercial production in the Great Lakes (U.S. and Canada combined) reached a peak of nearly 16 million pounds in 1960. Production in Lake Superior has generally been small but increased during the 1950's to reach 948,000 pounds in 1960. All O-group and spring I-group smelt had scales with sufficient sculpturing to permit detection of the first annulus. Annulus formation began after 6 June in 1960. In 1961, all smelt had completed the annulus by 24 August. The body-scale relation is a straight line with an intercept of -0.9 inch on the axis of fish length. The weight of western Lake Superior smelt increased as the 2.952 power of the length. A large range of length in each age group and resulting overlap of age-groups II-VI made length a poor index of age. Female smelt grew faster than males after the second year and dominated strongly in age-groups IV-VII. Both sexes made their best annual growth in length (3.3 inches) during their second year of life; the largest weight increments (0.74 ounce, males; 0.85 ounce, females) came in the third year. Best production from a commercial pound net in 1961 occurred when the sex ratios of spawning smelt were nearest 50:50. Spawning male smelt were consistently shorter than females and the average lengths of both sexes decreased as the spawning season progressed. Shortest mature smelt of each sex were 5.0 to 5.2 inches but the males are probably the first to reach 100 percent maturity. All year-old smelt were immature. Among 2-year-old fish, 40.7 per cent of the males and 17.7 percent of the females had reached maturity. All smelt more than 2 years old were mature. Ovaries of 10 smelt contained an average of 31,338 eggs for fish 7.3 to 8.8 inches long.

75 FR 67950 - Notice of Designation of the Lake Superior National Estuarine Research Reserve in Wisconsin

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-04

... Reserve is available upon request. Federal Domestic Assistance Catalog Number 11.420 (Coastal Zone..., Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric... Lake Superior National Estuarine Research Reserve in Wisconsin pursuant to Section 315 of the Coastal...

Use of classification trees to apportion single echo detections to species: Application to the pelagic fish community of Lake Superior

USGS Publications Warehouse

Yule, Daniel L.; Adams, Jean V.; Hrabik, Thomas R.; Vinson, Mark R.; Woiak, Zebadiah; Ahrenstroff, Tyler D.

2013-01-01

Acoustic methods are used to estimate the density of pelagic fish in large lakes with results of midwater trawling used to assign species composition. Apportionment in lakes having mixed species can be challenging because only a small fraction of the water sampled acoustically is sampled with trawl gear. Here we describe a new method where single echo detections (SEDs) are assigned to species based on classification tree models developed from catch data that separate species based on fish size and the spatial habitats they occupy. During the summer of 2011, we conducted a spatially-balanced lake-wide acoustic and midwater trawl survey of Lake Superior. A total of 51 sites in four bathymetric depth strata (0–30 m, 30–100 m, 100–200 m, and >200 m) were sampled. We developed classification tree models for each stratum and found fish length was the most important variable for separating species. To apply these trees to the acoustic data, we needed to identify a target strength to length (TS-to-L) relationship appropriate for all abundant Lake Superior pelagic species. We tested performance of 7 general (i.e., multi-species) relationships derived from three published studies. The best-performing relationship was identified by comparing predicted and observed catch compositions using a second independent Lake Superior data set. Once identified, the relationship was used to predict lengths of SEDs from the lake-wide survey, and the classification tree models were used to assign each SED to a species. Exotic rainbow smelt (Osmerus mordax) were the most common species at bathymetric depths 100 m (384 million; 6.0 kt). Cisco (Coregonus artedi) were widely distributed over all strata with their population estimated at 182 million (44 kt). The apportionment method we describe should be transferable to other large lakes provided fish are not tightly aggregated, and an appropriate TS-to-L relationship for abundant pelagic fish species can be determined.

Turbidity in extreme western Lake Superior. [contamination of Duluth, Minnesota water intake

NASA Technical Reports Server (NTRS)

Sydor, M.

1975-01-01

Data were obtained from ERTS images for western Lake Superior for 1972-74. Data examination showed that for easterly winds the turbidity originating along the Wisconsin shore and the resuspension areas are transported northward then out along a N.E. path where it disperses, and often, for large storms, contaminates the Duluth water intake. Contaminants such as dredging fines anywhere along these paths would likewise find their way to the intake areas in concentrations comparable to the relative red clay concentration.

National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States

EPA Science Inventory

The National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States presents the results of a second evaluation of the lakes in the United States. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed t...

40 CFR 35.1630 - State lake classification surveys.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false State lake classification surveys. 35... Freshwater Lakes § 35.1630 State lake classification surveys. States that wish to participate in the clean... Federal financial assistance under this subpart until they complete their survey. ...

40 CFR 35.1630 - State lake classification surveys.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 1 2011-07-01 2011-07-01 false State lake classification surveys. 35... Freshwater Lakes § 35.1630 State lake classification surveys. States that wish to participate in the clean... Federal financial assistance under this subpart until they complete their survey. ...

40 CFR 35.1630 - State lake classification surveys.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 1 2013-07-01 2013-07-01 false State lake classification surveys. 35... Freshwater Lakes § 35.1630 State lake classification surveys. States that wish to participate in the clean... Federal financial assistance under this subpart until they complete their survey. ...

40 CFR 35.1630 - State lake classification surveys.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 1 2012-07-01 2012-07-01 false State lake classification surveys. 35... Freshwater Lakes § 35.1630 State lake classification surveys. States that wish to participate in the clean... Federal financial assistance under this subpart until they complete their survey. ...

Status and trends of prey fish populations in Lake Superior, 2008

USGS Publications Warehouse

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Falck, Jill M.; Yule, Daniel

2009-01-01

The Great Lakes Science Center has conducted annual daytime bottom trawl surveys of the Lake Superior nearshore (15-80 m bathymetric depth zone) every spring since 1978 to provide a long-term index of relative abundance and biomass of the fish community. Between May 5 and June 14, 2008, 58 stations were sampled around the perimeter of the lake with 12-m wide bottom trawls. Trawls were deployed cross-contour at median start and end depths of 17 and 55 m, respectively. The lakewide mean relative biomass estimate for the entire fish community was 4.61 kg/ha which was similar to that measured in 2007, 4.81 kg/ha. Dominant species in the catch were lake whitefish, rainbow smelt, longnose sucker and cisco, which represented 49, 18, 11, and 7 % of the total community biomass, respectively. Compared to 2007 levels, lake whitefish and cisco biomass increased 35% and 55%, respectively, while bloater and rainbow smelt biomass declined 69% and 41%, respectively. Increased biomass of lake whitefish and decreased biomass in bloater represent trends observed since 2007; however, reversed trends in biomass were observed for cisco and rainbow smelt. Year-class strength for the 2007 cisco cohort (0.20 fish/ha) was below the long-term (1977-2007) average (73.31 fish/ha), as was year-class strength for the 2007 bloater cohort (0.33 fish/ha) compared to the long-term average (11.11 fish/ha). Smelt year class strength (226.26 fish/ha) continues a trend of increasing strength from a 31-year low of 56.75 fish/ha in 2001 and was above the long-term average of 193.81 fish/ha. The 2008 cisco age structure was dominated by age 5 and older fish, which accounted for 82% of the mean relative density. Wisconsin waters continue to be the most productive (mean total community biomass of 17.09 kg/ha), followed by western Ontario (5.40 kg/ha), eastern Ontario (3.08 kg/ha), Michigan (2.82 kg/ha), and Minnesota (0.89 kg/ha).Densities of small (400 mm) hatchery lake trout continued a pattern of decline

Age and growth of the whitefish in Lake Superior

USGS Publications Warehouse

Dryer, William R.

1963-01-01

The average annual commercial production of whitefish in the U.S. waters of Lake Superior dropped from 2,194,000 pounds in 1879-1908 to 504,000 pounds in 1911-59. The modern production, though far below the earlier, has accounted for more than 10 percent of the total value of the fishery in all but one of the last 20 years. Data are given on growth rate, age and year-class composition, size distribution, and length-weight relation of 1,800 fish collected in 1957-59 at Bayfield, Wis., and Marquette, Whitefish Point, and Dollar Settlement, Mich. Studies of the body-scale relation, sex ratio, and age and size at maturity were limited to fish collected at Bayfield. The age composition and mean age varied widely by port and year of capture. Oldest fish were those of the 1957 Bayfield samples which were dominated by age group VII and averaged 5.5 years old. The youngest were from Whitefish Point in 1959; age-group III was dominant, and the mean age was 3.2 years. The evidence on the strength of year classes was not clear-cut, but it was obvious that fluctuations in stocks of different areas were largely independent. The percentage of legal-size fish (17 inches or longer) in age groups ranged widely; only 8.6 percent of the V group were legal in the 1957 Bayfield collections, whereas 100 percent of fish of the same age were legal in the 1957-59 collections from Whitefish Point. The weight of whitefish in the combined samples increased as the 3.2408 power of the length. The growth rate from the fastest to the slowest growing stocks ranked as follows: Whitefish Point; Dollar Settlement and Marquette (fish from the two ports reversed ranks after 3 years); Bayfield. The major differences in growth in length among the various stocks occurred during the first years of life. Beyond the fifth year the annual increments were nearly the same in all stocks. The whitefish from Whitefish Point, Dollar Settlement, and Marquette are among the fastest growing in the Great Lakes. The

Biotic and abiotic factors related to rainbow smelt recruitment in the Wisconsin waters of Lake Superior, 1978-1997

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

Lake Superior rainbow smelt (Osmerus mordax) recruitment to 12-13 months of age in the Wisconsin waters of Lake Superior varied by a factor of 9.3 during 1978-1997. Management agencies have sought models that accurately predict recruitment, but no satisfactory models had previously been developed. In this study, modeling was conducted to determine which factors best explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data accounted for 63% of the variability in recruitment data. The functional relationship that accounted for the greatest amount of recruitment variation (81%) included rainbow smelt stock size, May rainfall, and bloater (Coregonus hoyi) biomass. Model results were interpreted to mean that recruitment was affected negatively by increased river flows from increased rainfall, and affected positively by the biomass of bloater, and those results were interpreted to mean that bloater mediated the effects of lake trout predation on rainbow smelt recruits. Model results were also interpreted to mean that stock size caused compensatory, density-dependent mortality on rainbow smelt recruits. Correlations observed here may be of value to managers seeking approaches to either enhance or control populations of this species, which is not indigenous to the Great Lakes.

Time trends (1983-1999) for organochlorines and polybrominated diphenyl ethers in rainbow smelt (Osmerus mordax) from Lakes Michigan, Huron and Superior, USA

USGS Publications Warehouse

Chernyak, Sergei M.; Rice, Clifford P.; Quintal, Richard T.; Begnoche, Linda J.; Hickey, James P.; Vinyard, Bryan T.

2005-01-01

The U.S. Geological Service Great Lakes Science Center has archived rainbow smelt (Osmerus mordax) collected from the early 1980s to the present. These fish were collected to provide time- and site-dependent contaminant residue data needed by researchers and managers to fill critical data gaps regarding trends and behavior of persistent organic contaminants in the Great Lakes ecosystem. In the present study, data are presented for concentrations of several organochlorine (OC) contaminants in the archived smelt, including DDT, polychlorinated biphenyls (PCBs), toxaphene, and chlordanes in Lakes Michigan and Huron (MI, USA) and in Lake Superior (MN, USA). The trends for all the OCs were declining as a first-order decay over the sampled time series (1983/1985–1993/1999) with the exception of toxaphene in Lake Superior and PCBs at the Charlevoix/Little Traverse Bay site in Lake Michigan. Concentration of the emerging contaminant, polybrominated diphenyl ethers (PBDEs), also was traced from its apparent entry into this ecosystem in approximately 1980 until 1999. Time trends for the PBDEs were increasing exponentially at all sites, with concentration-doubling times varying from 1.58 to 2.94 years.

Evaluating the importance of abiotic and biotic drivers on Bythotrephes biomass in Lakes Superior and Michigan

USGS Publications Warehouse

Keeler, Kevin M.; Bunnell, David B.; Diana, James S.; Adams, Jean V.; Mychek-Londer, Justin G.; Warner, David M.; Yule, Daniel; Vinson, Mark

2015-01-01

The ability of planktivorous fishes to exert top-down control on Bythotrephes potentially has far-reaching impacts on aquatic food-webs, given previously described effects of Bythotrephes on zooplankton communities. We estimated consumption of Bythotrephes by planktivorous and benthivorous fishes, using bioenergetics and daily ration models at nearshore (18 m), intermediate (46 m), and offshore (110 m) depths along one western Lake Superior transect (April, and September-November) and two northern Lake Michigan transects (April, July, September). In Lake Superior, consumption (primarily by cisco Coregonus artedi) exceeded Bythotrephes production at all offshore sites in September-November (up to 396% of production consumed) and at the intermediate site in November (842%) with no evidence of consumption nearshore. By comparing Bythotrephes biomass following months of excessive consumption, we conservatively concluded that top-down control was evident only at the offshore site during September-October. In Lake Michigan, consumption by fishes (primarily alewife Alosa pseudoharengus) exceeded production at nearshore sites (up to 178%), but not in deeper sites (< 15%). Evidence for top-down control in the nearshore was not supported, however, as Bythotrephes never subsequently declined. Using generalized additive models, temperature, and not fish consumption, not zooplankton prey density, best explained variability in Bythotrephes biomass. The non-linear pattern revealed Bythotrephes to increase with temperature up to 16 °C, and then decline between 16 and 23 °C. We discuss how temperature likely has direct negative impacts on Bythotrephes when temperatures near 23 °C, but speculate that predation also contributes to declining biomass when temperatures exceed 16 °C.

Lake Superior Zooplankton Biomass Predictions from LOPC Tow Surveys Compare Well with a Probability Based Net Survey

EPA Science Inventory

We conducted a probability-based sampling of Lake Superior in 2006 and compared the zooplankton biomass estimate with laser optical plankton counter (LOPC) predictions. The net survey consisted of 52 sites stratified across three depth zones (0-30, 30-150, >150 m). The LOPC tow...

Seasonally dynamic diel vertical migrations of Mysis diluviana, coregonine fishes, and siscowet lake trout in the pelagia of western Lake Superior

USGS Publications Warehouse

Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Stockwell, Jason D.; Yule, Daniel L.; Sass, Greg G.

2011-01-01

Diel vertical migrations are common among many aquatic species and are often associated with changing light levels. The underlying mechanisms are generally attributed to optimizing foraging efficiency or growth rates and avoiding predation risk (μ). The objectives of this study were to (1) assess seasonal and interannual changes in vertical migration patterns of three trophic levels in the Lake Superior pelagic food web and (2) examine the mechanisms underlying the observed variability by using models of foraging, growth, and μ. Our results suggest that the opossum shrimp Mysis diluviana, kiyi Coregonus kiyi, and siscowet lake trout Salvelinus namaycush migrate concurrently during each season, but spring migrations are less extensive than summer and fall migrations. In comparison with M. diluviana, kiyis, and siscowets, the migrations by ciscoes C. artedi were not as deep in the water column during the day, regardless of season. Foraging potential and μ probably drive the movement patterns of M. diluviana, while our modeling results indicate that movements by kiyis and ciscoes are related to foraging opportunity and growth potential and receive a lesser influence from μ. The siscowet is an abundant apex predator in the pelagia of Lake Superior and probably undertakes vertical migrations in the water column to optimize foraging efficiency and growth. The concurrent vertical movement patterns of most species are likely to facilitate nutrient transport in this exceedingly oligotrophic ecosystem, and they demonstrate strong linkages between predators and prey. Fishery management strategies should use an ecosystem approach and should consider how altering the densities of long-lived top predators produces cascading effects on the nutrient cycling and energy flow in lower trophic levels.

ELEMENTAL MERCURY IN COPPER, SILVER, AND GOLD ORES: AN UNEXPECTED CONTRIBUTION TO LAKE SUPERIOR SEDIMENTS WITH GLOBAL IMPLICATIONS

EPA Science Inventory

Mercury and copper inventories are low in central Lake Superior and increase markedly towards the Keweenaw Peninsula...where copper, mercury, and silver inventories are elevated and highly correlated. High copper, silver, and mercury inventories can be traced back to shoreline st...

REGIONAL, WATERSHED, AND SITE-SPECIFIC ENVIRONMENTAL INFLUENCES ON FISH ASSEMBLAGE STRUCTURE AND FUNCTION IN WESTERN LAKE SUPERIOR TRIBUTARIES

EPA Science Inventory

The relative importance of regional, watershed, and in-stream environmental factors on stream fish assemblage structure and function was investigated as part of a comparative watershed project in the western Lake Superior basin. We selected 48 second and third order watersheds fr...

The People's Lake

ERIC Educational Resources Information Center

Carlson, Karen Townsend

1975-01-01

Citizen action to stop the disposal of taconite tailings into Lake Superior was unsuccessful when the courts settled in the favor of industry. Although citizen research revealed a form of asbestos, as well as other toxic chemicals in the discharged wastes, company representatives stated that there were no health hazards. (MA)

The Great Lakes of the United States, National Security and the Budget

DTIC Science & Technology

2005-02-14

ship transport. Taconite pellets are shipped to the Duluth-Superior harbor from mines located in the upper peninsula of Michigan, Minnesota ...example, the Port of Duluth-Superior located on the far northwestern portion of Lake Superior is a major hub for cross loading taconite pellets from rail to...northwest Ontario and northern Ontario. Therefore mining activities take place on both USA and Canadian shores and have a commensurate international

Examining indirect effects of lake trout recovery

EPA Science Inventory

With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths < 60 m, and siscowet lake trout occupied depths > 60 m...

75 FR 35294 - Safety Zone; Marquette 4th of July Fireworks, Marquette Harbor, Lake Superior, Marquette, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-22

...-AA00 Safety Zone; Marquette 4th of July Fireworks, Marquette Harbor, Lake Superior, Marquette, MI... vessels from a portion of Marquette Harbor during the Marquette 4th of July Fireworks display. This... vessels during the setup and launching of fireworks in conjunction with the Marquette 4th of July...

Concentrations, Trends, and Air-Water Exchange of PAHs and PBDEs Derived from Passive Samplers in Lake Superior in 2011.

PubMed

Ruge, Zoe; Muir, Derek; Helm, Paul; Lohmann, Rainer

2015-12-01

Polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenylethers (PBDEs) are both currently released into the environment from anthropogenic activity. Both are hence primarily associated with populated or industrial areas, although wildfires can be an important source of PAHs, as well. Polyethylene passive samplers (PEs) were simultaneously deployed in surface water and near surface atmosphere to determine spatial trends and air-water gaseous exchange of 21 PAHs and 11 PBDEs at 19 sites across Lake Superior in 2011. Surface water and atmospheric PAH concentrations were greatest at urban sites (up to 65 ng L(-1) and 140 ng m(-3), respectively, averaged from June to October). Near populated regions, PAHs displayed net air-to-water deposition, but were near equilibrium off-shore. Retene, probably depositing following major wildfires in the region, dominated dissolved PAH concentrations at most Lake Superior sites. Atmospheric and dissolved PBDEs were greatest near urban and populated sites (up to 6.8 pg L(-1) and 15 pg m(-3), respectively, averaged from June to October), dominated by BDE-47. At most coastal sites, there was net gaseous deposition of BDE-47, with less brominated congeners contributing to Sault Ste. Marie and eastern open lake fluxes. Conversely, the central open lake and Eagle Harbor sites generally displayed volatilization of PBDEs into the atmosphere, mainly BDE-47.

75 FR 38721 - Safety Zone; Munising 4th of July Fireworks, South Bay, Lake Superior, Munising, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

...-AA00 Safety Zone; Munising 4th of July Fireworks, South Bay, Lake Superior, Munising, MI AGENCY: Coast... portion of South Bay during the Munising 4th of July Fireworks display, July 4, 2010. This temporary... from hazards associated with the Munising 4th of July Fireworks display. Based on the explosive hazards...

A study of Minnesota forests and lakes using data from Earth Resources Technology Satellites

NASA Technical Reports Server (NTRS)

1974-01-01

Highlights of research and practical benefits are discussed for the following projects which utilized ERTS 1 data to provide municipal, state, federal, and industrial users with environmental resource information for the state of Minnesota: (1) forest disease detection and control; (2) evaluation of water quality by remote sensing techniques; (3) forest vegetation classification and management; (4) detection of saline soils in the Red River Valley; (5) snowmelt flood prediction; (6) remote sensing applications to hydrology; (7) Rice Creek watershed project; (8) water quality in Lake Superior and the Duluth Superior Harbor; and (9) determination of Lake Superior currents from turbidity patterns.

A 200-year perspective on alternative stable state theory and lake management from a biomanipulated shallow lake.

PubMed

Hobbs, William O; Hobbs, Joy M Ramstack; LaFrançois, Toben; Zimmer, Kyle D; Theissen, Kevin M; Edlund, Mark B; Michelutti, Neal; Butler, Malcolm G; Hanson, Mark A; Carlson, Thomas J

2012-07-01

Multiple stressors to a shallow lake ecosystem have the ability to control the relative stability of alternative states (clear, macrophyte-dominated or turbid, algal-dominated). As a consequence, the use of remedial biomanipulations to induce trophic cascades and shift a turbid lake to a clear state is often only a temporary solution. Here we show the instability of short-term manipulations in the shallow Lake Christina (Minnesota, USA) is governed by the long-term state following a regime shift in the lake. During the modern, managed period of the lake, three top-down manipulations (fish kills) were undertaken inducing temporary (5-10 years) unstable clear-water states. Paleoecological remains of diatoms, along with proxies of primary production (total chlorophyll a and total organic carbon accumulation rate) and trophic state (total P) from sediment records clearly show a single regime shift in the lake during the early 1950s; following this shift, the functioning of the lake ecosystem is dominated by a persistent turbid state. We find that multiple stressors contributed to the regime shift. First, the lake began to eutrophy (from agricultural land use and/or increased waterfowl populations), leading to a dramatic increase in primary production. Soon after, the construction of a dam in 1936 effectively doubled the depth of the lake, compounded by increases in regional humidity; this resulted in an increase in planktivorous and benthivorous fish reducing phytoplankton grazers. These factors further conspired to increase the stability of a turbid regime during the modern managed period, such that switches to a clear-water state were inherently unstable and the lake consistently returned to a turbid state. We conclude that while top-down manipulations have had measurable impacts on the lake state, they have not been effective in providing a return to an ecosystem similar to the stable historical period. Our work offers an example of a well-studied ecosystem forced

Lake States regional forest resources assessment: technical papers.

Treesearch

Henry H. Webster; J. Michael Vasievich

1997-01-01

Contains 21 technical working papers prepared for the Lake States regional forest resources assessment, Lake States Forestry Alliance 1995. They represent significant contributions from many individuals and organizations and form the technical background for the assessment.

Simulating timber management in Lake States forests.

Treesearch

Gary J. Brand

1981-01-01

Describes in detail a management subsystem to simulate cutting in Lake States forest types. This subsystem is part of a Stand and Tree Evaluation and Modeling System (STEMS) contained in the Forest Resource Evaluation Program (FREP) for the Lake States. The management subsystem can be used to test the effect of alternate management strategies.

Abundance indices for determining the status of lake trout restoration in Michigan waters of Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Schorfhaar, Richard G.; Peck, James W.; Selgeby, James H.; Taylor, William W.

1995-01-01

Self-sustaining populations of lake trout Salvelinus namaycush have returned to most areas in Lake Superior, but progress toward achieving historic commercial yields has been difficult to measure because of unrecorded losses to predation by sea lamprey Petromyzon marinus and to fisheries. Consequently, we developed restoration targets (catch per effort, CPE; geometric mean number per kilometer of 114-mm stretch-meaure gill net during 1929-1943, when historic yields were sustained) from linear relationships between CPE in commercial and assessment fisheries in Michigan. Target CPEs for lake trout restoration were higher and less variable than the modern CPEs in all areas. Modern CPEs generally increased during the 1970s and early 1980s but declined during the late 1980s and early 1990s. Modern CPEs were highest in western Michigan from the Keweenaw Peninsula to Marquette (71 to 81% of target CPEs), but coefficients of variation (CV,SD/mean) of mean CPEs were 1.4 to 2.4 times greater than target CVs. Around Munising, the modern CPE was lower (41% of the target CPE), whereas the CV was 1.9 times greater than the target CV. Around Grand Marais, the modern CPE was lowest among all areas (17% of the target CPE), but the CV was nearly the same (1.1 times the target CV). In Whitefish Bay, the modern CPE was only 28% of the target CPE and the CV was 9.0 times greater, though the modern period was based on only the years 1979-1982 and 1984-1985. Further progress in restoration in most areas can be achieved only if fishery managers adequately protect existing stocks of wild fish from sea lamprey predation and fishery exploitation.

ROSGREN STREAM TYPES AS A TOOL FOR PREDICTING BEDLOAD AND SUSPENDED SEDIMENT EXPORT IN LOW-ORDER LAKE SUPERIOR WATERSHEDS

EPA Science Inventory

Bedload samples were collected from 48 second and third order Lake Superior tributaries during snowmelt in 1998 and 1999. Suspended sediment samples were collected over a three-year period during baseflow, rain events, and snowmelt. This work was part of a comparative watershed...

The spatial variability of coastal surface water temperature during upwelling. [in Lake Superior

NASA Technical Reports Server (NTRS)

Scarpace, F. L.; Green, T., III

1979-01-01

Thermal scanner imagery acquired during a field experiment designed to study an upwelling event in Lake Superior is investigated. Temperature data were measured by the thermal scanner, with a spatial resolution of 7 m. These data were correlated with temperatures measured from boats. One- and two-dimensional Fourier transforms of the data were calculated and temperature variances as a function of wavenumber were plotted. A k-to-the-minus-three dependence of the temperature variance on wavenumber was found in the wavenumber range of 1-25/km. At wavenumbers greater than 25/km, a k-to-the-minus-five-thirds dependence was found.

THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION SCHEMES

EPA Science Inventory

Main and interactive effects of watershed storage and forest fragmentation on watershed exports, habitat quality, community composition and food-web relationships were compared within and acoss two hydrogeomorphic regions (HGM, North Shore Highlands and Lake Superior clay plains/...

Establishment Patterns of Non-native Fishes: Lessons from the Duluth-Superior Harbor and Lower St. Louis River, an Invasion-prone Great Lakes Freshwater Estuary

EPA Science Inventory

The St. Louis River freshwater estuary which drains into western Lake Superior and includes the Duluth-Superior (MN-WI) harbor, has a long history of non-native fish introductions. From 1985 to 2002, seven new fishes were identified in the estuary, an unprecedented rate of non-n...

