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1

The Reproductive Biology of Siscowet and Lean Lake Trout in Southern Lake Superior  

Microsoft Academic Search

Lean and siscowet morphotypes of lake trout Salvelinus namaycush in Lake Superior are thought to be genetically separate, but the reproductive isolating mechanism is unknown. The testicular and ovarian cycles and reproductive hormone levels of these morphotypes were determined from May to October in populations east and west of the Keweenaw Peninsula in southern Lake Superior. The gonadosomatic index (GSI)

Frederick Goetz; Shawn Sitar; Daniel Rosauer; Penny Swanson; Charles R. Bronte; Jon Dickey; Crystal Simchick

2011-01-01

2

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

USGS Publications Warehouse

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.

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

2003-01-01

3

Historic and Modern Abundance of Wild Lean Lake Trout in Michigan Waters of Lake Superior: Implications for Restoration Goals  

Microsoft Academic Search

Populations of lake trout Salvelinus namaycushin Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreysPetromyzon 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 com- parisons of the contemporary

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

2003-01-01

4

A genetic basis for the phenotypic differentiation between siscowet and lean lake trout (Salvelinus namaycush).  

PubMed

In Lake Superior there are three principal forms of lake trout (Salvelinus namaycush): lean, siscowet and humper. Wild lean and siscowet differ in the shape and relative size of the head, size of the fins, location and size of the eyes, caudal peduncle shape and lipid content of the musculature. To investigate the basis for these phenotypic differences, lean and siscowet lake trout, derived from gametes of wild populations in Lake Superior, were reared communally under identical environmental conditions for 2.5 years. Fish were analysed for growth, morphometry and lipid content, and differences in liver transcriptomics were investigated using Roche 454 GS-FLX pyrosequencing. The results demonstrate that key phenotypic differences between wild lean and siscowet lake trout such as condition factor, morphometry and lipid levels, persist in these two forms when reared in the laboratory under identical environmental conditions. This strongly suggests that these differences are genetic and not a result of environmental plasticity. Transcriptomic analysis involving the comparison of hepatic gene frequencies (RNA-seq) and expression (quantitative reverse transcription-polymerase chain reaction (qPCR)) between the two lake trout forms, indicated two primary gene groups that were differentially expressed; those involving lipid synthesis, metabolism and transport (acyl-CoA desaturase, acyl-CoA binding protein, peroxisome proliferator-activated receptor gamma, and apolipoproteins), and those involved with immunity (complement component C3, proteasome, FK506 binding protein 5 and C1q proteins). The results demonstrate that RNA-seq can be used to identify differentially expressed genes; however, some discrepancies between RNA-seq analysis and qPCR indicate that methods for deep sequencing may need to be refined and/or different RNA-seq platforms utilized. PMID:20331779

Goetz, Frederick; Rosauer, Daniel; Sitar, Shawn; Goetz, Giles; Simchick, Crystal; Roberts, Steven; Johnson, Ronald; Murphy, Cheryl; Bronte, Charles R; Mackenzie, Simon

2010-03-01

5

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

Microsoft Academic Search

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

Eric K. Moody; Brian C. Weidel; Tyler D. Ahrenstorff; William P. Mattes; James F. Kitchell

2011-01-01

6

Lake Trout Rehabilitation in Lake Ontario 2005  

Microsoft Academic Search

Abstract Each year we report ,on the ,progress toward rehabilitation of the ,Lake Ontario lake trout population covering the results of stocking, annual assessment surveys, creel surveys, and evidence of natural reproduction observed from all standard surveys performed by USGS and NYSDEC. During 2005, the number of yearling lake trout stocked in May was 45% below the target level of

B. f. Lantry; S. E. Prindle

7

Longevity of Lake Superior lake trout  

USGS Publications Warehouse

The age structure of mature lake trout Salvelinus namaycush from the Wisconsin waters of Lake Superior increased following a population recovery that has taken place since the 1960s. As the population aged, it became apparent that scales were unreliable aging structures. Beginning in 1986, we examined both scale and sagittal otolith ages from tagged fish with a known period at liberty. We found large discrepancies in scale and sagittal otolith ages of mature fish, such that scale ages were biased low. We estimated lake trout living up to 42 years, which is greater than previously reported from Lake Superior. Investigators studying lake trout population dynamics in the Great Lakes should be aware that lake trout can live longer than previously thought.

Schram, Stephen T.; Fabrizio, Mary C.

1998-01-01

8

Lake trout rehabilitation in Lake Huron  

USGS Publications Warehouse

Efforts to restore lake trout (Salvelinus namaycush) in Lake Huron after their collapse in the 1940s were underway in the early 1970s with completion of the first round of lampricide applications in tributary streams and the stocking of several genotypes. We assess results of rehabilitation and establish a historical basis for comparison by quantifying the catch of spawning lake trout from Michigan waters in 1929-1932. Sixty-eight percent of this catch occurred in northern waters (MH-1) and most of the rest (15%) was from remote reefs in the middle of the main basin. Sea lampreys (Petromyzon marinus) increased in the early 1980s in the main basin and depressed spawning populations of lake trout. This increase was especially severe in northern waters and appeared to be associated with untreated populations in the St. Marys River. Excessive commercial fishing stemming from unresolved treaty rights also contributed to loss of spawning fish in northern Michigan waters. Seneca-strain lake trout did not appear to be attacked by sea lampreys until they reached a size > 532 mm. At sizes > 632 mm, Seneca trout were 40-fold more abundant than the Marquette strain in matched-planting experiments. Natural reproduction past the fry stage has occurred in Thunder Bay and South Bay, but prospects for self-sustaining populations of lake trout in the main basin are poor because sea lampreys are too abundant, only one side of the basin is stocked, and stocking is deferred to allow commercial gillnetting in areas where most of the spawning occurred historically. Backcross lake trout, a lake trout x splake (s. Fontinalis x s. Namaycush) hybrid, did not reproduce in Georgian Bay, but this genotype is being replaced with pure-strain lake trout, whose early performance appears promising.

Eshenroder, Randy L.; Payne, N. Robert; Johnson, James E.; Bowen, Charles, II; Ebener, Mark P.

1995-01-01

9

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

USGS Publications Warehouse

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.

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

2011-01-01

10

Lake Trout Rehabilitation in Lake Erie: A Case History  

Microsoft Academic Search

Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the

Floyd C. Cornelius; Kenneth M. Muth; Roger Kenyon

1995-01-01

11

Spatial patterns in PCB concentrations of Lake Michigan lake trout  

USGS Publications Warehouse

Most of the PCB body burden in lake trout (Salvelinus namaycush) of the Great Lakes is from their food. PCB concentrations were determined in lake trout from three different locations in Lake Michigan during 1994-1995, and lake trout diets were analyzed at all three locations. The PCB concentrations were also determined in alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), slimy sculpin (Cottus cognatus), and deepwater sculpin (Myoxocephalus thompsoni), five species of prey fish eaten by lake trout in Lake Michigan, at three nearshore sites in the lake. Despite the lack of significant differences in the PCB concentrations of alewife, rainbow smelt, bloater, slimy sculpin, and deepwater sculpin from the southeastern nearshore site near Saugatuck (Michigan) compared with the corresponding PCB concentrations from the northwestern nearshore site near Sturgeon Bay (Wisconsin), PCB concentrations in lake trout at Saugatuck were significantly higher than those at Sturgeon Bay. The difference in the lake trout PCB concentrations between Saugatuck and Sturgeon Bay could be explained by diet differences. The diet of lake trout at Saugatuck was more concentrated in PCBs than the diet of Sturgeon Bay lake trout, and therefore lake trout at Saugatuck were more contaminated in PCBs that Sturgeon Bay lake trout. These findings were useful in interpreting the long-term monitoring series for contaminants in lake trout at both Saugatuck and the Wisconsin side of the lake.

Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.; Brown, Edward H., Jr.; Eck, Gary W.; Schmidt, Larry J.; Hesselberg, Robert J.; Chernyak, Sergei M.; Passino-Reader, Dora R.

1999-01-01

12

Evidence of offshore lake trout reproduction in Lake Huron  

USGS Publications Warehouse

Six Fathom Bank-Yankee Reef, an offshore reef complex, was an historically important spawning area believed to represent some of the best habitat for the rehabilitation of lake trout Salvelinus namaycush in Lake Huron. Since 1986, lake trout have been stocked on these offshore reefs to reestablish self-sustaining populations. We sampled with beam trawls to determine the abundance of naturally reproduced age-0 lake trout on these offshore reefs during May-July in 1994-1998 and 2000-2002. In total, 123 naturally reproduced lake trout fry were caught at Six Fathom Bank, and 2 naturally reproduced lake trout fry were caught at nearby Yankee Reef. Our findings suggest that this region of Lake Huron contains suitable habitat for lake trout spawning and offers hope that lake trout rehabilitation can be achieved in the main basin of Lake Huron.

DeSorcie, Timothy J.; Bowen, Charles A., II

2003-01-01

13

Suitability of habitat for spawning lake trout  

Microsoft Academic Search

We provide further insight into the reproductive ecology and spawning requirements of lake trout. New comparative information about substrate characteristics, sediment transport, quality of interstitial water at spawning substrates, and the role of temperature in site selection and time of spawning is given for lakes Simcoe and Manitou (Ontario) and Seneca Lake (New York). Spawning lake trout commonly use stable

P. G. Sly; D. O. Evans

1996-01-01

14

Lake Trout Assessment and Management in Michigan Waters of Lake Superior, 1993-97.  

National Technical Information Service (NTIS)

Lean and siscowet lake trout Salvelinus namaycush population data for Michigan management areas 2-7 during 1993-97 are presented and analyzed. Wild fish made up over 80% of populations in all areas. Relative abundance (number of fish per 1,000 feet of gil...

J. W. Peck S. P. Sitar

2000-01-01

15

Laboratory Evaluation of a Lake Trout Bioenergetics Model  

Microsoft Academic Search

Lake trout Salvelinus namaycush, aged 3 and 6 years and with average weights of 700 and 2,000 g, were grown in laboratory tanks for up to 407 d under a thermal regime similar to that experienced by lake trout in nearshore Lake Michigan. Lake trout were fed alewife Alosa pseudoharengus and rainbow smelt Osmerus mordax, prey typical of lake trout

Charles P. Madenjian; Daniel V. OConnor

1999-01-01

16

Socioeconomic Aspects of Lake Trout Rehabilitation in the Great Lakes  

Microsoft Academic Search

During the 1940s and 1950s, the major fisheries for lake trout Salvelinus namaycush in the Great Lakes declined precipitously because of predation by sea lampreys Petromyzon marinus and overfishing. The need to control the sea lamprey and rehabilitate lake trout resulted in the establishment of institutional arrangements among the responsible state, provincial, and federal fishery agencies. The early arrangements were

Randy L. Eshenroder

1987-01-01

17

Survival of Juvenile Lake Trout Stocked in Western Lake Huron during 1974–1992  

Microsoft Academic Search

The population of lake trout Salvelinus namaycush in the main basin of Lake Huron collapsed in the late 1940s from the combined effects of overfishing and predation by sea lampreys Petromyzon marinus. Stocking juvenile lake trout has been one of the key management strategies in efforts toward lake trout rehabilitation. However, the survival of juvenile stocked lake trout has decreased

Michael J. Wilberg; James R. Bence; James E. Johnson

2002-01-01

18

Estimating Potential Yeild and Harvest of Lake Trout 'Salvelinus namaycush' in Minnesota's Lake Trout Lakes, Exclusive of Lake Superior.  

National Technical Information Service (NTIS)

Given that lake trout are highly sought-after and are a limited resource in Minnesota, lake trout populations that may be stressed should be identified. They should be considered for greater protection from over-exploitation by anglers, and greater protec...

G. D. Siesennop

2000-01-01

19

Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex  

USGS Publications Warehouse

The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large, fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

Janssen, J.; Jude, D. J.; Edsall, T. A.; Paddock, R. W.; Wattrus, N.; Toneys, M.; McKee, P.

2006-01-01

20

Brook Trout Rehabilitation Plan for Lake Superior.  

National Technical Information Service (NTIS)

The goal for brook trout (Salvelinus fontinalis) rehabilitation in Lake Superior is to maintain widely distributed, self-sustaining populations throughout their original habitats. Reaching the goal will require, singly or in combination, actions to restor...

L. E. Newman R. B. DuBois T. N. Halpern

2003-01-01

21

PCB concentrations in lake trout (Salvelinus namaycush) are correlated to habitat use and lake characteristics.  

PubMed

This study considers the importance of lake trout habitat as a factor determining persistent organochlorine (OC) concentration. Lake trout is a stenothermal, cold water species and sensitive to hypoxia. Thus, factors such as lake depth, thermal stratification, and phosphorus enrichment may determine not only which lakes can support lake trout but may also influence among-lake variability in lake trout population characteristics including bioaccumulation of OCs. A survey of 23 lakes spanning much of the natural latitudinal distribution of lake trout provided a range of lake trout habitat to test the hypothesis that lake trout with greater access to littoral habitat for feeding will have lower concentrations of OCs than lake trout that are more restricted to pelagic habitat. Using the delta13C stable isotope signature in lake trout as an indicator of influence of benthic littoral feeding, we found a negative correlation between lipid-corrected delta13C and sigmaPCB concentrations supporting the hypothesis that increasing accessto littoral habitat results in lower OCs in lake trout. The prominence of mixotrophic phytoplankton in lakes with more contaminated lake trout indicated the pelagic microbial food web may exacerbate the biomagnification of OCs when lake trout are restricted to pelagic feeding. A model that predicted sigmaPCB in lake trout based on lake area and latitude (used as proximate variables for proportion of littoral versus pelagic habitat and accessibility to littoral habitat respectively) explained 73% of the variability in sigmaPCBs in lake trout in the 23 lakes surveyed. PMID:19068800

Guildford, S J; Muir, D C G; Houde, M; Evans, M S; Kidd, K A; Whittle, D M; Drouillard, K; Wang, X; Anderson, M R; Bronte, C R; Devault, D S; Haffner, D; Payne, J; Kling, H J

2008-11-15

22

Availability of lake trout reproductive habitat in the Great Lakes  

USGS Publications Warehouse

A decades-long program to reestablish self-sustaining stocks of lake trout (Salvelinus namaycush) in the four lower Great Lakes produced excellent fisheries supported by stocked fish. These fish spawned widely and small numbers of their offspring were collected intermittently from Lakes Michigan, Huron, and Ontario, but no self-sustaining stocks were established. Irt this paper we address habitat sufficiency as a factor in the failure of stocked lake trout to established self-sustaining populations in the four lower Great Lakes. We present the previously unpublished results of lake trout spawning habitat surveys conducted at seven sites in the Great Lakes since 1987 and we compare them with the published results of similar surveys conducted at 24 other sites in the four lower lakes since 1981. Our evaluation indicates all but two of these sites can support the production of viable fry from spawnings by the shallow-water strains of lake trout that are stocked in the Great Lakes. However, some of the best spawning, egg, and fry habitat in the lower Great Lakes seems to be at deeper offshore sites that may be unattractive to these shallow-water strains. Thus, we suggest also stocking the lower four lakes with strains from Lake Superior that might more fully exploit the best spawning habitat at these deeper, offshore sites.

Edsall, Thomas A.; Kennedy, Gregory W.

1995-01-01

23

INDIVIDUAL TISSUE TO TOTAL BODY-WEIGHT RELATIONSHIPS AND TOTAL, POLAR, AND NON-POLAR LIPIDS IN TISSUES OF HATCHERY LAKE TROUT  

EPA Science Inventory

Tissue body weight relaltionships, total lipid, and major lipid subclasses were measured in 20 adult hatchery lake trout to obtain a more in-depth understanding of the major lipid compartments of the "lean" lake trout for use in modeling the disposition of xenobiotics. It is sug...

24

Recruitment Dynamics of Lake Trout in Western Lake Superior during 1988–1995  

Microsoft Academic Search

Stocks of lake trout Salvelinus namaycush in Lake Superior are recovering from historical collapse. Stocking, control of sea lampreys Petromyzon marinus, and harvest restrictions have aided lake trout recovery, but the contribution of stocked lake trout to contemporary recruitment has not been quantified in western Lake Superior. Using variants of the Ricker stock–recruit model, we evaluated the production of age-7

Lisa M. Corradin; Michael J. Hansen; Donald R. Schreiner; Michael J. Seider

2008-01-01

25

Biology of young lake trout (Salvelinus namaycush) in Lake Michigan  

USGS Publications Warehouse

Experimental fishing with gill nets of 5 mesh sizes (2 3/8 to 3 inches) in Lake Michigan in 1930-32 yielded more than 16,000 young lake trout. Data are presented here on age, growth, length-weight relationship, abundance, geographical and bathymetric distribution, and other details of their biology.

Van Oosten, John; Eschmeyer, Paul H.