Habitat use by fishes of Lake Superior. II. Consequences of diel habitat use for habitat linkages and habitat coupling in nearshore and offshore waters

USGS Publications Warehouse

Gorman, Owen T.; Yule, Daniel L.; Stockwell, Jason D.

2012-01-01

Diel migration patterns of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of Lake Superior were examined to assess the potential for diel migration to link benthic and pelagic, and nearshore and offshore habitats. In our companion article, we described three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no diel migration. DVM was expressed by fishes migrating from benthopelagic to pelagic positions and DBM was expressed by fishes migrating horizontally from deep to shallow waters at night. Fishes not exhibiting diel migration typically showed increased activity by moving from benthic to benthopelagic positions within demersal habitat. The distribution and biomass of fishes in Lake Superior was characterized by examining 704 bottom trawl samples collected between 2001 and 2008 from four depth zones: ≤40, 41–80, 81–160, and >160 m. Diel migration behaviors of fishes described in our companion article were applied to estimates of areal biomass (kg ha−1) for each species by depth zone. The relative strength of diel migrations were assessed by applying lake area to areal biomass estimates for each species by depth zone to yield estimates of lake-wide biomass (metric tonnes). Overall, species expressing DVM accounted for 83%, DBM 6%, and non-migration 11% of the total lake-wide community biomass. In nearshore waters, species expressing DVM represented 74% of the biomass, DBM 25%, and non-migration 1%. In offshore waters, species expressing DVM represented 85%, DBM 1%, and non-migration 14% of the biomass. Of species expressing DVM, 83% of total biomass occurred in offshore waters. Similarly, 97% of biomass of non-migrators occurred in offshore waters while 83% of biomass of species expressing DBM occurred in nearshore waters. A high correlation (R2 = 0.996) between lake area and community biomass by depth zone resulted in 81% of the lake-wide biomass occurring in offshore waters. Accentuating this

Spatial and Ontogenetic Variation in Mercury in Lake Superior Basin Sea Lamprey (Petromyzon marinus).

PubMed

Moses, Sara K; Polkinghorne, Christine N; Mattes, William P; Beesley, Kimberly M

2018-01-01

Mercury concentrations were measured in eggs, larvae, and adult spawning-phase sea lampreys (Petromyzon marinus) collected in tributaries of Lake Superior to investigate spatial and ontogenetic variation. There were significant differences in mercury concentrations between all three life stages, with levels highest in adults (mean = 3.01 µg/g), followed by eggs (mean = 0.942 µg/g), and lowest in larvae (mean = 0.455 µg/g). There were no significant differences in mercury concentrations by location for any life stage or by sex in adults. Mercury was not correlated with adult or larval lamprey length or mass. Mercury levels in adult lampreys exceeded U.S. and Canadian federal guidelines for human consumption. Mercury concentrations in all life stages exceeded criteria for the protection of piscivorous wildlife, posing a threat to local fish, birds, and mammals. High mercury levels in adult lampreys combined with their semelparous life history make them a potential source of lake-derived mercury to spawning streams.

40 CFR 35.1620-5 - State work programs and lake priority lists.

Code of Federal Regulations, 2010 CFR

2010-07-01

... lakes according to trophic condition (§ 35.1630) and to set priorities for implementing clean lakes... 40 Protection of Environment 1 2010-07-01 2010-07-01 false State work programs and lake priority... Publicly Owned Freshwater Lakes § 35.1620-5 State work programs and lake priority lists. (a)(1) A State...

Proceedings of the fourth Lake States forest tree improvement conference

Treesearch

Lake States Forest Experiment Station

1960-01-01

The Lake States Forest Experiment Station is glad to facilitate the work of the Lake States Forest Tree Improvement Committee in encouraging and coordinating forest genetics activities in this region. We are happy, therefore, to publish this Proceedings of the Fourth Lake States Forest Tree Improvement Conference, as we did for the preceding three conferences in 1953,...

Proceedings of the fifth Lake States forest tree improvement conference

Treesearch

Lake States Forest Experiment Station

1962-01-01

The Lake States Forest Experiment Station has given active support to the Lake States Forest Tree Improvement Committee since the Committee's inception in 1953. In the interests of encouraging and coordinating forest genetics activities in this region, we are happy to publish this Proceedings of the Fifth Lake States Forest Tree Improvement Conference, as we did...

Lake fisheries need lamprey control and research

USGS Publications Warehouse

Moffett, James W.

1953-01-01

Since 1921, when the first sea lamprey was recorded from Lake Erie, concern about this parasite in the Great Lakes above Niagara Falls, where previously it had never occurred, grew successively. At first, the concern was shared only in scientific circles, but as the parasite continued its persistent and rapid spread throughout the upper Great Lakes this concern was voiced by state conservation departments, the U.S. Fish and Wildlife Service, and interested fishermen. Catches of lake trout especially, and other species secondarily, began to fall below anything representing normal fluctuations in abundance. The fishing industry on Lake Huron and Lake Michigan became extremely concerned due to the fact that income was diminishing greatly. Producers on Lake Superior were fearful that the same decline in production would soon characterize their fishery.

Status and trends in the Lake Superior fish community, 2015

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel L.

2016-01-01

In 2015, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 33 offshore stations. Spring and summer water temperatures in 2015 were colder than average, but warmer than that observed in 2014. In the nearshore zone, a total of 11,882 individuals from 22 species or morphotypes were collected. Nearshore lakewide mean biomass was 1.8 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 12,433 individuals from 8 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 5.9 kg/ha. The mean of the four previous years was 7.1 kg/ha. The abundance of age-1 Cisco was 14.3 fish/ha which was similar to that measured in 2009. We collected larval Coregonus in surface trawls at 94 locations and estimated a nearshore lakewide average density of 1,459 fish/ha which was nearly twice that measured in 2014.

Status and trends in the Lake Superior fish community, 2014

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2015-01-01

In 2014, the Lake Superior fish community was sampled with daytime bottom trawls at 73 nearshore and 30 offshore stations. Spring and summer water temperatures were the coldest measured for the period of records for the surveys. In the nearshore zone, a total of 15,372 individuals from 28 species or morphotypes were collected. Nearshore lakewide mean biomass was 6.9 kg/ha, which was higher than that observed in the past few years, but below the long-term average of 9.2 kg/ha. In the offshore zone, a total 12,462 individuals from 11 species were collected lakewide. Offshore lakewide mean biomass was 6.6 kg/ha. The mean of the three previous years was 8.6 kg/ha. We collected larval Coregonus in surface trawls at 94 locations and estimated a lakewide average density of 577 fish/ha with a total lakewide population estimate of 14.2 billion (standard error + 30 million).

Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

USGS Publications Warehouse

Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

2009-01-01

Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (<250 mm total length) and large fish to expected trawl catches based on acoustic densities in the trawl path. We found the relationship between observed and expected catches approached unity over a wide range of densities, suggesting that our acoustic method provided reasonable estimates of fish density, and that midwater trawling methods were free of species- and size-selectivity issues. Rainbow smelt Osmerus mordax was by number the most common species captured in the nearshore (<80 m bathymetric depth) stratum during all three surveys, while kiyi Coregonus kiyi was predominant offshore except during November. Total biomass estimates of rainbow smelt in the western arm were similar during all three surveys, while total biomass of kiyi was similar between summer and October, but was lower in November. Total biomass of large cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance

Relationships between bald eagle productivity and dynamics of fish populations and fisheries in the Wisconsin waters of Lake Superior, 1983-1999

USGS Publications Warehouse

Hoff, Michael H.; Meyer, Michael W.; Van Stappen, Julie; Fratt, Thomas W.

2004-01-01

Bald eagle (Haliaeetus leucocephalus) abundance declined in the 1950s and 1960s along the Wisconsin waters of Lake Superior, and were nearly absent along Wisconsin's Lake Superior shoreline. The population began to increase again between 1980 and 1983, and since then bald eagles nesting on islands along Wisconsin's Lake Superior shoreline (i.e., Apostle Islands) reproduced at a lower rate than have those nesting along the mainland shoreline of the lake and inland. Recent research indicated that bioaccumulation of toxic chemicals in the aquatic food chain no longer limits bald eagle reproduction there, and that productivity at island nests was lower than at mainland nests and inland nests as the result of low food availability. Management agencies have sought models that accurately predict productivity and explain ecological relationships, but no satisfactory models had previously been developed. Modeling was conducted here to determine which factors best explained productivity variability. The Ricker stock-recruitment model derived from only the bivariate breeding pair and productivity data explained only 1% of the variability in productivity data. The functional relationship that explained the greatest amount of productivity variation (83%) included the number of breeding pairs, burbot (Lota lota) biomass, longnose sucker (Catostomus catostomus) biomass, and commercial harvest of nontarget fishes. Model results were interpreted to mean that productivity was positively affected by populations of burbot and longnose sucker, which are important prey items, and by commercial fishermen feeding nontarget fish to bald eagles. Harvest of nontarget fishes by tribal fishermen and burbot and longnose sucker populations have not tended to change during the entire study period, although the burbot population has declined since 1991. Therefore, bald eagle productivity is not predicted to increase unless burbot, longnose sucker, or other preferred prey of bald eagles increases

Rural-urban differences in cancer care: results from the Lake Superior Rural Cancer Care Project.

PubMed

Elliott, Thomas E; Elliott, Barbara A; Renier, Colleen M; Haller, Irina V

2004-09-01

Past studies have shown significant differences between rural and urban cancer patients in many measures of cancer care. There is little recent information about this disparity, which generally has shown disadvantages in rural populations. This study reports the rural and urban differences in cancer care using data from the Lake Superior Rural Cancer Care Project. The study used a prospective, population-based design that included all incident cases of breast, colorectal, lung, and prostate cancers diagnosed in northeastern Minnesota, northwestern Wisconsin, and the western portion of Michigan's Upper Peninsula from 1992 to 1997. The outcome measures were 9 endpoints that represented state-of-the-art cancer care during the study. Rural cancer patients as compared with their urban counterparts were disadvantaged in proportion staged, stage at diagnosis, initial management procedures, post-treatment surveillance testing, and participation in cancer clinical trials. These findings are similar to previously published studies. Further research is needed to determine more clearly the barriers in rural cancer care and to find more effective strategies.

Proceedings: third lake states forest tree improvement conference

Treesearch

Forest Service U.S.

1958-01-01

The Third Lake States Forest Tree Improvement Conference culminated the activities of the Lake States Forest Tree Improvement Committee and offered an opportmity to report on committee work for the past biennium. It also provided an important means for the Committee to meet its major objective - the encouraging and coordinating of forest tree improvement activities in...

An investigation of size-fractionated organic matter from Lake Superior and a tributary stream using radiocarbon, stable isotopes and NMR

NASA Astrophysics Data System (ADS)

Zigah, Prosper K.; Minor, Elizabeth C.; Abdulla, Hussain A. N.; Werne, Josef P.; Hatcher, Patrick G.

2014-02-01

This study investigated the concentration and isotopic composition of different size fractions of organic matter (OM) in Lake Superior and in one of its many tributary streams and rivers (Amity Creek, Duluth, Minnesota, USA). Structural compositional drivers of the Δ14C of high molecular weight (HMW, >1 kDa) dissolved organic carbon (DOC) in the lake were also evaluated. Low molecular weight (LMW, <1 kDa) DOC was the fraction containing the largest proportion (68-88%) of organic carbon (OC) in the lake. Particulate organic carbon (POC, >0.7 μm) was generally 13C-depleted (-29 ± 1.2‰) relative to “bulk” (<0.7 μm) DOC (-26.4 ± 0.7‰), “init” (<0.2 μm) DOC (-26.6 ± 0.8‰), HMW DOC (-26.9 ± 0.3‰) and LMW DOC (-26.5 ± 0.9‰), and had more variable 14C content (Δ14C of -94‰ to 53‰; 735 years BP to modern) than the other size fractions. Init DOC (Δ14C of 17-59‰), HMW DOC (Δ14C of 23-64‰) and LMW DOC (Δ14C of 16-62‰) all reflected contemporary (modern) radiocarbon signatures. Bulk DOC (Δ14C of -19‰ to 57‰; 90 years BP to modern) had modern radiocarbon values in the offshore sites (Δ14C of 2-57‰) with pre-aged samples (Δ14C of -8‰ to -19‰) seen at the nearshore site. HMW DOM was relatively N-poor (C:N of 12-19) compared to particulate organic matter (POM, C:N of 8-10) revealing either a more diagenetically altered state or contrasting sources. 13C NMR data showed that biochemical composition of HMW DOC in Lake Superior was dominated by carbohydrates (53-65%) with only trace aromatic components (2-4%). Structurally complex components such as heteropolysaccharides (HPS), amide/peptides and amino sugars (AMS) constitute 75-84% of HMW DOC whereas carboxylic-rich alicyclic molecules (CRAM) made up 16-25% of HMW DOC in the lake. Combined HPS and AMS, O-alkyl carbohydrate carbon, and total carbohydrate carbon contents were significantly positively correlated to the Δ14C of HMW DOC suggesting they contribute a contemporary 14C

Patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes

USGS Publications Warehouse

Miller, Michael A.; Madenjian, Charles P.; Masnado, Robert G.

1992-01-01

To investigate spatial and temporal patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes, we examined laboratory contaminant analysis data of muscle tissue samples from Lake Michigan (n=317) and Lake Superior (n=53) fish. Concentrations of polychlorinated biphenyls (PCBs), chlordane, and dieldrin, reported as mg/kg wet weight in 620 mm to 640 mm mean length Lake Michigan lake trout, decreased over time. Mean total PCB concentration declined exponentially from 9.7 in 1975 to 1.9 in 1990. Total chlordane concentration declined 63 percent from 0.48 in 1983 to 0.18 in 1990, and dieldrin declined 52 percent during this same period, from 0.21 to 0.10. The bioaccumulation rate of PCBs is significantly lower for lake trout inhabiting Lake Michigan's midlake reef complex, compared to lake trout from the nearshore waters of western Lake Michigan. Organochlorine compound concentrations were greater in Lake Michigan lake trout than Lake Superior fish. Lake Superior lean lake trout and siscowet exhibited similar rates of PCB bioaccumulation despite major differneces in muscle tissue lipid content between the two subspecies. The lack of a significant difference in the PCB bioaccumulation rates of lean trout and siscowet suggests that lipid content may not be an important factor influencing PCB bioaccumulation in lake trout, within the range of lipid concentrations observed. Relative concentrations of the various organochlorine contaminants found in lake trout were highly correlated, suggesting similar mass balance processes for these compounds. Evidence presented revealing spatial and temporal patterns of organochlorine contamination may be of value in reestablishing self-sustaining populations of lake trout in Lake Michigan.

Glacial Lake Lind, Wisconsin and Minnesota

USGS Publications Warehouse

Johnson, M.D.; Addis, K.L.; Ferber, L.R.; Hemstad, C.B.; Meyer, G.N.; Komai, L.T.

1999-01-01

Glacial Lake Lind developed in the pre-late Wisconsinan St. Croix River valley, Minnesota and Wisconsin, and lasted more than 1000 yr during the retreat of the Superior lobe at the end of the Wisconsinan glaciation. Lake Lind sediment consists primarily of red varved silt and clay, but also includes mud-flow deposits, nearshore silt (penecontemporaneously deformed in places), nearshore rippled sand, and deltaic sand. Lake Lind varved red clay is not part of glacial Lake Grantsburg, as suggested by earlier authors, because the red varves are separated from overlying glacial Lake Grantsburg silt and clay by a unit of deltaic and fluvial sand. Furthermore, varve correlations indicate that the base of the red varves is younger to the north, showing that the basin expanded as the Superior lobe retreated and was not a lake basin dammed to the southwest by the advancing Grantsburg sublobe. Varve correlations indicate that the Superior lobe retreated at a rate of about 200 m/yr. Uniform winter-clay thickness throughout most of the varve couplets suggests thermal stratification in the lake with clay trapped in the epilimnion; some clay would exit the lake at the outlet prior to winter freeze. Zones of thicker winter-clay layers, in places associated with mud-flow layers, indicate outlet incision, lake-level fall, and shoreline erosion and resuspension of lake clay. The most likely outlet for glacial Lake Lind was in the southwest part of the lake near the present site of Minneapolis, Minnesota. Nearshore sediment indicates that the lake level of glacial Lake Lind was around 280 m. The elevation of the base of the Lake Lind sediments indicates water depth was 20 to 55 m. Evidence in the southern part of the lake basin suggests that the Superior lobe readvanced at least once during the early stages of glacial Lake Lind. Lake Lind ended not by drainage but by being filled in by prograding deltas and outwash plains composed of sand derived from the retreating Superior lobe. It

Lake Superior as seen from Skylab

NASA Image and Video Library

1974-01-06

SL4-139-3953 (7 Jan. 1974) --- An oblique view of a portion of the Middle West looking northeastward toward Lake Superior and Ontario, Canada, as seen from the Skylab space station in Earth orbit. This picture was taken by one of the Skylab 4 crewmen with a hand-held 70mm Hasselblad camera using a 100mm lens. Most of the land mass in the foreground is Wisconsin. Iowa is in the lower left corner. Minnesota is at left and upper left. Ontario is in the far right background. Michigan is at right center. Note the circular-shaped feature at center left which was first observed by the Skylab 4 crewmen. The feature is 85 kilometers (55 miles) in diameter, and it is centered near 91.5 degrees west longitude and 44.5 degrees north latitude. The Mississippi River Valley forms the southwest side of the circular feature. The City of La Crosse, Wisconsin, is just south of the near side of the circle, and the Black River completes the southern and eastern part. The City of Eau Claire is at the north edge of the circle. The most likely origin of circular features of this magnitude are (1) volcanic, (2) structural, or (3) meteorite impact. The feature is not volcanic -- the rocks are the wrong type. Possibly it is structural, formed by slight warping of layered rocks into a basin or dome, followed by erosion of all but the most subtle trace of the structure. The feature could be a severely eroded meteorite impact crater. If so, a thorough study of the area may yield evidence of the extreme pressure and temperature the rocks were subjected to by the shock of an impacting meteorite. Photo credit: NASA

Males exceed females in PCB concentrations of cisco (Coregonus artedi) from Lake Superior

USGS Publications Warehouse

Madenjian, Charles P.; Yule, Daniel L.; Chernyak, Sergei M.; Begnoche, Linda J.; Berglund, Eric K.; Isaac, Edmund J.

2014-01-01

We determined whole-fish polychlorinated biphenyl (PCB) concentrations of 25 male and 25 female age-7 ciscoes (Coregonus artedi) captured from a spawning aggregation in Thunder Bay, Lake Superior, during November 2010. We also determined PCB concentrations in the ovaries and somatic tissue of five additional female ciscoes (ages 5–22). All 55 of these ciscoes were in ripe or nearly ripe condition. Bioenergetics modeling was used to determine the contribution of the growth dilution effect toward a difference in PCB concentrations between the sexes, as females grew substantially faster than males. Results showed that the PCB concentration of males (mean = 141 ng/g) was 43% greater than that of females (mean = 98 ng/g), and this difference was highly significant (P < 0.0001). Mean PCB concentrations in the ovaries and the somatic tissue of the five females were 135 and 100 ng/g, respectively. Based on these PCB determinations for the ovaries and somatic tissue, we concluded that release of eggs by females at previous spawnings was not a contributing factor to the observed difference in PCB concentrations between the sexes. Bioenergetics modeling results indicated that the growth dilution effect could explain males being higher than females in PCB concentration by only 3–7%. We concluded that the higher PCB concentration in males was most likely due to higher rate of energy expenditure, originating from greater activity and a higher resting metabolic rate. Mean PCB concentration in the cisco eggs was well below the U. S. Food and Drug Administration and Ontario Ministry of Environment guidelines of 2000 and 844 ng/g, respectively, and this finding may have implications for the cisco roe fishery currently operating in Lake Superior.

Males exceed females in PCB concentrations of cisco (Coregonus artedi) from Lake Superior.

PubMed

Madenjian, Charles P; Yule, Daniel L; Chernyak, Sergei M; Begnoche, Linda J; Berglund, Eric K; Isaac, Edmund J

2014-09-15

We determined whole-fish polychlorinated biphenyl (PCB) concentrations of 25 male and 25 female age-7 ciscoes (Coregonus artedi) captured from a spawning aggregation in Thunder Bay, Lake Superior, during November 2010. We also determined PCB concentrations in the ovaries and somatic tissue of five additional female ciscoes (ages 5-22). All 55 of these ciscoes were in ripe or nearly ripe condition. Bioenergetics modeling was used to determine the contribution of the growth dilution effect toward a difference in PCB concentrations between the sexes, as females grew substantially faster than males. Results showed that the PCB concentration of males (mean = 141 ng/g) was 43% greater than that of females (mean = 98 ng/g), and this difference was highly significant (P<0.0001). Mean PCB concentrations in the ovaries and the somatic tissue of the five females were 135 and 100 ng/g, respectively. Based on these PCB determinations for the ovaries and somatic tissue, we concluded that release of eggs by females at previous spawnings was not a contributing factor to the observed difference in PCB concentrations between the sexes. Bioenergetics modeling results indicated that the growth dilution effect could explain males being higher than females in PCB concentration by only 3-7%. We concluded that the higher PCB concentration in males was most likely due to higher rate of energy expenditure, originating from greater activity and a higher resting metabolic rate. Mean PCB concentration in the cisco eggs was well below the U. S. Food and Drug Administration and Ontario Ministry of Environment guidelines of 2000 and 844 ng/g, respectively, and this finding may have implications for the cisco roe fishery currently operating in Lake Superior. Published by Elsevier B.V.

Uncovering state-dependent relationships in shallow lakes using Bayesian latent variable regression.

PubMed

Vitense, Kelsey; Hanson, Mark A; Herwig, Brian R; Zimmer, Kyle D; Fieberg, John

2018-03-01

Ecosystems sometimes undergo dramatic shifts between contrasting regimes. Shallow lakes, for instance, can transition between two alternative stable states: a clear state dominated by submerged aquatic vegetation and a turbid state dominated by phytoplankton. Theoretical models suggest that critical nutrient thresholds differentiate three lake types: highly resilient clear lakes, lakes that may switch between clear and turbid states following perturbations, and highly resilient turbid lakes. For effective and efficient management of shallow lakes and other systems, managers need tools to identify critical thresholds and state-dependent relationships between driving variables and key system features. Using shallow lakes as a model system for which alternative stable states have been demonstrated, we developed an integrated framework using Bayesian latent variable regression (BLR) to classify lake states, identify critical total phosphorus (TP) thresholds, and estimate steady state relationships between TP and chlorophyll a (chl a) using cross-sectional data. We evaluated the method using data simulated from a stochastic differential equation model and compared its performance to k-means clustering with regression (KMR). We also applied the framework to data comprising 130 shallow lakes. For simulated data sets, BLR had high state classification rates (median/mean accuracy >97%) and accurately estimated TP thresholds and state-dependent TP-chl a relationships. Classification and estimation improved with increasing sample size and decreasing noise levels. Compared to KMR, BLR had higher classification rates and better approximated the TP-chl a steady state relationships and TP thresholds. We fit the BLR model to three different years of empirical shallow lake data, and managers can use the estimated bifurcation diagrams to prioritize lakes for management according to their proximity to thresholds and chance of successful rehabilitation. Our model improves upon

Volcanic nutrient inputs and trophic state of Lake Caviahue, Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Pedrozo, Fernando L.; Temporetti, Pedro F.; Beamud, Guadalupe; Diaz, Mónica M.

2008-12-01

The strategies for eutrophication control, remediation, and policy management are often defined for neutral to alkaline freshwater systems, as they are most suitable for human use. The influence of nutrients on eutrophication in a naturally-acidic lake is poorly known. The main purpose of the present work is to evaluate the significance of volcanic nutrients in the control of the trophic state of the acidic Lake Caviahue, located at North Patagonia, Argentina. Acidic water systems were most studied on artificial acidified lakes, such as mining lakes in Germany or pit lakes in the United States. Lake Caviahue received a very high P load (42-192 ton P/yr) and low N load (14 ton N/yr), mainly as ammonium with quite low N:P ratios (< 1.0). The magmatic activity of the Copahue volcano represents the main natural contribution of nutrients and acidity to the Lake Caviahue. The lake is oligotrophic in terms of CHLa. Neither the transparency nor the nutrient, dissolved or particulate, contents are to date representative of the trophic state of the lake. High P loads do not imply the eutrophication of the lake. We suggest that nitrogen and not phosphorus represents the key control nutrient in volcanically acidified lakes as TON was better related to CHLa observed (0.13-0.36 mg/m 3) in the lake. The pH increased around one unit (pH 2.0-3.0) during the last five years suggesting that the lake has not yet returned to a stable state.

Biological consequences of the coaster brook trout restoration stocking program in Lake Superior tributaries with Pictured Rocks National Lakeshore

USGS Publications Warehouse

Leonard, Jill B.K.; Stott, Wendylee; Loope, Delora M.; Kusnierz, Paul C.; Sreenivasan, Ashwin

2013-01-01

The coaster Brook Trout Salvelinus fontinalis is a Lake Superior ecotype representing intraspecific variation that has been impacted by habitat loss and overfishing. Hatchery strains of Brook Trout derived from populations in Lake Superior were stocked into streams within Pictured Rocks National Lakeshore, Michigan, as part of an effort to rehabilitate adfluvial coaster Brook Trout. Wild and hatchery Brook Trout from three streams (Mosquito River, Hurricane River, and Sevenmile Creek) were examined for movement behavior, size, physiology, and reproductive success. Behavior and size of the stocked fish were similar to those of wild fish, and less than 15% of the stocked, tagged Brook Trout emigrated from the river into which they were stocked. There was little evidence of successful reproduction by stocked Brook Trout. Similar to the results of other studies, our findings suggest that the stocking of nonlocal Brook Trout strains where a local population already exists results in limited natural reproduction and should be avoided, particularly if the mechanisms governing the ecotype of interest are poorly understood.

Rapid Stable Isotope Turnover of Larval Fish in a Lake Superior Coastal Wetland: Implications for Diet and Life History Studies

EPA Science Inventory

Trophic linkages of larval fish in Lake Superior coastal wetlands, rivers and embayments can be identified using naturally occurring differences in the stable isotope ratios of nitrogen (15N:14N, ?15N) and carbon (13C:12C, ?13C). We sampled pelagic fish larvae weekly during sprin...

Trophic state determination for shallow coastal lakes from Landsat imagery

NASA Technical Reports Server (NTRS)

Welby, C. W.; Witherspoon, A. M.; Holman, R. E., III

1981-01-01

A study has been carried out to develop a photo-optical technique by which Landsat imagery can be used to monitor trophic states of lakes. The proposed technique uses a single number to characterize the trophic state, and a feature within the satellite scene is used as an internal standard for comparison of the lakes in time. By use of the technique it is possible to assess in retrospect the trophic state of each individual lake.

FACTORS INFLUENCING CARBON, NITROGEN, AND PHOSPHORUS CONTENT OF FISH FROM A LAKE SUPERIOR COASTAL WETLAND: LIFE HISTORY VERSUS MORPHOMETRICS.

EPA Science Inventory

The narrow fish nutrient ranges (C, 42.8-48.4%; N. 9.6-12.7%; P, 1.91-2.74%) in this study suggest that overall mean values are adequate for quantifying movement of C, N, or P as part of fish-mediated nutrient transport. We measured C, N, or P in 20 species of Lake Superior coas...

FACTORS INFLUENCING CARBON, NITROGEN, AND PHOSPHORUS CONTENT OF FISH FROM A LAKE SUPERIOR COASTAL WETLAND: LIFE HISTORY VERSUS MORPHOMETRICS

EPA Science Inventory

The narrow fish nutrient ranges (C, 42.8-48.4%; N, 9.6-12.7%; P, 1.91-2.74%) in this study suggest that overall mean values are adequate for quantifying movement of C, N, or P as part of fish-mediated nutrient transport. We measured C, N, and P in 20 species of Lake Superior coa...

Pulpwood Production in the Lake States Counties 1963

Treesearch

Arthur G. Horn

1964-01-01

This is the fifth annual report on the pulpwood harvest in the Lakes States counties. Another record in pulpwood production was established in 1963 when the Lake States cut amounted to 3,662,300 cords--10 percent larger than the previous high of 3,342,400 cords in 1962. Pulpwood from roundwood accounted for 96 percent of the total cut; the remaining 4 percent came...

Pulpwood Production in the Lake States Counties 1964

Treesearch

Arthur G. Horn

1965-01-01

This is the sixth annual report on the pulpwood harvest in the Lakes States counties. The 1964 harvest of pulpwood in the Lakes States amounted to approximately 3.628,000 cords, 1 percent less than the all-time high in 1963. Ninety-six percent of the pulpwood production was roundwood, while the remaining 4 percent was wood residue supplied by local primary wood-using...

Habitat and diet differentiation by two strains of rainbow trout in Lake Superior based on archival tags, stable isotopes, and bioenergetics

EPA Science Inventory

Two strains of potamodromous rainbow trout Oncorhynchus mykiss in the Minnesota waters of Lake Superior exhibited differences in behavior and temperature tolerance at egg and fry stages, but the extent of these differences was not well understood in adult fish. To gain a better u...

No Small Matter? An Increase of 30 Trillion Amphipods (plus or minus a few) in Lake Superior between 1973 and 2005

EPA Science Inventory

We compared a lakewide biological sampling in 2005 with the other lakewide biological sampling of Lake Superior in 1973...Lakewide, there were 40 trillion Diporeia in 2005, an increase of approx. 30 trillion compared with 1973. The open questions: what caused this apparen...

Vertical distribution of fish biomass in Lake Superior: Implications for day bottom trawl surveys

USGS Publications Warehouse

Stockwell, J.D.; Yule, D.L.; Hrabik, T.R.; Adams, J.V.; Gorman, O.T.; Holbrook, B.V.

2007-01-01

Evaluation of the biases in sampling methodology is essential for understanding the limitations of abundance and biomass estimates of fish populations. Estimates from surveys that rely solely on bottom trawls may be particularly vulnerable to bias if pelagic fish are numerous. We evaluated the variability in the vertical distribution of fish biomass during the U.S. Geological Survey's annual spring bottom trawl survey of Lake Superior using concurrent hydroacoustic observations to (1) test the assumption that fish are generally demersal during the day and (2) evaluate the potential for predictive models to improve bottom trawl–determined biomass estimates. Our results indicate that the assumption that fish exhibit demersal behavior during the annual spring bottom trawl survey in Lake Superior is unfounded. Bottom trawl biomass (BBT) estimates (mean ± SE) for species known to exhibit pelagic behavior (cisco Coregonus artedi, bloater C. hoyi, kiyi C. kiyi, and rainbow smelt Osmerus mordax; 3.01 ± 0.73 kg/ha) were not significantly greater than mean acoustic pelagic zone biomass (BAPZ) estimates (6.39 ± 2.03 kg/ha). Mean BAPZ estimates were 1.6- to 4.8-fold greater than mean BBT estimates over 4 years of sampling. The relationship between concurrent BAPZ and BBT estimates was marginally significant and highly variable. Predicted BAPZ estimates using cross-validation models were sensitive to adjustments for back-transforming from the logarithmic to the linear scale and poorly corresponded to observed BAPZ estimates. We conclude that statistical models to predict BAPZ from day BBT cannot be developed. We propose that night sampling with multiple gears will be necessary to generate better biomass estimates for management needs.

2009 Spawning cisco investigations in the Canadian waters of Lake Superior

USGS Publications Warehouse

Yule, Daniel L.; Cholwek, Gary A.; Evrard, Lori M.; E. Berglund,; K.I. Cullis,

2010-01-01

We sampled with acoustics (AC) and midwater trawls (MT) to determine cisco abundance in Lake Superior’s Thunder and Black bays during 8-14 November, 2009. Total abundance of spawning-size (≥ 250 mm total length) ciscoes was estimated at 6.25 million in Thunder Bay and 1.12 million in Black Bay. Exploitation fractions of market-size (≥ age 6) females from Thunder and Black bays for 2009 were estimated at 7.1% and 11.3%, respectively; below the recommended maximum annual harvest of 15% recently adopted by Lake Superior fisheries managers. Given Thunder Bay spawner densities are on a downward trajectory, and recruitment since the 2003 year-class has been low, it is likely the exploitation fractions will increase in the future. After 2010, the Ontario Ministry of Natural Resources (OMNR) will carry on the AC program as a management activity. It is likely suspended experimental gill net (GN) samples will be used to ground truth future AC samples. In 2009, we characterized the length and age structure of Thunder Bay ciscoes using both MT samples and GN samples. Females represented 49% of the MT catch, but only 39% in GN samples. Catching a smaller proportion of females in GN samples resulted in a lower female population estimate and a higher estimated exploitation fraction (10.4%) compared to MT samples (7.1%). Experimental gill net effort was limited to 10-11.8 m water column depths where midwater trawl samples also caught roughly 40% females. Ciscoes ≥ age 17 (≥ 1992 year class) were common in Black Bay, but rare in Thunder Bay suggesting: 1) the stocks may be distinct; and 2) total mortality of ciscoes returning to spawn in Black Bay in recent years has been lower than ciscoes returning to Thunder Bay. Our mid-November 2009 effort to assess the Black Bay stock by sampling outside of the 3 bay in the lake proper was deemed successful, but this should be confirmed by sampling the Black Bay region during both mid- and late-November 2010.

Great Lakes Literacy Principles

NASA Astrophysics Data System (ADS)

Fortner, Rosanne W.; Manzo, Lyndsey

2011-03-01

Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

Status and trends in the Lake Superior fish community, 2016

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2017-01-01

In 2016, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 35 offshore stations. Spring and summer water temperatures in 2016 were warmer than average and considerably warmer than observed in 2014 and 2015. In the nearshore zone, a total of 17,449 individuals from 20 species or morphotypes were collected. Nearshore lakewide mean biomass was 2.2 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 8,487 individuals from 16 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 4.5 kg/ha, which was the lowest biomass recorded since the offshore survey began in 2011. The density of age-1 Cisco was 5.0 fish/ha, which was 35% of that measured in 2015. Larval Coregonus were collected in surface trawls at 144 locations lakewide from May to July. The average nearshore lakewide larval Coregonus density estimate was 1,630 fish/ha, which was similar to that estimated in 2015.

Geography of Alaska Lake Districts: Identification, Description, and Analysis of Lake-Rich Regions of a Diverse and Dynamic State

USGS Publications Warehouse

Arp, Christopher D.; Jones, Benjamin M.

2009-01-01

Lakes are abundant landforms and important ecosystems in Alaska, but are unevenly distributed on the landscape with expansive lake-poor regions and several lake-rich regions. Such lake-rich areas are termed lake districts and have landscape characteristics that can be considered distinctive in similar respects to mountain ranges. In this report, we explore the nature of lake-rich areas by quantitatively identifying Alaska's lake districts, describing and comparing their physical characteristics, and analyzing how Alaska lake districts are naturally organized and correspond to climatic and geophysical characteristics, as well as studied and managed by people. We use a digital dataset (National Hydrography Dataset) of lakes greater than 1 hectare, which includes 409,040 individual lakes and represents 3.3 percent of the land-surface area of Alaska. The selection criteria we used to identify lake districts were (1) a lake area (termed limnetic ratio, in percent) greater than the mean for the State, and (2) a lake density (number of lakes per unit area) greater than the mean for the State using a pixel size scaled to the area of interest and number of lakes in the census. Pixels meeting these criteria were grouped and delineated and all groups greater than 1,000 square kilometers were identified as Alaska's lake districts. These lake districts were described according to lake size-frequency metrics, elevation distributions, geology, climate, and ecoregions to better understand their similarities and differences. We also looked at where lake research and relevant ecological monitoring has occurred in Alaska relative to lake districts and how lake district lands and waters are currently managed. We identified and delineated 20 lake districts in Alaska representing 16 percent of the State, but including 65 percent of lakes and 75 percent of lake area. The largest lake districts identified are the Yukon-Kuskokwim Delta, Arctic Coastal Plain, and Iliamna lake districts with

Analysis of suspended solids by single-particle scattering. [for Lake Superior pollution monitoring

NASA Technical Reports Server (NTRS)

Diehl, S. R.; Smith, D. T.; Sydor, M.

1979-01-01

Light scattering by individual particulates is used in a multiple-detector system to categorize the composition of suspended solids in terms of broad particulate categories. The scattering signatures of red clay and taconite tailings, the two primary particulate contaminants in western Lake Superior, along with two types of asbestiform fibers, amphibole and chrysolite, were studied in detail. A method was developed to predict the concentration of asbestiform fibers in filtration plant samples for which electron microscope analysis was done concurrently. Fiber levels as low as 50,000 fibers/liter were optically detectable. The method has application in optical categorization of samples for remote sensing purposes and offers a fast, inexpensive means for analyzing water samples from filtration plants for specific particulate contaminants.

Densities and Diel Vertical Migration of Mysis relicta in Lake Superior: A Comparison of Optical Plankton Encounter and Net-based Approaches

EPA Science Inventory

In this study, we used data from an OPC, and LOPC, and vertical net tows to estimate densities and describe the day/night vertical distribution of Mysis at a series of stations distributed throughout Lake Superior, and to evaluate the efficacy of using (L)OPC for examining DVM of...

40 CFR 35.1620-5 - State work programs and lake priority lists.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 1 2014-07-01 2014-07-01 false State work programs and lake priority... Publicly Owned Freshwater Lakes § 35.1620-5 State work programs and lake priority lists. (a)(1) A State shall submit to the Regional Administrator as part of its annual work program (§ 35.1513 of this...

Status of Lake Superior’s lower trophic levels

EPA Science Inventory

To meet the Fish Community Objectives set for Lake Superior by the Great Lakes Fishery Commission, a key factor is the condition of the lower food web that supports productivity of fisheries. To assess the condition of lower trophic levels and inform the Lake Superior Technical C...

Perchlorate in the Great Lakes: isotopic composition and origin.

PubMed

Poghosyan, Armen; Sturchio, Neil C; Morrison, Candice G; Beloso, Abelardo D; Guan, Yunbin; Eiler, John M; Jackson, W Andrew; Hatzinger, Paul B

2014-10-07

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ(18)O, Δ(17)O) and chlorine (δ(37)Cl) along with the abundance of the radioactive isotope (36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ(18)O values range from -4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The (36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10(-12) (Lake Ontario) to 6.7 × 10(-11) (Lake Superior). These (36)ClO4(-) abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high (36)ClO4(-) abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of (36)Cl-enriched perchlorate deposited during the period of elevated atmospheric (36)Cl activity following thermonuclear bomb tests in the Pacific Ocean.

First record of trypanosomes from the blood of sculpins (Cottus ricei and C. cognatus) from Lake Superior, WI, USA

USGS Publications Warehouse

Pronina, Svetlana V.; Pronin, Nikolai M.; Selgeby, Jim H.

1999-01-01

During parasitological research of fishes in Lake Superior (USA) in August-September 1994, infection with trypanosomes of the blood of sculpins (Cottus ricei and C. cognatus) was recorded for the first time. The descriptions of three morphological groups of the genus Trypanosoma: T. sp. I, found in blood of C. ricei, T. sp. II and T. sp. III from blood of C. cognatus, have been provided.

COSEE Superior Creates Passion for Science

EPA Science Inventory

COSEE was a transformative educational experience that has changed the way I teach. In July, I participated in the COSEE Lake Superior Shipboard and Shoreline Science program. I spent a week on the US EPA’s R/V Lake Guardian with 14 other teachers and a crew of sailors and scient...

DETERMINING THE INFLUENCE OF LANDSCAPE AND RESEARCH-SPECIFIC HABITAT VARIABLES ON VARIATION OF THERMAL CHARACTERISTICS OF STREAMS WITHIN WESTERN LAKE SUPERIOR WATERSHEDS

EPA Science Inventory

As part of a study to develop and test a framework for predicting sensitivity of watersheds to land-use activities, temperatures were monitored in 48 second- and third- order streams on the north and south shores of western Lake Superior. Maximun 21-day average temperatures, whic...

Hardwood thinning opportunities in the Lake States.

Treesearch

John A. Sturos

1986-01-01

The symposium presents and discusses new information on the hardwood resource, silviculture, harvesting, economics, and product potential from hardwood thinnings in the Lake States. Included are forest management perspectives from the logger, private industry, and state and federal forest managers.

Geomicrobiology of Fe-rich crusts in Lake Superior sediment

NASA Astrophysics Data System (ADS)

Dittrich, M.; Monreau, L.; Quazi, S.; Raoof, B.; Chesnyuk, A.; Katsev, S.; Fulthorpe, R.

2012-04-01

The limnological puzzles of Lake Superior are increasingly attracting scientists, and very little is known about the sediments and their associated microflora. The sediments are organic poor (less than 5%C) and the lake is deep oligotrophic, with water temperatures at the bottom around 3C. Previous studies reveal Fe-rich layers in the sediments at multiple loccations around the lake. The origin and mechanisms of formation of this layer remain unknown. In this study we investigated geochemical and microbiological processes that may lead to the formation of a two cm thick iron layer about 10 cm below the sediment surface. Sediment cores from two stations (EM, 230m water depth and ED, 310m water depth) in the East Basin were used. We monitored oxygen and pH depth profiles with microsensors, porewater and sediment solid matter were analyzed for nutrient and metal contents. Furthermore, phosphorus and iron sequantial extractions of sediment cores have been perfomed. The total cell count was determined using DAPI epifluoresence microscopy. DNA was extracted from the sediment samples and 16S ribosonal RNA amplicons were analyzed with denaturing gradient gel electrophoresis (DGGE). For a more in depth analysis, DNA samples from 8-10 cm and 10-12 cm were sent to the Research and Testing Lab (Texas) for pyrosequencing of 16S rRNA gene amplicons amplified using barcoded universal primers 27f-519r. The scanning electron microscope (SEM) images from the iron layer 10-12cm show filaments that were encrusted with spheres ca. 20 nm in diameter. SEM observations of thin sections also indicate the presence of very fine particles showing various morphologies. Analyses of the deposit material by SEM and energy dispersive X-ray spectroscopy (EDS) indicate that bacteria cells surfaces served as nucleation surfaces for Fe-oxide formation. EDS line-scans through bacterial cells covered with precipitates reveal phosphorus and carbon peaks at interface between cell surface and Fe

Species succession and fishery exploitation in the Great Lakes

USGS Publications Warehouse

Smith, Stanford H.

1968-01-01

collapses of various stocks after periods of stable production may give some indication of their sustainable yield. The sea lamprey is being brought under control in Lakes Superior, Michigan, and Huron; lake trout are being established; and chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), kokanee salmon (O. nerka), and the splake, a hybrid of lake trout and brook trout (Salvelinus fontinalis), are being introduced to reestablish a new species balance. Fish stocks are in a state of extreme instability in these lakes. Careful control of stocking programs and fisheries, and coordination of management among the various states of the United States and the province of Canada (Ontario) which manage the fish stocks, will be required to restore and maintain a useful fishery balance.

The Photodegradation of Ibuprofen and Dissolved Organic Matter in Lake Superior and St. Louis River Water

PubMed Central

Moynan, Angela B.

2012-01-01

Abstract Ibuprofen can enter bodies of water via waste water treatment. The question was what effect does photodegradation have on ibuprofen and dissolved organic matter (DOM) in Lake Superior (oligiotrophic) and St. Louis (tannic stained) River water? Ibuprofen concentrations of 15,000, 30,000, and 60,000 μg/L were made from lake, river, and distilled water, as well as additional distilled concentrations of 7,500 and 120,000 μg/L. Half of the eighty-four trial cups were placed in an ultraviolet light cabinet and half of the set were placed in a dark cabinet for three days. After the exposure period, a UV-Vis was performed to measure change in molar mass and the summed absorbance of colored dissolved organic matter (CDOM). It appears that ibuprofen decreases in molar mass after exposure to light in distilled and lake water with 15,000 μg/L of ibuprofen. Surprisingly, the molar mass of DOM in river water increases after UV exposure. Possibly, this occurred because the river water has such a high molar mass of DOM and was not filtered. Microbial biomass could also have contributed to this increase. Ibuprofen entering bodies of water via the waste water treatment system appears to be affected by UV light exposure, but in different ways. PMID:23244688

The Hardwood Gneiss: Evidence for high P-T Archean metamorphism in the southern province of the Lake Superior region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, J.W.; Geiger, C.A.

1990-03-01

The Hardwood Gneiss is an areally small unit of Precambrian granulite-grade rocks exposed in the Archean gneiss terrane of the southern Lake Superior region. The rocks are located in the southwestern portion of the Upper Peninsula of Michigan and consist of a structurally conformable package of quartzitic, metapelitic, amphibolitic, and metabasic units. Three texturally distinct garnet types are present in the metabasites and are interpreted to represent two metamorphic events. Geothermobarometry indicates conditions of {approximately}8.2-11.6 kbar and {approximately}770C for M1, and conditions of {approximately}6.0-10.1 kbar and {approximately}610-740C for M2. It is proposed that M1 was Archean and contemporaneous with amore » high-grade metamorphic event recorded in the Minnesota River Valley. The M2 event was probably Early Proterozoic and pre-Penokean, with metamorphic conditions more intense than those generally ascribed to the Penokean Orogeny in Michigan, but similar to the conditions reported for the Kapuskasing zone of Ontario. The high paleopressures and temperatures of the M1 event make the Hardwood Gneiss distinct from any rocks previously described in the southern Lake Superior region, and suggest intense tectonic activity during the Archean.« less

Pulpwood Production in the Lake States

Treesearch

James E. Blyth; Jerold T. Hahn

1977-01-01

This 31st annual report shows 1976 pulpwood production by county and species group in Michigan, Minnesota, and Wisconsin. Production in these three Lake States climbed to 4.7 million cords from 4.1 million cords in 1975

The mesoproterozoic midcontinent rift system, Lake Superior region, USA

USGS Publications Warehouse

Ojakangas, R.W.; Morey, G.B.; Green, J.C.

2001-01-01

Exposures in the Lake Superior region, and associated geophysical evidence, show that a 2000 km-long rift system developed within the North American craton ??? 1109-1087 Ma, the age span of the most of the volcanic rocks. This system is characterized by immense volumes of mafic igneous rocks, mostly subaerial plateau basalts, generated in two major pulses largely by a hot mantle plume. A new ocean basin was nearly formed before rifting ceased, perhaps due to the remote effect of the Grenville continental collision to the east. Broad sagging/subsidence, combined with a system of axial half-grabens separated along the length of the rift by accommodation zones, provided conditions for the accumulation of as much as 20 km of volcanic rocks and as much as 10 km of post-rift clastic sediments, both along the rift axis and in basins flanking a central, post-volcanic horst. Pre-rift mature, quartzose sandstones imply little or no uplift prior to the onset of rift volcanism. Early post-rift red-bed sediments consist almost entirely of intrabasinally derived volcanic sediment deposited in alluvial fan to fluvial settings; the exception is one gray to black carbon-bearing lacustrine(?) unit. This early sedimentation phase was followed by broad crustal sagging and deposition of progressively more mature red-bed, fluvial sediments with an extra-basinal provenance. ?? 2001 Elsevier Science B.V. All rights reserved.

REDUCING EXPOSURE UNCERTAINTY FOR ASSESSMENT OF DIOXIN TOXICITY RISKS TO LAKE TROUT POPULATIONS IN THE GREAT LAKES

EPA Science Inventory

During the 20th century, declines of lake trout (Salvelinus namaycush) populations to virtual extinction in all the Great Lakes except Lake Superior were followed by failure of stocked lake trout to achieve recruitment through natural reproduction. Stresses such as excessive harv...

Lake-level variability and water availability in the Great Lakes

USGS Publications Warehouse

Wilcox, Douglas A.; Thompson, Todd A.; Booth, Robert K.; Nicholas, J.R.

2007-01-01

years ago. Within that record is a quasi-periodic rise and fall of about 160 ? 40 years in duration and a shorter fluctuation of 32 ? 6 years that is superimposed on the 160-year fluctuation. Recorded lake-level history from 1860 to the present falls within the longer-term pattern and appears to be a single 160-year quasi-periodic fluctuation. Independent investigations of past climate change in the basin over the long-term period of record confirm that most of these changes in lake level were responses to climatically driven changes in water balance, including lake-level highstands commonly associated with cooler climatic conditions and lows with warm climate periods. The mechanisms underlying these large hydroclimatic anomalies are not clear, but they may be related to internal dynamics of the ocean-atmosphere system or dynamical responses of the ocean-atmosphere system to variability in solar radiation or volcanic activity. The large capacities of the Great Lakes allow them to store great volumes of water. As calculated at chart datum, Lake Superior stores more water (2,900 mi3) than all the other lakes combined (2,539 mi3). Lake Michigan's storage is 1,180 mi3; Lake Huron's, 850 mi3; Lake Ontario's, 393 mi3; and Lake Erie's, 116 mi3. Seasonal lake-level changes alter storage by as much as 6 mi3 in Lake Superior and as little as 2.1 mi3 in Lake Erie. The extreme high and low lake levels measured in recorded lake-level history have altered storage by as much as 31 mi3 in Lake Michigan-Huron and as little as 9 mi3 in Lake Ontario. Diversions of water into and out of the lakes are very small compared to the total volume of water stored in the lakes. The water level of Lake Superior has been regulated since about 1914 and levels of Lake Ontario since about 1960. The range of Lake Superior water-level fluctuations and storage has not been altered greatly by regulation. However, fluctuations on Lake Ontario have been reduced from 6.6 ft preregulation

Prediction of lake depth across a 17-state region in the United States

USGS Publications Warehouse

Oliver, Samantha K.; Soranno, Patricia A.; Fergus, C. Emi; Wagner, Tyler; Winslow, Luke A.; Scott, Caren E.; Webster, Katherine E.; Downing, John A.; Stanley, Emily H.

2016-01-01

Lake depth is an important characteristic for understanding many lake processes, yet it is unknown for the vast majority of lakes globally. Our objective was to develop a model that predicts lake depth using map-derived metrics of lake and terrestrial geomorphic features. Building on previous models that use local topography to predict lake depth, we hypothesized that regional differences in topography, lake shape, or sedimentation processes could lead to region-specific relationships between lake depth and the mapped features. We therefore used a mixed modeling approach that included region-specific model parameters. We built models using lake and map data from LAGOS, which includes 8164 lakes with maximum depth (Zmax) observations. The model was used to predict depth for all lakes ≥4 ha (n = 42 443) in the study extent. Lake surface area and maximum slope in a 100 m buffer were the best predictors of Zmax. Interactions between surface area and topography occurred at both the local and regional scale; surface area had a larger effect in steep terrain, so large lakes embedded in steep terrain were much deeper than those in flat terrain. Despite a large sample size and inclusion of regional variability, model performance (R2 = 0.29, RMSE = 7.1 m) was similar to other published models. The relative error varied by region, however, highlighting the importance of taking a regional approach to lake depth modeling. Additionally, we provide the largest known collection of observed and predicted lake depth values in the United States.

Practical breeding programs for jack pine in the Lake States

Treesearch

James P. King

1973-01-01

Jack pine (Pinus banksiana Lamb.) is the most common pine in the Lake States and is expected to play an increasingly important role in Lake States planting programs. This species is easy to plant successfully even on dry, sandy soils. Its rapid growth during the first 30 years makes it suitable for intensive-culture, short-rotation forestry. And it...

Proceedings of the sixth Lake States forest tree improvement conference

Treesearch

Paul O. Rudolf

1964-01-01

In April of 1953 the Lake States Forest Tree Improvement Committee was formed, following a regional conference sponsored by the Lake States Forest Experiment Station. Since that time there has been a marked increase in the amount of tree improvement work done in this region, and the Committee has performed a valuable service in encouraging and coordinating such...

Factors of ecologic succession in oligotrophic fish communities of the Laurentian Great Lakes

USGS Publications Warehouse

Smith, Stanford H.

1972-01-01

Oligotrophic fish communities of the Great Lakes have undergone successive disruptions since the mid-1800s. Major contributing factors have been intensive selective fisheries, extreme modification of the drainage, invasion of marine species, and progressive physical–chemical changes of the lake environments. Lake Ontario was the first to be affected as its basin was settled and industrialized earliest, and it was the first to be connected by canals to the mid-Atlantic where the alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) which ultimately became established in the Great Lakes were abundant. Oligotrophic fish communities were successively disrupted in Lakes Erie, Huron, Michigan, and Superior as the affects of population growth, industrialization, and marine invaders spread upward in the Laurentian drainage.The degree and sequence of response of families offish and species within families differed for each factor, but the sequence of change among families and species has been the same in response to each factor as it affected various lakes at different times. The ultimate result of the disruption of fish communities has been a reduction of productivity of oligotrophic species that ranges from extreme in Lake Ontario to moderate in Lake Superior, and which has reached a state of instability and rapid change in the upper three Great Lakes by the rnid-1900s similar to the situation in Lake Ontario in the mid-1800s. Since oligotrophic species (primarily salmonines, coregonines, and deepwater cottids) are the only kinds of fish that fully occupied the entire volume of the deepwater Great Lakes (Ontario, Huron, Michigan, and Superior), the fish biomass of these lakes has been reduced as various species declined or disappeared. In Lake Erie, which is shallow, and in the shallow bays of the deep lakes, oligotrophic species were replaced by mesotrophic species, primarily percids, which have successively increased and declined. All oligotrophic

A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

NASA Astrophysics Data System (ADS)

Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

Aircraft and satellite monitoring of water quality in Lake Superior near Duluth

NASA Technical Reports Server (NTRS)

Scherz, J. P.; Sydor, M.; Vandomelen, J. F.