1956-01-01

26

Lake Trout Rehabilitation in the Great Lakes: an Evolutionary, Ecological, and Ethical Perspective  

Microsoft Academic Search

We reviewed key features of the evolutionary biology of lake trout (Salvelinus namaycush) and their significance for rehabilitation programs in the Great Lakes. Despite repeated transloca-tion by glacial advances during the Ice Age (the Pleistocene) that eliminated most populations, lake trout have genetic diversity comparable with other North American salmonines. Various embryological and adult features suggest lake trout had a

Randy L. Eshenroder; E. J. Crossman; Gary K. Meffe; Charles H. Olver; Edwin P. Pister

1995-01-01

27

Survival of Rainbow Trout and Lake Trout after Sea Lamprey Attack  

Microsoft Academic Search

Survival was significantly higher (P = 0.054) for rainbow trout Oncorhynchus mykiss (formerly Salmo gairdneri) than for lake trout Salvelinus namaycush when the fish were subjected in the laboratory to a single attack by a sea lamprey Petromyzon marinus. Of 77 rainbow trout, 40% died (35% by direct attack and 5% by secondary infection) and 60% survived; of 77 lake

William D. Swink; Lee H. Hanson

1989-01-01

28

First evidence of successful natural reproduction by planted lake trout in Lake Huron  

USGS Publications Warehouse

Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

Nester, Robert T.; Poe, Thomas P.

1984-01-01

29

Swimming Endurance of Bull Trout, Lake Trout, Arctic Char, and Rainbow Trout following Challenge with Renibacterium salmoninarum  

Microsoft Academic Search

We tested the swimming endurance of juvenile bull trout Salvelinus confluentus, lake trout S. namaycush, Arctic char S. alpinus, and rainbow trout Oncorhynchus mykiss at 9°C and 15°C to determine whether sublethal infection from a moderate challenge of Renibacterium salmoninarum administered months before testing affected the length of time fish could maintain a swimming speed of 5–6 body lengths per

Darin T. Jones; Christine M. Moffitt

2004-01-01

30

Survival and Growth of Rainbow Trout and Brown Trout in Farm Dugouts and Winterkill Lakes  

Microsoft Academic Search

Rainbow trout (Oncorhynchus mykiss, formerly Salmo gairdneri) and brown trout (Salmo trutta) were stocked sympatrically in four eutrophic winterkill lakes in 1987 and 1988 and allopatrically in 20 farm dugouts (elsewhere called stock tanks) in 1987. Fish survival and growth were monitored to ascertain the feasibility of using brown trout as an alternative species in prairie aquaculture. In dugouts, survival

C. L. Glenn; A. O. Bush; R. C. Rounds

1989-01-01

31

Contaminant Trends in Lake Trout and Walleye From the Laurentian Great Lakes  

Microsoft Academic Search

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, ?DDT, dieldrin, and oxychlordane, with declines initially following first order loss kinetics. Mean PCB concentrations in Lake Michigan lake trout increased from 13 ?g\\/g in

David S. De Vault; Robert Hesselberg; Paul W. Rodgers; Timothy J. Feist

1996-01-01

32

Rehabilitation of lake trout in the Apostle Islands region of Lake Superior  

USGS Publications Warehouse

Marked success of rehabilitation of lake trout in Lake Superior has been due principally to the control of the sea lamprey and closure of the lake trout fishery in 1962 and large-scale plantings of yearling lake trout in 1959-66. After the sea lamprey became established in the late 1940s, spawning stocks of lake trout began to decrease and were almost nonexistent by 1960-61. After control of the sea lamprey and closure of the commercial fishery for lake trout in 1962, the abundance of spawning stocks began to rise and reached the highest levels on record in 1964-66. Successful spawning in 1964 and 1965 was demonstrated by catches of age-0 lake trout in 1965 and 1966, the first evidence of natural reproduction since 1959. Plantings of hatchery-reared lake trout in Wisconsin waters of Lake Superior began in 1952. The percentage of hatchery-reared fish in catches of juvenile lake trout increased almost steadily from 1953 to 1965 (when nearly all were of hatchery origin). The abundance of juvenile fish increased from 1959 to 1962 and remained nearly constant in 1962-66. The success of lake trout plantings was highest in 1959-61 but generally declined after 1961; the success of the plantings was inversely related to the abundance of older lake trout. Annual increments of growth of hatchery-reared lake trout varied from 1.1 to 5.0 inches after planting. The average lengths of fish of identical age-groups varied according to gear of capture, depth of water, and season. More than 65% of the season's growth of age-III lake trout took place after September. The findings indicate that the present rate of stocking lake trout may be higher than necessary to maintain optimum abundance.

Dryer, William R.; King, George R.

1968-01-01

33

Evaluation of offshore stocking of Lake Trout in Lake Ontario  

USGS Publications Warehouse

Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration targets.

Lantry, B. F.; O'Gorman, R.; Strang, T. G.; Lantry, J. R.; Connerton, M. J.; Schanger, T.

2011-01-01

34

Genetic Assessment of Strain-Specific Sources of Lake Trout Recruitment in the Great Lakes  

Microsoft Academic Search

Populations of wild lake trout Salvelinus namaycush have been extirpated from nearly all their historical habitats across the Great Lakes. Efforts to restore self-sustaining lake trout populations in U.S. waters have emphasized the stocking of coded-wire-tagged juveniles from six hatchery strains (Seneca Lake, Lewis Lake, Green Lake, Apostle Islands, Isle Royale, and Marquette) into vacant habitats. Strain-specific stocking success has

Kevin S. Page; Kim T. Scribner; Kristine R. Bennett; Laura M. Garzel; Mary K. Burnham-Curtis

2003-01-01

35

Lake trout population dynamics in the Northern Refuge of Lake Michigan: implications for future rehabilitation  

USGS Publications Warehouse

The Northern Refuge was established in 1985 as part of the lake trout Salvelinus namaycush rehabilitation effort for Lake Michigan. To evaluate progress toward lake trout rehabilitation in the Northern Refuge, we conducted annual (1991–2008) gill-net surveys in the fall to assess the adult population and beam trawl surveys in the spring to assess naturally reproduced age-0 lake trout. Our criteria for evaluating progress included the density of “wild” age-0 fish within the Northern Refuge, the proportion of wild fish within the adult population, density of spawners, adult survival, growth, and wounding rate by sea lampreys Petromyzon marinus. No wild age-0 lake trout were caught in the Northern Refuge during 1991–2008. Overall, wild lake trout did not recruit to the adult population to any detectable degree. The mean density of spawning lake trout decreased from 45 fish·305 m of gill net?1·d?1 during 1991–1999 to only 4 fish·305 m?1·d?1 during 2000–2008. Although the sea lamprey wounding rate more than doubled between these two time periods, catch curve analysis revealed that mortality of adult lake trout actually decreased between the two periods. Therefore, the 90% decrease in abundance of spawning lake trout between the two periods could not be attributed to increased sea lamprey predation but instead was probably due in part to the reduced lake trout stocking rate during 1995–2005. The paucity of natural reproduction in the Northern Refuge during 1991–2008 most likely resulted from alewife Alosa pseudoharengus interference with lake trout reproduction and from the relatively low lake trout spawner density during 2000–2008. Our results suggest that the annual stocking rate of lake trout yearlings should be increased to at least 250,000 fish/reef to achieve greater densities of spawners.

Madenjiana, Charles P.; Desorcie, Timothy J.

2010-01-01

36

Status of Lake Trout Rehabilitation in the Northern Refuge of Lake Michigan  

Microsoft Academic Search

The Northern Refuge in Lake Michigan was established in 1985 as part of a rehabilitation program to stock yearling lake trout Salvelinus namaycush in areas with the best potential for success. Stocking of hatchery-reared lake trout within the refuge began in 1986 at three reefs: Boulder Reef, Gull Island Reef, and Richards Reef. On each reef from 1991 to 1997

Charles P. Madenjian; Timothy J. DeSorcie

1999-01-01

37

Status of lake trout rehabilitation on Six Fathom Bank and Yankee Reef in Lake Huron  

USGS Publications Warehouse

Six Fathom Bank, an offshore reef in the central region of Lake Huron's main basin, was stocked annually with hatchery-reared lake trout Salvelinus namaycush during 1985-1998, and nearby Yankee Reef was stocked with hatchery-reared lake trout in 1992, 1997, and annually during 1999-2001. We conducted gill-net surveys during spring and fall to evaluate performances of each of the various strains of lake trout, as well as the performance of the entire lake trout population (all strains pooled), on these two offshore reefs during 1992-2000. Criteria to evaluate performance included the proportion of 'wild' fish within the population, spawner density, adult survival, growth, maturity, and wounding rate by sea lamprey Petromyzon marinus. Although naturally reproduced age-0 lake trout fry were caught on Six Fathom Bank and Yankee Reef, wild lake trout did not recruit to the adult population to any detectable degree. The density of spawning lake trout on Six Fathom Bank (>100 fish/305 m of gill net) during 1995-1998 appeared to be sufficiently high to initiate a self-sustaining population. However, annual mortality estimates for all lake trout strains pooled from catch curve analyses ranged from 0.48 to 0.62, well exceeding the target level of 0.40 suggested for lake trout rehabilitation. Annual mortality rate for the Seneca Lake strain (0.34) was significantly lower than that for the Superior-Marquette (0.69) and Lewis Lake (0.69) strains. This disparity in survival among strains was probably attributable to the lower sea-lamprey-induced mortality experienced by the Seneca Lake strain. The relatively high mortality experienced by adult lake trout partly contributed to the lack of successful natural recruitment to the adult population on these offshore reefs, but other factors were probably also involved. We recommend that both stocking of the Seneca Lake strain and enhanced efforts to reduce sea lamprey abundance in Lake Huron be continued.

Madenjian, Charles P.; DeSorcie, Timothy J.; McClain, Jerry R.; Woldt, Aaron P.; Holuszko, Jeffrey D.; Bowen, Charles A., II

2004-01-01

38

Status of lake trout rehabilitation in the Northern Refuge of Lake Michigan  

USGS Publications Warehouse

The Northern Refuge in Lake Michigan was established in 1985 as part of a rehabilitation program to stock yearling lake trout Salvelinus namaycush in areas with the best potential for success. Stocking of hatchery-reared lake trout within the refuge began in 1986 at three reefs: Boulder Reef, Gull Island Reef, and Richards Reef. On each reef from 1991 to 1997 we conducted gill-net surveys during the fall spawning season to evaluate performance of adult lake trout, and we conducted beam trawl surveys for naturally reproduced age-0 lake trout in the spring. Criteria to evaluate performance included spawner density, growth, maturity, and mortality. We found no evidence of natural reproduction by lake trout from our surveys. Nevertheless, density of spawning lake trout on Boulder Reef (69 fish/305 m of gill net/night) and Gull Island Reef (34 fish/305 m of gill net/night) appeared to be sufficiently high to initiate a self-sustaining population. Growth and maturity rates of lake trout in the Northern Refuge were similar to those for lake trout stocked in the nearshore region of Lake Michigan. In the Northern Refuge, growth rate for the Marquette strain of lake trout was slightly higher than for the Lewis Lake strain. Annual mortality estimates from catch curve analyses ranged from 0.46 to 0.41, and therefore, these estimates approached a level that was considered to be sufficiently low to allow for a self-sustaining population. Thus, it appeared that the lack of evidence for natural reproduction by lake trout in the Northern Refuge should not be attributed to inability of the population to attain a sufficiently large stock of spawners.

Madenjian, Charles P.; DeSorcie, Timothy J.

1999-01-01

39

Conservation Genetics of Inland Lake Trout in the Upper Mississippi River Basin: Stocked or Native Ancestry?  

Microsoft Academic Search

Although stocking for sport fishery enhancement has been practiced by resource managers for decades, the potential genetic effects of these stocking practices have remained largely unknown. We investigated the genetic contributions of stocking lake trout Salvelinus namaycush in two inland lakes in Wisconsin (Trout and Black Oak lakes in Vilas County), which represent the only known indigenous lake trout populations

Kyle R. Piller; Chris C. Wilson; Carol Eunmi Lee; John Lyons

2005-01-01

40

Swimming endurance of bull trout, lake trout, arctic char, and rainbow trout following challenge with Renibacterium salmoninarum  

USGS Publications Warehouse

We tested the swimming endurance of juvenile bull trout Salvelinus confluentus, lake trout S. namaycush, Arctic char S. alpinus, and rainbow trout Oncorhynchus mykiss at 9??C and 15??C to determine whether sublethal infection from a moderate challenge of Renibacterium salmoninarum administered months before testing affected the length of time fish could maintain a swimming speed of 5-6 body lengths per second in an experimental flume. Rainbow trout and Arctic char swam longer in trials than did bull trout or lake trout, regardless of challenge treatment. When we tested fish 14-23 weeks postchallenge, we found no measurable effect of R. salmoninarum on the swimming endurance of the study species except for bull trout, which showed a mixed response. We conducted additional trials with bull trout 5-8 weeks postchallenge to determine whether increasing the challenge dose would affect swimming endurance and hematocrit. In those tests, bull trout with clinical signs of disease and those exposed to the highest challenge doses had significantly reduced swimming endurance compared with unchallenged control fish. Fish hematocrit levels measured at the end of all swimming endurance tests varied among species and between test temperatures, and patterns were not always consistent between challenged and control fish.

Jones, D. T.; Moffitt, C. M.

2004-01-01

41

Yellowstone Lake Crisis: Confronting a Lake Trout Invasion. A Report to the Director of the National Park Service.  

National Technical Information Service (NTIS)

Yellowstone Lake is home of the premier surviving inland cutthroat trout fishery in North America. This fishery is threatened with destruction by illegally introduced lake trout, which were discovered in 1994. The lake trout are known to exist in at least...

J. D. Varley P. Schullery

1995-01-01

42

Predation of lake trout and lake whitefish embryos by crayfish: Implications of shifts in crayfish dominance in Lake Simcoe  

Microsoft Academic Search

We compared predation rates of two Lake Simcoe crayfish, Orconectes virilis and Orconectes propinquus, on lake trout and lake whitefish eggs and alevins in laboratory experiments and assessed the potential impact of predation on egg survival in the lake. Experiments were conducted at 4 and 8°C on gravel and one or three layers of cobble substrate. Predation rates on lake

Kristine Mason; David O. Evans

2011-01-01

43

The Movement of Tagged Lake Trout in Lake Superior, 1950–1952  

Microsoft Academic Search

A total of 733 native lake trout was tagged at two widely separated localities in Lake Superior; subsequent recaptures numbered 155 fish (21.1 percent) during the year following marking. In October 1950, 116 large lake trout (average total length, 27.3 inches) were tagged near Keweenaw Point, Michigan. Fifteen (12.9 percent) were recovered during the first year at points as far

Paul H. Eschmeyer; Russell Daly; Leo F. Erkkila

1953-01-01

44

Progress Toward the Rehabilitation of Lake Trout ( Salvelinus namaycush) in South Bay, Lake Huron  

Microsoft Academic Search

Our objective was to evaluate the status of lake trout Salvelinus namaycush rehabilitation in South Bay, Lake Huron. Standardized surveys were conducted to quantify natural recruitment, annual mortality, and the contribution of wild-versus hatchery-origin lake trout. Some indicators suggest a high level of natural recruitment. The spawning population was comprised of multiple ages, and the mean age of spawners (8.4

Yolanda E. Morbey; David M. Anderson; Bryan A. Henderson

2008-01-01

45

Side-scan sonar mapping of lake trout spawning habitat in northern Lake Michigan  

USGS Publications Warehouse

Native stocks of lake trout Salvelinus namaycush were virtually or completely extirpated from the lower four Great Lakes by the early 1960s. The failure of early attempts to reestablish self-sustaining populations of lake trout was attributed partly to the practice of stocking hatchery-reared juveniles at locations and over substrates that had not been used in the past for spawning by native fish. Subsequent attempts to improve the selection of stocking locations were impeded by the lack of reliable information on the distribution of substrates on historical spawning grounds. Here we demonstrate the potential of side-scan sonar to substantially expand the data base needed to pinpoint the location of substrates where lake trout eggs, fry or juveniles could be stocked to maximize survival and help ensure that survivors returning to spawn would encounter suitable substrates. We also describe are the substrates and bathymetry of large areas on historical lake trout spawning grounds in the Fox Island Lake Trout Sanctuary in northern Lake Michigan. These areas could be used to support a contemporary self-sustaining lake trout population in the sanctuary and perhaps also in adjacent waters.

Edsall, Thomas A.; Poe, Thomas P.; Nester, Robert T.; Brown, Charles L.

1989-01-01

46

Lake trout population dynamics at Drummond Island Refuge in Lake Huron: Implications for future rehabilitation  

USGS Publications Warehouse

The Drummond Island Refuge (DIR) was established in 1985 as part of the rehabilitation effort for lake trout Salvelinus namaycush in Lake Huron. Since then, several strains of hatchery-reared lake trout have been stocked annually at the DIR. An intensive lampricide treatment of the St. Marys River during 1998-2001 was expected to lower the abundance of sea lamprey Petromyzon marinus within the DIR by 2000. We conducted annual gill-net surveys during spring and fall to evaluate the performance of each of the strains of lake trout as well as that of the entire lake trout population (all strains pooled) in the DIR during 1991-2005. The criteria to evaluate performance included the proportion of "wild" fish within the population, spawner density, adult survival, growth, maturity, and wounding rate by sea lampreys. Wild lake trout did not recruit to the adult population to any detectable degree. During 1991-2005, the average density of spawning lake trout appeared to be marginally sufficient to initiate a self-sustaining population. Survival of the Seneca Lake (SEN) strain of lake trout was significantly higher than that of the Superior-Marquette (SUP) strain, in part because of the higher sea-lamprey-induced mortality suffered by the SUP strain. However, other factors were also involved. Apparently SUP fish were more vulnerable to fishing conducted in waters near the refuge boundaries than SEN fish. The St. Marys River treatment appeared to be effective in reducing the sea lamprey wounding rate on SEN fish. We recommend that the stocking of SEN lake trout in the DIR, control of sea lampreys in the St. Marys River, and reduction of commercial fishery effort in waters near the DIR be maintained. ?? Copyright by the American Fisheries Society 2008.