1974-01-01

Satellite images and low altitude aerial photographs often show vivid discolorations in water bodies. Extensive laboratory analysis shows that water reflectance, which causes brightness on aerial images, positively correlates to the water quality parameter of turbidity, which on a particular day correlates to suspended solids. Work with low altitude photography on three overcast days and with ERTS images on five clear days provides positive correlation of image brightness to the high turbidity and solids which are present in Lake Superior near Duluth over 50% of the time. Proper use of aerial images would have shown that an $8,000,000 drinking water intake constructed in the midst of this unpotable, turbid water should have been located 6 miles north in clear, usable water. Noise effects such as skylight reflection, atmospheric effects, and depth penetration also must be understood for operational use of remote sensing for water quality monitoring and are considered in the paper.

Modeling lake trophic state: a random forest approach

EPA Science Inventory

Productivity of lentic ecosystems has been well studied and it is widely accepted that as nutrient inputs increase, productivity increases and lakes transition from low trophic state (e.g. oligotrophic) to higher trophic states (e.g. eutrophic). These broad trophic state classi...

Using multiple gears to assess acoustic detectability and biomass of fish species in lake superior

USGS Publications Warehouse

Yule, D.L.; Adams, J.V.; Stockwell, J.D.; Gorman, O.T.

2007-01-01

Recent predator demand and prey supply studies suggest that an annual daytime bottom trawl survey of Lake Superior underestimates prey fish biomass. A multiple-gear (acoustics, bottom trawl, and midwater trawl) nighttime survey has been recommended, but before abandoning a long-term daytime survey the effectiveness of night sampling of important prey species must be verified. We sampled three bottom depths (30, 60, and 120 m) at a Lake Superior site where the fish community included all commercially and ecologically important species. Day and night samples were collected within 48 h at all depths during eight different periods (one new and one full moon period during both early summer and late summer to early fall over 2 years). Biomass of demersal and benthic species was higher in night bottom trawl samples than in day bottom trawl samples. Night acoustic collections showed that pelagic fish typically occupied water cooler than 15°C and light levels less than 0.001 lx. Using biomass in night bottom trawls and acoustic biomass above the bottom trawl path, we calculated an index of acoustic detectability for each species. Ciscoes Coregonus artedi, kiyis C. kiyi, and rainbow smeltOsmerus mordax left the bottom at night, whereas bloaters C. hoyi stayed nearer the bottom. We compared the biomass of important prey species estimated with two survey types: day bottom trawls and night estimates of the entire water column (bottom trawl biomass plus acoustic biomass). The biomass of large ciscoes (>200 mm) was significantly greater when measured at night than when measured during daylight, but the differences for other sizes of important species did not vary significantly by survey type. Nighttime of late summer is a period when conditions for biomass estimation are largely invariant, and all important prey species can be sampled using a multiple-gear approach.

Ciscoes (Coregonus, subgenus Leucichthys) of the Laurentian Great Lakes and Lake Nipigon

USGS Publications Warehouse

Eshenroder, Randy L.; Vecsei, Paul; Gorman, Owen T.; Yule, Daniel; Pratt, Thomas C.; Mandrak, Nicholas E.; Bunnell, David B.; Muir, Andrew M.

2016-01-01

This study of the ciscoes (Coregonus, subgenus Leucichthys) of the Great Lakes and Lake Nipigon represents a furtherance through 2015 of field research initiated by Walter Koelz in 1917 and continued by Stanford Smith in the mid-1900s—a period spanning nearly a century. Like Koelz’s study, this work contains information on taxonomy, geographical distribution, ecology, and status of species (here considered forms). Of the seven currently recognized forms (C. artedi, C. hoyi, C. johannae, C. kiyi, C. nigripinnis, C. reighardi, and C. zenithicus) described by Koelz as major in his 1929 monograph, two (C. johannae and C. reighardi) are extinct. In addition, C. alpenae, described by Koelz but subsequently synonymized with C. zenithicus, although extinct, is recognized as valid making a total of eight major forms. Six of these forms, all but C. artedi and C. hoyi, have been lost from Lake Michigan, and seven have been lost from Lake Huron, leaving in Lake Huron only C. artedi and an introgressed deepwater form that we term a hybrid swarm. C. artedi appears, like its sister form C. alpenae, to have been lost from Lake Erie. Only C. artedi remains extant in Lake Ontario, its three sister forms (C. hoyi, C. kiyi, and C. reighardi) having disappeared long ago.Lakes Superior and Nipigon have retained their original species flocks consisting of four forms each: C. artedi, C. hoyi, and C. zenithicus in both lakes; C. kiyi in Lake Superior; and C. nigripinnis in Lake Nipigon. Morphological deviations from the morphotypes described by Koelz have been modest in contemporary samples. Overall, C. kiyi and C. artedi were the most morphologically stable forms while C. hoyi, C. nigripinnis, and C. zenithicus were the least stable. Although contemporary populations of C. artedi from Lakes Michigan and Huron are highly diverged from the morphotypes described by Koelz, the contemporary samples were of undescribed deep-bodied forms unlikely to have been sampled by Koelz because of

Energy density of bloaters in the upper Great Lakes

USGS Publications Warehouse

Pothoven, Steven A.; Bunnell, David B.; Madenjian, Charles P.; Gorman, Owen T.; Roseman, Edward F.

2012-01-01

We evaluated the energy density of bloaters Coregonus hoyi as a function of fish size across Lakes Michigan, Huron, and Superior in 2008–2009 and assessed how differences in energy density are related to factors such as biomass density of bloaters and availability of prey. Additional objectives were to compare energy density between sexes and to compare energy densities of bloaters in Lake Michigan between two time periods (1998–2001 and 2008–2009). For the cross-lake comparisons in 2008, energy density increased with fish total length (TL) only in Lake Michigan. Mean energy density adjusted for fish size was 8% higher in bloaters from Lake Superior than in bloaters from Lake Huron. Relative to fish in these two lakes, small (175 mm TL) bloaters had higher energy density. In 2009, energy density increased with bloater size, and mean energy density adjusted for fish size was about 9% higher in Lake Michigan than in Lake Huron (Lake Superior was not sampled during 2009). Energy density of bloaters in Lake Huron was generally the lowest among lakes, reflecting the relatively low densities of opossum shrimp Mysis diluviana and the relatively high biomass of bloaters reported for that lake. Other factors, such as energy content of prey, growing season, or ontogenetic differences in energy use strategies, may also influence cross-lake variation in energy density. Mean energy density adjusted for length was 7% higher for female bloaters than for male bloaters in Lakes Michigan and Huron. In Lake Superior, energy density did not differ between males and females. Finally, energy density of bloaters in Lake Michigan was similar between the periods 2008–2009 and 1998–2001, possibly due to a low population abundance of bloaters, which could offset food availability changes linked to the loss of prey such as the amphipods Diporeia spp.

Survival of lake trout eggs and fry reared in water from the upper Great Lakes

USGS Publications Warehouse

Mac, Michael J.; Edsall, Carol Cotant; Seelye, James G.

1985-01-01

As part of continuing studies of the reproductive failure of lake trout (Salvelinus namaycush) in Lake Michigan, we measured the survival of lake trout eggs and fry of different origins and reared in different environments. Eggs and milt were stripped from spawning lake trout collected in the fall of 1980 from southeastern Lake Michigan, northwestern Lake Huron, south central Lake Superior, and from hatchery brood stock. Eggs from all sources were incubated, and the newly hatched fry were reared for 139 days in lake water from each of the three upper Great Lakes and in well water. Survival of eggs to hatching at all sites was lowest for those from Lake Michigan (70% of fertilized eggs) and highest for eggs from Lake Superior (96%). Comparisons of incubation water from the different lakes indicated that hatching success of eggs from all sources was highest in Lake Huron water, and lowest in Lake Michigan water. The most notable finding was the nearly total mortality of fry from eggs of southeastern Lake Michigan lake trout. At all sites, the mean survival of Lake Michigan fry through 139 days after hatching was only 4% compared to near 50% for fry from the other three sources. In a comparison of the rearing sites, little influence of water quality on fry survival was found. Thus, the poor survival was associated with the source of eggs and sperm, not the water in which the fry were reared.

New Observations at the Slate Islands Impact Structure, Lake Superior

NASA Technical Reports Server (NTRS)

Dressler, B. O.; Sharpton, V. L.; Schnieders, B.; Scott, J.

1995-01-01

Slate Islands, a group of 2 large and several small islands, is located in northern Lake Superior, approximately 10 km south of Terrace Bay. Shatter cones, breccias and shock metamorphic features provide evidence that the Slate Islands Structure was formed as a result of asteroid or comet impact. Most of the island group is believed to represent the central uplift of a complex impact crater. The structure possibly has a diameter of about 32 km. For Sage (1978, 1991) shock metamorphic features, shatter cones and pervasive rock brecciation are the results of diatreme activity. The present investigations represent the second year of a co-operative study of the Lunar and Planetary Institute, Houston, Texas and the Field Services Section (Northwest) of the Ontario Geological Survey. The objective of this investigation is to come to a better understanding of the formation of mid-size impact structures on Earth and the planets of the solar system. Impact processes played a fundamental role in the formation of the planets and the evolution of life on Earth. Meteorite and comet impacts are not a phenomenon of the past. Last year, more than 20 pieces of the Shoemaker-Levy 9 impacted on Jupiter and the Tunguska comet impacted in Siberia in the early years of this century. The study of impact processes is a relatively young part of geoscience and much is still to be learnt by detailed field and laboratory investigations. The State Islands Structure has been selected for the present detailed investigations because of the excellent shoreline outcrops of rock units related to the impact. The structure is a complex impact crater that has been eroded so that important lithological and structural elements are exposed. We know of no other mid-size terrestrial impact structure with equal or better exposures. In this publication we present preliminary results of our 1994 and 1995 field and laboratory investigations. We have tentatively identified a few impact melt and a considerable

Lake Superior water quality near Duluth from analysis of aerial photos and ERTS imagery

NASA Technical Reports Server (NTRS)

Scherz, J. P.; Van Domelen, J. F.

1973-01-01

ERTS imagery of Lake Superior in the late summer of 1972 shows dirty water near the city of Duluth. Water samples and simultaneous photographs were taken on three separate days following a heavy storm which caused muddy runoff water. The water samples were analyzed for turbidity, color, and solids. Reflectance and transmittance characteristics of the water samples were determined with a spectrophotometer apparatus. This same apparatus attached to a microdensitometer was used to analyze the photographs for the approximate colors or wavelengths of reflected energy that caused the exposure. Although other parameters do correlate for any one particular day, it is only the water quality parameter of turbidity that correlates with the aerial imagery on all days, as the character of the dirty water changes due to settling and mixing.

The reproduction of lake trout in southern Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.

1955-01-01

Thirteen fish identified by commercial fishermen as siscowets (Salvelinus namaycush siscowet) also showed extensive individual variation in numbers of eggs, although egg production tended to increase with increasing length and weight of the fish. A mature female siscowet as small as 16.5 inches long and a 15.7-inch mature male were collected about 45 miles north of Grand Marais, Michigan. Combined data from all collections showed that spawning of lake trout or siscowets may occur during at least 6 months of the year (June to November).

EPA Research Strengthens Great Lakes Restoration Initiative

EPA Science Inventory

As the largest group of freshwater lakes on Earth, the Great Lakes (Lakes Erie, Huron, Michigan, Ontario and Superior) are a source of economic prosperity, recreation and raw materials. Human activity, however, has resulted in pollution and other stressors. The Great Lakes curren...

Introduction to the Proceedings of the 1994 International Conference on Restoration of Lake Trout in the Laurentian Great Lakes

USGS Publications Warehouse

Selgeby, James H.

1995-01-01

Lake trout (Salvelinus namaycush) restoration in the Great Lakes began in the 1950s when stocking of artificially propagated lake trout was coupled with the first attempts at sea lamprey (Petromyzon marinus) control. A major milestone in the restoration process was recorded when a selective sea lamprey larvicide was identified in 1958 (Applegate et al. 1958) and then applied broad scale in Lake Superior in 1958-60 (Applegate et al. 1961). Other milestones include the expansion of the sea lamprey control programs into Lakes Michigan and Huron in 1960 (sustained usage in Lake Huron began in 1966, Smith and Tibbles 1980), Lake Ontario in 1971-72 (Elrod et al. 1995), and Lake Erie in 1986 (Cornelius et al. 1995). Following the collapse of lake trout in the Great Lakes and the implementation of massive stocking of hatchery-reared fish and effective sea lamprey control, the first documented evidence of nearshore natural reproduction of lake trout was in Lake Superior in 1965 (Dryer and King 1968), in Lake Michigan in 1980 (Jude et al. 1981), in Lake Huron in 1981-82 (Nester and Poe 1984), and in Lake Ontario in 1986 (Marsden et al. 1988).

Status of the amphipod Diporeia Spp. in Lake Superior, 2011

EPA Science Inventory

Amphipods of the genus Diporeia have historically been the dominant benthic macroinvertebrates in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relativ...

Pulpwood Production in the Lake States, 1993

Treesearch

Ronald J. Piva

1995-01-01

Pulpwood production in the Lake States increased from 8.8 million cords in 1992 to 9.4 million cords in 1993. Michigan, Minnesota, and Wisconsin pulpwood production is shown by county and species group.

Taking Teachers from the River to the Coast: a COSEE Great Lakes and Lake Superior NERR Collaboration

EPA Science Inventory

The Center for Ocean Sciences Education Excellence (COSEE) Great Lakes Shipboard and Shoreline Science Workshop provides 15 formal and informal educators of G5-10 an opportunity to spend a week aboard the US EPA’s 180’ R/V Lake Guardian working side-by-side with Great Lakes scien...

HISTORICAL SNOW AMOUNTS IN THE LAKE EFFECT REGION OF LAKE SUPERIOR: EVIDENCE OF CLIMATE CHANGE IN THE GREAT LAKES

EPA Science Inventory

Recent studies (Levitus et al., .2000) suggest a warming of the world ocean over the past 50 years. This could be occurring in the Great Lakes also but thermal measurements are lacking. Historical trends in natural phenomena, such as the duration of ice cover on lakes, provide in...

STATE OF THE LAKES ECOSYSTEM CONFERENCE AND SUITE OF INDICATORS

EPA Science Inventory

The State of the Lakes Ecosystem Conference (SOLEC) is a biennial assessment and report from the governments of the U.S. and Canada on progress toward meeting the goals of the Great Lakes Water Quality Agreement (GLWQA). The SOLEC approach has three main elements: 1) The bienn...

Embryotoxicity of Great Lakes lake trout extracts to developing rainbow trout

USGS Publications Warehouse

Wright, Peggy J.; Tillitt, Donald E.

1999-01-01

Planar halogenated hydrocarbons (PHHs), such as polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls are present in aquatic systems, and are known to produce adverse effects in fish. This study investigated the embryotoxicity of PHH mixtures through the nanoinjection of environmental extracts into newly fertilized eggs from two strains of rainbow trout. Organic extracts were obtained from whole adult lake trout collected from Lake Michigan in 1988 and Lake Superior in 1994. The graded doses of the final extracts used for injection were quantified as 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic-equivalents (TEQs) based on the concentrations of dioxins, furans and non-o-PCBs in each, and as equivalent amounts found in the eggs of the original lake trout (eggEQ). Total TEQs in the lake trout were 14.7 pg TEQ/g in the Lake Michigan sample and 7.3 pg TEQ/g in the Lake Superior sample. The extract of the Lake Michigan lake trout was embryotoxic to rainbow trout; LD50 values were 35 eggEQ (15–90, 95% F.L.) in the Arlee strain and 14 eggEQ (5–99, 95% F.L.) in the Erwin strain of rainbow trout. The LD50 values of the Lake Michigan extract in either of these strains of rainbow trout fall within the actual range of TCDD LD50values based on TEQs. This indicates that an additive model of toxicity is appropriate to quantify PHHs in relation to early life stage mortality in fish. Gross lesions characteristic of exposure to PHHs (i.e. yolk-sac edema, craniofacial deformities, and hemorrhaging) increased in a dose-related manner. The lowest observable adverse effect concentrations (LOAEC) for these gross lesions and cumulative mortalities suggests that current concentrations of PHHs in lake trout from Lake Michigan are above a threshold for adverse effects and these compounds may have implications on the lack of recruitment in certain Great Lakes lake trout populations.

Regenerating yellow birch in the Lake States

Treesearch

Richard M. Godman; Gayne G. Erdmann

1992-01-01

The future of the yellow birch supply in the Lake States is uncertain. Growing-stock volume has declined more than one third since 1963, prompting the search for better ways to handle the difficult job of regenerating the species.

Age, growth, and maturity of round whitefish of the Apostle Islands and Isle Royale Regions, Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1963-01-01

The round whitefish has been of some commercial importance in the upper Great Lakes but production in Lake Superior has generally been small; the United States average was 26,600 pounds for 1929-59. This study is based on 1,173 fish collected in the Apostle Islands in 1958-60 and 103 collected at Isle Royale in 1958 and 1960. The average age of 6.0 years at Isle Royale was concluded to be significantly higher than the mean of 4.2 years in the Apostle Islands. The body-scale relation is a straight line with an intercept of 1.1 inches on the length axis. Weight of Apostle Islands round whitefish captured in several months increased as the 3.22 power of the length. Growth in length was relatively slow; nearly or fully 7 years were required to reach an acceptable commercial length of 14 inches in both the Apostle Islands and at Isle Royale. The calculated weights at the end of the seventh year were 12.6 ounces in the Apostle Islands and 13.8 ounces at Isle Royale. Minimum length at maturity of male round whitefish (7.0-7.4 inches) was less than that of females (8.5-8.9 inches). At age-group II, 11.1 percent of male round whitefish, but only 1.5 percent of the females were mature. All males were mature as age-group V and all females as age-group VI. Males dominated the younger age groups but females were more numerous in the older ones. Estimates of the number of eggs in 37 round whitefish ovaries yielded an average of 5,330 eggs for fish 10.5-17.4 inches long.

An evaluation of Lake States STEMS85.

Treesearch

Margaret R. Holdaway

1986-01-01

An updated version of the Lake States variant of STEMS is evaluated and compared with the previous version. The new version is slightly more accurate and precise. The strengths and weaknesses of this tree growth projection system are also identified.

Imaging the midcontinent rift beneath Lake Superior using large aperture seismic data

USGS Publications Warehouse

Tréhu, Anne M.; Morel-a-l'Huissier, Patrick; Meyer, R.; Hajnal, Z.; Karl, J.; Mereu, R.F.; Sexton, John L.; Shay, J.; Chan, W. K.; Epili, D.; Jefferson, T.; Shih, X. R.; Wendling, S.; Milkereit, B.; Green, A.; Hutchinson, Deborah R.

1991-01-01

We present a detailed velocity model across the 1.1 billion year old Midcontinent Rift System (MRS) in central Lake Superior. The model was derived primarily from onshore-offshore large-aperture seismic and gravity data. High velocities obtained within a highly reflective half-graben that was imaged on coincident seismic reflection data demonstrate the dominantly mafic composition of the graben fill and constrain its total thickness to be at least 30km. Strong wide-angle reflections are observed from the lower crust and Moho, indicating that the crust is thickest (55–60km) beneath the axis of the graben. The total crustal thickness decreases rapidly to about 40 km beneath the south shore of the lake and decreases more gradually to the north. Above the Moho is a high-velocity lower crust interpreted to result from syn-rift basaltic intrusion into and/or underplating beneath the Archean lower crust. The lower crust is thickest beneath the axis of the main rift half-graben. A second region of thick lower crust is found approximately 100km north of the axis of the rift beneath a smaller half graben that is interpreted to reflect an earlier stage of rifting. The crustal model presented here resembles recent models of some passive continental margins and is in marked contrast to many models of both active and extinct Phanerozoic continental rift zones. It demonstrates that the Moho is a dynamic feature, since the pre-rift Moho is probably within or above the high-velocity lower crust, whereas the post-rift Moho is defined as the base of this layer. In the absence of major tectonic activity, however, the Moho is very stable, since the large, abrupt variations in crustal thickness beneath the MRS have been preserved for at least a billion years.

Genetic identity of brook trout in Lake Superior south shore streams: Potential for genetic monitoring of stocking and rehabilitation efforts

USGS Publications Warehouse

Sloss, Brian L.; Jennings, Martin J.; Franckowiak, R.; Pratt, D.M.

2008-01-01

Rehabilitation of migratory ('coaster') brook trout Salvelinus fontinalis along Lake Superior's south shore is a topic of high interest among resource stakeholders and management agencies. Proposed strategies for rehabilitation of this brook trout life history variant in Wisconsin include supplemental stocking, watershed management, habitat rehabilitation, harvest regulations, or a combination thereof. In an effort to evaluate the success of coaster brook trout rehabilitation efforts, we collected genetic data from four populations of interest (Whittlesey Creek, Bois Brule River, Bark River, and Graveyard Creek) and the hatchery sources used in the Whittlesey Creek supplementation experiment. We characterized the genetic diversity of 30 individuals from each of four populations using 13 microsatellite DNA loci. Levels of genetic variation were consistent with those in similar studies conducted throughout the basin. Significant genetic variation among the populations was observed, enabling adequate population delineation through assignment tests. Overall, 208 of the 211 sampled fish (98.6%) were correctly assigned to their population of origin. Simulated F1 hybrids between two hatchery strains and the Whittlesey Creek population were identifiable in the majority of attempts (90.5-100% accuracy with 0-2.5% error). The genetic markers and analytical techniques described provide the ability to monitor the concurrent coaster brook trout rehabilitation efforts along Wisconsin's Lake Superior south shore, including the detection of hybridization between hatchery and native populations. ?? Copyright by the American Fisheries Society 2008.

Fish community changes in the St. Louis River estuary, Lake Superior, 1989-1996: Is it ruffe or population dynamics?

USGS Publications Warehouse

Bronte, Charles R.; Evrard, Lori M.; Brown, William P.; Mayo, Kathleen R.; Edwards, Andrew J.

1998-01-01

Ruffe (Gymnocephalus cernuus) have been implicated in density declines of native species through egg predation and competition for food in some European waters where they were introduced. Density estimates for ruffe and principal native fishes in the St. Louis River estuary (western Lake Superior) were developed for 1989 to 1996 to measure changes in the fish community in response to an unintentional introduction of ruffe. During the study, ruffe density increased and the densities of several native species decreased. The reductions of native stocks to the natural population dynamics of the same species from Chequamegon Bay, Lake Superior (an area with very few ruffe) were developed, where there was a 24-year record of density. Using these data, short- and long-term variations in catch and correlations among species within years were compared, and species-specific distributions were developed of observed trends in abundance of native fishes in Chequamegon Bay indexed by the slopes of densities across years. From these distributions and our observed trend-line slopes from the St. Louis River, probabilities of measuring negative change at the magnitude observed in the St. Louis River were estimated. Compared with trends in Chequamegon Bay, there was a high probability of obtaining the negative slopes measured for most species, which suggests natural population dynamics could explain, the declines rather than interactions with ruffe. Variable recruitment, which was not related to ruffe density, and associated density-dependent changes in mortality likely were responsible for density declines of native species.

A previously unrecognized path of early Holocene base flow and elevated discharge from Lake Minong to Lake Chippewa across eastern Upper Michigan

USGS Publications Warehouse

Loope, Walter L.; Jol, Harry M.; Fisher, Timothy G.; Blewett, William L.; Loope, Henry M.; Legg, Robert J.

2014-01-01

It has long been hypothesized that flux of fresh meltwater from glacial Lake Minong in North America's Superior Basin to the North Atlantic Ocean triggered rapid climatic shifts during the early Holocene. The spatial context of recent support for this idea demands a reevaluation of the exit point of meltwater from the Superior Basin. We used ground penetrating radar (GPR), foundation borings from six highway bridges, a GIS model of surface topography, geologic maps, U.S. Department of Agriculture–Natural Resources Conservation Service soils maps, and well logs to investigate the possible linkage of Lake Minong with Lake Chippewa in the Lake Michigan Basin across eastern Upper Michigan. GPR suggests that a connecting channel lies buried beneath the present interlake divide at Danaher. A single optical age hints that the channel aggraded to 225 m as elevated receipt of Lake Agassiz meltwater in the Superior Basin began to wane <10.6 ka. The large supply of sediment required to accommodate aggradation was immediately available at the channel's edge in the littoral shelves of abandoned Lake Algonquin and in distal parts of post-Algonquin fans. As discharge decreased further, the aggraded channel floor was quickly breached and interbasin flow to Lake Chippewa was restored. Basal radiocarbon ages on wood from small lakes along the discharge path and a GIS model of Minong's shoreline are consistent with another transgression of Minong after ca. 9.5 ka. At the peak of the latter transgression, the southeastern rim of the Superior Basin (Nadoway Drift Barrier) failed, ending Lake Minong. Upon Minong's final drop, aggradational sediments were deposited at Danaher, infilling the prior breach.

Pulpwood Production in the Lake States, by County, 1978

Treesearch

James E. Blyth; W. Brad Smith

1979-01-01

Pulpwood production in the Lake States - Michigan, Minnesota, and Wisconsin - advances from 4.74 million cords in 1977 to 4.91 millions cords in 1978. Pulpwood production is shown by county and species group for these three States

Statewide lake classification utilizing LANDSAT imagery for the state of Wisconsin

NASA Technical Reports Server (NTRS)

Martin, R. H.; Merideth, R. W., Jr.

1981-01-01

A cooperative program between the Wisconsin Department of Natural Resources and the University of Wisconsin-Madison resulted in the assessment of the trophic condition of approximately 3,000 significant inland lakes in Wisconsin. The feasibility of using both photographic and digital representations of LANDSAT multispectral scanner data for lake classification was investigated. The result was the development of a nearly automated system which, with minimal human interaction, locates and extracts the lake data, then corrects the data for atmospheric effects, and finally classifies all the significant lakes in the state as to trophic condition.

Watershed research and management in the lake states and northeastern United States

Treesearch

Elton S. Verry; James W. Hornbeck; H. Albert

2000-01-01

We present a brief synopsis of the beginnings of watershed management research and practice in the Lake States and Northeastern United States, followed by a summary of significant research findings on many aspects of watershed management, and finally, a review of four examples of how watershed management research has been incorporated into national forest management...

Status of the Amphipod Diporeia spp. in Lake Superior, poster presentation

EPA Science Inventory

The amphipod Diporeia has historically been the dominant benthic macroinvertebrate in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relatively stable i...

Sulfur-Oxidizing Bacteria in Soap Lake (Washington State), a Meromictic, Haloalkaline Lake with an Unprecedented High Sulfide Content▿

PubMed Central

Sorokin, Dimitry Y.; Foti, Mirjam; Pinkart, Holly C.; Muyzer, Gerard

2007-01-01

Culture-dependent and -independent techniques were used to study the diversity of chemolithoautotrophic sulfur-oxidizing bacteria in Soap Lake (Washington State), a meromictic, haloalkaline lake containing an unprecedentedly high sulfide concentration in the anoxic monimolimnion. Both approaches revealed the dominance of bacteria belonging to the genus Thioalkalimicrobium, which are common inhabitants of soda lakes. A dense population of Thioalkalimicrobium (up to 107 cells/ml) was found at the chemocline, which is characterized by a steep oxygen-sulfide gradient. Twelve Thioalkalimicrobium strains exhibiting three different phenotypes were isolated in pure culture from various locations in Soap Lake. The isolates fell into two groups according to 16S rRNA gene sequence analysis. One of the groups was closely related to T. cyclicum, which was isolated from Mono Lake (California), a transiently meromictic, haloalkaline lake. The second group, consisting of four isolates, was phylogenetically and phenotypically distinct from known Thioalkalimicrobium species and unique to Soap Lake. It represented a new species, for which we suggest the name Thioalkalimicrobium microaerophilum sp. nov. PMID:17114324

Habitat use by fishes of Lake Superior. I. Diel patterns of habitat use in nearshore and offshore waters of the Apostle Islands region

USGS Publications Warehouse

Gorman, O.T.; Yule, D.L.; Stockwell, J.D.

2012-01-01

Diel patterns of distribution of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of the Apostle Islands region of Lake Superior were described using bottom trawls, mid-water trawls, and acoustic gear during day and night sampling. These data revealed three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no migration. DVM was expressed by fishes migrating from benthopelagic to pelagic strata and DBM was expressed by fishes migrating horizontally from deeper waters in the day to shallower waters at night while remaining within the benthopelagic stratum. Most fishes that did not exhibit diel migration showed increased nighttime densities as a result of increased activity and movement from benthic to benthopelagic strata. Rainbow Smelt (Osmerus mordax), Cisco (Coregonus artedi), Bloater (C. hoyi), Kiyi (C. kiyi), juvenile Trout-Perch (Percopsis omiscomaycus), and adult siscowet (Salvelinus namaycush siscowet) exhibited DVM. Lake Whitefish (C. clupeaformis), lean Lake Trout (Salvelinus namaycush namaycush), and juvenile siscowet exhibited DBM. Adult Trout-Perch and adult Pygmy Whitefish (Prosopium coulteri) exhibited a mixture of DBM and DVM. Burbot (Lota lota), Slimy Sculpin (Cottus cognatus), Spoonhead Sculpin (C. ricei), and Deepwater Sculpin (Myoxocephalus thompsonii) did not exhibit diel migration, but showed evidence of increased nocturnal activity. Ninespine Stickleback (Pungitius pungitius) exhibited a mixture of DVM and non-migration. Juvenile Pygmy Whitefish did not show a diel change in density or depth distribution. Species showing ontogenetic shifts in depth distribution with larger, adult life stages occupying deeper waters included, Rainbow Smelt, lean and siscowet Lake Trout, Lake Whitefish, Pygmy Whitefish, Ninespine Stickleback and Trout-Perch. Of these species, siscowet also showed an ontogenetic shift from primarily DBM as juveniles to primarily DVM as adults. Across all depths, fishes

Sea lamprey mark type, marking rate, and parasite-host relationships for lake trout and other species in Lake Ontario

USGS Publications Warehouse

Lantry, Brian F.; Adams, Jean V.; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

2015-01-01

We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

1986 Great Lakes Seismic refraction survey (GLIMPCE): Line A - refraction mode

USGS Publications Warehouse

Morel-a-l'Huissier, Patrick; Karl, John H.; Tréhu, Anne M.; Hajnal, Zoltan; Mereu, Robert F.; Meyer, Robert P.; Sexton, John L.; Ervin, C. Patrick; Green, Alan G.; Hutchinson, Deborah

1990-01-01

In the fall of 1986, the Geological Survey of Canada (GSC), the United States Geological Survey (USGS), two Canadian universities -- University of Western Ontario and University of Saskatchewan, and four American universities -- Northern Illinois University, Southern Illinois University, University of Wisconsin-Madison and University of Wisconsin-Oshkosh participated in a major deep seismic experiment in Lake Superior under the GLIMPCE (Great Lakes International Multidisciplinary Program on Crustal Evolution) umbrella. This Open-File Report presents the seismic sections for line A, which was shot specifically for refraction recording. The main target for study by this line was the Mid-Continent Rift System. All recording stations, 31 in total (26 land stations and 5 OBSs), recorded energy from shots fired every two minutes (333 m spacing) by a tuned airgun array towed by a contracted ship along line A in Lake Superior. These data are the densest such data ever recorded in the continental North America over such distances. It is also unique since coincident seismic reflection and refraction are available.

STATUS OF THE AMPHIPOD DIPOREIA SPP. IN LAKE SUPERIOR, 1994-2000

EPA Science Inventory

The amphipod Diporeia spp. is the dominant component of the Great Lakes benthic macroinvertebrate fauna in terms of both numbers and biomass, and plays an important role in the ecosystem. The Great Lakes Water Quality Agreement calls for the use of Diporeia as an indicator of ec...

Demographic and Component Allee Effects in Southern Lake Superior Gray Wolves

PubMed Central

Stenglein, Jennifer L.; Van Deelen, Timothy R.

2016-01-01

Recovering populations of carnivores suffering Allee effects risk extinction because positive population growth requires a minimum number of cooperating individuals. Conservationists seldom consider these issues in planning for carnivore recovery because of data limitations, but ignoring Allee effects could lead to overly optimistic predictions for growth and underestimates of extinction risk. We used Bayesian splines to document a demographic Allee effect in the time series of gray wolf (Canis lupus) population counts (1980–2011) in the southern Lake Superior region (SLS, Wisconsin and the upper peninsula of Michigan, USA) in each of four measures of population growth. We estimated that the population crossed the Allee threshold at roughly 20 wolves in four to five packs. Maximum per-capita population growth occurred in the mid-1990s when there were approximately 135 wolves in the SLS population. To infer mechanisms behind the demographic Allee effect, we evaluated a potential component Allee effect using an individual-based spatially explicit model for gray wolves in the SLS region. Our simulations varied the perception neighborhoods for mate-finding and the mean dispersal distances of wolves. Simulation of wolves with long-distance dispersals and reduced perception neighborhoods were most likely to go extinct or experience Allee effects. These phenomena likely restricted population growth in early years of SLS wolf population recovery. PMID:26930665

Demographic and Component Allee Effects in Southern Lake Superior Gray Wolves.

PubMed

Stenglein, Jennifer L; Van Deelen, Timothy R

2016-01-01

Recovering populations of carnivores suffering Allee effects risk extinction because positive population growth requires a minimum number of cooperating individuals. Conservationists seldom consider these issues in planning for carnivore recovery because of data limitations, but ignoring Allee effects could lead to overly optimistic predictions for growth and underestimates of extinction risk. We used Bayesian splines to document a demographic Allee effect in the time series of gray wolf (Canis lupus) population counts (1980-2011) in the southern Lake Superior region (SLS, Wisconsin and the upper peninsula of Michigan, USA) in each of four measures of population growth. We estimated that the population crossed the Allee threshold at roughly 20 wolves in four to five packs. Maximum per-capita population growth occurred in the mid-1990s when there were approximately 135 wolves in the SLS population. To infer mechanisms behind the demographic Allee effect, we evaluated a potential component Allee effect using an individual-based spatially explicit model for gray wolves in the SLS region. Our simulations varied the perception neighborhoods for mate-finding and the mean dispersal distances of wolves. Simulation of wolves with long-distance dispersals and reduced perception neighborhoods were most likely to go extinct or experience Allee effects. These phenomena likely restricted population growth in early years of SLS wolf population recovery.

Contaminant trends in lake trout and walleye from the Laurentian Great Lakes

USGS Publications Warehouse

DeVault, David S.; Hesselberg, Robert J.; Rodgers, Paul W.; Feist, Timothy J.

1996-01-01

Trends in PCBs, DDT, and other contaminants have been monitored in Great Lakes lake trout and walleye since the 1970s using composite samples of whole fish. Dramatic declines have been observed in concentrations of PCB, ΣDDT, dieldrin, and oxychlordane, with declines initially following first order loss kinetics. Mean PCB concentrations in Lake Michigan lake trout increased from 13 μg/g in 1972 to 23 μg/g in 1974, then declined to 2.6 μg/g by 1986. Between 1986 and 1992 there was little change in concentration, with 3.5 μg/g observed in 1992. ΣDDT in Lake Michigan trout followed a similar trend, decreasing from 19.2 μg/g in 1970 to 1.1 μg/g in 1986, and 1.2 μg/g in 1992. Similar trends were observed for PCBs and ΣDDT in lake trout from Lakes Superior, Huron and Ontario. Concentrations of both PCB and ΣDDT in Lake Erie walleye declined between 1977 and 1982, after which concentrations were relatively constant through 1990. When originally implemented it was assumed that trends in the mean contaminant concentrations in open-lake fish would serve as cost effective surrogates to trends in the water column. While water column data are still extremely limited it appears that for PCBs in lakes Michigan and Superior, trends in lake trout do reasonably mimic those in the water column over the long term. Hypotheses to explain the trends in contaminant concentrations are briefly reviewed. The original first order loss kinetics used to describe the initial decline do not explain the more recent leveling off of contaminant concentrations. Recent theories have examined the possibilities of multiple contaminant pools. We suggest another hypothesis, that changes in the food web may have resulted in increased bioaccumulation. However, a preliminary exploration of this hypothesis using a change point analysis was inconclusive.

Watershed and discharge influences on the phase distribution and tributary loading of total mercury and methylmercury into Lake Superior.

PubMed

Babiarz, Christopher; Hoffmann, Stephen; Wieben, Ann; Hurley, James; Andren, Anders; Shafer, Martin; Armstrong, David

2012-02-01

Knowledge of the partitioning and sources of mercury are important to understanding the human impact on mercury levels in Lake Superior wildlife. Fluvial fluxes of total mercury (Hg(T)) and methylmercury (MeHg) were compared to discharge and partitioning trends in 20 sub-basins having contrasting land uses and geological substrates. The annual tributary yield was correlated with watershed characteristics and scaled up to estimate the basin-wide loading. Tributaries with clay sediments and agricultural land use had the largest daily yields with maxima observed near the peak in water discharge. Roughly 42% of Hg(T) and 57% of MeHg was delivered in the colloidal phase. Tributary inputs, which are confined to near-shore zones of the lake, may be more important to the food-web than atmospheric sources. The annual basin-wide loading from tributaries was estimated to be 277 kg yr(-1) Hg(T) and 3.4 kg yr(-1) MeHg (5.5 and 0.07 mg km(-2) d(-1), respectively). Copyright © 2011 Elsevier Ltd. All rights reserved.

Midcontinent rift volcanism in the Lake Superior region: Sr, Nd, and Pb isotopic evidence for a mantle plume origin

USGS Publications Warehouse

Nicholson, S.W.; Shirey, S.B.

1990-01-01

Between 1091 and 1098 Ma, most of a 15- to 20-km thickness of dominantly tholeiitic basalt erupted in the Midcontinent Rift System of the Lake Superior region, North America. The Portage Lake Volcanics in Michigan, which are the younget MRS flood basalts, fall into distinctly high- and low-TiO2 types having different liquid lines of descent. Incompatible trace elements in both types of tholeiites are enriched compared to depleted or primitive mantle and both basalt types are isotopically indistinguishable. The isotopic enrichment of the MRS source compared to depleted mantle is striking and must have occurred at least 700 m.y. before 1100 Ma. There are two likely sources for such magmatism: subcontinental lithospheric mantle enriched during the early Proterozoic or enriched mantle derived from an upwelling plume. Decompression melting of an upwelling enriched mantle plume in a region of lithosphere thinned by extension could have successfully generated the enormous volume (850 ?? 103 km3) of relatively homogeneous magma in a restricted time interval. -from Authors

Changes in depth occupied by Great Lakes lake whitefish populations and the influence of survey design

USGS Publications Warehouse

Rennie, Michael D.; Weidel, Brian C.; Claramunt, Randall M.; Dunlob, Erin S.

2015-01-01

Understanding fish habitat use is important in determining conditions that ultimately affect fish energetics, growth and reproduction. Great Lakes lake whitefish (Coregonus clupeaformis) have demonstrated dramatic changes in growth and life history traits since the appearance of dreissenid mussels in the Great Lakes, but the role of habitat occupancy in driving these changes is poorly understood. To better understand temporal changes in lake whitefish depth of capture (Dw), we compiled a database of fishery-independent surveys representing multiple populations across all five Laurentian Great Lakes. By demonstrating the importance of survey design in estimating Dw, we describe a novel method for detecting survey-based bias in Dw and removing potentially biased data. Using unbiased Dw estimates, we show clear differences in the pattern and timing of changes in lake whitefish Dw between our reference sites (Lake Superior) and those that have experienced significant benthic food web changes (lakes Michigan, Huron, Erie and Ontario). Lake whitefish Dw in Lake Superior tended to gradually shift to shallower waters, but changed rapidly in other locations coincident with dreissenid establishment and declines in Diporeia densities. Almost all lake whitefish populations that were exposed to dreissenids demonstrated deeper Dw following benthic food web change, though a subset of these populations subsequently shifted to more shallow depths. In some cases in lakes Huron and Ontario, shifts towards more shallow Dw are occurring well after documented Diporeia collapse, suggesting the role of other drivers such as habitat availability or reliance on alternative prey sources.

Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

USGS Publications Warehouse

Sierszen, Michael E.; Hrabik, Thomas R.; Stockwell, Jason D.; Cotter, Anne M; Hoffman, Joel C.; Yule, Daniel L.

2014-01-01

Support of whole-lake food webs through trophic linkages among pelagic, profundal and littoral habitats appears to be integral to the functioning of large lakes. These linkages can be disrupted though ecosystem disturbance such as eutrophication or the effects of invasive species and should be considered in native species restoration efforts.

Estimation of a Trophic State Index for selected inland lakes in Michigan, 1999–2013

USGS Publications Warehouse

Fuller, Lori M.; Jodoin, Richard S.

2016-03-11

A 15-year estimated Trophic State Index (eTSI) for Michigan inland lakes is available, and it spans seven datasets, each representing 1 to 3 years of data from 1999 to 2013. On average, 3,000 inland lake eTSI values are represented in each of the datasets by a process that relates field-measured Secchi-disk transparency (SDT) to Landsat satellite imagery to provide eTSI values for unsampled inland lakes. The correlation between eTSI values and field-measured Trophic State Index (TSI) values from SDT was strong as shown by R2 values from 0.71 to 0.83. Mean eTSI values ranged from 42.7 to 46.8 units, which when converted to estimated SDT (eSDT) ranged from 8.9 to 12.5 feet for the datasets. Most eTSI values for Michigan inland lakes are in the mesotrophic TSI class. The Environmental Protection Agency (EPA) Level III Ecoregions were used to illustrate and compare the spatial distribution of eTSI classes for Michigan inland lakes. Lakes in the Northern Lakes and Forests, North Central Hardwood Forests, and Southern Michigan/Northern Indiana Drift Plains ecoregions are predominantly in the mesotrophic TSI class. The Huron/Erie Lake Plains and Eastern Corn Belt Plains ecoregions, had predominantly eutrophic class lakes and also the highest percent of hypereutrophic lakes than other ecoregions in the State. Data from multiple sampling programs—including data collected by volunteers with the Cooperative Lakes Monitoring Program (CLMP) through the Michigan Department of Environmental Quality (MDEQ), and the 2007 National Lakes Assessment (NLA)—were compiled to compare the distribution of lake TSI classes between each program. The seven eTSI datasets are available for viewing and download with eSDT from the Michigan Lake Water Clarity Interactive Map Viewer at http://mi.water.usgs.gov/projects/RemoteSensing/index.html.

Genetic variability among lake whitefish from Isle Royale and the Upper Great Lakes

USGS Publications Warehouse

Stott, Wendylee; Todd, Thomas N.; Kallemeyn, Larry

2004-01-01

The coregonine fishes from Isle Royale National Park represent a unique group that has escaped the successional changes observed elsewhere in North America. Analysis of microsatellite DNA loci revealed significant genetic differences among samples of lake whitefish (Coregonus clupeaformis) from Isle Royale, Lake Superior, and Lake Huron. The amount of genetic variation observed is consistent with that seen in other studies of whitefishes from North America. The lake whitefish from Isle Royale had previously been assigned sub-species status, but no evidence was found to support this. The effects of common ancestry and demographics both play a role in determining the relatedness of the populations. As with other fish species from Isle Royale and the upper Great Lakes, the lake whitefish have their origins in the Mississippi refugium.

State and regional water-quality characteristics and trophic conditions of Michigan's inland lakes, 2001-2005

USGS Publications Warehouse

Fuller, L.M.; Minnerick, R.J.

2008-01-01

The U.S. Geological Survey and the Michigan Department of Environmental Quality are jointly monitoring selected water-quality constituents of inland lakes through 2015 as part of Michigan’s Lake Water Quality Assessment program. During 2001–2005, 433 lake basins from 364 inland lakes were monitored for baseline water-quality conditions and trophic status. This report summarizes the water-quality characteristics and trophic conditions of those monitored lake basins throughout the State. Regional variation of water quality in lake basins was examined by grouping on the basis of the five Omernik level III ecoregions within Michigan. Concentrations of most constituents measured were significantly different between ecoregions. Less regional variation of phosphorus concentrations was noted between Northern Lakes and Forests (50) and North Central Hardwoods (51) ecoregions during summer possibly because water samples were collected when lake productivity was high; hence the utilization of the limited amount of phosphorus by algae and macrophytes may have resulted in the more uniform concentrations between these two ecoregions. Concentrations of common ions (calcium, magnesium, potassium, sodium, chloride, and sulfate) measured in the spring typically were higher in the Michigan southern Lower Peninsula in the Eastern Corn Belt Plains (55), Southern Michigan/Northern Indiana Drift Plains (56), and Huron/Erie Lake Plains (57) ecoregions. Most ions whose concentrations were less than the minimum reporting levels or were nondetectable were from lakes in the Michigan northern Lower Peninsula and the Upper Peninsula in the Northern Lakes and Forests (50) and North Central Hardwoods (51) ecoregions. Chlorophyll a concentrations followed a similar distribution pattern. Measured properties such as pH and specific conductance (indicative of dissolved solids) also showed a regional relation. The lakes with the lowest pH and specific conductance were generally in the western

Watershed vs. within-lake drivers of nitrogen: phosphorus dynamics in shallow lakes.

PubMed

Ginger, Luke J; Zimmer, Kyle D; Herwig, Brian R; Hanson, Mark A; Hobbs, William O; Small, Gaston E; Cotner, James B

2017-10-01

Research on lake eutrophication often identifies variables affecting amounts of phosphorus (P) and nitrogen (N) in lakes, but understanding factors influencing N:P ratios is important given its influence on species composition and toxin production by cyanobacteria. We sampled 80 shallow lakes in Minnesota (USA) for three years to assess effects of watershed size, proportion of watershed as both row crop and natural area, fish biomass, and lake alternative state (turbid vs. clear) on total N : total P (TN : TP), ammonium, total dissolved phosphorus (TDP), and seston stoichiometry. We also examined N:P stoichiometry in 20 additional lakes that shifted states during the study. Last, we assessed the importance of denitrification by measuring denitrification rates in sediment cores from a subset of 34 lakes, and by measuring seston δ 15 N in four additional experimental lakes before and after they were experimentally manipulated from turbid to clear states. Results showed alternative state had the largest influence on overall N:P stoichiometry in these systems, as it had the strongest relationship with TN : TP, seston C:N:P, ammonium, and TDP. Turbid lakes had higher N at given levels of P than clear lakes, with TN and ammonium 2-fold and 1.4-fold higher in turbid lakes, respectively. In lakes that shifted states, TN was 3-fold higher in turbid lakes, while TP was only 2-fold higher, supporting the notion N is more responsive to state shifts than is P. Seston δ 15 N increased after lakes shifted to clear states, suggesting higher denitrification rates may be important for reducing N levels in clear states, and potential denitrification rates in sediment cores were among the highest recorded in the literature. Overall, our results indicate lake state was a primary driver of N:P dynamics in shallow lakes, and lakes in clear states had much lower N at a given level of P relative to turbid lakes, likely due to higher denitrification rates. Shallow lakes are often

77 FR 58204 - International Joint Commission Invites Public Comment on Upper Great Lakes Report via...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... of its International Upper Great Lakes Study Board, Lake Superior Regulation: Addressing Uncertainty... for comments has also been extended to September 30, 2012. The Study examines whether the regulation of outflows from Lake Superior through the compensating works and power dams on the St. Marys River...

Climate-driven changes in riverine inputs affecting the stoichiometry of Earth's largest lake

NASA Astrophysics Data System (ADS)

Sterner, R.; Small, G. E.

2014-12-01

Lake Superior, Earth's largest lake by area, has seen a steady increase in nitrate levels over the past century, while phosphorus remains exceedingly low, resulting in an increasingly imbalanced stoichiometry. Although its ratio of watershed area:lake area is relatively small, rivers emptying into Lake Superior could be important drivers of long-term changes in lake stoichiometry. To better assess how the Lake Superior watershed affects its stoichiometry, we examined the chemistry of two of its largest tributaries, the Saint Louis River and the Nipigon River, at their confluences with Lake Superior. Both of these rivers have high dissolved organic carbon (DOC) but low nitrate (NO3) concentrations relative to the lake. Using simple mixing models, we found these nearshore confluences to create sinks of lake NO3 as a result of relatively high rates of denitrification. Climate change is altering the amounts and patterns of delivery of materials from land to lakes and we also examined the plume from a June, 2012 100-year flood in the Saint Louis River. Three days after this historic rain event, we found elevated chlorophyll levels throughout the plume, up to 5-fold higher than in the open lake. Combining our samples with satellite imagery, we conservatively estimate that this plume contained 598,000 kg of phosphorus in dissolved and particulate form, or 40% of the average annual P input to the lake. If storm events such as this occur with increasing frequency as predicted in climate change scenarios, the lake's productivity may increase and stoichiometry could become more balanced, through greater P input and increased N retention due to sedimentation and denitrification.

Centrarchid assemblages in Mississippi state-operated fishing lakes

USGS Publications Warehouse

Olive, J.A.; Miranda, L.E.; Hubbard, W.D.

2005-01-01

We evaluated electrofishing catch per effort in 27 state-operated fishing lakes in Mississippi to identify patterns of centrarchid community composition and to determine whether those patterns were related to selected environmental characteristics and to artificial nutrient enrichment. Ordination with detrended correspondence analysis recognized two major axes accounting for 77% of the variability in species ordination. Axis 1 showed a distinct separation between the body sizes of various species. A notable exception was the density of small (<30 cm) largemouth bass Micropterus salmoides, which aligned with the large individuals of other centrarchid species. This pattern suggested that through predation, high densities of small largemouth bass exerted significant control over the size structure of fish communities. Axis 2 separated species of crappies Pomoxis spp., suggesting that conditions other than strong species interactions also moderated the composition of crappies in the assemblages. However, neither lake morphometry nor watershed composition exhibited a major influence over axes 1 or 2. In small, intensively managed lakes with low habitat complexity, the regulatory importance of biotic interactions may overwhelm that of abiotic factors. Nutrient enrichment influenced community structure by changing the densities of bluegill Lepomis macrochirus and largemouth bass substantially but had a minor or no effect on other species. The management techniques used in these state-operated lakes are usually targeted toward a particular species without adequately considering the other species within the community. Our results show that attention to community-level interactions could provide valuable insight into factors that affect the quality of the fishery, insight that is not available through traditional population-level assessments. ?? Copyright by the American Fisheries Society 2005.

Cyanotoxins in Inland Lakes of the United States: Occurrence and Potential Recreational Health Risks in the EPA National Lakes Assessment 2007

EPA Science Inventory

A large nation-wide survey or cyanotoxlns (1161 lakes)in the United States (U.S.) was conducted dunng the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse to...

The importance of lake-specific characteristics for water quality across the continental United States.

PubMed

Read, Emily K; Patil, Vijay P; Oliver, Samantha K; Hetherington, Amy L; Brentrup, Jennifer A; Zwart, Jacob A; Winters, Kirsten M; Corman, Jessica R; Nodine, Emily R; Woolway, R Iestyn; Dugan, Hilary A; Jaimes, Aline; Santoso, Arianto B; Hong, Grace S; Winslow, Luke A; Hanson, Paul C; Weathers, Kathleen C

2015-06-01

Lake water quality is affected by local and regional drivers, including lake physical characteristics, hydrology, landscape position, land cover, land use, geology, and climate. Here, we demonstrate the utility of hypothesis testing within the landscape limnology framework using a random forest algorithm on a national-scale, spatially explicit data set, the United States Environmental Protection Agency's 2007 National Lakes Assessment. For 1026 lakes, we tested the relative importance of water quality drivers across spatial scales, the importance of hydrologic connectivity in mediating water quality drivers, and how the importance of both spatial scale and connectivity differ across response variables for five important in-lake water quality metrics (total phosphorus, total nitrogen, dissolved organic carbon, turbidity, and conductivity). By modeling the effect of water quality predictors at different spatial scales, we found that lake-specific characteristics (e.g., depth, sediment area-to-volume ratio) were important for explaining water quality (54-60% variance explained), and that regionalization schemes were much less effective than lake specific metrics (28-39% variance explained). Basin-scale land use and land cover explained between 45-62% of variance, and forest cover and agricultural land uses were among the most important basin-scale predictors. Water quality drivers did not operate independently; in some cases, hydrologic connectivity (the presence of upstream surface water features) mediated the effect of regional-scale drivers. For example, for water quality in lakes with upstream lakes, regional classification schemes were much less effective predictors than lake-specific variables, in contrast to lakes with no upstream lakes or with no surface inflows. At the scale of the continental United States, conductivity was explained by drivers operating at larger spatial scales than for other water quality responses. The current regulatory practice of using

Projecting the aspen resource in the Lake States.