Madenjian, C. P.; Ebener, M. P.; Desorcie, T. J.

2008-01-01

47

Starvation resistance in lake trout fry  

USGS Publications Warehouse

Newly hatched fry were acclimated to 7 or 12A?C and either fed daily (controls) or denied food for varying lengths of time and then fed daily until the end of the study (day 91 at 7A?C and day 43 at 12A?C). Growth was reduced by delays in the onset of feeding of 27 or more days at 7A?C and 7 or more days at 12A?C. Mortality of fry unfed for more than 34 days at 7A?C, or more than 21 days at 12A?C, was higher than among controls. Daily mortality increased with the length of the food deprivation period and did not cease immediately when food was made available, but reached zero by the end of the study. Mortality among unfed fry reached 50% in about 59 days at 7A?C and 32 days at 12A?C. Study results permitted calculation of the 'point-of-no-return' (PNR) mortality, which included the mortality that occurred during the period of food deprivation, and also the delayed component of mortality that was directly attributable to starvation and that occurred after food was made available. The PNR for 50% mortality for food-deprived fry occurred after 52 days at 7A?C and 24 days at 12A?C. Thus, both measures of mortality indicate that lake trout fry would be highly resistant to death by starvation in the thermal habitat they would be expected to occupy in the Great Lakes. We conclude that a more likely adverse effect of reduced food availability would result from a reduction in growth rate that extends the length of time fry remain small and vulnerable to predation by adult alewives and other non-native fishes with which they associate.

Edsall, Thomas A.; Manny, Bruce A.; Kennedy, Gregory W.

2003-01-01

48

Genetic Diversity of Wild and Hatchery Lake Trout Populations: Relevance for Management and Restoration in the Great Lakes  

Microsoft Academic Search

The biological diversity of lake trout Salvelinus namaycush in the upper Great Lakes was historically high, consisting of many recognizable morphological types and discrete spawning populations. During the 1950s and 1960s, lake trout populations were extirpated from much of the Great Lakes primarily as a result of overfishing and predation by the parasitic sea lamprey Petromyzon marinus. Investigations of how

Kevin S. Page; Kim T. Scribner; Mary Burnham-Curtis

2004-01-01

49

Lake Trout, Sea Lampreys, and Overfishing in the Upper Great Lakes: A Review and Reanalysis  

Microsoft Academic Search

To assess the role of commercial fishing in the destruction of lake trout Salvelinus namaycush in Lakes Huron, Michigan, and Superior in the 1940s and 1950s, we reviewed the literature and analyzed catch and effort data for U.S. waters by regression analysis. There is abundant evidence of the effect of the sea lamprey Petromyzon marinus in the destruction of lake

Daniel W. Coble; Richard E. Bruesewitz; Thomas W. Fratt; Jeffrey W. Scheirer

1990-01-01

50

Restoration of Lake Trout in the Great Lakes: Challenges and Strategies for Future Management  

Microsoft Academic Search

Rehabilitation of lake trout (Salvelinus namaycush) populations has shown many signs of success in Lake Superior, but few are apparent in Lakes Huron, Michigan, Erie, and Ontario. This paper identifies key factors that have blocked rehabilitation and proposes management actions to address these problems based on the proceedings of the RESTORE Conference held in 1994. Important factors that have prevented

Charles C. Krueger; Michael L. Jones; William W. Taylor

1995-01-01

51

Spring-summer diet of lake trout on Six Fathom Bank and Yankee Reef in Lake Huron  

USGS Publications Warehouse

We examined the stomach contents of 1,045 lake trout (Salvelinus namaycush) caught on Six Fathom Bank and Yankee Reef, two offshore reef complexes in Lake Huron, during late spring and early summer 1998-2003. Lake trout ranged in total length from 213 to 858 mm, and in age from 2 to 14 years. In total, 742 stomachs contained food. On a wet-weight basis, alewife (Alosa pseudoharengus) dominated the spring-summer diet of lake trout on both of these offshore reef complexes. Alewives accounted for 75 to 90% of lake trout diet, depending on the lake trout size category. Size of alewives found in lake trout stomachs increased with increasing lake trout size. Faster growth of juvenile lake trout on Six Fathom Bank and Yankee Reef than on Sheboygan Reef in Lake Michigan was attributed to greater availability of small alewives on the offshore reefs in Lake Huron. Our findings indicated that alewives inhabited Six Fathom Bank and Yankee Reef during spring and summer months. Thus, our study provided support for the contention that alewives may have interfered with natural reproduction by lake trout on these offshore reef complexes in Lake Huron.

Madenjian, C. P.; Holuszko, J. D.; Desorcie, T. J.

2006-01-01

52

Embryonic developmental progression in lake trout (Salvelinus namaycush) (Walbaum, 1792) and its relation to lake temperature  

USGS Publications Warehouse

Developmental progression of lake trout (Salvelinus namaycush) embryos was examined with light and scanning electron microscopy. From this examination, key developmental stages were described in detail. The key developmental stages were then applied to individual lake trout egg lots incubated in constant temperatures of 2, 4, 6, 8, and 10A?C. We used Belehradek's, Thermodynamic, and Power models, and also developed the Zero model to determine stage specific developmental rates of lake trout eggs for each background temperature. From the models, hatch dates and staging were predicted for temperature regimes from Lake Superior (1990-91) and Lake Huron (1996-97). Based on the existing lake temperature data and the observed spawning dates, the Zero and the Power models predict that post peak spawning may contribute significantly to overall recruitment success for these years.

Allen, Jeffrey D.; Walker, Glenn K.; Adams, Jean V.; Nichols, S. Jerrine; Edsall, Carol C.

2005-01-01

53

Patterns of egg deposition by lake trout and lake whitefish at Tawas artificial Reef, Lake Huron, 1990-1993  

USGS Publications Warehouse

In August 1987, the Michigan Department of Natural Resources (MDNR), with the help and co-sponsorship of Walleyes for Iosco County, constructed Tawas artificial reef to improve recreational fishing in Tawas Bay. Post-construction assessment in October, 1987, by the MDNR found twice as many adult lake trout in a gill net set on the reef as in a similar net set off the reef, indicating that lake trout already had begun to investigate this new habitat. Similar netting efforts in October 1989 caught three times as many adults on the reef as off it, even though the on-reef net was set for less than one third as long a period. Using a remotely operated vehicle (ROV), we detected prespawning aggregations of lake trout on the reef in fall 1989, and MDNR biologists set emergent fly traps on the reef in April-May 1990-1991. These fry traps captured several newly emerged lake trout and lake whitefish fry, demonstrating that eggs of both species has hatched successfully. Gill netting in 1992-1993 by U.S. Fish and Wildlife Service biologists netted large numbers of ripe lake trout in late October and ripe lake whitefish in early to mid-November. The purpose of this paper is to describe the relative quantities of eggs deposited and the spatial patterns of egg deposition by lake trout and lake whitefish at Tawas artificial reef during 1990-1993.

Foster, N.R.; Kennedy, G.W.

1995-01-01

54

Cultural Basis of Sport Anglers' Response to Reduced Lake Trout Catch Limits  

Microsoft Academic Search

The cultural domain of southeastern Wisconsin anglers along Lake Michigan was assessed from responses to a state-proposed reduction in the daily allowable catch of lake trout Salvelinus namaycush. The study's baseline was an extensive random survey in 1980 of the area's anglers with respect to Lake Michigan fishery resources. The 1984 lake trout issue was addressed by a restudy involving

Richard W. Stoffle; Florence V. Jensen; Danny L. Rasch

1987-01-01

55

Limitations to lake trout (Salvelinus namaycush) rehabilitation in the Great Lakes imposed by biotic interactions occurring at early life stages  

USGS Publications Warehouse

We examine evidence that biotic factors, particularly predation, may be limiting early survival of wild lake trout (Salvelinus namaycush) juveniles in many areas of the Great Lakes. The Great Lakes contain numerous potential predators of lake trout eggs and fry, some of which are recent invaders, and most of which were probably absent when lake trout most recently re-invaded the Great Lakes after the last ice age. Simple quantitative models of predation suggest that plausible assumptions about prey densities, predator feeding rates, and duration of exposure of predator to prey can lead to very high estimates of predation mortality, in some instances approaching 100%. Indirect evidence from inter-Great Lake comparisons and inland lake examples also suggest that biotic factors may impede successful lake trout colonization. Our synthesis of the evidence leads to recommendations for research to better define field feeding rates of lake trout egg and fry predators and comparative studies of densities of potential egg and fry predators on lake trout spawning reefs. Management options should be designed to provide useful information as well as achieve short-term goals. From a management standpoint we recommend that: newly constructed lake trout reefs should be placed well away from concentrations of potential predators; offshore spawning reefs should be stocked; salmonine stocking, nutrient abatement, and commercial harvest of alewives should all be considered as options to enhance survival of young lake trout; hatchery lake trout should not be stocked at sites where wild lake trout are showing signs of recovery; and exotic species expansions or introductions must be curtailed to maintain or improve on our recent successes in lake trout rehabilitation.

Jones, Michael L.; Eck, Gary W.; Evans, David O.; Fabrizio, Mary C.; Hoff, Michael H.; Hudson, Patrick L.; Janssen, John; Jude, David; O'Gorman, Robert; Savino, Jacqueline F.

1995-01-01

56

Comparative hatching success of lake trout eggs in Lake Michigan water and well water  

USGS Publications Warehouse

A study was undertaken to examine the influence of water from southern Lake Michigan on the survival of lake trout (Salvelinus namaycush) eggs by comparing the hatching success of eggs from the same source incubated in water from Lake Michigan, or from the laboratory well. It is concluded that the observed differences in hatching are probably attributable to chemical constituents of water from the lake (eg, chlorinated hydrocarbons, metals and other industrial and agricultural chemicals).

Edsall, Carol C.; Mac, Michael J.

1982-01-01

57

The Lake Trout of Cold Stream Pond, Enfield, Maine  

Microsoft Academic Search

Lake trout, Cristivomer namaycush (Walbaum), were netted in Cold Stream Pond, Enfield, Maine during the spawning seasons of 1951, 1952, 1953. The fish were weighed, measured and tagged with monel-metal jaw tags, and scale samples were secured for age determinations. A creel census, conducted during the fishing seasons of 1952 and 1953, contributed additional age and growth information and tag

Stuart E. DeRoche; Lyndon H. Bond

1957-01-01

58

Gamete ripening and hormonal correlates in three strains of lake trout  

USGS Publications Warehouse

In our 2-year laboratory study of hatchery-reared adult lake trout Salvelinus namaycush of the Seneca Lake, Marquette (Lake Superior Lean), and Jenny Lake strains, we compared gamete ripening times and changes in plasma concentrations of seven hormones. If interstrain differences in these traits were found, such differences might help explain the apparent failure of stocked fish of these strains to develop large, naturally reproducing populations in the Great Lakes. The complex temporal changes in plasma hormone levels that occur during sexual maturation in lake trout have not been previously described. We detected little evidence of temporal isolation that would prevent interbreeding among the three strains. Strain had no effect on ovulation date (OD) in either year. Strain did not affect spermiation onset date (SOD) in year 1 but did in year 2, when the mean SOD of Jenny Lake males was earlier than that of Seneca Lake males but not different from that of Marquette males. Hormonal data were normalized around ODs for individual females and SODs for individual males. In females, estradiol-17beta (E2) was highest 8 weeks before the OD; the highest testosterone (T) level occurred 6 weeks before the OD, and the next highest level occurred simultaneously with the highest level of 11-ketotestosterone (11-KT) 2 weeks before the OD. Plasma levels of 17alpha-hydroxy-20beta-dihydroprogesterone (DHP) peaked 1 week before the OD, then abruptly declined immediately after. Cortisol (F), triiodothyronine (T3), and thyroxine (T4) were highly variable, but F was the only hormone that showed no trend with week in either year. In males, plasma E2 levels were highest 3 weeks before the SOD, highest levels of T and of 11-KT occurred simultaneously 2 weeks after the SOD, and DHP peaked 5 weeks after the SOD and 3 weeks after the highest levels of T and 11-KT. As in females, plasma levels of F, T3, and T4 were highly variable, and F was the only hormone that showed no trend with week in either year. Strain had no effect on any hormones in females and only on T and F in males. The lack of pronounced interstrain differences in gamete ripening dates and reproductive endocrinology and the similarity of the temporal patterns and relative concentrations of hormones to those reported for other salmonids suggest nothing unusual or dysfunctional about these reproductive traits that would impede lake trout rehabilitation in the Great Lakes.

Foster, N.R.; O'Connor, D.V.; Schreck, C.B.

1993-01-01

59

Evidence of widespread natural reproduction by lake trout Salvelinus namaycush in the Michigan waters of Lake Huron  

USGS Publications Warehouse

Localized natural reproduction of lake trout Salvelinus namaycush in Lake Huron has occurred since the 1980s near Thunder Bay, Michigan. During 2004-2006, USGS spring and fall bottom trawl surveys captured 63 wild juvenile lake trout at depths ranging from 37-73 m at four of five ports in the Michigan waters of the main basin of Lake Huron, more than five times the total number captured in the previous 30-year history of the surveys. Relatively high catches of wild juvenile lake trout in bottom trawls during 2004-2006 suggest that natural reproduction by lake trout has increased and occurred throughout the Michigan waters of the main basin. Increased catches of wild juvenile lake trout in the USGS fall bottom trawl survey were coincident with a drastic decline in alewife abundance, but data were insufficient to determine what mechanism may be responsible for increased natural reproduction by lake trout. We recommend further monitoring of juvenile lake trout abundance and research into early life history of lake trout in Lake Huron.

Riley, S. C.; He, J. X.; Johnson, J. E.; O'Brien, T. P.; Schaeffer, J. S.

2007-01-01

60

CALCULATED CONTRIBUTION OF SURFACE MICROLAYER PCB TO CONTAMINATION OF LAKE MICHIGAN LAKE TROUT  

EPA Science Inventory

The possible significance of PCB concentration in the surface microlayer of Lake Michigan to contamination of lake trout was examined using a modification of a previously developed food chain model. Vertically migrating zooplankton were assumed to spend a fraction of each day exp...

61

Returns of hatchery-reared lake trout in southern Lake Superior, 1955-62  

USGS Publications Warehouse

Experimental plantings of fin-clipped lake trout (Salvelinus namaycush) of various ages have been made in southern Lake Superior since 1952. The catch of planted lake trout by the commercial fishery was used to measure the success of stocking. Estimates of total returns were based on samples of 8.2 to 21.2% of the Wisconsin catches in 1955-62 and 36.4 to 46.8% of the Michigan catches in 1959-62. Marked lake trout were assigned to various plantings according to the fin mark, length of fish, readings of age from scales, and locations of capture. Estimated returns from Wisconsin plantings of 9-month-old lake trout varied from 2.1 to 6.4%. Wisconsin releases of 16-month-old fish yielded returns of 5.7 to 37.3%. Returns from plantings in Michigan were 0.3% for 9-month-old fish and 1.5 to 3.8% for 16-month-old fish. The ratios of the returns from plantings of 16-month-old fish to those of 9-month-old fish were 3.9:1 for Wisconsin releases and 6.7:1 for Michigan releases. Lake trout planted in Wisconsin generally survived better than those released in Michigan. Returns from fish planted at ages of 17 to 40 months in Michigan in 1958-59 were far greater than those from 16-month-old fish released in Michigan, but were not as high as from the most successful plantings of 16-month-old fish in Wisconsin. Lake trout released in 1960 from shore and from boats survived equally well. Average size of lake trout at release was more closely related to survival than any other factor. All except 1 of 10 highly successful releases were of fish larger than 22 per lb, and all 6 poor releases were of fish smaller than 34 per lb. Fish that ran 22 to 33 per lb survived only moderately well. A size of 17 to 20 fish per lb appears to be close to optimum. Abundance of native lake trout, American smelt (Osmerus mordax), and sea lampreys (Petromyzon marinus) all appeared to be unrelated to stocking success. The only apparent method of rapidly improving the success of stocking is to rear all lake trout to an average size of 17 to 20 per lb.

Pycha, Richard L.; King, George R.

1967-01-01

62

Population biology of lake trout (Salvelinus namaycush) of Lake Superior before 1950  

USGS Publications Warehouse

Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10-0.25. The Ricker model was used to calculate yield per recruitment, which varied with natural mortality and growth. Natural mortality was more critical than growth; yield per recruitment increased 183.3% with a 60% decrease in instantaneous natural mortality (from 0.25 to 0.10). For the prelamprey lake trout population the yield per recruitment was about 12-34 lb; the recruitment of about 3.6-10.1 million lake trout of age 1.5 resulted in an annual commercial production of 4 million lb.

Sakagawa, Gary T.; Pycha, Richard L.

1971-01-01

63

Ecology of Kokanee Salmon and Rainbow Trout in Crater Lake, Oregon  

Microsoft Academic Search

Originally barren of fish, Crater Lake was stocked with approximately 1.8 million salmonids from 1888 to 1941. Rainbow trout (Oncorhynchus mykiss) and kokanee salmon (O. nerka) now inhabit the lake. This study was conducted from 1986 to 1991 to document and compare kokanee salmon and rainbow trout ecology in the lake to better evaluate the ecological implications of the presence

Mark W. Buktenica; Gary L. Larson

1996-01-01

64

Genetic assessment of strain-specific sources of lake trout recruitment in the Great Lakes  

USGS Publications Warehouse

Populations of wild lake trout Salvelinus namaycush have been extirpated from nearly all their historical habitats across the Great Lakes. Efforts to restore self-sustaining lake trout populations in U.S. waters have emphasized the stocking of coded-wire-tagged juveniles from six hatchery strains (Seneca Lake, Lewis Lake, Green Lake, Apostle Islands, Isle Royale, and Marquette) into vacant habitats. Strain-specific stocking success has historically been based on estimates of the survival and catch rates of coded-wire-tagged adults returning to spawning sites. However, traditional marking methods and estimates of relative strain abundance provide no means of assessing strain fitness (i.e., the realized contributions to natural recruitment) except by assuming that young-of-the-year production is proportional to adult spawner abundance. We used microsatellite genetic data collected from six hatchery strains with likelihood-based individual assignment tests (IA) and mixed-stock analysis (MSA) to identify the strain composition of young of the year recruited each year. We show that strain classifications based on IA and MSA were concordant and that the accuracy of both methods varied based on strain composition. Analyses of young-of-the-year lake trout samples from Little Traverse Bay (Lake Michigan) and Six Fathom Bank (Lake Huron) revealed that strain contributions differed significantly from estimates of the strain composition of adults returning to spawning reefs. The Seneca Lake strain contributed the majority of juveniles produced on Six Fathom Bank and more young of the year than expected within Little Traverse Bay. Microsatellite markers provided a method for accurately classifying the lake trout hatchery strains used for restoration efforts in the Great Lakes and for assessment of strain-specific reproductive success.

Page, Kevin S.; Scribner, Kim T.; Bennett, Kristine R.; Garzel, Laura M.; Burnham-Curtis, Mary K

2003-01-01

65

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

USGS Publications Warehouse

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.

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

2004-01-01

66

Lake trout (Salvelinus namaycush) and sea lamprey (Petromyzon marinus) populations in Lake Michigan, 1971-78  

USGS Publications Warehouse

Lake trout (Salvelinus namaycush) was exterminated in Lake Michigan by the mid-1950s as a result of the combined effects of an intensive fishery and predation by the sea lamprey (Petromyzon marinus). The widespread application of lampricide in tributary streams had greatly reduced the abundance of lampreys by the early 1960s, and a program to restore self-sustaining populations of lake trout through stocking of yearlings and fingerlings was initiated in 1965. Although the hatchery-reared fish spawned widely in Lake Michigan each year after 1970, no progeny were observed except in an isolated area in Grand Traverse Bay. During 1971-78, sea lamprey abundance was generally greater in Wisconsin than in other parts of the lake. However, the rate of occurrence of sea lamprey wounds on lake trout dropped dramatically there in 1978 after the Peshtigo River, a tributary to Green Bay, was treated with lampricide. Application of Lake Michigan wounding rates to a regression model relating mortality to lamprey wounding developed from Lake Superior data, yielded lamprey-induced mortality estimates in 1977 of 5% in Michigan plus Indiana (combined) and 31% in Wisconsin; corresponding estimates for 1978 were 5 and 15%.

Wells, LaRue

1980-01-01

67

Short-duration electrical immobilization of lake trout  

USGS Publications Warehouse

Chemical anesthetics induce stress responses, and most leave residues in fish tissues that require a certain withdrawal time before the animal can be released into the environment. Therefore, alternatives are needed in cases when fish must be released immediately, for example, during egg-collecting operations or after implanting elastomer tags. To evaluate pulsed direct current as an alternative method of immobilization, individual lake trout Salvelinus namaycush were electrically immobilized using various pulsed-DC voltage gradients and shock durations. Duration of opercular recovery and narcosis were measured for individual fish. Fish were euthanized 24 h after electrical immobilization and processed for lateral radiograph analysis and assessment of perivertebral hemorrhaging by dissection. Survival of lake trout after electrical immobilization at 0.6 V/cm for 30 or 40 s or 0.8 V/cm for 5 or 15 s was monitored for 81 or 84 d after immobilization. Mean narcosis duration increased with voltage gradient and shock duration. Larger fish had longer periods of narcosis at the same combination of voltage gradient and shock duration. Radiological evaluation indicated that 9 of 28 fish in the oldest age-class tested had detectable injuries of the vertebral column, but all but one were in the lowest injury category. Although vertebral column injuries were observed in most small fish, the majority of vertebral column injuries were minor compressions involving two to seven vertebrae. Of the 82 lake trout electrically immobilized to assess long-term survival, only 5 died (6%). Our data suggest that lake trout could be electrically immobilized for a sufficient period to allow field workers to collect length and weight data and implant visible implant tags or colored elastomer tags. The technique we used, however, is probably not appropriate for procedures that require immobilization for more than 2a??3 min.

Gaikowski, Mark P.; Gingerich, William H.; Gutreuter, Steve

2001-01-01

68

Growth and survival of stocked lake trout with nuclear cataracts in Lake Ontario  

USGS Publications Warehouse

Four strains of yearling lake trout Salvelinus namaycush from the 1985 and 1986 year-classes at the Allegheny National Fish Hatchery were evaluated for nuclear cataracts prior to stocking in Lake Ontario in June 1986 and 1987. Lake trout recaptured by bottom trawling from April to August 1987 and 1988 were examined for cataracts. Cataract frequencies in three strains of yearling lake trout at stocking in 1986 and after 14 and 26 months in the lake were: Seneca Lake- 35, 24, and 29%; Lake Ontario- 32, 24, and 42%; and Lake Superior- 7, 4, and 6%. Cataract frequencies for yearlings at stocking in 1987 and after 2 and 14 months were: Seneca Lake- 51, 37, and 51%; Lake Superior- 7, 12, and 12%; and Jenny Lake- 46, 13, and 36%. Cataract frequency was lower (P < 0.05) at capture in three of the six groups recaptured in 1987 and in two of the six groups in 1988. Fish with cataracts in the 1987 recovery had survival ratios of 17-186% after 2 months in the lake and 48-67% after 14 months, compared with normal-eyed fish of the same strain. Nuclear cataract frequency was relatively stable after the first year of lake residency, when equilibrium was achieved between the increased mortality of cataract phenotypes and the rate of cataract development in normal-eyed phenotypes. Within groups, weight and length were not different between healthy fish and fish with cataracts. The absence of growth depression in fish with cataracts and the reduced survival rate suggested that faster growing fish were more susceptible to cataract formation.

Kincaid, Harold L.; Elrod, Joseph H.

1991-01-01

69

Migrations and Biological Characteristics of Adfluvial Coaster Brook Trout in a South Shore Lake Superior Tributary  

Microsoft Academic Search

We used fish traps and electrofishing surveys to characterize the biology, life history traits, and potential biotic interactors important to the rehabilitation of native, adfluvial coaster brook trout Salvelinus fontinalis in Lake Superior. This study focused on the Salmon Trout River, Michigan, which is the site of the last known remnant population of adfluvial brook trout on the south shore

Casey J. Huckins; Edward A. Baker

2008-01-01

70

Modeling Seasonal Trophic Interactions of Adfluvial Bull Trout in Lake Billy Chinook, Oregon  

Microsoft Academic Search

We examined the trophic interactions of bull trout Salvelinus confluentus in Lake Billy Chinook, Oregon, using a bioenergetics model combined with data on annual growth, seasonal diet, distribution, and thermal experience to determine the seasonal and size-specific prey requirements of bull trout and the influence of bull trout predation on some of their major prey species in the reservoir. Per

David A. Beauchamp; Jason J. Van Tassell

2001-01-01

71

Do toxic substances pose a threat to rehabilitation of lake trout in the Great Lakes? A review of the literature  

USGS Publications Warehouse

Toxic substances have been suspected of being one of the causes of Great Lakes lake trout reproductive failure. Because toxic substances are present in the Great Lakes basin, managers should be aware of the role of contaminants in preventing lake trout rehabilitation. This paper summarizes studies which have sought to establish a relation between toxic substances and lake trout mortality or morbidity, and offers recommendations for future research and management. The review suggests that exposure to toxic substances has the possibility of affecting the species' rehabilitation. A variety of toxic substances, specifically organochlorine compounds, concentrated in lake trout eggs, fry, and the environment, have affected the hatching success of lake trout in the laboratory, but the strength of the relation between toxic substances and lake trout mortality and morbidity in the field remains unclear. In order to clarify this relation, more information is needed on lake trout physiology, biochemistry, behavior, and genetics. An interdisciplinary workshop should be convened to evaluate existing evidence by epidemiological methods, to set priorities for further research, and to develop management strategies.

Zint, Michaela T.; Taylor, William W.; Carl, Leon; Edsall, Carol C.; Heinrich, John; Sippel, Al; Lavis, Dennis; Schaner, Ted

1995-01-01

72

Use of a Seismic Air Gun to Reduce Survival of Nonnative Lake Trout Embryos: A Tool for Conservation?  

Microsoft Academic Search

The detrimental impacts of nonnative lake trout Salvelinus namaycush in the western USA have prompted natural resource management agencies in several states to implement lake trout suppression programs. Currently, these programs rely on mechanical removal methods (i.e., gill nets, trap nets, and angling) to capture subadult and adult lake trout. We conducted a study to explore the potential for using

Benjamin S. Cox; Andrew M. Dux; Michael C. Quist; Christopher S. Guy

2012-01-01

73

Lake trout spawning habitat in the Great Lakes u a review of current knowledge  

USGS Publications Warehouse

We review existing information on lake trout spawning habitat, which might indicate whether habitat is now a limiting factor in lake trout reproductive success. Lake trout spawning habitat quality is defined by the presence or absence of olfactory cues for homing, reef location with respect to the shoreline, water depth, proximity to nursery areas, reef size, contour, substrate size and shape, depth of interstitial spaces, water temperature at spawning time, water quality in interstitial spaces, and the presence of egg and fry predators. Data on factors which attracted native spawners to spawning reefs are lacking, due to the absence of historic data on egg deposition. No direct evidence of egg deposition has been collected from sites deeper than 18 m. Interstitial space and, therefore, substrate size and shape, appear to be critical for both site selection by adults and protection of eggs and fry. Water quality is clearly important for egg incubation, but the critical parameters which define water quality have not yet been well determined in the field. Exposure to wave energy, dictated in part by reef location, may maintain high water quality but may also damage or dislodge eggs. The importance of olfactory cues, water temperature, and proximity to nursery habitat to spawning trout is unclear. Limited data suggest that egg and fry predators, particularly exotic species, may critically affect fry production and survival. Although availability of physical spawning habitat is probably not limiting lake trout reproduction, changes in water quality and species composition may negatively affect early life stages. This review of habitat factors that affect early life stages of lake trout suggests several priorities for research and management.

Marsden, J. Ellen; Casselman, John M.; Edsall, Thomas A.; Elliott, Robert F.; Fitzsimons, John D.; Horns, William H.; Manny, Bruce A.; McAughey, Scott C.; Sly, Peter G.; Swanson, Bruce L.

1995-01-01

74

Visual observations of historical lake trout spawning grounds in western Lake Huron  

USGS Publications Warehouse

Direct underwater video observations were made of the bottom substrates at 12 spawning grounds formerly used by lake trout Salvelinus namaycush in western Lake Huron to evaluate their present suitability for successful reproduction by lake trout. Nine locations examined north of Saginaw Bay in the northwestern end of the lake are thought to provide the best spawning habitat. The substrate at these sites consisted of angular rough cobble and rubble with relatively deep interstitial spaces (a?Y 0.5 m), small amounts of fine sediments, and little or no periphytic growth. Conditions at the three other sampling locations south of Saginaw Bay seemed much less suitable for successful reproduction based on the reduced area of high-quality substrate, shallow interstitial spaces, high infiltration of fine sediments, and greater periphytic growth.

Nester, Robert T.; Poe, Thomas P.

1987-01-01

75

Environmental contaminants and the reproductive success of lake trout in the Great Lakes: An epidemiological approach  

SciTech Connect

Epidemiological criteria were used to examine the influence of environmental contamination on reproductive success of lake trout (Salvelinus namaycush) in the Laurentian Great Lakes. Most of the information was obtained from lake trout eggs collected in southeastern Lake Michigan and reared in the laboratory. Two separate end points that measure reproductive success--egg hatchability and fry survival--were used in the evaluation. Strong evidence for maternally derived polychlorinated biphenyls causing reduced egg hatchability were observed for the time order, strength of association, and coherence criteria. Equally strong evidence for organic environmental contaminants, also of maternal origin, causing a swim-up fry mortality syndrome were presented for the strength of association, specificity, replication, and coherence criteria. The epidemiological approach for demonstrating cause-and-effect relations was useful because of the difficulty in demonstrating definite proof of causality between specific environmental contaminants and reproductive dysfunction in feral fish.

Mac, M.J.; Edsall, C.C. (U.S. Fish and Wildlife Service, National Fisheries Research Center-Great Lakes, Ann Arbor, MI (USA))

1991-08-01

76

Effects of hypoxia on scope-for-activity and power capacity of lake trout ( Salvelinus namaycush )  

Microsoft Academic Search

This study develops a quantitative model of the combined effects of temperature and ambient dissolved oxy- gen on metabolic scope-for-activity and power capacity of juvenile lake trout (Salvelinus namaycush). The model pro- vides a framework for evaluating the effects of hypoxia on the capacity of lake trout to perform critical daily life support activities. Maximum power output for sustained swimming

David O. Evans

2007-01-01

77

Recreational Fishing Use-Values for Michigan's Great Lake Trout and Salmon Fisheries  

Microsoft Academic Search

The manuscript summarizes the results of a travel cost model developed for recreational angling in Michigan. The model and method are briefly described. The discussion focusses on how Great Lakes trout and salmon catch rates were related to angler behavior. The model is used to value changes in trout and salmon catch rates at Great Lakes fishing sites in Michigan.

Frank Lupi; John P. Hoehn

78

The Accumulation of DDT in Lake Trout and the Effect on Reproduction  

Microsoft Academic Search

Hatchery losses of lake trout fry from areas of high DDT use led to a 4-year study of the accumulation of the chemical in fish flesh and eggs from a number of waters in New York. Graphs are presented to indicate the range of DDT content of ether-extracted oils from spawning female lake trout and a comparison of the amount

G. E. Burdick; E. J. Harris; H. J. Dean; T. M. Walker; Jack Skea; David Colby

1964-01-01

79

Visualizing the geology of lake trout spawning sites; northern Lake Michigan  

USGS Publications Warehouse

Geologists and biologists are working together to understand the links between lake floor geology (composition and shape) and the distribution of lake trout throughout their life cycle. Lake floor geology is one of the main factors determining where lake trout spawn, feed, and hide. In support of ongoing research to study Lake Michigan trout habitats, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers mapped the morphology of principle lake trout spawning sites. Using the Army Corps of Engineer's SHOALS airborne lidar (Light Detection and Ranging) system we mapped six regions in Northern Lake Michigan in order to identify ideal spawning regions composed of shallow, clean, gravel/cobble substrate, adjacent to deeper water. Lidar mapping systems, which use laser pulses to measure water depths from an airplane, are now available to map the nearshore lake morphology at meter-scale detail. Maps generated from the bathymetric data are used to define regions with smooth homogeneous substrate, regions with higher relief, and mixed regions with both smooth and rough relief. This morphologic information combined with sediment samples and direct bottom observations enable geologists to map areas with rougher relief composed of rock outcrop, boulders, and cobbles, as well as smooth regions covered with sand or mud. This information helps biologists, fishery managers, and ecologists visualize the lake floor in significant detail which promotes better fishery management, species protection, and habitat identification. These maps present the maps and discuss the geology of the six lake trout spawning sites mapped by the lidar system. Where the mapping approached land, aerial photography of the land is combined with the bathymetric data to help visualize the scale of the offshore features. Map and perspective views of Boulder Reef, Hog Island Reef, and Little Traverse Bay are shown on sheet 1, whereas map and perspective views of Trout and High Island Shoal, Gull Island Reef, and Dahlia Shoal are shown on sheet 2. Additional information, bathymetric data, imagery, and metadata are available online at http://geopubs.wr.usgs.gov/open-file/of03-120/.

Dartnell, Peter; Barnes, Peter; Gardner, James V.; Lee, Kristen

2006-01-01

80

Visualizing the geology of lake trout spawning sites, northern Lake Michigan  

USGS Publications Warehouse

Geologists and biologists are working together to understand the links between lake floor geology (composition and shape) and the distribution of lake trout throughout their life cycle. Lake floor geology is one of the main factors determining where lake trout spawn, feed, and hide. In support of ongoing research to study Lake Michigan trout habitats, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers mapped the morphology of principle lake trout spawning sites. Using the Army Corps of Engineer's SHOALS airborne lidar (Light Detection and Ranging) system we mapped six regions in Northern Lake Michigan in order to identify ideal spawning regions composed of shallow, clean, gravel/cobble substrate, adjacent to deeper water. Lidar mapping systems, which use laser pulses to measure water depths from an airplane, are now available to map the nearshore lake morphology at meter-scale detail. Maps generated from the bathymetric data are used to define regions with smooth homogeneous substrate, regions with higher relief, and mixed regions with both smooth and rough relief. This morphologic information combined with sediment samples and direct bottom observations enable geologists to map areas with rougher relief composed of rock outcrop, boulders, and cobbles, as well as smooth regions covered with sand or mud. This information helps biologists, fishery managers, and ecologists visualize the lake floor in significant detail which promotes better fishery management, species protection, and habitat identification. These maps present the maps and discuss the geology of the six lake trout spawning sites mapped by the lidar system. Where the mapping approached land, aerial photography of the land is combined with the bathymetric data to help visualize the scale of the offshore features. Map and perspective views of Boulder Reef, Hog Island Reef, and Little Traverse Bay are shown on sheet 1, whereas map and perspective views of Trout and High Island Shoal, Gull Island Reef, and Dahlia Shoal are shown on sheet 2. Additional information, bathymetric data, imagery, and metadata are available online at http://geopubs.wr.usgs.gov/open-file/of03-120/.