Treesearch

William A. Leuschner

1972-01-01

Aspen growing stock inventories for nine Lake States forest survey units were updated to the common base year of 1968. Cut and inventory were projected to the year 2000 under three sets of assumptions. Potential shortages were found in northeastern Wisconsin and Michigan if historical trends continue.

Lake States Pulpwood Production Rises 11 Percent in 1969

Treesearch

James E. Blyth

1970-01-01

This 24th annual report shows that 1969 Lake States pulpwood output rose to about 3.9 million cords from about 3.5 million cords in 1968. Pulpwood harvesting increased 150,000 cords in Wisconsin, 113,000 cords in Minnesota, and 102,000 cords in Michigan. For the first time, pulpwood imports from western States exceeded those from Canada.

Ninespine Stickleback Abundance in Lake Michigan Increases After Dreissenid Mussel Invasion

USGS Publications Warehouse

Madenjian, Charles P.; Bunnell, David B.; Gorman, Owen T.

2010-01-01

Based on data from our annual lakewide bottom trawl survey of Lake Michigan, we determined that density of ninespine sticklebacks Pungitius pungitius increased from an average of 0.234 kg/ha during 1973–1995 to an average of 1.318 kg/ha during 1996–2007. This greater-than-fivefold increase in density coincided with the dreissenid mussel invasion of Lake Michigan. Intervention analysis revealed that ninespine stickleback density in Lake Michigan significantly increased between the two time periods. In contrast, based on data from our annual bottom trawl survey of U.S. waters of Lake Superior, ninespine stickleback density decreased from an average of 0.133 kg/ha during 1978–1999 to an average of only 0.026 kg/ha during 2000–2007. This greater-than-fivefold density decrease, which was found to be significant via intervention analysis, coincided with population recovery for both lean and fat morphotypes of lake trout Salvelinus namaycush in Lake Superior. In contrast to Lake Michigan, dreissenid mussels have not invaded Lake Superior on a lakewide basis. Thus, a comparison of these two lakes indicated that the increase in ninespine stickleback abundance in Lake Michigan was most likely attributable to the dreissenid mussel invasion. In addition, based on our correlation analysis, alewives Alosa pseudoharengus did not have an adverse effect on ninespine stickleback abundance in Lake Michigan. Perhaps the recent increase in biomass of green algae Cladophora spp. associated with the dreissenid mussel invasion improved spawning habitat quality for ninespine sticklebacks and led to their stepwise abundance increase in Lake Michigan beginning in 1996

Growth and yield of white spruce plantations in the Lake States (a literature review).

Treesearch

H. Michael Rauscher

1984-01-01

This summary of the white spruce literature covers the structure, site relations, population dynamics, and cultural practices applicable to established plantations in the Lake States. The objective of this paper is to assemble and organize all information relevant to the silviculture, growth, and yield of white spruce plantations in the Lake States .

Sea lamprey mark type, wounding rate, and parasite-host preference and abundance relationships for lake trout and other species in Lake Ontario

USGS Publications Warehouse

Lantry, Brian F.; Adams, Jean; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

2015-01-01

We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

ASSESSING WATER QUALITY CHANGES IN THE LAKES OF THE NORTHEASTERN UNITED STATES USING SEDIMENT DIATOMS

EPA Science Inventory

Diatom assemblages were selected as indicators of lake condition and to assess historical lake water quality changes in 257 lakes in the northeastern United States. The "top" (surface sediments, present-day) and "bottom" (generally from >30 cm deep, representing historical condit...

DEEPWATER AND NEARSHORE FOOD WEB CHARACTERIZATIONS IN LAKE SUPERIOR

EPA Science Inventory

Due to the difficulty associated with sampling deep aquatic systems, food web relationships among deepwater fauna are often poorly known. We are characterizing nearshore versus offshore habitats in the Great Lakes and investigating food web linkages among profundal, pelagic, and ...

A computerized tree growth projection system for forest resource evaluation in the lake states

Treesearch

Allen L. Lundgren; Burton L. Essex

1978-01-01

A computerized tree growth projection system has been developed for the Lake States Region as part of a larger Forest Resources Evaluation Program (FREP). Incorporating data from more than 1500 permanent growth plots throughout the Lake States, this system projects tree growth, mortality, regeneration, and removals in stands with any mixture of tree species and sizes,...

Genetically improved conifers for the Lake States

Treesearch

Jonathan W. Wright

1973-01-01

The Lake States provenance test of jack pine was started by Paul Rudolf of the USDA Forest Service in 1951. That marked the beginning of two decades of serious tree improvement research in the region. In this paper I shall recount some of the progress that has been made. But it is also necessary to consider the extent to which genetic improvements have been put to...

Proceedings: first Lake States forest genetics conference

Treesearch

Lake States Forest Experiment Station

1953-01-01

Over the years there has been a small but impportant amount of research in forest genetics in the Lake States, and recently there has beeen a growing awareness of the importance of tree improvement in this region. For these reasons it appeared that a meeting of people active or interested in forest genetics might be worth while. So after consultation with a number of...

Age, growth, and maturity of the longnose sucker Catostomus catostomus, of western Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1969-01-01

Studies of age, growth, and maturity were based on 1760 fish collected in western Lake Superior in 1964-65. The body:scale relation was curvilinear and the curve had an intercept of 1.65 inches on the length axis. The weight increased as the 2.85 power of the length. Some fish formed an annulus before May 18 in 1965; all had completed annuli by late September. Longnose suckers grew 3.6 inches the 1st year, reached 12 inches in the 6th year, and 18 inches in the 11th year. Fish from Pikes Bay grew faster than those from Gull Island Shoal. Over 6 years were required for weight to reach 1 lb and nearly 10 years to reach 2 lb. Minimum length at maturity was 10.5 inches for males and 11.5 inches for females. The youngest mature male belonged to age-group IV and the youngest mature female to age-group V. All males were mature at 14.5-14.9 inches (age-group VIII) and all females at 15.0-15.4 inches (age-group IX). Finclipped longnose suckers returned to spawn in the Brule River in successive years. One fish returned to spawn in 4 successive years. Many of the fish were not recaptured until 2 or 3 years after marking. The time of the Brule River spawning migration depended more on water temperature than on length of day. The average water temperature during the peak of the spawning runs of 1958-64 was 55.4 F. Larval suckers apparently spend little time in the Brule River and adjacent streams and drift downstream to the lake soon after hatching. The number of eggs in the ovaries of eight suckers ranged from 14 to 35 thousand and averaged 24 thousand for fish 13.9-17.7 inches long.

Pulpwood Production in the Lake States by County, 1977

Treesearch

James E. Blyth; W. Brad Smith

1978-01-01

This 32nd annual report shows 1977 pulpwood production by county and species group in Michigan, Minnesota, and Wisconsin. Production in these three Lake States inched ahead to 4.74 million cords from 4.69 million cords in 1976

The Great Lakes' regional climate regimes

NASA Astrophysics Data System (ADS)

Sugiyama, Noriyuki

For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

Timber harvesting trends in the Lake States, 1983-1987.

Treesearch

W. Brad Smith; James E. Blyth

1989-01-01

Growing-stock removals for products have increased by 12% in the Lake States since 1983. Regional gains are led by red pine, aspen, and other hardwoods. New mills and technology promise to further improve markets for underutilized species throughout the region.

Catchment and atmospheric effects on acidity of lakes in the northeastern United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, R.B.; Anderson, D.S.; Rhodes, T.E.

1995-06-01

Sedimentary evidence from 12 lakes in northeastern United States reveals that both catchment and atmospheric processes have caused changes in lake acidity. Diatom remains indicate pH 5.2 to 5.8 (one lake 6.8) for one to two centuries before impacts on the catchment by Euro-americans. These low-alkalinity lakes were very sensitive to altered fluxes of base cations and acids. Several lakes increased in pH by 0.2 to 0.6 unit in the 1800s and early 1900s when their catchments were logged. Re-acidification of some of the lakes was initially due to forest succession. Older sediment from one of the lakes also showsmore » alkalization by natural disturbance, and acidification paralleling forest succession. However, much of the recent acidification, to uniquely low levels by the 1970s is due to high sulfur deposition.« less

Conservation and management of fisheries and aquatic communities in Great Lakes connecting channels

USGS Publications Warehouse

Roseman, Edward F.; Thompson, Patricia A.; Farrell, John M.; Mandrak, Nicholas E.; Stepien, Carol A.

2014-01-01

The North American Laurentian Great Lakes are linked by a unique series of riverine and lacustrine waters known as the Great Lakes connecting channels that are as integral to the basin's ecology and economies as the lakes themselves. The St. Marys River (SMR) is the northernmost channel and flows from Lake Superior to Lake Huron. Waters from the upper Great Lakes (Lakes Superior, Michigan, and Huron) empty from Lake Huron via the St. Clair–Detroit River system (SCDRS, also known as the Huron–Erie Corridor) into Lake Erie. The SCDRS is composed of the St. Clair River, Lake St. Clair, and the Detroit River. The Niagara River (NR) serves as the outflow from Lake Erie into Lake Ontario. The NR above Niagara Falls is bisected by Grand Island and contains several other islands and man-made embayments whereas the NR below the falls is more linear. The outflow from Lake Ontario, representing the natural outlet of all the Great Lakes, is the St. Lawrence River (SLR) which empties into the Gulf of St. Lawrence in the northwest Atlantic Ocean.

Biogeochemical phosphorus mass balance for Lake Baikal, southeastern Siberia, Russia

USGS Publications Warehouse

Callender, E.; Granina, L.

1997-01-01

Extensive data for Lake Baikal have been synthesized into a geochemical mass balance for phosphorus (P). Some of the P budget and internal cycling terms for Baikal have been compared to similar terms for oligotrophic Lake Superior, mesotrophic Lake Michigan and the Baltic Sea, and the Ocean. Lake Baikal has a large external source of fluvial P compared to the Laurentian upper Great Lakes and the Ocean. The major tributary to Lake Baikal has experienced substantial increases in organic P loading during the past 25 years. This, coupled with potential P inputs from possible phosphorite mining, may threaten Baikal's oligotrophic status in the future. Water-column remineralization of particulate organic P is substantially greater in Lake Baikal than in the Laurentian Great Lakes. This is probably due to the great water depths of Lake Baikal. There is a gradient in P burial efficiency, with very high values (80%) for Lake Baikal and Lake Superior, lower values (50%) for Lake Michigan and the Baltic Sea, and a low value (13%) for the Ocean. The accumulation rate of P in Lake Baikal sediments is somewhat greater than that in the Laurentian upper Great Lakes and the Baltic Sea, and much greater than in the Ocean. Benthic regeneration rates are surprisingly similar for large lacustrine and marine environments and supply less than 10% of the P utilized for primary production in these aquatic environments.

Finger Lake Region, NY State, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This view of the central portion of upstate New York, centers on the Finger Lakes. The large city on the shore of Lake Ontario, is Rochester. Although the city, being a business, educational and technical center, has no heavy industry, the outline of the city shows fairly well in the snow, but not as well as the outlines of industrial cities elsewhere in the world. The Finger Lakes are large linear lakes carved out by glaciers during the last ice age.

Ecology of Lake Superior: Linking Landscape to Nearshore Condition

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

Lake Superior: Nearshore Variability and a Landscape Driver Concept

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

Survey design for lakes and reservoirs in the United States to assess contaminants in fish tissue.

PubMed

Olsen, Anthony R; Snyder, Blaine D; Stahl, Leanne L; Pitt, Jennifer L

2009-03-01

The National Lake Fish Tissue Study (NLFTS) was the first survey of fish contamination in lakes and reservoirs in the 48 conterminous states based on a probability survey design. This study included the largest set (268) of persistent, bioaccumulative, and toxic (PBT) chemicals ever studied in predator and bottom-dwelling fish species. The U.S. Environmental Protection Agency (USEPA) implemented the study in cooperation with states, tribal nations, and other federal agencies, with field collection occurring at 500 lakes and reservoirs over a four-year period (2000-2003). The sampled lakes and reservoirs were selected using a spatially balanced unequal probability survey design from 270,761 lake objects in USEPA's River Reach File Version 3 (RF3). The survey design selected 900 lake objects, with a reserve sample of 900, equally distributed across six lake area categories. A total of 1,001 lake objects were evaluated to identify 500 lake objects that met the study's definition of a lake and could be accessed for sampling. Based on the 1,001 evaluated lakes, it was estimated that a target population of 147,343 (+/-7% with 95% confidence) lakes and reservoirs met the NLFTS definition of a lake. Of the estimated 147,343 target lakes, 47% were estimated not to be sampleable either due to landowner access denial (35%) or due to physical barriers (12%). It was estimated that a sampled population of 78,664 (+/-12% with 95% confidence) lakes met the NLFTS lake definition, had either predator or bottom-dwelling fish present, and could be sampled.

Red Pine in the Northern Lake States

Treesearch

Thomas L. Schmidt

2003-01-01

Red pine is an important tree species for the Northern Lake States. About 4 percent of the total area of timberland is dominated by red pine but most other forest types also have red pine as a component. The red pine forest type in the region has dramatically increased in area since the 1930s. Stand-size class distribution of the red pine forest type has changed over...

Great Lakes, No Clouds

NASA Image and Video Library

2017-12-08

NASA image acquired August 28, 2010 Late August 2010 provided a rare satellite view of a cloudless summer day over the entire Great Lakes region. North Americans trying to sneak in a Labor Day weekend getaway on the lakes were hoping for more of the same. The Great Lakes comprise the largest collective body of fresh water on the planet, containing roughly 18 percent of Earth's supply. Only the polar ice caps contain more fresh water. The region around the Great Lakes basin is home to more than 10 percent of the population of the United States and 25 percent of the population of Canada. Many of those people have tried to escape record heat this summer by visiting the lakes. What they found, according to The Hamilton Spectator, was record-breaking water temperatures fueled by record-breaking air temperatures in the spring and summer. By mid-August, the waters of Lake Superior were 6 to 8°C (11 to 14°F) above normal. Lake Michigan set records at about 4°C (7°F) above normal. The other three Great Lakes – Huron, Erie, and Ontario -- were above normal temperatures, though no records were set. The image was gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite at 1:30 p.m. Central Daylight Time (18:30 UTC) on August 28. Open water appears blue or nearly black. The pale blue and green swirls near the coasts are likely caused by algae or phytoplankton blooms, or by calcium carbonate (chalk) from the lake floor. The sweltering summer temperatures have produced an unprecedented bloom of toxic blue-green algae in western Lake Erie, according to the Cleveland Plain Dealer. NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Mike Carlowicz. Instrument: Aqua - MODIS Click here to see more images from NASA Goddard’s Earth Observatory NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft

Slate Islands, Lake Superior, Canada: A mid-size, Complex Impact Structure

NASA Technical Reports Server (NTRS)

Dressler, B. O.; Sharpton, V. L.; Copeland, P.

1999-01-01

The target rocks of the 30-32-km diameter Slate Islands impact structure in northern Lake Superior, Canada, are Archean supracrustal and igneous rocks and supracrustal Proterozoic rocks. Shatter cones, pseudotachylites, impact glasses, and microscopic shock metamorphic features were formed during the contact and compression phase of the impact process, followed, during excavation and central uplift, by polymict, clastic matrix breccias in the uplifted target, and by allogenic fall-back breccias (suevite and bunte breccia). Monomict, autoclastic breccias were mainly observed on Mortimer Island and the other outlying islands of the archipelago and were probably generated relatively late in the impact process (central uplift and/or crater modification). The frequency of low index planar shock metamorphic features in quartz was correlated with results from shock experiments to estimate shock pressures experienced by the target rocks. The resulting shock attenuation plan across the archipelago is irregular, probably because the shock wave did not expand from a point or spherical source, and because of the destruction of an originally more regular shock attenuation plan during the central uplift and crater modification stages of the impact process. No impact melt rock bodies have been positively identified on the islands. An impact melt may be present in the annular trough around the islands, though and-based on a weighted mixture of target rocks-may have an intermediate-mafic composition. No such impact melt was found on the archipelago. An Ar-40-Ar-39 release spectrum of a pseudotachylite provides an age of about 436 Ma for the impact structure, substantiating age constraints based on various stratigraphic considerations.

Inventory and transport of plastic debris in the Laurentian Great Lakes.

PubMed

Hoffman, Matthew J; Hittinger, Eric

2017-02-15

Plastic pollution in the world's oceans has received much attention, but there has been increasing concern about the high concentrations of plastic debris in the Laurentian Great Lakes. Using census data and methodologies used to study ocean debris we derive a first estimate of 9887 metric tonnes per year of plastic debris entering the Great Lakes. These estimates are translated into population-dependent particle inputs which are advected using currents from a hydrodynamic model to map the spatial distribution of plastic debris in the Great Lakes. Model results compare favorably with previously published sampling data. The samples are used to calibrate the model to derive surface microplastic mass estimates of 0.0211 metric tonnes in Lake Superior, 1.44 metric tonnes in Huron, and 4.41 metric tonnes in Erie. These results have many applications, including informing cleanup efforts, helping target pollution prevention, and understanding the inter-state or international flows of plastic pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

REGIONAL LAKE TROPHIC PATTERNS IN THE NORTHEASTERN UNITED STATES: THREE APPROACHES

EPA Science Inventory

During the summers of 1991-1994, the Environmental Monitoring and Assessment Progam (EMAP) conducted variable probability sampling on 344 lakes throughout the northeastern United States. Trophic state data were analyzed for the Northeast as a whole and for each of its three major...

Proceedings: second Lake States forest tree improvement conference

Treesearch

Lake States Forest Experiment Station

1955-01-01

I am firmly convinced that the Lake States Forest Tree Improvement Committee, and similar groups in other regions, can play an important role in encouraging and coordinating research and other activities in forest genetics. As this new field of work continues to expand, which it assuredly will, it will become of increasing importance to maintain close liaison among the...

Simulation of the effects of the Devils Lake State Outlet on hydrodynamics and water quality in Lake Ashtabula, North Dakota, 2006-10

USGS Publications Warehouse

Galloway, Joel M.

2011-01-01

In 2010, a two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Lake Ashtabula, North Dakota, was developed by the U.S. Geological Survey in cooperation with the North Dakota State Water Commission to understand the dynamics of chemical constituents in the reservoir and to provide a tool for the management and operation of the Devils Lake State Outlet in meeting the water-quality standards downstream from Baldhill Dam. The Lake Ashtabula model was calibrated for hydrodynamics, sulfate concentrations, and total dissolved-solids concentrations to ambient conditions from June 2006 through June 2010. The calibrated model then was used to simulate four scenarios that represent various Devils Lake outlet options that have been considered for reducing the water levels in Devils Lake. Simulated water temperatures compared well with measured temperatures and differences varied spatially in Lake Ashtabula from June 2006 through June 2010. The absolute mean error ranged from 0.7 degrees Celsius to 1.0 degrees Celsius and the root mean square error ranged from 0.7 degrees Celsius to 1.1 degrees Celsius. Simulated sulfate concentrations compared well with measured concentrations in Lake Ashtabula. In general, simulated sulfate concentrations were slightly overpredicted with mean differences between simulated and measured sulfate concentrations ranging from -2 milligram per liter to 18 milligrams per liter. Differences between simulated and measured sulfate concentrations varied temporally in Lake Ashtabula from June 2006 through June 2010. In 2006, sulfate concentrations were overpredicted in the lower part of the reservoir and underpredicted in the upper part of the reservoir. Simulated total dissolved solids generally were greater than measured total dissolved-solids concentrations in Lake Ashtabula from June 2006 through June 2010. The mean difference between simulated and measured total dissolved-solids concentrations ranged from -3 milligrams per liter to

Residues of DDT in lake trout (Salvelinus namaycush) and coho salmon (Oncorhynchus kisutch) from the Great Lakes

USGS Publications Warehouse

Reinert, Robert E.; Bergman, Harold L.

1974-01-01

Concentrations of DDT residues were higher in lake trout (Salvelinus namaycush) from southern Lake Michigan in 1966–70 (average 18.1 ppm in fish 558–684 mm long) than in lake trout of the same size-class from Lake Superior in 1968–69 (4.4 ppm), and higher in adult coho salmon (Oncorhynchus kisutch) from Lake Michigan in 1968–71 (averages for different year-classes, 9.9–14.0 ppm) than in those from Lake Erie in 1969 (2.2 ppm). Residues were significantly higher in lake trout from southern Lake Michigan than in those from the northern part of the lake. In lakes Michigan and Superior, the levels increased with length of fish and percentage oil. In Lake Michigan coho salmon, the residues remained nearly stable (2–4 ppm) from September of the 1st yr of lake residence through May or early June of the 2nd yr, but increased three to four times in the next 3 mo. Residues in Lake Erie coho salmon did not increase during this period, which preceded the spawning season. Although the concentrations of total residues in whole, maturing Lake Michigan coho salmon remained unchanged from August 1968 until near the end of the spawning season in January 1969, the residues were redistributed in the tissues of the spawning-run fish; concentrations in the loin and brain were markedly higher in January than in August. This relocation of DDT residues accompanied a marked decrease in the percentage of oil in the fish, from 13.2 in August to 2.8 in January. Concentrations of residues were relatively high in eggs of both lake trout (4.6 ppm) and coho salmon (7.4–10.2 ppm) from Lake Michigan. The percentage composition of the residues (p,p′DDE, o,p′/DDT, p,p′DDT, and p,p′DDT) did not differ significantly with life stage, size, age, or locality, or date of collection of lake trout or coho salmon.

The regional abundance and size distribution of lakes and reservoirs in the United States and implication for estimates of global lake extent

USGS Publications Warehouse

McDonald, Cory P.; Rover, Jennifer; Stets, Edward G.; Striegl, Robert G.

2012-01-01

We analyzed complete geospatial data for the 3.5 million lakes and reservoirs larger than 0.001 km2, with a combined surface area of 131,000 km2, in the contiguous United States (excluding the Laurentian Great Lakes) and identified their regional distribution characteristics. For Alaska, we also analyzed (1) incomplete data that suggest that the state contains 1–2.5 million lakes larger than 0.001 km2 covering over 50,000 km2 and (2) localized high-resolution (5 m) data that suggest that the number of very small water bodies (< 0.001 km2) may be comparable with the number of lakes > 0.001 km2 in some areas. The Pareto distribution cannot accurately describe the lake abundance-size relationship across the entire size spectrum, and extrapolation of this density function to small size classes has likely resulted in the overestimation of the number of small lakes in the world. While small water bodies dominate in terms of numbers, they are not numerous enough to dominate in terms of surface area, as has been previously suggested. Extending our results to the global scale suggests that there are on the order of 64 million water bodies larger than 0.001 km2 in the world, with a total surface area of approximately 3.8 million km2.

Age, year‐class strength variability, and partial age validation of Kiyis from Lake Superior

USGS Publications Warehouse

Lepak, Taylor A.; Ogle, Derek H.; Vinson, Mark

2017-01-01

ge estimates of Lake Superior Kiyis Coregonus kiyi from scales and otoliths were compared and 12 years (2003–2014) of length frequency data were examined to assess year‐class strength and validate age estimates. Ages estimated from otoliths were precise and were consistently older than ages estimated from scales. Maximum otolith‐derived ages were 20 years for females and 12 years for males. Age estimates showed high numbers of fish of ages 5, 6, and 11 in 2014, corresponding to the 2009, 2008, and 2003 year‐classes, respectively. Strong 2003 and 2009 year‐classes, along with the 2005 year‐class, were also evident based on distinct modes of age‐1 fish (<110 mm) in the length frequency distributions from 2004, 2010, and 2006, respectively. Modes from these year‐classes were present as progressively larger fish in subsequent years. Few to no age‐1 fish (<110 mm) were present in all other years. Ages estimated from otoliths were generally within 1 year of the ages corresponding to strong year‐classes, at least for age‐5 and older fish, suggesting that Kiyi age may be reliably estimated to within 1 year by careful examination of thin‐sectioned otoliths.

40 CFR Appendix E to Part 132 - Great Lakes Water Quality Initiative Antidegradation Policy

Code of Federal Regulations, 2013 CFR

2013-07-01

... lower water quality is necessary to accommodate important economic or social development in the area in... concern are subject to best technology in process and treatment requirements. Lake Superior Basin... to the Lake Superior Basin shall identify the best technology in process and treatment to eliminate...

40 CFR Appendix E to Part 132 - Great Lakes Water Quality Initiative Antidegradation Policy

Code of Federal Regulations, 2011 CFR

2011-07-01

... lower water quality is necessary to accommodate important economic or social development in the area in... concern are subject to best technology in process and treatment requirements. Lake Superior Basin... to the Lake Superior Basin shall identify the best technology in process and treatment to eliminate...

40 CFR Appendix E to Part 132 - Great Lakes Water Quality Initiative Antidegradation Policy

Code of Federal Regulations, 2012 CFR

2012-07-01

... lower water quality is necessary to accommodate important economic or social development in the area in... concern are subject to best technology in process and treatment requirements. Lake Superior Basin... to the Lake Superior Basin shall identify the best technology in process and treatment to eliminate...

Picloram in Spaced Stem Injections to Control Lake States Hardwoods

Treesearch

Kenneth A. Brinkman

1970-01-01

Picloram (4 amino-3, 5, 6-tri-chloropicolinic acid), manufactured under the name of Tordon, controls most pole-size and smaller hardwoods in the Lake States by stem injections spaced up to 6 incest apart.

Integrating Climate Change into Great Lakes Protection

NASA Astrophysics Data System (ADS)

Hedman, S.

2012-12-01

Agreements. EPA has provided GLRI funding for a diverse suite of climate change-related projects including Great Lakes climate change research and modeling; adaptation plan development and implementation; ecosystem vulnerability assessments; outreach and education programs; habitat restoration and protection projects that will increase ecosystem resilience; and other projects that address climate change impacts. This presentation will discuss how the GLRI is helping to improve the climate change science needed to support the Action Plan. It will further describe how the GLRI is helping coordinate climate change efforts among Great Lakes states, tribes, Federal agencies, and other stakeholders. Finally, it will discuss how the GLRI is facilitating adaptation planning by our Great Lakes partners. The draft Lake Superior Ecosystem Climate Change Adaptation Plan serves as a case study for an integrated, collaborative, and coordinated climate change effort.

2016 Lake Michigan Lake Trout Working Group Report

USGS Publications Warehouse

Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

2017-01-01

This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

Perspective View, New York State, Lake Ontario to Long Island

NASA Image and Video Library

2000-06-15

From Lake Ontario and the St. Lawrence River and extending to Long Island, this perspective view shows the varied topography of eastern New York State and parts of Massachusetts, Connecticut, Pennsylvania, New Jersey and Rhode Island.

Use of Landsat data to predict the trophic state of Minnesota lakes

NASA Technical Reports Server (NTRS)

Lillesand, T. M.; Johnson, W. L.; Deuell, R. L.; Lindstrom, O. M.; Meisner, D. E.