Dartnell, Peter; Barnes, Peter; Gardner, James V.; Lee, Kristen

2004-01-01

81

Seasonal habitat selection by lake trout (Salvelinus namaycush) in a small Canadian shield lake: Constraints imposed by winter conditions  

USGS Publications Warehouse

The need for cold, well-oxygenated waters significantly reduces the habitat available for lake trout (Salvelinus namaycush) during stratification of small temperate lakes. We examined the spatial and pelagic distribution of lake trout over two consecutive summers and winters and tested whether winter increased habitat availability and access to littoral regions in a boreal shield lake in which pelagic prey fish are absent. In winter, lake trout had a narrowly defined pelagic distribution that was skewed to the upper 3 m of the water column and spatially situated in the central region of the lake. Individual core areas of use (50% Kernel utilization distributions) in winter were much reduced (75%) and spatially non-overlapping compared to summer areas, but activity levels were similar between seasons. Winter habitat selection is in contrast to observations from the stratified season, when lake trout were consistently located in much deeper waters (>6 m) and widely distributed throughout the lake. Winter distribution of lake trout appeared to be strongly influenced by ambient light levels; snow depth and day length accounted for up to 69% of the variation in daily median fish depth. More restricted habitat use during winter than summer was in contrast to our original prediction and illustrates that a different suite of factors influence lake trout distribution between these seasons. ?? Springer Science+Business Media B.V. 2009.

Blanchfield, P. J.; Tate, L. S.; Plumb, J. M.; Acolas, M. -L.; Beaty, K. G.

2009-01-01

82

Investigations into the effects of PCB congeners on reproduction in lake trout from the Great Lakes  

USGS Publications Warehouse

Eggs of feral lake trout collected in Lake Michigan were reared under laboratory conditions and monitored for egg hatchability, physical abnormalities, and survival of fry. Subsamples of eggs were also analyzed for PCB congeners. A negative correlation was found between egg hatchability and total PCBs but expressing PCB dose as dioxin equivalents did not produce as strong a correlation. No other measure of reproductive success correlated significantly with PCB concentration in the egg.

Mac, Michael J.; Schwartz, T.R.

1992-01-01

83

Population Dynamics of Lake Ontario Lake Trout during 1985–2007  

Microsoft Academic Search

Lake trout Salvelinus namaycush were extirpated from Lake Ontario circa 1950 owing to commercial and recreational fishing, predation by sea lampreys Petromyzon marinus, and habitat degradation. Since the 1970s, substantial efforts have been devoted to reestablishing a self-sustaining population through stocking, sea lamprey control, and harvest reduction. Although a stocking-supported population has been established, only limited natural reproduction has been

Travis O. Brenden; James R. Bence; Brian F. Lantry; Jana R. Lantry; Ted Schaner

2011-01-01

84

Growth of lake trout in Lake Superior before the maximum abundance of sea lampreys  

USGS Publications Warehouse

The growth in length of lake trout (Salvelinus namaycush) from the inshore water of Lake Superior in 1953 increased with age from the 3rd to 9th year, and was nearly constant from the 9th to the 12th year. Growth was greatest in the 1st year (4.0 inches) and least in the 2nd and 3rd years (2.3 inches). Between the 4th and 9th years the increments increased from 2.6 to 3.5 inches. Growth was calculated from a curvilinear body-scale relation. Intraseasonal growth in length extended from late April until well after October; most growth was in late summer and fall. The younger fish started growth earlier, and some mature fish did not increase in length until after the October spawning. Lake trout reached the minimum legal weight (1.5 pounds) in the 7th year of life and the average size taken in the commercial fishery (about 3 pounds) in the 8th year. The annual increase in weight in the 8th year of life was over 64%. Fish used in this study grew more slowly than those from Lakes Michigan and Huron taken during the period when sea lamprey abundance was increasing, but at about the same rate as lake trout of Lake Michigan before the sea lamprey appeared.

Rahrer, Jerold F.

1967-01-01

85

Hatching, Dispersal, and Bathymetric Distribution of Age0 Wild Lake Trout at the Gull Island Shoal Complex, Lake Superior  

Microsoft Academic Search

We studied age-0 lake trout (Salvelinus namaycush) associated with spawning and nursery areas of the Gull Island Shoal complex in western Lake Superior. Post-emergent age-0 lake trout were captured on rocky spawning substrate with a 3-m beam trawl and at the nursery area with a bottom trawl from June to September 1990 and June to August 1991. Catch data suggested

Charles R. Bronte; James H. Selgeby; James H. Saylor; Gerald S. Miller; Neal R. Foster

1995-01-01

86

Simulation of the effects of time and size at stocking on PCB accumulation in lake trout  

USGS Publications Warehouse

Manipulations of size at stocking and timing of stocking have already been used to improve survival of stocked salmonines in the Great Lakes. It should be possible to stock salmonines into the Great Lakes in a way that reduces the rate of polychlorinated biphenyl (PCB) accumulation in these fishes. An individual-based model (IBM) was used to investigate the effects of size at stocking and timing of stocking on PCB accumulation by lake trout (Salvelinus namaycush) in Lake Michigan. The individual-based feature of the model allowed lake trout individuals to encounter prey fish individuals and then consume sufficiently small prey fish. The IBM accurately accounted for the variation in PCB concentrations observed within the Lake Michigan lake trout population. Results of the IBM simulations revealed that increasing the average size at stocking from 110 to 160 mm total length led to an increase in the average PCB concentration in the stocked cohort at age 5, after the fish had spent 4 years in the lake, from 2.33 to 2.65 mg/kg; the percentage mg/kg or more increased from 62% to 79%. Thus, PCB contamination was reduced when the simulated size at stocking was smallest. An overall stocking strategy for lake trout into Lake Michigan should weigh this advantage regarding PCB contamination against the poor survival of lake trout that may occur if the trout are stocked at too small a size.

Madenjian, Charles P.; Carpenter, Stephen R.

1993-01-01

87

Changes in the lake trout population of southern Lake Superior in relation to the fishery, the sea lamprey, and stocking, 1950-70  

USGS Publications Warehouse

Reduction of sea lamprey abundance resulted in an immediate increase in survival and abundance of lake trout, especially of the larger sizes. As abundance of lake trout progressively increased in 1962-70, survival of the smaller legal-size lake trout increased, probably due to reduction of the predator-prey ratio and an increase in availability of larger lake trout preferred by sea lampreys. Abundance of spawning-size lake trout was limited by high natural mortality in 1965-70. Circumstantial evidence suggested that sea lamprey predation contributed a major part of the high natural mortality.

Pycha, Richard L.; King, George R.

1975-01-01

88

The Salmon and Trout Fishery of the Fish River Lakes, Maine  

Microsoft Academic Search

Partial creel censuses were operated on five of the Fish River Lakes in 1957-59 and on one of the lakes in 1954 and 1961 also. The salmon and brook trout fishing in general compared favorably with other large Maine lakes. Fishing success in Square Lake declined by 62 percent between 1954 and 1961. The decline is attributed to a reduced

Kendall Warner; Owen C. Fenderson

1963-01-01

89

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

USGS Publications Warehouse

The Lake Superior fish community underwent massive changes in the second half of the 20th century. Those changes are largely reflected in changes in abundance of the adults of principal prey species, the ciscoes (Coregonus spp.), the invasive rainbow smelt (Osmerus mordax), and the principal predator, lake trout (Salvelinus namaycush). To better understand changes in species abundances, a comprehensive series of gillnet and bottom trawl data collected from 1958 to 2008 were examined. In the late 1950s/early 1960s, smelt abundance was at its maximum, wild lake trout was at its minimum, and an abundance of hatchery lake trout was increasing rapidly. The bloater (Coregonus hoyi) was the prevalent cisco in the lake; abundance was more than 300% greater than the next most abundant cisco, shortjaw cisco (C. zenithicus), followed by kiyi (C. kiyi) and lake cisco (C. artedi). By the mid-1960s, abundance of hatchery lake trout was nearing maximum, smelt abundance was beginning to decline, and abundances of all ciscoes declined, but especially that of shortjaw cisco and kiyi. By the late 1970s, recovery of wild lake trout stocks was well underway and abundances of hatchery lake trout and smelt were declining and the ciscoes were reaching their nadir. During 1980–1990, the fish community underwent a dramatic shift in organization and structure. The rapid increase in abundance of wild lake trout, concurrent with a rapid decline in hatchery lake trout, signaled the impending recovery. Rainbow smelt abundance dropped precipitously and within four years, lake cisco and bloater populations rebounded on the heels of a series of strong recruitment events. Kiyi populations showed signs of recovery by 1989, and shortjaw by 2000, though well below historic maximum abundances. High abundance of adult smelt prior to 1980 appears to be the only factor linked to recruitment failure in the ciscoes. Life history traits of the cisco species were examined to better understand their different 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.

Gorman, Owen T.

2012-01-01

90

Vateritic sagitta in wild and stocked lake trout: Applicability to stock origin  

USGS Publications Warehouse

Aragonite is the normal form of calcium carbonate found in teleost otoliths, but it is sometimes replaced by vaterite, an alternate crystalline structure. We investigated the assumption that sagittal otoliths with vaterite replacement were unique to stocked lake trout Salvelinus namaycush in the Laurentian Great Lakes. Earlier studies had attributed these abnormalities to stocking stress, and proposed that the presence of vaterite could separate individual unmarked stocked lake trout from their wild counterparts. We examined and described the frequency of vateritic sagittae in two wild and three stocked populations of lake trout from the Great Lakes and a wild population from a remote inland lake in northern Canada. Among lake trout caught 2-12 years after being stocked, prevalence of vateritic sagittae was 66% for Lake Superior fish, 75% for Lake Huron fish, and 86% for Lake Ontario fish. Among wild fish caught, vateritic sagittae were present in 37% of Lake Superior fish, 22% of Lake Huron fish, and 49% of northern Canada fish. We also compared year-to-year differences in prevalence in four year-classes of fingerling lake trout reared in two U.S. national lake trout hatcheries. Prior to release, between 53 and 84% of the hatchery fish had at least one vateritic sagitta, and prevalence increased with handling associated with hatchery practices. Vateritic sagittae in wild fish might also indicate stress in nature. The presence of vateritic sagittae in both wild and stocked fish compromises the use of this characteristic as an unequivocal indicator of a particular fish's origin. Among-population differences in both the prevalence and the extent of vaterite replacement, however, may provide a means of differentiating between stocks of sympatric unmarked wild and stocked lake trout.

Bowen, Charles A., II; Bronte, Charles R.; Argyle, Ray L.; Adams, Jean V.; Johnson, James E.

1999-01-01

91

Factors associated with stocked cutthroat trout populations in high-mountain lakes  

USGS Publications Warehouse

High-mountain lakes provide important fisheries in the Rocky Mountains; therefore we sought to gain an understanding of the relationships among environmental factors, accessibility to anglers, stocking rates, and features of stocks of cutthroat trout Oncorhynchus clarki in high-mountain lakes of the Bighorn Mountains, Wyoming. We sampled fish with experimental gill nets, measured lake habitat features, and calculated factors affecting angler access among 19 lakes that lacked sufficient natural reproduction to support salmonid fisheries and that were stocked at 1-, 2-, or 4-year intervals with fingerling cutthroat trout. We found that angler accessibility was probably the primary factor affecting stock structure, whereas stocking rates affected the densities of cutthroat trout among lakes. The maximum number of years survived after stocking appeared to have the greatest affect on biomass and population structure. Our findings suggest that control of harvest and manipulation of stocking densities can affect the density, biomass, and structure of cutthroat trout stocks in high-elevation lakes.

Bailey, P. E.; Hubert, W. A.

2003-01-01

92

Population recovery and natural recruitment of lake trout at Gull Island Shoal, Lake Superior, 1964-1992  

USGS Publications Warehouse

We documented an increase in the abundance of wild lake trout (Salvelinus namaycush) at Gull Island Shoal in western Lake Superior and examined the relationship between parental-stock size and recruitment of age-0 fish in 1964-1992. Abundance of adult wild female lake trout and densities of age-0 fish both increased during the 28-year period. A significant positive, linear relationship (p = 0.0002) was found between the abundance of wild females on the spawning reef in the fall and density of age-0 lake trout on adjacent nursery grounds in August and September of the following year. The abundance of hatchery-origin females did not explain significant amounts (p = 0.107) of variation in recruitment. We concluded that most recruitment in 1965-1992 was the result of natural reproduction of wild females. After 28 years of recovery the Gull Island Shoal lake trout population appears to have additional capacity to increase because the stock-recruitment relationship is still linear. Therefore, restoration periods on the order of 30 years may be needed for other lake trout populations in the Great Lakes. We recommend that the refuge established to protect this population be maintained to allow further study of the relationship between parental stock and recruitment, and to provide a major source of recruitment to the lake trout population in the surrounding waters.

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

1995-01-01

93

Preliminary Investigation of Spawning Habitat Conditions and Reproduction of Lake Trout in Eastern Lake Michigan Near Port Sheldon, Michigan.  

National Technical Information Service (NTIS)

Why stocked lake trout apparently fail to reproduce in most areas of the Great Lakes remains a perplexing biological question. The only locations in Lake Michigan where fry have been observed since the stocking program began in 1965 are areas of artificia...

J. A. Dorr D. J. Jude G. R. Heufelder S. A. Klinger G. E. Noguchi

1981-01-01

94

Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake trout (Salvelinus namaycush) from its prey.  

PubMed

Lake trout (Salvelinus namaycush) were fed bloater (Coregonus hoyi) in eight laboratory tanks over a 135-d experiment. At the start of the experiment, four to nine fish in each tank were sacrificed, and the concentrations of 75 polychlorinated biphenyl (PCB) congeners within these fish were determined. Polychlorinated biphenyl congener concentrations were also determined in the 10 lake trout remaining in each of the eight tanks at the end of the experiment as well as in the bloater fed to the lake trout. Each lake trout was weighed at the start and the end of the experiment, and the amount of food eaten by the lake trout was recorded. Using these measurements, net trophic transfer efficiency (?) from the bloater to the lake trout in each of the eight tanks was calculated for each of the 75 congeners. Results showed that ? did not vary significantly with the degree of chlorination of the PCB congeners, and ? averaged 0.66 across all congeners. However, ? did show a slight, but significant, decrease as log K(OW) increased from 6.0 to 8.2. Activity level of the lake trout did not have a significant effect on ?. PMID:22927164

Madenjian, Charles P; David, Solomon R; Rediske, Richard R; O'Keefe, James P

2012-10-10

95

Interactions between introduced trout and larval salamanders (Ambystoma macrodactylum) in high-elevation lakes  

USGS Publications Warehouse

The larval stage of the long-toed salamander (Ambystoma macrodactylum) is the top vertebrate predator in high-elevation fishless lakes in the North Cascades National Park Service Complex, Washington (U.S.A.). Although most of these high-elevation lakes were naturally fishless, trout have been stocked in many of them. We sought to determine the effects of physicochemical factors and introduced trout on abundance and behavior of A. macrodactylum larvae. Larval salamander densities were estimated by snorkeling. Snorkelers carefully searched through substrate materials within 2 m of the shoreline and recorded the number of larvae observed and if larvae were hidden in benthic substrates. Physicochemical factors were measured in each lake on the same day that snorkel surveys were conducted. In fishless lakes, larval salamander densities were positively related to total Kjeldahl-N concentration and negatively related to lake elevation. Crustacean zooplankton, especially cladocerans, were important food resources for larval A. macrodactylum. Crustacean zooplankton and cladoceran densities were positively related to total Kjeldahl-N, suggesting that increased food resources contributed to increased densities of larval A. macrodactylum. Differences in larval salamander densities between fish and fishless lakes were related to total Kjeldahl-N concentrations and the reproductive status of trout. Mean larval salamander densities for fishless lakes with total Kjeldahl-N < 0.045 mg/L were not significantly different from mean larval densities in lakes with reproducing trout or in lakes with nonreproducing trout. In fishless lakes with total Kjeldahl-N a?Y 0.045 mg/L, however, mean larval densities were significantly higher than in lakes with reproducing trout where fish reached high densities. In fishless lakes with total Kjeldahl-N a?Y 0.095 mg/L, mean larval densities were significantly higher than in lakes with nonreproducing trout where trout fry were stocked at low densities. Reduced larval salamander densities in lakes with trout likely resulted from trout predation. There were no significant differences in the percentage of larvae hidden in benthic substrates between fishless lakes and lakes with fish. Our results imply that assessment of the effects of fish on amphibians requires an understanding of natural abiotic and biotic factors and processes influencing amphibian distribution and abundance.

Tyler, T.; Liss, W. J.; Ganio, L.; Larson, Gary L.; Hoffman, Robert L.; Deimling, E.; Lomnicky, G. A.

1998-01-01

96

Patterns of PCB accumulation by fry of lake trout  

SciTech Connect

A study examining the accumulation pattern of PCBs by lake trout fry exposed through the period of yolk absorption and the onset of feeding is presented. The PCB uptake pattern was examined by exposing the fry to a nominal concentration of 50 ng/l PCB (Aroclor 1254) for 48 days. The fry were sampled and analyzed for PCB concentration seven times during the exposure. The patterns of PCB concentration in the lake trout fry appeared similar, regardless of how the data were expressed (wet weight concentration, dry weight concentration, or body burden). PCBs in exposed fry increased slowly, peaked at day 32 (just before yolk absorption was complete) and decreased by day 48. Although these patterns appeared similar, important differences in the relative changes in PCB levels of exposed fry became evident when the different ways of expressing the uptake data were compared. It was determined that physiological changes in the fry through yolk absorption and initial feeding were responsible for the differences between PCB levels based on wet weight, dry weight, and body burden.

Mac, M.T.; Seelye, J.G.

1981-09-01

97

Heritage strain and diet of wild young of year and yearling lake trout in the main basin of Lake Huron  

USGS Publications Warehouse

Restoration of lake trout Salvelinus namaycush stocks in Lake Huron is a fish community objective developed to promote sustainable fish communities in the lake. Between 1985 and 2004, 12.65 million lake trout were stocked into Lake Huron representing eight different genetic strains. Collections of bona fide wild fish in USGS surveys have increased in recent years and this study examined the ancestry and diet of fish collected between 2004 and 2006 to explore the ecological role they occupy in Lake Huron. Analysis of microsatellite DNA revealed that both pure strain and inter-strain hybrids were observed, and the majority of fish were classified as Seneca Lake strain or Seneca Lake hybrids. Diets of 50 wild age-0 lake trout were examined. Mysis, chironomids, and zooplankton were common prey items of wild age-0 lake trout. These results indicate that stocked fish are successfully reproducing in Lake Huron indicating a level of restoration success. However, continued changes to the benthic macroinvertebrate community, particularly declines of Mysis, may limit growth and survival of wild fish and hinder restoration efforts.

Roseman, E. F.; Stott, W.; O'Brien, T. P.; Riley, S. C.; Schaeffer, J. S.

2009-01-01

98

Lake trout status in the main basin of Lake Huron, 1973-2010  

USGS Publications Warehouse

We developed indices of lake trout Salvelinus namaycush status in the main basin of Lake Huron (1973-2010) to understand increases in the relative abundance of wild year-classes during 1995-2010. Sea lamprey Petromyzon marinus wounds per 100 lake trout declined from 23.63 in 2000 to 5.86-10.64 in 2002-2010. The average age-7 lake trout catch per effort per recruitment (CPE/R; fish•305mof gill net-1•million stocked yearlings-1) increased from 0.56 for the 1973-1990 year-classes to 0.92 for the 1991-2001 year-classes. Total CPE (fish/305 m of gill net) declined from 16.4 fish in 1996 to 4.1 fish in 2010, but the percentage of age-5 and younger lake trout steadily decreased from more than 70% before 1996 to less than 10% by 2009. The modal age in gill-net catches increased from age 5 before 1996 to age 7 by 2005. The average adult CPE increased from 2.8 fish/305 m of gill net during 1978-1995 to 5.34 fish/305 m of gill net during 1996-2010. The 1995-2010 year-classes of wild fish weremore abundant than previous year-classes and were associated with the relatively high adult abundance during 1996-2010. Until the 2002 year-class, there was no decline in age-7 CPE/R; until 2008, there was no decline in adult CPE. Low survival of the 2002 and 2003 year-classes of stocked fish was related to the event of alewife Alosa pseudoharengus population collapse in 2003-2004. Lake trout in the main basin of Lake Huron are undergoing a transition from a hatchery stock to a wild stock, accompanied by an increased uncertainty in delayed recruitment. Future management should pay more attention to the protection of wild recruitment and the abundance of the spawning stock.

He, Ji X.; Ebener, Mark P.; Riley, Stephen C.; Cottrill, Adam; Kowalski, Adam; Koproski, Scott; Mohr, Lloyd; Johnson, James E.;

2012-01-01

99

Simulation of the effects of time and size at stocking on PCB accumulation in Lake Trout  

SciTech Connect

Manipulations of size at stocking and timing of stocking have already been used to improve survival of stocked salmonines in the Great Lakes. It should be possible to stock salmonines into the Great Lakes in a way that reduces the rate of polychlorinated biphenyl (PCB) accumulation in these fishes. An individual-based model (IBM) was used to investigate the effects of size at stocking and timing of stocking on PCB accumulation by lake trout Salvelinus namaycush in Lake Michigan. The individual-based feature of the model allowed lake trout individuals to encounter prey fish individuals and then consume sufficiently small prey fish. The IBM accurately accounted for the variation in PCB concentrations observed within the Lake Michigan lake trout population. Results of the IBM simulations revealed that increasing the average size at stocking from 110 to 160 mm total length led to an increase in the average PCB concentration in the stocked cohort at age 5, after the fish had spent 4 years in the lake, from 2.33 to 2.65 mg/kg; the percentage of lake trout in the cohort at the end of the simulated time period with PCB concentration of 2 mg/kg or more increased from 62% to 79%. Thus, PCB contamination was reduced when the simulated size at stocking was smallest. An overall stocking strategy for lake trout into Lake Michigan should weight this advantage regarding PCB contamination against the poor survival of lake trout that may occur if the trout are stocked at too small a size. 28 refs., 5 figs., 1 tab.

Madenjian, C.P. (National Fisheries Research Center-Great Lakes, Sandusky Biological Station, Sandusky, OH (United States))

1993-05-01

100

Factors Associated with Stocked Cutthroat Trout Populations in High-Mountain Lakes  

Microsoft Academic Search

High-mountain lakes provide important fisheries in the Rocky Mountains; therefore we sought to gain an understanding of the relationships among environmental factors, accessibility to anglers, stocking rates, and features of stocks of cutthroat trout Oncorhynchus clarki in high-mountain lakes of the Bighorn Mountains, Wyoming. We sampled fish with experimental gill nets, measured lake habitat features, and calculated factors affecting angler

Paul E. Bailey; Wayne A. Hubert

2003-01-01

101

Post Audit of Lake Michigan Lake Trout PCB Model Forecasts  

EPA Science Inventory

The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

102

Evaluating the Reintroduction Potential of Lahontan Cutthroat Trout in Fallen Leaf Lake, California  

Microsoft Academic Search

We evaluated the potential for reintroducing Lahontan cutthroat trout Oncorhynchus clarkii henshawi, a species listed under the Endangered Species Act, into a lacustrine system where the biotic community has changed dramatically since the species' extirpation there. Since 2002, 76,547 Lahontan cutthroat trout have been reintroduced into Fallen Leaf Lake, California; we used creel surveys, diet data, mark–recapture methods, bioenergetics modeling,

Robert Al-Chokhachy; Mary Peacock; Lisa G. Heki; Gary Thiede

2009-01-01

103

Thiamine Status of Cayuga Lake Rainbow Trout and Its Influence on Spawning Migration  

Microsoft Academic Search

Rainbow trout Oncorhynchus mykiss in Cayuga Lake, New York, appear to be suffering from a thiamine deficiency because their progeny develop general weakness, loss of equilibrium, and increased mortality, which are prevented by treatment with thiamine. Thiamine status and its effect on adults are unknown. In 2000 and 2002, we captured, tagged, and released 64 and 189 prespawning rainbow trout,

H. George Ketola; Thomas L. Chiotti; Robert S. Rathman; John D. Fitzsimons; Dale C. Honeyfield; Peter J. Van Dusen; Graham E. Lewis

2005-01-01

104

Movements of Rainbow Trout in Response to Dissolved Oxygen and Food Availability in Lake Ogallala, Nebraska  

Microsoft Academic Search

In October 1997, Lake Ogallala, Nebraska was treated to remove non-game competitors, and in June 1998 an aeration system was installed to increase dissolved oxygen concentrations. Ultrasonic telemetry was used to determine movements, habitat use, and distribution of 51 rainbow trout (Oncorhynchus mykiss) before and after treatment. Rainbow trout preferred areas with abundant food items, water less than 2 m

Tadd M. Barrow; Edward J. Peters

2001-01-01

105

Vertical distribution of brown trout ( Salmo Trutta ) and perch ( Perca Fluviatilis ) in an acidified lake  

Microsoft Academic Search

Brown trout (Salmo trutta) and perch (Perca fluviatilis) had different vertical distributions throughout the year in the acidified lake Gjerstadvann. During summer, the brown trout lived in the 0 to 16 m depth interval, whereas the perch lived in the 0 to 8 m interval. In Gjerstadvann, the thermocline lies at 8 to 10 m depth. The epilimnion pH was

Arne Linløkken; Hedmark County

1988-01-01

106

Effect of size on lake trout survival after a single sea lamprey attack  

USGS Publications Warehouse

When lake trout Salvelinus namaycush were subjected to a single attack by a sea lamprey Petromyzon marinus in laboratory tests in 1986, percentage mortality was significantly higher in small fish (64%; 469-557 mm; N = 67) than in medium (44%; 559-643 mm; N = 45) or large fish (43%; 660-799 mm; N = 47). Additional studies conducted in 1987 with 55 medium (559-650 mm) and 52 large (660-825 mm) lake trout confirmed that there was no difference in mortality between the two larger size-groups. Mortality declined in lake trout over 559 mm, but was still greater than 43%. This level of mortality and the sea lampreys' apparently active selection of larger fish indicated that, contrary to previously published opinions, large size in lake trout (up to ?800 mm in length) might not allow better survival from single sea lamprey attacks.

Swink, William D.

1990-01-01

107

Protection of Native Yellowstone Cutthroat Trout in Yellowstone Lake-Yellowstone National Park, Wyoming.  

National Technical Information Service (NTIS)

The cutthroat trout population in Yellowstone Lake has fluctuated considerably during the 20th century, primarily due to historical high levels of angler harvest and hatchery-related egg collections (Gresswell et al. 1994; Koel et al. 2003). Until recentl...

P. E. Bigelow T. M. Koel D. Mahony B. Ertel B. Rowdon S. T. Olliff

2003-01-01

108

DECLINE AND EXTINCTION OF LAKE TROUT IN THE GREAT LAKES: CAN BIOLOGICAL INDICATORS HELP DIAGNOSE CAUSES, IDENTIFY REMEDIAL ACTIONS, AND PREDICT FUTURE CONDITIONS?  

EPA Science Inventory

The lake trout, Salvelinus namaycush, is the predominant top predator native fish species of the Great Lakes. Lake trout are valued for commercial and recreational use in addition to their ecological importance. In the last half of the 20th century, population declines lead to vi...

109

Polybrominated diphenyl ethers (PBDEs): turning the corner in Great Lakes trout 1980-2009.  

PubMed

Lake trout and walleye composites were collected between 2004 and 2009 as part of the Great Lakes Fish Monitoring and Surveillance Program (GLFMSP) and analyzed for polybrominated diphenyl ethers (PBDEs). Yearly mean total PBDE concentrations (sum of congeners BDE-47, BDE-99, BDE-100, BDE-153, BDE-154) ranged from 44-192, 28-113, 50-107, 37-111, and 11-22 ng/g wet wt. for Lakes Michigan, Huron, Ontario, and Superior lake trout, and Lake Erie walleye, respectively. A 1980-2009 temporal record of PBDE concentrations in the Great Lakes' top predator fish (lake trout and walleye) was assembled by integrating previous GLFMSP data (1980-2003) with current results (2004-2009). Temporal profiles show obvious breakpoints between periods of PBDE accumulation and decline in trout for Lakes Huron, Michigan and Ontario with a significant (p < 0.0001 and r = 0.55, 0.72, and 0.51, respectively) decrease in concentration after 2000-2001. A similar transition was observed in Lake Superior for the nearshore site accompanied by a less significant decreasing trend (p = 0.016, r = 0.33), suggesting concentrations are declining very slowly or have leveled off. In contrast, Lake Erie walleye concentrations began leveling off in the late 1990s and no statistically significant trend (increasing or decreasing) has been observed in recent years. A decrease in the BDE-47/BDE-153 ratio was also recently observed, suggesting a transition to more highly brominated PBDEs is occurring in Great Lakes trout. This study provides region-wide evidence that PBDE concentrations are generally declining in Great Lakes trout, although there are clear exceptions to this trend. Results from this study reflect the positive impact of the 2004 PentaBDE ban on macro-scale aquatic freshwater ecosystems. PMID:22928882

Crimmins, Bernard S; Pagano, James J; Xia, Xiaoyan; Hopke, Philip K; Milligan, Michael S; Holsen, Thomas M

2012-09-06

110

Lactate dehydrogenase ontogeny, paternal gene activation, and tetramer assembly in embryos of brook trout, lake trout, and their hybrids  

Microsoft Academic Search

Measurement of lactate dehydrogenase in reciprocal hybrids of trout during development revealed that a maternal effect was involved in the regulation of enzyme levels until resorption of the yolk sac was completed. Malate dehydrogenase specific activities were the same in these embryos and larvae. The more negatively charged B subunits of LDH predominated during early stages of embryogenesis in lake

Erwin Goldberg; J. P. Cuerrier; J. C. Ward

1969-01-01

111

Genetic variation over space and time: Analyses of extinct and remnant lake trout populations in the Upper Great Lakes  

USGS Publications Warehouse

Lake trout (Salvelinus namaycush) in the upper Laurentian Great Lakes of North America experienced striking reductions in abundance and distribution during the mid-twentieth century. Complete collapse of populations was documented for Lake Michigan, and a few remnant populations remained only in lakes Huron and Superior. Using DNA obtained from historical scale collections, we analysed patterns of genetic diversity at five microsatellite loci from archived historical samples representing 15 populations (range 1940-1959) and from three contemporary remnant populations across lakes Huron and Superior (total n = 893). Demographic declines in abundance and the extirpation of native lake trout populations during the past 40 years have resulted in the loss of genetic diversity between lakes owing to extirpation of Lake Michigan populations and a temporal trend for reduction in allelic richness in the populations of lakes Superior and Huron. Naturally reproducing populations in Lake Superior, which had been considered to be remnants of historical populations, and which were believed to be responsible for the resurgence of lake trout numbers and distribution, have probably been affected by hatchery supplementation.

Guinand, B.; Scribner, K. T.; Page, K. S.; Burnham-Curtis, M. K.

2003-01-01

112

Genetic variation over space and time: analyses of extinct and remnant lake trout populations in the Upper Great Lakes.  

PubMed Central

Lake trout (Salvelinus namaycush) in the upper Laurentian Great Lakes of North America experienced striking reductions in abundance and distribution during the mid-twentieth century. Complete collapse of populations was documented for Lake Michigan, and a few remnant populations remained only in lakes Huron and Superior. Using DNA obtained from historical scale collections, we analysed patterns of genetic diversity at five microsatellite loci from archived historical samples representing 15 populations (range 1940-1959) and from three contemporary remnant populations across lakes Huron and Superior (total n = 893). Demographic declines in abundance and the extirpation of native lake trout populations during the past 40 years have resulted in the loss of genetic diversity between lakes owing to extirpation of Lake Michigan populations and a temporal trend for reduction in allelic richness in the populations of lakes Superior and Huron. Naturally reproducing populations in Lake Superior, which had been considered to be remnants of historical populations, and which were believed to be responsible for the resurgence of lake trout numbers and distribution, have probably been affected by hatchery supplementation.

Guinand, B; Scribner, K T; Page, K S; Burnham-Curtis, M K

2003-01-01

113

Acclimation in Simulated Lake Water Increases Survival of Lahontan Cutthroat Trout Challenged with Saline, Alkaline Water from Walker Lake, Nevada  

Microsoft Academic Search

We investigated the effect of acclimation and condition factor (K) on short-term survival of subyearling Lahontan cutthroat trout Oncorhynchus clarkii henshawi reared at Lahontan National Fish Hatchery, Gardnerville, Nevada, and challenged for 1 week with saline, alkaline water from Walker Lake, Nevada. The effect of acclimation and lake-water challenge on plasma osmolality was also investigated. Fish were acclimated for 0,

John P. Bigelow; Wendy M. Rauw; Luis Gomez-Raya

2010-01-01

114

Influence of lake characteristics on the biomagnification of persistent organic pollutants in lake trout food webs.  