1983-01-01

Near-concurrent Landsat Multispectral Scanner (MSS) and ground data were obtained for 60 lakes distributed in two Landsat scene areas. The ground data included measurement of secchi disk depth, chlorophyll-a, total phosphorous, turbidity, color, and total nitrogen, as well as Carlson Trophic State Index (TSI) values derived from the first three parameters. The Landsat data best correlated with the TSI values. Prediction models were developed to classify some 100 'test' lakes appearing in the two analysis scenes on the basis of TSI estimates. Clouds, wind, poor image data, small lake size, and shallow lake depth caused some problems in lake TSI prediction. Overall, however, the Landsat-predicted TSI estimates were judged to be very reliable for the secchi-derived TSI estimation, moderately reliable for prediction of the chlorophyll-a TSI, and unreliable for the phosphorous value. Numerous Landsat data extraction procedures were compared, and the success of the Landsat TSI prediction models was a strong function of the procedure employed.

Forest harvesting and water: the Lake States experience

Treesearch

Elon S. Verry

1986-01-01

The impact of forests on water has been a subject of argument for more than a century. It still is; and many studies conform that there is no single right answer in the debate. In the Lake States, clearcutting natural peatlands will not change annual streamflow nor will it seriously impact water quality if logging is done on frozen soils. However, clearcutting will...

Lake States Pulpwood Production Drops Seven Percent, 1967

Treesearch

James E. Blyth

1968-01-01

This twenty-second annual report shows the Lake States pulpwood harvest decreased to about 4 million cords from a record high of 4 1/2 million cords in 1966. Pulpwood receipts remained high in Wisconsin but decreased in Michigan and Minnesota. Minnesota shipped 106,000 cords more to Wisconsin than in 1966. As a result, only Minnesota's 1967 pulpwood production...

Physical Mechanisms of Rapid Lake Warming

NASA Astrophysics Data System (ADS)

Lenters, J. D.

2016-12-01

Recent studies have shown significant warming of inland water bodies around the world. Many lakes are warming more rapidly than the ambient surface air temperature, and this is counter to what is often expected based on the lake surface energy balance. A host of reasons have been proposed to explain these discrepancies, including changes in the onset of summer stratification, significant loss of ice cover, and concomitant changes in winter air temperature and/or summer cloud cover. A review of the literature suggests that no single physical mechanism is primarily responsible for the majority of these changes, but rather that the large heterogeneity in regional climate trends and lake geomorphometry results in a host of potential physical drivers. In this study, we discuss the variety of mechanisms that have been proposed to explain rapid lake warming and offer an assessment of the physical plausibility for each potential contributor. Lake Superior is presented as a case study to illustrate the "perfect storm" of factors that can cause a deep, dimictic lake to warm at rate that exceeds the rate of global air temperature warming by nearly an order of magnitude. In particular, we use a simple mixed-layer model to show that spatially variable trends in Lake Superior surface water temperature are determined, to first order, by variations in bathymetry and winter air temperature. Summer atmospheric conditions are often of less significance, and winter ice cover may simply be a correlate. The results highlight the importance of considering the full range of factors that can lead to trends in lake surface temperature, and that conventional wisdom may often not be the best guide.

Are the Laurentian Great Lakes a CO2 Source or Sink?

NASA Astrophysics Data System (ADS)

Fernandez, J.; Townsend-Small, A.

2016-12-01

As concentrations of CO2 increase in our atmosphere, large bodies of water are prone to an accompanying increase in CO2. Accruing CO2 sinking into the Great Lakes can create more acidic waters, which is detrimental to the healthy growth of organisms producing calcium carbonate skeletons - a phenomenon that has been confirmed in modern oceans. Recent estimates suggests that Lake Huron, Lake Michigan, and Lake Superior are sources of atmospheric CO2, while Lake Erie and Lake Ontario are CO2 sinks, although this is based largely on water volume and little research has been done to validate these predictions. Water samples were collected aboard the University National Oceanographic Laboratory System RV Blue Heron and the Canadian Coast Guard RV Limnos from Lake Superior, Lake Michigan, and Lake Erie during the summer of 2016. Alkalinity and pCO2 were analyzed in lab to further calculate dissolved concentrations and fluxes of CO2, providing more information to resolve whether the Great Lakes are a CO2 source or sink. Additional work involves sampling all five of the Great lakes throughout the year to determine any seasonal trends in CO2. 13C-DIC will also be measured in order to differentiate methane oxidation and respiration to the CO2 pool.

Predicting lake trophic state by relating Secchi-disk transparency measurements to Landsat-satellite imagery for Michigan inland lakes, 2003-05 and 2007-08

USGS Publications Warehouse

Fuller, L.M.; Jodoin, R.S.; Minnerick, R.J.

2011-01-01

Inland lakes are an important economic and environmental resource for Michigan. The U.S. Geological Survey and the Michigan Department of Natural Resources and Environment have been cooperatively monitoring the quality of selected lakes in Michigan through the Lake Water Quality Assessment program. Sampling for this program began in 2001; by 2010, 730 of Michigan’s 11,000 inland lakes are expected to have been sampled once. Volunteers coordinated by the Michigan Department of Natural Resources and Environment began sampling lakes in 1974 and continue to sample (in 2010) approximately 250 inland lakes each year through the Michigan Cooperative Lakes Monitoring Program. Despite these sampling efforts, it still is impossible to physically collect measurements for all Michigan inland lakes; however, Landsat-satellite imagery has been used successfully in Minnesota, Wisconsin, Michigan, and elsewhere to predict the trophic state of unsampled inland lakes greater than 20 acres by producing regression equations relating in-place Secchi-disk measurements to Landsat bands. This study tested three alternatives to methods previously used in Michigan to improve results for predicted statewide Trophic State Index (TSI) computed from Secchi-disk transparency (TSI (SDT)). The alternative methods were used on 14 Landsat-satellite scenes with statewide TSI (SDT) for two time periods (2003– 05 and 2007–08). Specifically, the methods were (1) satellitedata processing techniques to remove areas affected by clouds, cloud shadows, haze, shoreline, and dense vegetation for inland lakes greater than 20 acres in Michigan; (2) comparison of the previous method for producing a single open-water predicted TSI (SDT) value (which was based on an area of interest (AOI) and lake-average approach) to an alternative Gethist method for identifying open-water areas in inland lakes (which follows the initial satellite-data processing and targets the darkest pixels, representing the deepest water

Application and partial validation of a habitat model for moose in the Lake Superior region

USGS Publications Warehouse

Allen, A.W.; Terrell, J.W.; Mangus, W.L.; Lindquist, E.L.

1991-01-01

A modified version of the dormant-season portion of a Habitat Suitability Index (HSI) model developed for assessing moose (Alces alces) habitat in the Lake Superior Region was incorporated in a Geographic Information System (GIS) for 490 km2 of Minnesota's Superior National Forest. Moose locations (n=235) were plotted during aerial surveys conducted in December 1988 and January 1990-1991. Dormant-season forage and cover quality for 1,000-m, 500-m, and 200-m radii plots around random points and moose locations were compared using U.S. Forest Service stand examination data. Cover quality indices were lower than forage quality indices within all plots. The median value for the average cover quality index was greater (P=0.003) within 200-m plots around cow moose locations than for plots around random points for the most severe winter of the study. The proportion of highest-quality winter cover, such as mixed stands dominated by mid-age class white spruce (Picea glauca) and balsam fir (Abies balsanea), was greater within 500-m and 200-m plots around cow moose than within similar plots around random points during the two most severe winters. These results indicate that suboptimum ratings of winter habitat quality used in the GIS for dormant-season forage >100 m from cover, as suggested in the original HSI model, are reasonable. Integrating the habitat model with forest stand data using a GIS permitted analysis of moose habitat within a relatively large geographic area. Simulation of habitat quality indicated a potential shortage of late-winter cover in the study area. The effects of forest management actions on moose habitat quality can be simulated without collecting additional data.

Forest resources within the Lake States ceded territories 1980 - 2013

Treesearch

Cassandra M. Kurtz; W. Keith Moser; Mark H. Hansen; Dale D. Gormanson; Mark A. Hatfield; Paul A. Sowers; Michael J. Dockry; Marla R. Emery; Christopher W. Woodall; Brian F. Walters; Grant M. Domke; Jonathan Gilbert; Alexandra Wrobel

2015-01-01

The Lake States ceded territories are the portions of northern Michigan, northeastern Minnesota, and northern Wisconsin that were ceded by tribes of the Ojibwe to the government of the United States of America in the treaties of 1836, 1837, 1842, and 1854. The tribes retain rights to hunt, fish, and gather in the 1837, 1842, and 1854 treaty areas. This report...

Ecological monitoring for assessing the state of the nearshore and open waters of the Great Lakes

USGS Publications Warehouse

Neilson, Melanie A.; Painter, D. Scott; Warren, Glenn; Hites, Ronald A.; Basu, Ilora; Weseloh, D.V. Chip; Whittle, D. Michael; Christie, Gavin; Barbiero, Richard; Tuchman, Marc; Johannsson, Ora E.; Nalepa, Thomas F.; Edsall, Thomas A.; Fleischer, Guy; Bronte, Charles; Smith, Stephen B.; Baumann, Paul C.

2003-01-01

The Great Lakes Water Quality Agreement stipulates that the Governments of Canada and the United States are responsible for restoring and maintaining the chemical, physical and biological integrity of the waters of the Great Lakes Basin Ecosystem. Due to varying mandates and areas of expertise, monitoring to assess progress towards this objective is conducted by a multitude of Canadian and U.S. federal and provincial/state agencies, in cooperation with academia and regional authorities. This paper highlights selected long-term monitoring programs and discusses a number of documented ecological changes that indicate the present state of the open and nearshore waters of the Great Lakes.

Ten-year height growth variation in Lake States jack pine

Treesearch

James P. King

1966-01-01

Jack pine (Pinus banksiana Lamb.) is one of the major pulpwood producing species in the Lake States. It is found on a variety of sites, but its outstanding characteristic is its ability to make early rapid growth on dry sandy soils.

Lake Life.

ERIC Educational Resources Information Center

Ohrn, Deborah Gore, Ed.

1993-01-01

This quarterly publication of the State Historical Society of Iowa features articles and activities for elementary school students. This summer issue focuses on the topic of lake life. The issue includes the following features: (1) "Where the Lakes Are Map"; (2) "Letter from the Lake"; (3) "Lake People"; (4)…

History of salmon in the Great Lakes, 1850-1970

USGS Publications Warehouse

Parsons, John W.

1973-01-01

This history of the salmon in the Great Lakes describes the decline and extinction of the Atlantic salmon (Salmo salar) in Lake Ontario in the 1800's; the failure to establish, by salmon culture, permanent or sizable populations of Atlantic or Pacific salmon in any of the Great Lakes in 1867-1965; and the success of the plantings of coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytsha) in the Great Lakes, in 1966-70 -- particularly in Lake Michigan. Despite plantings of 5 million fry and fingerlings from Lake Ontario stocks in 1866-84, the native Atlantic salmon in Lake Ontario became extinct in the late 1800's primarily because tributaries in which they spawned were blocked by mill dams. Plantings of 13 million chinook salmon and landlocked and anadromous forms of Atlantic salmon in Lake Ontario and the other Great Lakes in 1873-1947 failed completely. The first species to develop a self-sustaining population was the pink salmon (O. gorbuscha), which was planted in Lake Superior in 1956; however, it has not become abundant. A salmon fishery finally was established when 15 million coho salmon and 6 million chinook salmon were planted as smolt in the Great Lakes in 1966-70. In 1970, for example, 576,000 coho salmon (12% of those planted in 1969) were caught by anglers in Lake Michigan. Most weighed 5 to 10 pounds (2.3-4.5 kg). Sport fishing for salmon was fair in Lakes Superior and Huron, and poor in Lakes Erie and Ontario. By 1970, natural reproduction of coho, chinook, pink, and kokanee (O. nerka) salmon had occurred in some tributaries of one or more of the upper three Great Lakes. It is expected, however, that the sport fishery will continue to be supported almost entirely by planted fish.

Trophic state in Voyageurs National Park lakes before and after implementation of a revised water-level management plan

USGS Publications Warehouse

Christensen, Victoria G.; Maki, Ryan P.

2015-01-01

We compiled Secchi depth, total phosphorus, and chlorophyll a (Chla) data from Voyageurs National Park lakes and compared datasets before and after a new water-level management plan was implemented in January 2000. Average Secchi depth transparency improved (from 1.9 to 2.1 m, p = 0.020) between 1977-1999 and 2000-2011 in Kabetogama Lake for August samples only and remained unchanged in Rainy, Namakan, and Sand Point Lakes, and Black Bay in Rainy Lake. Average open-water season Chla concentration decreased in Black Bay (from an average of 13 to 6.0 μg/l, p = 0.001) and Kabetogama Lake (from 9.9 to 6.2 μg/l, p = 0.006) between 1977-1999 and 2000-2011. Trophic state index decreased significantly in Black Bay from 59 to 51 (p = 0.006) and in Kabetogama Lake from 57 to 50 (p = 0.006) between 1977-1999 and 2000-2011. Trophic state indices based on Chla indicated that after 2000, Sand Point, Namakan, and Rainy Lakes remained oligotrophic, whereas eutrophication has decreased in Kabetogama Lake and Black Bay. Although nutrient inputs from inflows and internal sources are still sufficient to produce annual cyanobacterial blooms and may inhibit designated water uses, trophic state has decreased for Kabetogama Lake and Black Bay and there has been no decline in lake ecosystem health since the implementation of the revised water-level management plan.

Historical evidence for discrete stocks of lake trout (Salvelinus namaycush) in Lake Michigan

USGS Publications Warehouse

Brown, Edward H.; Eck, G.W.; Foster, N.R.; Horrall, R.M.; Coberly, C.E.

1981-01-01

Although few biological data exist on the now extinct native lake trout, Salvelinus namaycush, of Lake Michigan, historical records and interviews with former commercial fishermen strongly suggest that this once widespread resource was composed of a number of discrete spawning populations or stocks. A natural division of the resource into distinct stocks is consistent with the size of Lake Michigan and its varied physiography. The native trout may have undergone subtle genetic changes over the millennia, although we cannot determine whether the physical and behavioral differences represented different genotypes or only temporary effects of the local environment. Because of physiographic similarities among the upper Great Lakes and probable interchanges of lake trout during the last glacial period, we recommend that progeny of extant wild stocks, particularly from Lake Superior, are genetically most suitable for recolonizing Lake Michigan. Moreover, the hatchery-held parents of such fish should be infused periodically with genes of the wild or feral donor populations. Despite the sound historical basis for these recommendations, we also recognize that sufficiently high stocking rates coupled with a reduction of heavy exploitation may be even more important than heritability in obtaining self-sustaining populations.

Rising Pulpwood Prices Stimulate Largest Lake States Pulpwood Harvest, 1966

Treesearch

James E. Blyth

1967-01-01

The 1966 Lake States pulpwood harvest climbed to 4 1/2 million cords, an 18 percent increase from 1965. Woods labor continued to be scarce, but a better logging season coupled with the higher prices provided the incentive for reaching the record harvest.

Relationship of lake herring (Coregonus artedi) gill raker characteristics to retention probabilities of zooplankton prey

USGS Publications Warehouse

Link, Jason; Hoff, Michael H.

1998-01-01

We measured morphometric and meristic parameters of gill rakers from the first gill arch of 36 adult lake herring (Coregonus artedi) from Lake Superior that ranged in length from 283–504 mm. These data, coupled with the mean of the smallest two body dimensions (length, width, or breadth) of various zooplankton prey, allowed us to calculate retention probabilities for zooplankton taxa that are common in Lake Superior. The mean of the smallest two body dimensions was positively correlated with body length for cladocerans and copepods. The large cladoceran, Daphnia g. mendotae, is estimated to be retained at a greater probability (74%) than smaller cladocerans (18%-38%). The same is true for the large copepod, Limnocalanus macrurus (60%), when compared to smaller copepods (6–38%). Copepods have a lower probability of being retained than cladocerans of similar length. Lake herring gill rakers and total filtering area are also positively correlated with fish total length. These data provide further evidence that lake herring are primarily planktivores in Lake Superior, and our data show that lake herring can retain a broad range of prey sizes.

Expanding models of lake trophic state to predict cyanobacteria in lakes

EPA Science Inventory

Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chlor...

Plume magmatism and crustal growth at 2.9 to 3.0 Ga in the Steep Rock and Lumby Lake area, Western Superior Province

NASA Astrophysics Data System (ADS)

Tomlinson, K. Y.; Hughes, D. J.; Thurston, P. C.; Hall, R. P.

1999-01-01

The greenstone belts of the western Superior Province are predominantly 2.78 to 2.69 Ga and provide evidence of oceanic and arc volcanism during the accretionary phase of development of the Superior Province. There is also scattered evidence of Meso-Archean crust (predominantly 2.9 to 3.0 Ga) within the western Superior Province. The Meso-Archean greenstone belts commonly contain platformal sediments and unconformably overlie granitoid basement. The platformal sediments occur associated with komatiitic and tholeiitic volcanic rocks that suggest a history of magmatism associated with rifting during the Meso-Archean. The central Wabigoon Subprovince is a key area of Meso-Archean crust and in its southern portion comprises the Steep Rock, Finlayson and Lumby Lake greenstone belts. The Steep Rock greenstone belt unconformably overlies 3 Ga continental basement and contains platformal sediments succeeded by komatiitic and tholeiitic volcanic rocks. The Lumby Lake greenstone belt contains thick sequences of mafic volcanics, a number of komatiite horizons, and thin platformal sedimentary units. The two belts are joined by the predominantly mafic volcanic Finlayson greenstone belt. The volcanics throughout these three greenstone belts may be correlated to some extent and a range of basaltic and komatiite types is present. Al-undepleted komatiites present in the Lumby Lake greenstone belt have an Al 2O 3/TiO 2 ratio ranging from 14 to 27 and (Gd/Yb) N from 0.7 to 1.3. These are divided into basaltic komatiites with generally unfractionated mantle-normalised multi-element profiles, and spinifex-textured high-Mg basalts with slightly light REE enriched multi-element profiles and small negative Nb and Ta anomalies. The unfractionated basaltic komatiites represent high degree partial melts of the upper mantle whereas the spinifex-textured high-Mg basalts represent evolutionary products of the komatiite liquids following olivine and chromite fractionation and crustal

Diet and feeding periodicity of ruffe in the St. Louis River estuary, Lake Superior

USGS Publications Warehouse

Ogle, Derek H.; Selgeby, James H.; Newman, Raymond M.; Henry, Mary G.

1995-01-01

Ruffe Gymnocephalus cernuus, a percid native to Europe and Asia, is established in the Lake Superior drainage and could have negative impacts on native fish through competition for forage and predation on fish eggs. We investigated the diet of ruffes in the 4,654-ha St. Louis River estuary in May–October 1989–1990 and the feeding periodicity of ruffes in two adjacent habitats during five 24-h periods in summers 1990–1991. Ruffes were primarily benthophagous. Age-0 ruffes fed mostly on cladocerans and copepods in early summer and midge larvae (Chironomidae) in late summer and fall. Adult ruffes less than 12 cm fed mostly on midges and other macrobenthos but also consumed large numbers of microcrustaceans. Adult ruffes 12 cm and larger fed mostly on midges, burrowing mayflies Hexagenia spp., and caddisflies (Trichoptera). Ruffes consumed few fish eggs. Adult ruffes in deeper waters and all age-0 ruffes fed throughout the day as indicated by weight patterns of stomach contents. However, adult ruffes generally moved to shallower waters at night to feed most heavily. Results of this study indicate that ruffes will probably compete with other benthic-feeding fishes such as yellow perch Perca flavescens and trout-perch Percopsis omiscomaycus.

High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn.

PubMed

Ives, Anthony R; Einarsson, Arni; Jansen, Vincent A A; Gardarsson, Arnthor

2008-03-06

Complex dynamics are often shown by simple ecological models and have been clearly demonstrated in laboratory and natural systems. Yet many classes of theoretically possible dynamics are still poorly documented in nature. Here we study long-term time-series data of a midge, Tanytarsus gracilentus (Diptera: Chironomidae), in Lake Myvatn, Iceland. The midge undergoes density fluctuations of almost six orders of magnitude. Rather than regular cycles, however, these fluctuations have irregular periods of 4-7 years, indicating complex dynamics. We fit three consumer-resource models capable of qualitatively distinct dynamics to the data. Of these, the best-fitting model shows alternative dynamical states in the absence of environmental variability; depending on the initial midge densities, the model shows either fluctuations around a fixed point or high-amplitude cycles. This explains the observed complex population dynamics: high-amplitude but irregular fluctuations occur because stochastic variability causes the dynamics to switch between domains of attraction to the alternative states. In the model, the amplitude of fluctuations depends strongly on minute resource subsidies into the midge habitat. These resource subsidies may be sensitive to human-caused changes in the hydrology of the lake, with human impacts such as dredging leading to higher-amplitude fluctuations. Tanytarsus gracilentus is a key component of the Myvatn ecosystem, representing two-thirds of the secondary productivity of the lake and providing vital food resources to fish and to breeding bird populations. Therefore the high-amplitude, irregular fluctuations in midge densities generated by alternative dynamical states dominate much of the ecology of the lake.

Educators' Guide to Great Lakes Materials: Books, Films, Maps and Pamphlets for Classroom Use.

ERIC Educational Resources Information Center

Johnson, Pam

This annotated bibliography presents Great Lakes information for grades six through nine classroom use. It is meant to facilitate and encourage Great Lakes study, particularly of Lakes Michigan and Superior. Material is presented on history, science, lake management, environmental concerns, and recreational use. Included are both fiction and…

Lake States Roundwood Pulpwood Markets: A Short-Term Outlook

Treesearch

David C. Lothner

1974-01-01

Recent changes in the behavios of factors influencing the Lake States roundwood pulpwood market indicate there is potential for change within the pulpwood market. Softwood roundwood pulpwood production could increase at an annual rate of near 2 percent, while all roundwood pulpwood production could moderate to an average annual rate of near 1 percent over the short-...

Ecology and management of aspen: A Lake States perspective

Treesearch

David T. Cleland; Larry A. Leefers; Donald I. Dickmann

2001-01-01

Aspen has been an ecologically important, though relatively minor, component of the Lake States (Michigan, Wisconsin, and Minnesota) forests for millennia. General Land Office records from the 1800s indicate that aspen comprised a small fraction of the region's eastern forests, but was more extensive on the western edge. Then Euro-American settlement in the 1800s...

Age, growth, spawning season, and fecundity of the trout-perch (Percopsis omiscomaycus) in southeastern Lake Michigan

USGS Publications Warehouse

House, Robert; Wells, LaRue

1973-01-01

Growth of trout-perch (Percopsis omiscomaycus) in the first 2 years of life was somewhat slower in southeastern Lake Michigan (average length at end of second year, 83 mm) than in Lower Red Lake, Minnesota (90 mm), but considerably faster than in Lake Superior (58 mm); size differences in later years were slightly less pronounced. Young fish began growing earlier in the year (some before June 20) than older ones (as late as August). Females tended to live longer than males, as they do in Lower Red Lake and Lake Superior. Trout-perch spawned from late June or early July until late September, somewhat later than in Lower Red Lake (May to August) or Lake Erie (June to August). Fecundity was similar to that in Lake Erie; mature females 94-146 mm long contained from 126 to 1329 yolked eggs.

Benthic-planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes.

PubMed

Genkai-Kato, Motomi; Vadeboncoeur, Yvonne; Liboriussen, Lone; Jeppesen, Erik

2012-03-01

Alternative stable states in shallow lakes are typically characterized by submerged macrophyte (clear-water state) or phytoplankton (turbid state) dominance. However, a clear-water state may occur in eutrophic lakes even when macrophytes are absent. To test whether sediment algae could cause a regime shift in the absence of macrophytes, we developed a model of benthic (periphyton) and planktonic (phytoplankton) primary production using parameters derived from a shallow macrophyte-free lake that shifted from a turbid to a clear-water state following fish removal (biomanipulation). The model includes a negative feedback effect of periphyton on phosphorus (P) release from sediments. This in turn induces a positive feedback between phytoplankton production and P release. Scenarios incorporating a gradient of external P loading rates revealed that (1) periphyton and phytoplankton both contributed substantially to whole-lake production over a broad range of external P loading in a clear-water state; (2) during the clear-water state, the loss of benthic production was gradually replaced by phytoplankton production, leaving whole-lake production largely unchanged; (3) the responses of lakes to biomanipulation and increased external P loading were both dependent on lake morphometry; and (4) the capacity of periphyton to buffer the effects of increased external P loading and maintain a clear-water state was highly sensitive to relationships between light availability at the sediment surface and the of P release. Our model suggests a mechanism for the persistence of alternative states in shallow macrophyte-free lakes and demonstrates that regime shifts may trigger profound changes in ecosystem structure and function.

Depth gradients in food web processes linking large lake habitats

EPA Science Inventory

In large lakes around the world, shifts in ecological communities are often associated with water depth. This suggests that there may be concomitant changes in patterns of resource allocation. Using Lake Superior as an example, we explored this idea through stable isotope analyse...

Cyanotoxins in inland lakes of the continental United States: Photic Zone Occurrence and potential recreational health risks in the 2007 Survey of the Nation's lakes

EPA Science Inventory

The largest spatial survey of cylindrospermosins, microcystins, and saxitoxins in the United States was conducted as part of the 2007 U.S. Survey of the Nation’s Lakes. Integrated photic zone samples were collected from 1,161 lakes during May-September 2007. Cyanotoxin, cya...

Status and trends of pelagic prey fishes in Lake Huron, 2012

USGS Publications Warehouse

Warner, David M.; O'Brien, Timothy P.; Farha, Steve A.; Schaeffer, Jeff; Lenart, Stephen

2012-01-01

The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of 2011. Total biomass in 2012 was 74% of the 2011 value. Alewife Alosa pseudoharengus remained nearly absent, and only one cisco Coregonus artedi was captured. Rainbow smelt Osmerus mordax density was only 31% of the 2011 density. Bloater Coregonus hoyi density was less than half the 2011 density, mostly as a result of lower density of small bloater. Density and biomass of large bloater in 2012 were similar to 2011 levels. During 2012 we observed significantly higher fish biomass in North Channel than in the Main Basin or Georgian Bay. Prey availability during 2013 will likely be similar to 2012. Lake Huron now has pelagic fish biomass similar to that observed in recent lakewide acoustic surveys of Lake Michigan and Lake Superior, but species composition differs in the three lakes. There is an increasing diversity and prevalence of native species gradient from Lake Michigan to Lake Superior, with Lake Huron being intermediate in the prevalence of native fish species like coregonines and emerald shiner Notropis atherinoides.