PubMed

The biomagnification of polychlorinated biphenyls (PCBs) and major organochlorine pesticides (OCPs) was studied using lake trout (Salvelinus namaycush) and other food web organisms collected from 17 lakes in Canada and the northeastern United States between 1998 and 2001. Whole lake trout (n = 357) concentrations of the sum (Sigma) of 57 PCB congeners ranged between 1.67 and 2,890 ng/g wet weight (median 61.5 ng/g wet wt). Slimy sculpin had the highest mean concentrations of SigmaPCB of all forage fish (32-73 ng/g wet wt). Positive relationships between log (lipid wt) concentrations of PCB congener 153, PCB congener 52, p,p'-dichlorodiphenyldichloroethylene, hexachlorobenzene, cis-chlordane, trans-nonachlor, or dieldrin and trophic level (determined using stable nitrogen isotope ratios) were found for most of the 17 food webs, indicating biomagnification of these PCBs and OCPs. The p,p'-dichlorodiphenyldichloroethylene had the highest trophic magnification factors (TMFs) of the 14 individual compounds studied, averaging 4.0 +/- 1.8 across the 17 lakes, followed by trans-nonachlor (3.6 +/- 1.5) and PCB congener 153 (3.4 +/- 1.2). Average TMFs for 14 individual PCBs or OCPs were significantly correlated with log octanol-water partition coefficient, implying that the rate of accumulation along the food web is dependent on hydrophobicity and recalcitrance. Significant correlations (p < 0.05) were found between TMFs of SigmaPCBs, hexachlorobenzene, alpha-hexachlorocyclohexane, and lindane and lake area, latitude, and longitude, but not for 11 other PCBs or OCPs. Overall, the results of the present study show that biomagnification of PCBs and most OCPs, as measured by TMFs, is only weakly influenced by such factors as latitude and longitude. Exceptions are hexachlorocyclohexane isomers and hexachlorobenzene, which had generally greater TMFs in northern lakes, possibly due to lower rates of elimination and biotransformation in the food web. PMID:18444699

Houde, Magali; Muir, Derek C G; Kidd, Karen A; Guildford, Stephanie; Drouillard, Ken; Evans, Marlene S; Wang, Xiaowa; Whittle, D Michael; Haffner, Doug; Kling, Hedy

2008-10-01

115

Dynamics of individual growth in a recovering population of lake trout (Salvelinus namaycush)  

USGS Publications Warehouse

In 1976, the Wisconsin Department of Natural Resources established a refuge for a nearly depleted population of lake trout (Salvelinus namaycush) at Gull Island Shoal, Lake Superior. The refuge was intended to reduce fishing mortality by protecting adult lake trout. We examined the growth dynamics of these lake trout during the period of recovery by comparing estimates of ndividual growth before and after the refuge was established. Our estimates are based on an annual mark-recapture survey conducted at the spawning area since 1969. We developed a model that allowed mean growth rates to differ among individuals of different sizes and that accommodated variation in growth rates of individuals of the same size. Likelihood ratio tests were used to determine if the mean growth increments of lake trout changed ater the refuge was established. Our results suggest that growth of mature lake trout (particularly wild fish) decreased significantly in the postrefuge period. This decreased growth may have been associated with a reduction in food availability. We also observed reductions in growth as wild fish grew older and larger, which suggests that the growth of these fish may be adequately approximated by a von Bertalanffy growth model if it becomes possible to obtain accurate ages.

Fabrizio, Mary C.; Dorazio, Robert M.; Schram, Stephen T.

2001-01-01

116

Stock Identification of Naturalized Brown Trout in Lake Superior Tributaries: Differentiation Based on Allozyme Data  

Microsoft Academic Search

Eight collections of brown trout Salmo trutta from four Lake Superior tributary systems in Wisconsin (the species' principal range in the Lake Superior drainage) were analyzed electrophoretically for enzyme expression at 15 polymorphic loci. Collections included site-specific samples from the Brule River, as well as anadromous and resident fish from the Brule and Sioux Rivers. Significant differences occurred among the

Charles C. Krueger; Bernie May

1987-01-01

117

Vateritic Sagitta in Wild and Stocked Lake Trout: Applicability to Stock Origin  

Microsoft Academic Search

Aragonite is the normal form of calcium carbonate found in teleost otoliths, but it is sometimes replaced by vaterite, an alternate crystalline structure. We investigated the assumption that sagittal otoliths with vaterite replacement were unique to stocked lake trout Salvelinus namaycush in the Laurentian Great Lakes. Earlier studies had attributed these abnormalities to stocking stress, and proposed that the presence

Charles A. Bowen II; Charles R. Bronte; Ray L. Argyle; Jean V. Adams; James E. Johnson

1999-01-01

118

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

USGS Publications Warehouse

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.

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

1994-01-01

119

Size-specific mortality in fry of lake trout (Salvelinus namaycush) from Lake Michigan  

SciTech Connect

A study to test the presence and magnitude of size-specific mortality in fry from Lake Michigan lake trout and fry of hatchery origin during exposure to PCBs is presented. Fry from both sources were exposed to 50 ng/l PCBs for about 50 days after hatching and fry from both sources were reared in water to which no PCBs were added. The average lengths of fry from all four groups were significantly less than fry from Lake Michigan. Size-specific mortality observed in fry of Lake Michigan origin could be the result of a number of factors, including origin and condition of parents and environmental stresses, including organic contaminants. Higher mortality of the smaller fry might be considered to have a positive effect on long-term fish production in the larger fish are being selected for, however, decreasing genetic variability in the fish population can result in lower production. Considering the similarity between the physiochemical properties of PCBs and DDT, the substantial concentrations of PCBs in the fry of lake origin may be an important factor in explaining the size-specific mortality observed.

Seelye, J.G.; Mac, M.J.

1981-09-01

120

Fossil zooplankton and the historical status of westslope cutthroat trout in a headwater lake of Glacier National Park, Montana  

USGS Publications Warehouse

Surviving pure-strain populations of westslope cutthroat trout Oncorhynchus clarki lewisi in headwater lakes of Glacier National Park could play an important role in the managed recovery of regional cutthroat trout fisheries. However, uncertainty exists about whether native trout could have naturally invaded several park lakes where they now occur. This study used paleolimnological techniques to address the question of whether the population of native trout in Avalanche Lake is indigenous or became established through an undocumented introduction. The validity of using fossil diapause eggs (ephippia) of the fish-sensitive cladocerans Daphnia spp. as indicators for the historical presence of zooplanktivorous fish was tested with a survey of live zooplankton and corresponding surface-sediment fossil assemblages in eight Glacier Park lakes with or without trout. Analysis of a sediment core from Avalanche Lake dated by lead radioisotopes, historical wildfires, and a flood allowed reconstruction of zooplankton dynamics from about 1700 A.D. to the present. Fossil Daphnia ephippia were rare or absent in Avalanche Lake sediments deposited before 1910, suggesting intense zooplanktivory due to sustained presence of an indigenous population of native cutthroat trout. Fossil evidence for larger Daphnia populations in the 1930s and early 1940s revealed a temporary disturbance of the lake's normal food web interactions during which zooplanktivory was significantly reduced. This disturbance may have resulted from a collapse of the native trout population caused indirectly by failed attempts between 1915 and 1943 to stock Avalanche Lake with Yellowstone cutthroat trout O. clarki bouvieri.

Verschuren, D.; Marnell, L. F.

1997-01-01

121

Homing of Rainbow Trout Transplanted in Lake Michigan: A Comparison of Three Procedures Used for Imprinting and Stocking  

Microsoft Academic Search

We compared the homing ability of three groups of rainbow trout (Salmo gairdneri) stocked in Lake Michigan by different procedures. One group of juvenile rainbow trout was imprinted to a synthetic chemical, morpholine, during the presmolt and smolt stages, and a second group was not imprinted. Both groups were stocked directly into Lake Michigan, 1 km north of the Little

A. T. Scholz; C. K. Gosse; J. C. Cooper; R. M. Horrall; A. D. Hasler; R. I. Daly; R. J. Poff

1978-01-01

122

Trophic transfer efficiency of methylmercury and inorganic mercury to lake trout Salvelinus namaycush from its prey.  

PubMed

Based on a laboratory experiment, we estimated the net trophic transfer efficiency of methylmercury to lake trout Salvelinus namaycush from its prey to be equal to 76.6 %. Under the assumption that gross trophic transfer efficiency of methylmercury to lake trout from its prey was equal to 80 %, we estimated that the rate at which lake trout eliminated methylmercury was 0.000244 day(-1). Our laboratory estimate of methylmercury elimination rate was 5.5 times lower than the value predicted by a published regression equation developed from estimates of methylmercury elimination rates for fish available from the literature. Thus, our results, in conjunction with other recent findings, suggested that methylmercury elimination rates for fish have been overestimated in previous studies. In addition, based on our laboratory experiment, we estimated that the net trophic transfer efficiency of inorganic mercury to lake trout from its prey was 63.5 %. The lower net trophic transfer efficiency for inorganic mercury compared with that for methylmercury was partly attributable to the greater elimination rate for inorganic mercury. We also found that the efficiency with which lake trout retained either methylmercury or inorganic mercury from their food did not appear to be significantly affected by the degree of their swimming activity. PMID:22552852

Madenjian, C P; David, S R; Krabbenhoft, D P

2012-05-03

123

Trends of Chlorinated Organic Contaminants in Great Lakes Trout and Walleye from 1970 to 1998  

Microsoft Academic Search

Levels of chlorinated organic contaminants in predator fish have been monitored annually in each of the Great Lakes since\\u000a the 1970s. This article updates earlier reports with data from 1991 to 1998 for lake trout (Salvelinus namaycush) and (Lake Erie only) walleye (Sander vitreus) to provide a record that now extends nearly 30 years. Whole fish were analyzed for a

J. P. Hickey; S. A. Batterman; S. M. Chernyak

2006-01-01

124

Annual Production and Production: Biomass Ratios for Three Species of Stream Trout in Lake Superior Tributaries  

Microsoft Academic Search

We made estimates of annual production of stream trout in two Lake Superior tributaries in northeastern Minnesota in 1977–1978. The Caribou River (total alkalinity, 34 mg\\/L as CaCO3) drains part of the north shore of Lake Superior in an igneous rock geology. The Blackhoof River (total alkalinity, 83 mg\\/L) drains glacial drift and lake clay at the western end of

Thomas F. Waters; Michael T. Doherty; Charles C. Krueger

1990-01-01

125

Hatching, dispersal, and bathymetric distribution of age-0 wild lake trout at the Gull Island Shoal complex, Lake Superior  

USGS Publications Warehouse

We studied age-0 lake trout (Salvelinus namaycush) associated with spawning and nursery areas of the Gull Island Shoal complex in western Lake Superior. Post-emergent age-0 lake trout were captured on rocky spawning substrate with a 3-m beam trawl and at the nursery area with a bottom trawl from June to September 1990 and June to August 1991. Catch data suggested that age-0 lake trout move distances of 7-11 km to the nursery area over a 3-month period. Water currents, measured at Gull Island Shoal, may be a part of the transport mechanism. Examination of daily-growth increments on the sagittae and back-calculation from the date of capture revealed that most fish hatched between 6 June and 19 July in 1990 and between 30 April and 30 May in 1991. The duration of the hatch was 100 days in 1990 and 120 days in 1991, and the estimated incubation period is about 7 months for lake trout eggs at this site. Similar hatch-date distributions of age-0 captured on different sampling dates suggested that natural mortality was low.

Bronte, Charles R.; Selgeby, James H.; Saylor, James H.; Miller, Gerald S.; Foster, Neal R.

1995-01-01

126

Swimming performance of young lake trout after chronic exposure to PCBs and DDE  

USGS Publications Warehouse

Swimming performance was measured in fry of lake trout (Salvelinus namaycush) exposed to PCB's, DDE, and a combination of these two contaminants in both food and water at concentrations equal to, and 5 and 25 times higher than, levels found in Lake Michigan water and plankton. Fry were tested after about 50, 110, and 165 days of exposure. We measured swimming performance by forcing the fry to swim through a continuous series of incrementally increased velocities until the fish were exhausted. Although we observed significant differences in swimming performance between a few test groups, we detected no relation between swimming performance of the fry and exposure to PCB's or DDE, or both, at the concentrations tested. Inasmuch as swimming performance apparently was not affected by the levels of contamination by PCB's and DDE in Lake Michigan, impairment of swimming by these contaminants cannot account for the failure of lake trout reproduction in Lake Michigan.

Rottiers, Donald V.; Bergstedt, Roger A.

1981-01-01

127

Declining Survival of Lake Trout Stocked during 1963–1986 in U.S. Waters of Lake Superior  

Microsoft Academic Search

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

MICHAEL J. HANSEN; MARK P. EBENER; RICHARD G. SCHORFHAAR; STEPHEN T. SCHRAM; DONALD R. SCHREINER; JAMES H. SELGEBY

1994-01-01

128

Evidence that lake trout served as a buffer against sea lamprey predation on burbot in Lake Erie  

USGS Publications Warehouse

The population of burbot Lota lota in Lake Erie recovered during 1986-2003, mainly because of the control of sea lamprey Petromyzon marinus, which began in 1986, Burbot populations continued to grow during 1996-1998, when sea lamprey control was substantially reduced. We calculated mortality parameters for burbot in Lake Erie by estimating age at capture for 2,793 burbot caught in annual gill-net surveys of eastern Lake Erie from 1994 to 2003. Based on catch-curve analysis, annual mortality in Lake Erie during 1994-2003 was estimated as 33%. Annual mortality of the 1992 year-class of burbot was estimated as 30%. The mortality of burbot during the years of reduced sea lamprey control was not different from that during the 3 years preceding reduced control and was significantly lower than that during the entire portion of the time series in which full sea lamprey control was conducted. These results suggest that the reduction in sea lamprey control did not lead to increased burbot mortality. The catch per gill-net lift of large burbot (total length > 600 mm), the size preferred by sea lampreys, was lower than that of adult lake trout Salvelinus namaycush (age 5 and older; total length > 700 mm) before lampricide application was reduced. Although adult lake trout populations declined, the abundance of large burbot did not change during the period of reduced lampricide application. These results support a hypothesis that a healthy population of adult lake trout can serve as a buffer species, acting to reduce predation of burbot by sea lampreys when sea lamprey populations increase. Burbot attained sexual maturity at a relatively early age (3 or 4 years) and a total length (approximately 500 mm) that was smaller than the preferred prey size for sea lampreys. These characteristics and the buffering effect of the lake trout population enabled growth of the burbot population during the brief period when lamprey control was reduced.

Stapanian, M. A.; Madenjian, C. P.

2007-01-01

129

Relationship between Mercury Concentration and Growth Rates for Walleyes, Northern Pike, and Lake Trout from Quebec Lakes  

Microsoft Academic Search

The relationship between mercury (Hg) concentrations in fish muscle and fish growth rates was assessed for 54 walleye Sander vitreus, 52 northern pike Esox lucius, and 35 lake trout Salvelinus namaycush populations throughout the Province of Quebec, Canada. We used the von Bertalanffy growth model to estimate the ages of fish specimens for a given length, and Hg concentrations in

Mélyssa Lavigne; Marc Lucotte; Serge Paquet

2010-01-01

130

Lethality of sea lamprey attacks on lake trout in relation to location on the body surface  

USGS Publications Warehouse

We compared the locations of healed attack marks of the sea lamprey Petromyzon marinus on live lake trout Salvelinus namaycush with those of unhealed attack marks on dead lake trout to determine if the lethality of a sea lamprey attack was related to attack location. Lake trout were collected from Lake Ontario, live fish with gill nets in September 1985 and dead fish with trawls in October 19831986. Attack location was characterized by the percent distances from snout to tail and from the ventral to the dorsal midline. Kolmogorov-Smirnov two-sample tests did not detect significant differences in the distribution of attack location along either the anteroposterior axis or the dorsoventral axis. When attack locations were grouped into six anatomical regions historically used to record sea lamprey attacks, dead fish did not exhibit a significantly higher proportion of attacks in the more anterior regions. Even if the differences in attack location on live and dead fish were significant, they were too small to imply substantial spatial differences in attack lethality that should be accounted for when modeling the effects of sea lampreys feeding on lake trout. We suggest that the tendency for sea lamprey attacks to occur on the anterior half of the fish is related to the lower amplitude of lateral body movement there during swimming and thus the lower likelihood of being dislodged.

Bergstedt, Roger A.; Schneider, Clifford P.; O'Gorman, Robert

2001-01-01

131

The Spawning Migration of Rainbow Trout at Skaneateles Lake, New York  

Microsoft Academic Search

At Skaneateles Lake, New York, the main body of migrating rainbow trout entered Grout Brook, a tributary stream, in April, 1941, at high water when the maximum temperature entered an observed range of 42° to 55° F. The attendant increased flow of water which resulted from rain and melting snow might have affected the migration. Thunderstorms seemed to have a

H. J. Rayner

1942-01-01

132

Diversity in Habitat Use and Trophic Ecology of Brook Trout in Lake Superior and Tributary Streams Revealed Through Stable Isotopes  

Microsoft Academic Search

Two distinct types of brook trout Salvelinus fontinalis have been hypothesized to occur in Lake Superior: large fish that inhabit Lake Superior for much of the year but spawn in tributary streams, and small fish that are resident in tributary streams. The lake type has declined markedly in range and abundance, and a greater understanding of the behavior and ecology

Melissa M. Robillard; Robert L. McLaughlin; Robert W. Mackereth

2011-01-01

133

Effects of High Levels of Total Dissolved Solids in Walker Lake, Nevada, on Survival and Growth of Lahontan Cutthroat Trout  

Microsoft Academic Search

Walker Lake, Nevada, is an endorheic terminal lake experiencing significant increases in total dissolved solids (TDS) because of culturally derived reductions in inflow and continued evaporative water losses. Maintenance of the Walker Lake fishery for native Lahontan cutthroat trout Oncorhynchus clarki henshawi requires artificial propagation because fish no longer have access to suitable spawning sites upstream in the Walker River.