Status and trends of pelagic prey fishes in Lake Huron, 2012

USGS Publications Warehouse

Warner, David M.; O'Brien, Timothy P.; Farha, Steve A.; Schaeffer, Jeff; Lenart, Stephen

2013-01-01

The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of 2011. Total biomass in 2012 was 74% of the 2011 value. Alewife Alosa pseudoharengus remained nearly absent, and only one cisco Coregonus artedi was captured. Rainbow smelt Osmerus mordax density was only 31% of the 2011 density. Bloater Coregonus hoyi density was less than half the 2011 density, mostly as a result of lower density of small bloater. Density and biomass of large bloater in 2012 were similar to 2011 levels. During 2012 we observed significantly higher fish biomass in North Channel than in the Main Basin or Georgian Bay. Prey availability during 2013 will likely be similar to 2012. Lake Huron now has pelagic fish biomass similar to that observed in recent lakewide acoustic surveys of Lake Michigan and Lake Superior, but species composition differs in the three lakes. There is an increasing diversity and prevalence of native species gradient from Lake Michigan to Lake Superior, with Lake Huron being intermediate in the prevalence of native fish species like coregonines and emerald shiner Notropis atherinoides.

Lake whitefish and Diporeia spp. in the Great lakes: an overview

USGS Publications Warehouse

Nalepa, Thomas F.; Mohr, Lloyd C.; Henderson, Bryan A.; Madenjian, Charles P.; Schneeberger, Philip J.

2005-01-01

Because of growing concern in the Great Lakes over declines in abundance and growth of lake whitefish (Coregonus clupeaformis) and declines in abundance of the benthic amphipod Diporeia spp., a workshop was held to examine past and current trends, to explore trophic links, and to discuss the latest research results and needs. The workshop was divided into sessions on the status of populations in each of the lakes, bioenergetics and trophic dynamics, and exploitation and management. Abundance, growth, and condition of whitefish populations in Lakes Superior and Erie are stable and within the range of historical means, but these variables are declining in Lakes Michigan and Ontario and parts of Lake Huron. The loss of Diporeia spp., a major food item of whitefish, has been a factor in observed declines, particularly in Lake Ontario, but density-dependent factors also likely played a role in Lakes Michigan and Huron. The loss of Diporeia spp. is temporally linked to the introduction and proliferation of dreissenid mussels, but a direct cause for the negative response of Diporeia spp. has not been established. Given changes in whitefish populations, age-structured models need to be re-evaluated. Other whitefish research needs to include a better understanding of what environmental conditions lead to strong year-classes, improved aging techniques, and better information on individual population (stock) structure. Further collaborations between assessment biologists and researchers studying the lower food web would enhance an understanding of links between trophic levels.

Lake shoreline in the contiguous United States: Quantity, distribution and sensitivity to observation resolution

USGS Publications Warehouse

Winslow, Luke A.; Read, Jordan S.; Hanson, Paul C.; Stanley, Emily H.

2013-01-01

1. Quantifying lake biogeochemical processing at broad spatial scales requires that we scale processes along with physical metrics. Past work has primarily scaled lentic processes using estimates of lake surface area. However, many processes important to lakes, such as material, energy and biological fluxes and biogeochemical cycling, scale with lake perimeter. 2. We estimate the total lake perimeter for the contiguous United States (U.S.) and examine the sensitivity of this estimate to measurement resolution. At the original mapping resolution, lakes in the contiguous U.S. have a total perimeter of over 1.8 million km. 3. The change in measured perimeter versus measurement resolution for the contiguous U.S. had a log-log slope (also known as the fractal dimension) of 0.21, generally less than previously reported estimates. With changing observation resolution, total measured perimeter was most sensitive to the inclusion or exclusion of small lakes, not shoreline complexity. 4. The total aquatic–terrestrial interface in lakes is less than one-tenth that of streams and rivers, which collectively account for over 21 million km of shoreline in the contiguous U.S. This study further describes the distribution of lake perimeter and proposes a technique that can contribute to understanding continental-scale processes.

Lake States Pulpwood Production Dips to 4 Million Cords in 1971

Treesearch

James E. Blyth

1973-01-01

This 26th annual report shows that 1971 Lake States pulpwood production fell 6 percent. Wood inventory reductions were a major cause of the decline. Canada is losing importance as a pulpwood supplier to Minnesota, Wisconsin, and Michigan.

Regional assessment of lake ecological states using Landsat: A classification scheme for alkaline-saline, flamingo lakes in the East African Rift Valley

NASA Astrophysics Data System (ADS)

Tebbs, E. J.; Remedios, J. J.; Avery, S. T.; Rowland, C. S.; Harper, D. M.

2015-08-01

In situ reflectance measurements and Landsat satellite imagery were combined to develop an optical classification scheme for alkaline-saline lakes in the Eastern Rift Valley. The classification allows the ecological state and consequent value, in this case to Lesser Flamingos, to be determined using Landsat satellite imagery. Lesser Flamingos depend on a network of 15 alkaline-saline lakes in East African Rift Valley, where they feed by filtering cyanobacteria and benthic diatoms from the lakes' waters. The classification developed here was based on a decision tree which used the reflectance in Landsat ETM+ bands 2-4 to assign one of six classes: low phytoplankton biomass; suspended sediment-dominated; microphytobenthos; high cyanobacterial biomass; cyanobacterial scum and bleached cyanobacterial scum. The classification accuracy was 77% when verified against in situ measurements. Classified imagery and timeseries were produced for selected lakes, which show the different ecological behaviours of these complex systems. The results have highlighted the importance to flamingos of the food resources offered by the extremely remote Lake Logipi. This study has demonstrated the potential of high spatial resolution, low spectral resolution sensors for providing ecologically valuable information at a regional scale, for alkaline-saline lakes and similar hypereutrophic inland waters.

Pulpwood Chip Productions and Markets in the Lake States

Treesearch

Eugene W. Fobes

1966-01-01

As a major pulp and paper production area, the Lake States is a potential market for pulpwood chips. As a producer of solid wood products, it has a considerable potential for the production of pulpwood chips from coarse sawmill residues (slabs, edgings, and trim) and other sources. Only a small amount of the available residues, however, is now being utilized. In...

Lake States Pulpwood Production Plummets 413,000 Cords, 1968

Treesearch

James E. Blyth

1969-01-01

This twenty-third annual report shows that the 1968 Lake States pulpwood output dropped to about 3 1/2 million cords from about 4 million cords in 1967. Michigan's roundwood harvest dropped 198,000 cords in 1968, while the Wisconsin and Minnesota harvests each fell more than 125,000 cords. Pulpwood receipts fell 1/2 million cords below the 1967 level in...

Tree volume and biomass equations for the Lake States.

Treesearch

Jerold T. Hahn

1984-01-01

Presents species specific equations and methods for computing tree height, cubic foot, and board foot volume, and biomass for the Lake States (Michigan, Minnesota, and Wisconsin). Height equations compute either total or merchantable height to a variable top d.o.b. from d.b.h., site index, and basal area. Volumes and biomass are computed from d.b.h. and height.

Textural Analysis and Substrate Classification in the Nearshore Region of Lake Superior Using High-Resolution Multibeam Bathymetry

NASA Astrophysics Data System (ADS)

Dennison, Andrew G.

Classification of the seafloor substrate can be done with a variety of methods. These methods include Visual (dives, drop cameras); mechanical (cores, grab samples); acoustic (statistical analysis of echosounder returns). Acoustic methods offer a more powerful and efficient means of collecting useful information about the bottom type. Due to the nature of an acoustic survey, larger areas can be sampled, and by combining the collected data with visual and mechanical survey methods provide greater confidence in the classification of a mapped region. During a multibeam sonar survey, both bathymetric and backscatter data is collected. It is well documented that the statistical characteristic of a sonar backscatter mosaic is dependent on bottom type. While classifying the bottom-type on the basis on backscatter alone can accurately predict and map bottom-type, i.e a muddy area from a rocky area, it lacks the ability to resolve and capture fine textural details, an important factor in many habitat mapping studies. Statistical processing of high-resolution multibeam data can capture the pertinent details about the bottom-type that are rich in textural information. Further multivariate statistical processing can then isolate characteristic features, and provide the basis for an accurate classification scheme. The development of a new classification method is described here. It is based upon the analysis of textural features in conjunction with ground truth sampling. The processing and classification result of two geologically distinct areas in nearshore regions of Lake Superior; off the Lester River,MN and Amnicon River, WI are presented here, using the Minnesota Supercomputer Institute's Mesabi computing cluster for initial processing. Processed data is then calibrated using ground truth samples to conduct an accuracy assessment of the surveyed areas. From analysis of high-resolution bathymetry data collected at both survey sites is was possible to successfully calculate

A provisional assessment of triclopyr herbicide for use in Lake States' forestry.

Treesearch

Donald A. Perala

1979-01-01

Compares rate-response curves of some typical Lake States hardwoods to triclopyr. Estimates the persistence and mobility of triclopyr in forest soil. Evaluates the safety of triclopyr to white spruce.

Fire effects on soils in Lake States forests: A compilation of published research to facilitate long-term investigations

Treesearch

Jessica Miesel; P. Goebel; R. Corace; David Hix; Randall Kolka; Brian Palik; David Mladenoff

2012-01-01

Fire-adapted forests of the Lake States region are poorly studied relative to those of the western and southeastern United States and our knowledge base of regional short- and long-term fire effects on soils is limited. We compiled and assessed the body of literature addressing fire effects on soils in Lake States forests to facilitate the re-measurement of previous...

U-Th-Pb zircon ages of some Keweenawan Supergroup rocks from the south shore of Lake Superior

USGS Publications Warehouse

Zartman, R.E.; Nicholson, S.W.; Cannon, W.F.; Morey, G.B.

1997-01-01

New single-crystal zircon U-Th-Pb ages for plutonic and rhyolitic Keweenawan Supergroup rocks from the south shore of Lake Superior provide geochronological constraints on magmatic evolution associated with the 1.1 Ga Midcontinent rift. Analyses of a granophyric phase of the Mineral Lake intrusion and the Meilen granite, both parts of the Meilen Intrusive Complex, and a laterally extensive rhyolite from the top of the Kallander Creek Volcanics have weighted average 207Pb/206Pb ages of 1102.0 ?? 2.8 Ma (N = 2), 1100.9 ?? 1.4 Ma (N = 5), and 1098.8 ?? 1.9 Ma (N = 4), respectively. Analyses of a pyroclastic rhyolite flow at the top of the Porcupine Volcanics result in variable 207Pb/206Pb ages that range from 1080 to 1137 Ma. This rhyolite exhibits a continuum between morphologically complex and simpler prismatic zircon crystals, the latter yielding concordant analyses having a weighted average 207Pb/206Pb age of 1093.6 ?? 1.8 Ma (N = 2). Four prismatic zircons from an aphyric rhyolite of the Chengwatana Volcanics in the Ashland syncline form a linear array intersecting concordia at 1094.6 ?? 2.1 Ma (MSWD = 1.3). Another presumed Chengwatana rhyolite recovered from drill core intersecting the Hudson-Afton horst in southeast Minnesota yielded only ???20 morphologically indistinguishable zircons. Six analyses give 207Pb/206Pb ages ranging from 1112 to 1136 Ma, including one analysis with a virtually concordant age of 1130 Ma. This age, however, is considerably older than that obtained for the Chengwatana Volcanics in the Ashland syncline or any other precisely dated rock from the Midcontinent rift.

Depth gradients in food web processes linking large lake habitats -presentation

EPA Science Inventory

In large lakes around the world, shifts in ecological communities are often associated with water depth. This suggests that there may be concomitant changes in patterns of resource allocation. Using Lake Superior as an example, we explored this idea through stable isotope analyse...

The present status of the United States commercial fisheries of the Great Lakes

USGS Publications Warehouse

Van Oosten, John

1949-01-01

This review of the trends in production on the Great Lakes suggests that great biological changes have taken place. The general abundance of the choicer varieties, and of some of the less choice fishes, has been lowered considerably; and the prospects are that this level will fall still farther. In addition, the niches occupied by these finer species in the lakes have not been filled by coarser forms. Much of the reduced abundance in modern fishery must be attributed to overfishing or unwise fishing (cisco, whitefish, lake trout, chubs). Part of it we believe was caused by an infectious disease as was true for the smelt; part of it by the parasitic predator, the sea lamprey. Perhaps increased competition for space or food such as might have been brought about by the smelt in Lakes Huron and Michigan or the alewives in Lake Ontario may have played a role. Pollution, too, may have taken its toll. Often we have no better explanation to offer than to state that some unknown change in the environment was responsible.

Continental-scale variation in controls of summer CO2 in United States lakes

NASA Astrophysics Data System (ADS)

Lapierre, Jean-Francois; Seekell, David A.; Filstrup, Christopher T.; Collins, Sarah M.; Emi Fergus, C.; Soranno, Patricia A.; Cheruvelil, Kendra S.

2017-04-01

Understanding the broad-scale response of lake CO2 dynamics to global change is challenging because the relative importance of different controls of surface water CO2 is not known across broad geographic extents. Using geostatistical analyses of 1080 lakes in the conterminous United States, we found that lake partial pressure of CO2 (pCO2) was controlled by different chemical and biological factors related to inputs and losses of CO2 along climate, topography, geomorphology, and land use gradients. Despite weak spatial patterns in pCO2 across the study extent, there were strong regional patterns in the pCO2 driver-response relationships, i.e., in pCO2 "regulation." Because relationships between lake CO2 and its predictors varied spatially, global models performed poorly in explaining the variability in CO2 for U.S. lakes. The geographically varying driver-response relationships of lake pCO2 reflected major landscape gradients across the study extent and pointed to the importance of regional-scale variation in pCO2 regulation. These results indicate a higher level of organization for these physically disconnected systems than previously thought and suggest that changes in climate and land use could induce shifts in the main pathways that determine the role of lakes as sources and sinks of atmospheric CO2.

ZOOPLANKTON - PHYTOPLANKTON BIOMASS SEZE STRUCTURE IN NEARSHORE REGIONS OF LAKE SUPERIOR

EPA Science Inventory

Presentation addresses new technologies and new strategies for developing biological indicators to assess the Great Lakes . . . We assessed biomass size-spectra acquired with an optical plankton counter (OPC) or laser optical counter (LOPC) and phytoplankton samples analyzed with...

Survey design for lakes and reservoirs in the United States to assess contaminants in fish tissue

EPA Science Inventory

The National Lake Fish Tissue Study (NLFTS) was the first survey of fish contamination in lakes and reservoirs in the 48 conterminous states based on probability survey design. This study included the largest set (268) of persistent, bioaccumulative, and toxic (PBT) chemicals ev...

Acoustic estimates of abundance and distribution of spawning lake trout on Sheboygan Reef in Lake Michigan

USGS Publications Warehouse

Warner, D.M.; Claramunt, R.M.; Janssen, J.; Jude, D.J.; Wattrus, N.

2009-01-01

Efforts to restore self-sustaining lake trout (Salvelinus namaycush) populations in the Laurentian Great Lakes have had widespread success in Lake Superior; but in other Great Lakes, populations of lake trout are maintained by stocking. Recruitment bottlenecks may be present at a number of stages of the reproduction process. To study eggs and fry, it is necessary to identify spawning locations, which is difficult in deep water. Acoustic sampling can be used to rapidly locate aggregations of fish (like spawning lake trout), describe their distribution, and estimate their abundance. To assess these capabilities for application to lake trout, we conducted an acoustic survey covering 22 km2 at Sheboygan Reef, a deep reef (<40 m summit) in southern Lake Michigan during fall 2005. Data collected with remotely operated vehicles (ROV) confirmed that fish were large lake trout, that lake trout were 1–2 m above bottom, and that spawning took place over specific habitat. Lake trout density exhibited a high degree of spatial structure (autocorrelation) up to a range of ~190 m, and highest lake trout and egg densities occurred over rough substrates (rubble and cobble) at the shallowest depths sampled (36–42 m). Mean lake trout density in the area surveyed (~2190 ha) was 5.8 fish/ha and the area surveyed contained an estimated 9500–16,000 large lake trout. Spatial aggregation in lake trout densities, similarity of depths and substrates at which high lake trout and egg densities occurred, and relatively low uncertainty in the lake trout density estimate indicate that acoustic sampling can be a useful complement to other sampling tools used in lake trout restoration research.

Lightning activity during the 1999 Superior derecho

NASA Astrophysics Data System (ADS)

Price, Colin G.; Murphy, Brian P.

2002-12-01

On 4 July 1999, a severe convective windstorm, known as a derecho, caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators of severe weather.

Lightning Activity During the 1999 Superior Derecho

NASA Astrophysics Data System (ADS)

Price, C. G.; Murphy, B. P.

2002-12-01

On 4 July 1999, a severe convective windstorm, known as a derecho, caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators of severe weather.

Hydroacoustic estimation of zooplankton biomass at two shoal complexes in the Apostle Islands Region of Lake Superior

USGS Publications Warehouse

Holbrook, B.V.; Hrabik, T.R.; Branstrator, D.K.; Yule, D.L.; Stockwell, J.D.

2006-01-01

Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with zooplankton dry weight biomass estimated from net tows. The relationship between zooplankton dry weight and backscatter was significant (p < 0.001) and explained 76% of the variability in the dry weight data. We applied this regression to hydroacoustic data collected monthly in 2003 and 2004 at two shoals in the Apostle Island Region of Lake Superior. After applying the regression model to convert hydroacoustic backscatter to zooplankton dry weight biomass, we used geostatistics to analyze the mean and variance, and ordinary kriging to create spatial zooplankton distribution maps. The mean zooplankton dry weight biomass estimates from plankton net tows and hydroacoustics were not significantly different (p = 0.19) but the hydroacoustic data had a significantly lower coefficient of variation (p < 0.001). The maps of zooplankton distribution illustrated spatial trends in zooplankton dry weight biomass that were not discernable from the overall means.

Sensitivity of Great Lakes Ice Cover to Air Temperature

NASA Astrophysics Data System (ADS)

Austin, J. A.; Titze, D.

2016-12-01

Ice cover is shown to exhibit a strong linear sensitivity to air temperature. Upwards of 70% of ice cover variability on all of the Great Lakes can be explained in terms of air temperature, alone, and nearly 90% of ice cover variability can be explained in some lakes. Ice cover sensitivity to air temperature is high, and a difference in seasonally-averaged (Dec-May) air temperature on the order of 1°C to 2°C can be the difference between a low-ice year and a moderate- to high- ice year. The total amount of seasonal ice cover is most influenced by air temperatures during the meteorological winter, contemporaneous with the time of ice formation. Air temperature conditions during the pre-winter conditioning period and during the spring melting period were found to have less of an impact on seasonal ice cover. This is likely due to the fact that there is a negative feedback mechanism when heat loss goes toward cooling the lake, but a positive feedback mechanism when heat loss goes toward ice formation. Ice cover sensitivity relationships were compared between shallow coastal regions of the Great Lakes and similarly shallow smaller, inland lakes. It was found that the sensitivity to air temperature is similar between these coastal regions and smaller lakes, but that the absolute amount of ice that forms varies significantly between small lakes and the Great Lakes, and amongst the Great Lakes themselves. The Lake Superior application of the ROMS three-dimensional hydrodynamic numerical model verifies a deterministic linear relationship between air temperature and ice cover, which is also strongest around the period of ice formation. When the Lake Superior bathymetry is experimentally adjusted by a constant vertical multiplier, average lake depth is shown to have a nonlinear relationship with seasonal ice cover, and this nonlinearity may be associated with a nonlinear increase in the lake-wide volume of the surface mixed layer.

Spatiotemporal Variability of Great Lakes Basin Snow Cover Ablation Events

NASA Astrophysics Data System (ADS)

Suriano, Z. J.; Leathers, D. J.

2017-12-01

In the Great Lakes basin of North America, annual runoff is dominated by snowmelt. This snowmelt-induced runoff plays an important role within the hydrologic cycle of the basin, influencing soil moisture availability and driving the seasonal cycle of spring and summer Lake levels. Despite this, relatively little is understood about the patterns and trends of snow ablation event frequency and magnitude within the Great Lakes basin. This study uses a gridded dataset of Canadian and United States surface snow depth observations to develop a regional climatology of snow ablation events from 1960-2009. An ablation event is defined as an inter-diurnal snow depth decrease within an individual grid cell. A clear seasonal cycle in ablation event frequency exists within the basin and peak ablation event frequency is latitudinally dependent. Most of the basin experiences peak ablation frequency in March, while the northern and southern regions of the basin experience respective peaks in April and February. An investigation into the inter-annual frequency of ablation events reveals ablation events significantly decrease within the northeastern and northwestern Lake Superior drainage basins and significantly increase within the eastern Lake Huron and Georgian Bay drainage basins. In the eastern Lake Huron and Georgian Bay drainage basins, larger ablation events are occurring more frequently, and a larger impact to the hydrology can be expected. Trends in ablation events are attributed primarily to changes in snowfall and snow depth across the region.

Land use in the lake states region: an analysis of past trends and projections of future changes.

Treesearch

Thomas E. Mauldin; Andrew J. Plantinga; Ralph J. Alig

1999-01-01

This paper presents the historic trends and future projections of forest, farm, and urban land uses for the Lake States of Michigan, Minnesota, and Wisconsin. Since the 1950s, forest and farm land have been decreasing, and urban and other land uses have been increasing throughout the Lake States. Forest, crop, and pasture land have decreased in the region by 3.2, 5.4...

Bathymetric Surveys of Lake Arthur and Raccoon Lake, Pennsylvania, June 2007

USGS Publications Warehouse

Hittle, Clinton D.; Ruby, A. Thomas

2008-01-01

In spring of 2007, bathymetric surveys of two Pennsylvania State Park lakes were performed to collect accurate data sets of lake-bed elevations and to develop methods and techniques to conduct similar surveys across the state. The lake-bed elevations and associated geographical position data can be merged with land-surface elevations acquired through Light Detection and Ranging (LIDAR) techniques. Lake Arthur in Butler County and Raccoon Lake in Beaver County were selected for this initial data-collection activity. In order to establish accurate water-surface elevations during the surveys, benchmarks referenced to NAVD 88 were established on land at each lake by use of differential global positioning system (DGPS) surveys. Bathymetric data were collected using a single beam, 210 kilohertz (kHz) echo sounder and were coupled with the DGPS position data utilizing a computer software package. Transects of depth data were acquired at predetermined intervals on each lake, and the shoreline was delineated using a laser range finder and compass module. Final X, Y, Z coordinates of the geographic positions and lake-bed elevations were referenced to NAD 83 and NAVD 88 and are available to create bathymetric maps of the lakes.

Lake Superior: Nearshore Variability and a Landscape Driver Concept (journal article)

EPA Science Inventory

Spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches also have been observed and found to be robust across seasonal time frames. Less is known about robustness of inter-annual variation wi...

Asynchrony in the inter-annual recruitment of lake whitefish Coregonus clupeaformis in the Great Lakes region

USGS Publications Warehouse

Zischke, Mitchell T.; Bunnell, David B.; Troy, Cary D.; Berglund, Eric K.; Caroffino, David C.; Ebener, Mark P.; He, Ji X.; Sitar, Shawn P.; Hook, Tomas O.

2017-01-01

Spatially separated fish populations may display synchrony in annual recruitment if the factors that drive recruitment success, particularly abiotic factors such as temperature, are synchronised across broad spatial scales. We examined inter-annual variation in recruitment among lake whitefish (Coregonus clupeaformis) populations in lakes Huron, Michigan and Superior using fishery-dependent and -independent data from 1971 to 2014. Relative year-class strength (RYCS) was calculated from catch-curve residuals for each year class across multiple sampling years. Pairwise comparison of RYCS among datasets revealed no significant associations either within or between lakes, suggesting that recruitment of lake whitefish is spatially asynchronous. There was no consistent correlation between pairwise agreement and the distance between datasets, and models to estimate the spatial scale of recruitment synchrony did not fit well to these data. This suggests that inter-annual recruitment variation of lake whitefish is asynchronous across broad spatial scales in the Great Lakes. While our method primarily evaluated year-to-year recruitment variation, it is plausible that recruitment of lake whitefish varies at coarser temporal scales (e.g. decadal). Nonetheless, our findings differ from research on some other Coregonus species and suggest that local biotic or density-dependent factors may contribute strongly to lake whitefish recruitment rather than inter-annual variability in broad-scale abiotic factors.

Depth gradients in food web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

EPA Science Inventory

In large lakes around the world, water depth is often associated with shifts in ecological communities. Depth-based changes in the abundance and distribution of invertebrate and fish species suggest that there may be concomitant changes in patterns of resource allocation. Using L...

Interacting Watershed Size and Landcover Influences on Habitat and Biota of Lake Superior Coastal Wetlands

EPA Science Inventory

Coastal wetlands are important contributors to the productivity and biodiversity of large lakes and important mediators of the lake - watershed connection. This study explores how strength of connection to the watershed (represented by watershed size and wetland morphological ty...

The effect of light on lake herring (Coregonus artedi) reactive volume

USGS Publications Warehouse

Link, Jason; Edsall, Thomas A.

1996-01-01

The lake herring (Coregonus artedi) is an important coldwater planktivore in the Laurentian Great Lakes and in smaller inland lakes in portions of Canada and the northern United States. Lake herring cruise the pelagia and feed selectively in both gulping and particulate modes. They are visual predators in environments with adequate illumination. Visual predation by fish consists of a series of discrete steps. We studied the first step in the predation sequence, reaction to prey, at light intensities of 2–1500 Lx in a simulated pelagic environment at 10–13°C. We measured lake herring reactive distances, the distance at which a prey item will be detected and attacked, to liveLimnocalanus macrurus, a natural prey of lake herring in Lake Superior. We used the reactive distances and associated angles of bearing and elevation, which described the location of the prey relative to the lake herring, to calculate reactive volume. This reactive volume can be envisioned as an irregular sphere surrounding the fish, within which prey are detected and attacked. All of the attacks on prey occurred in the anterior portions of the sagittal and lateral planes of the lake herring, as would be expected for a pelagic, cruising fish. The reactive volume surrounding the lake herring was generally spherical, but was more irregular than the simple spheres, hemispheres, cylinders, cones or other geometries assumed in previous studies. The reactive distances and the reactive volume changed with light intensity and were significantly smaller at 2–10 Lx than at 40–1500 Lx. At 40–1500 Lx, the reactive volume was expanded over that observed at 2–10 Lx laterally and caudally. Collectively our results indicate that lake herring can visually forage most effectively in environments with light levels >10 Lx.