Bobette R. Dickerson; Gary L. Vinyard

1999-01-01

134

Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics.  

PubMed

Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The "rate" of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios (?(15)N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to ?(15)N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (?(15)N; ?(13)C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. PMID:22982939

Kidd, Karen A; Muir, Derek C G; Evans, Marlene S; Wang, Xioawa; Whittle, Mike; Swanson, Heidi K; Johnston, Tom; Guildford, Stephanie

2012-09-13

135

Shifts in depth distributions of alewives, rainbow smelt, and age-2 lake trout in southern Lake Ontario following establishment of Dreissenids  

USGS Publications Warehouse

In the mid-1990s, biologists conducting assessments of fish stocks in Lake Ontario reported finding alewives Alosa pseudoharengus, rainbow smelt Osmerus mordax, and juvenile lake trout Salvelinus namaycush at greater depths than in the mid-1980s. To determine if depth distributions shifted coincident with the early 1990s colonization of Lake Ontario by exotic Dreissena mussels, we calculated mean depth of capture for each of the three species during trawl surveys conducted annually during 1978-1997 and examined the means for significant deviations from established patterns. We found that mean capture depth of alewives, rainbow smelt, and age-2 lake trout shifted deeper during the build up of the dreissenid population in Lake Ontario but that timing of the shift varied among seasons and species. Depth shifts occurred first for rainbow smelt and age-2 lake trout in June 1991. In 1992, alewives shifted deeper in June followed by age-2 lake trout in July-August. Finally, in 1993 and 1994, the distribution of lake trout and alewives shifted in April-May. Reasons why the three fishes moved to deeper water are not clear, but changes in distribution were not linked to temperature. Mean temperature of capture after the depth shift was significantly lower than before the depth shift except for alewives in April-May. Movement of alewives, rainbow smelt, and age-2 lake trout to colder, deeper water has the potential to alter growth and reproduction schedules by exposing the fish to different temperature regimes and to alter the food chain, increasing predation on Mysis relicta in deep water and decreasing alewife predation on lake trout fry over nearshore spawning grounds in spring.

O'Gorman, Robert; Elrod, Joseph H.; Owens, Randall W.; Schneider, Clifford P.; Eckert, Thomas H.; Lantry, Brian F.

2000-01-01

136

Effect of water temperature on sea lamprey growth and lake trout survival  

SciTech Connect

Percent mortality of lake trout Salvelinus namaycush subjected to single sea lamprey Petromyzon marinus attacks did not differ significantly between lower-temperature (mortality = 54%; temperature [le] 10[degrees]C; N = 33) and higher-temperature (mortality = 69%; temperature = 12.8-14.4[degrees]C; N = 45) laboratory studies conducted from 1 June to 28 November 1989. However, sea lampreys fed longer and killed fewer fish in colder water (mean attachment 467.0 h; 18 fish killed) than in warmer water (mean attachment 161.7 h; 31 fish killed), probably because food consumption was lower in colder water. These results indicate that the number of fish killed by sea lampreys could be much greater in warmer water and that temperature must be considered when fish losses from sea lamprey attacks are estimated. Previous studies (Swink and Hanson 1989; Swink 1990) of the effects of single sea lamprey Petromyzon marinus attacks on lake trout Salvelinus namaycush showed significantly less lake trout mortality at temperatures of 10[degrees]C and lower than at higher temperatures. The reduced host mortality, however, could not be attributed solely to lower temperature because warmwater and coldwater attacks occurred during different seasons. In those studies, the author was unable to hold water temperature at 10[degrees]C or less in late summer and early fall, when most fish are killed by sea lampreys in the Great Lakes (Christie and Kolenosky 1980; Bergstedt and Schneider 1988). Modifications to the fish holding facilities at the Hammond Bay Biological Station in 1988 allowed maintenance of a limited amount of water at 10[degrees]C or less throughout the year. Hence, the objective of this study was to compare sea lamprey-induced mortality of lake trout at 10[degrees]C or less with that at 12.8-14.4[degrees]C during the normal feeding season (June through November). 15 refs., 1 fig., 1 tab.

Swink, W.D. (Hammond Bay Biological Station, Millersburg, MI (United States))

1993-11-01

137

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.  

PubMed

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ? Erie > Huron > Superior ? Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid. PMID:22722738

Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

2012-06-22

138

Tc 1Like Transposable Elements in the Genome of Lake Trout ( Salvelinus namaycush )  

Microsoft Academic Search

.   This study reports on the DNA sequence of a Tc1-like transposable element Tsn1 from lake trout (Salvelinus namaycush). Tc1-like elements were amplified by PCR using an oligonucleotide primer based on the Tdr1 element of zebrafish. One full-length and two partial-length copies of the transposon were sequenced. In addition, partial\\u000a Tsn1 elements were recovered from PCR reactions run with primers

Kent M. Reed

1999-01-01

139

Natal?stream rearing in three populations of rainbow trout in Lake Taupo, New Zealand  

Microsoft Academic Search

Scales were taken from adult rainbow trout (Oncorhynchus mykiss, previously Salmo gairdneri) from the Waimarino, Tokaanu, and Hinemaiaia Rivers; these are tributaries of Lake Taupo, New Zealand. The scales showed both widely?spaced outer, and narrowly?spaced inner, circulus zones. Although there were no among?population differences in average circulus spacing in the outer growth zone, there were significant among?population differences in the

Marvin L. Rosenau

1991-01-01

140

Polybrominated diphenyl ethers in whitefish from Swiss lakes and farmed rainbow trout  

Microsoft Academic Search

A method for trace analysis of polybrominated diphenyl ethers (PBDE) in fish based on gas chromatography\\/electron ionization high resolution mass spectrometry (GC\\/EI-HRMS) was developed, and levels of PBDE were determined in whitefish (Coregonus sp.) from eight Swiss lakes and in rainbow trout (Oncorhynchus mykiss) from four Swiss fish farms. PBDE concentrations (sum of PBDE congeners BDE-28, BDE-47, BDE-99, BDE-100, BDE-153,

Markus Zennegg; Martin Kohler; Andreas C. Gerecke; Peter Schmid

2003-01-01

141

Metabolism and Fatty Acid profile in fat and lean rainbow trout lines fed with vegetable oil: effect of carbohydrates.  

PubMed

The present study investigated the effect of dietary carbohydrates on metabolism, with special focus on fatty acid bioconversion and flesh lipid composition in two rainbow trout lines divergently selected for muscle lipid content and fed with vegetable oils. These lines were chosen based on previously demonstrated potential differences in LC-PUFA synthesis and carbohydrate utilization. Applying a factorial study design, juvenile trout from the lean (L) and the fat (F) line were fed vegetable oil based diets with or without gelatinised starch (17.1%) for 12 weeks. Blood, liver, muscle, intestine and adipose tissue were sampled after the last meal. Feed intake and growth was higher in the L line than the F line, irrespective of the diet. Moderate postprandial hyperglycemia, strong induction of hepatic glucokinase and repressed glucose-6-phosphatase transcripts confirmed the metabolic response of both lines to carbohydrate intake. Further at the transcriptional level, dietary carbohydrate in the presence of n-3 LC-PUFA deficient vegetable oils enhanced intestinal chylomicron assembly, disturbed hepatic lipid metabolism and importantly elicited a higher response of key desaturase and elongase enzymes in the liver and intestine that endorsed our hypothesis. PPAR? was identified as the factor mediating this dietary regulation of fatty acid bioconversion enzymes in the liver. However, these molecular changes were not sufficient to modify the fatty acid composition of muscle or liver. Concerning the genotype effect, there was no evidence of substantial genotypic difference in lipid metabolism, LC-PUFA synthesis and flesh fatty acid profile when fed with vegetable oils. The minor reduction in plasma glucose and triglyceride levels in the F line was linked to potentially higher glucose and lipid uptake in the muscle. Overall, these data emphasize the importance of dietary macro-nutrient interface in evolving fish nutrition strategies. PMID:24124573

Kamalam, Biju Sam; Médale, Françoise; Larroquet, Laurence; Corraze, Geneviève; Panserat, Stephane

2013-10-04

142

Metabolism and Fatty Acid Profile in Fat and Lean Rainbow Trout Lines Fed with Vegetable Oil: Effect of Carbohydrates  

PubMed Central

The present study investigated the effect of dietary carbohydrates on metabolism, with special focus on fatty acid bioconversion and flesh lipid composition in two rainbow trout lines divergently selected for muscle lipid content and fed with vegetable oils. These lines were chosen based on previously demonstrated potential differences in LC-PUFA synthesis and carbohydrate utilization. Applying a factorial study design, juvenile trout from the lean (L) and the fat (F) line were fed vegetable oil based diets with or without gelatinised starch (17.1%) for 12 weeks. Blood, liver, muscle, intestine and adipose tissue were sampled after the last meal. Feed intake and growth was higher in the L line than the F line, irrespective of the diet. Moderate postprandial hyperglycemia, strong induction of hepatic glucokinase and repressed glucose-6-phosphatase transcripts confirmed the metabolic response of both lines to carbohydrate intake. Further at the transcriptional level, dietary carbohydrate in the presence of n-3 LC-PUFA deficient vegetable oils enhanced intestinal chylomicron assembly, disturbed hepatic lipid metabolism and importantly elicited a higher response of key desaturase and elongase enzymes in the liver and intestine that endorsed our hypothesis. PPAR? was identified as the factor mediating this dietary regulation of fatty acid bioconversion enzymes in the liver. However, these molecular changes were not sufficient to modify the fatty acid composition of muscle or liver. Concerning the genotype effect, there was no evidence of substantial genotypic difference in lipid metabolism, LC-PUFA synthesis and flesh fatty acid profile when fed with vegetable oils. The minor reduction in plasma glucose and triglyceride levels in the F line was linked to potentially higher glucose and lipid uptake in the muscle. Overall, these data emphasize the importance of dietary macro-nutrient interface in evolving fish nutrition strategies.

Kamalam, Biju Sam; Medale, Francoise; Larroquet, Laurence; Corraze, Genevieve; Panserat, Stephane

2013-01-01

143

An evaluation of restoration efforts in fishless lakes stocked with exotic trout  

USGS Publications Warehouse

Detrimental effects of introduced fishes on native amphibian populations have prompted removal of introduced cutthroat (Oncorhynchus clarki), rainbow (Oncorhynchus mykiss), and brook trout (Salvelinus fontinalis) from naturally fishless lakes at Mt. Rainier National Park, Washington (U.S.A.). Using paleolimnological indicators (diatoms, invertebrates, and sediment characteristics) in eight 480-year-old sediment cores from eight lakes, we (1) derived estimates of baseline environmental conditions and natural variation, (2) assessed the effects of stocking naturally fishless lakes, and (3) determined whether lakes returned to predisturbance conditions after fish removal (restoration). Diatom floras were relatively stable between 315 and 90 years before present in all lakes; we used this time period to define lake-specific "baseline" conditions. Dissimilarity analyses of diatoms revealed sustained, dramatic changes in diatom floras that occurred approximately 80 years ago (when fish were introduced) in four of five stocked lakes, whereas the diatom floras in two unstocked lakes had not changed significantly in the last 315 years. Diatoms were not preserved in an eighth lake. State changes also occurred in two lakes over 200 years before European settlement of the Pacific Northwest. Preserved invertebrate densities fluctuated dramatically over time in all cores, providing a poor reference for assessing the effects of fishes. Nevertheless, fish-invertebrate interactions have been demonstrated in other paleolimnological studies and may be useful for lower-elevation or more productive lakes. Because diatom communities have not returned to predisturbance assemblages in restored lakes, even 20-30 years after fish removal, we conclude that Mt. Rainier lakes were not successfully restored by the removal of fishes.

Drake, D. C.; Naiman, R. J.

2000-01-01

144

Quantifying the potential effects of climate change and the invasion of smallmouth bass on native lake trout populations across Canadian lakes  

Microsoft Academic Search

Climate change and invasive species are two stressors that should have large impacts on native species in aquatic and terrestrial ecosystems. We quantify and integrate the effects of climate change and the establishment of an invasive species (smallmouth bass Micropterus dolomieu) on native lake trout Salvelinus namaycush populations. We assembled a dataset of almost 22 000 Canadian lakes that contained

Sapna Sharma; Donald A. Jackson; Charles K. Minns

2009-01-01

145

Effects of Improved Water Quality and Stream Treatment Rotation on Sea Lamprey Abundance: Implications for Lake Trout Rehabilitation in the Great Lakes  

Microsoft Academic Search

Efforts over the past 25 years to improve water quality in the Great Lakes basin may be counteracting progress toward lake trout rehabilitation that has been made possible by sea lamprey control. Improved water quality in streams has been linked to increased amounts of suitable sea lamprey spawning and ammocoete habitat leading to increased sea lamprey production. To assess the

C. Paola Ferreri; William W. Taylor; Joseph F. Koonce

1995-01-01

146

Classifying Sea Lamprey Marks on Great Lakes Lake Trout: Observer Agreement, Evidence on Healing Times between Classes, and Recommendations for Reporting of Marking Statistics  

Microsoft Academic Search

In 1997 and 1998 two workshops were held to evaluate how consistent observers were at classifying sea lamprey (Petromyzon marinus) marks on Great Lakes lake trout (Salvelinus namaycush) as described in the King classification system. Two trials were held at each workshop, with group discussion between trials. Variation in counting and classifying marks was considerable, such that reporting rates for

Mark P. Ebener; James R. Bence; Roger A. Bergstedt; Katherine M. Mullett

2003-01-01

147

Classification of northern Finnish lakes and the suitability for the stocking for brown trout ( Salmo trutta (L.) m. lacustris)  

Microsoft Academic Search

Because there are some 15 000 Finnish lakes exceeding 10 ha in area, there is a pressing need in Finland for the development of effective stocking strategies for various types of Finnish lakes. The most common predatory fish employed in stocking in Finland for the past few decades has been brown trout (Salmo trutta (L.) m. lacustris), and the brown

Teppo Vehanen; Jouni Aspi

1996-01-01

148

The importance of diverse data types to calibrate a watershed model of the Trout Lake Basin, Northern Wisconsin, USA  

Microsoft Academic Search

As part of the USGS Water, Energy, and Biogeochemical Budgets project and the NSF Long-Term Ecological Research work, a parameter estimation code was used to calibrate a deterministic groundwater flow model of the Trout Lake Basin in northern Wisconsin. Observations included traditional calibration targets (head, lake stage, and baseflow observations) as well as unconventional targets such as groundwater flows to

Randall J. Hunt; Daniel T. Feinstein; Christine D. Pint; Mary P. Anderson

2006-01-01

149

Acute toxicities to larval rainbow trout of representative compounds detected in Great Lakes fish  

USGS Publications Warehouse

In recent years the National Fisheries Research Center-Great Lakes has ranked the potential hazard to fish and invertebrates of various chemical compounds detected in two Great Lakes fishes-- lake trout, Salvelinus namaycush, and walleye, Stizostedion vitreum vitreum (Hesselberg and Seelye 1982). This hazard assessment has included the identification of the potential sources of the compounds, determination of the occurrence and abundance of the compounds in Great Lakes fish, and the determination of acute toxicities of representative compounds of 19 chemical classes (Passino and Smith 1987a). In further studies Smith et al. (1988) focused on 6 of the 19 classes of compounds using the zooplankter Daphnia pulex as the test organism. They ranked the six classes as follows (in decreasing order of toxicity): polycyclic aromatic hydrocarbons (PAHs), alkyl halides, nitrogen-containing compounds, cyclic alkanes, heterocyclic nitrogen compounds, and silicon-containing compounds.

Edsall, Carol Cotant

1991-01-01

150

Lake Roosevelt Rainbow Trout : Habitat/Passage Improvement Project Annual Report 2000.  

SciTech Connect

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of the lake and its fishery have been limited. Early studies indicate that natural reproduction within the lake and tributaries are not sufficient to support a rainbow trout (Onchoryhnchus mykiss) fishery (Scholz et. al., 1988). These studies indicate that the rainbow trout population may be limited by lack of suitable habitat for spawning and rearing (Scholz et. al., 1988). The initial phase of this project (Phase I, baseline data collection- 1990-91) was directed at the assessment of limiting factors such as quality and quantity of available spawning gravel, identification of passage barriers, and assessment of other limiting factors. Population estimates were conducted using the Seber/LeCren removal/depletion method. After the initial assessment of stream parameters, several streams were selected for habitat/passage improvement projects (Phase II, implementation-1992-96). At the completion of project habitat improvements, the final phase (Phase III, monitoring) began. This phase will assess changes and gauge the success achieved through the improvements. The objective of the project is to correct passage barriers and improve habitat conditions of selected tributaries to Lake Roosevelt for adfluvial rainbow trout that utilize tributary streams for spawning and rearing. Streams with restorable habitats were selected for improvements. Completion of improvement efforts should increase the adfluvial rainbow trout contribution to the resident fishery in Lake Roosevelt. Three co-operating agencies, the Confederated Tribes of the Colville Reservation (CCT), the Spokane Tribe of Indians (STI) and the Washington Department of Fish and Wildlife initiated the project fieldwork in 1990. Phase II included only the Confederated Tribes of the Colville Reservation and the Spokane Tribe of Indians. Phase III is being completed by the Confederated Tribes of the Colville Reservation.

Sear, Sheri

2001-02-01

151

Lake Roosevelt Rainbow Trout : Habitat/Passage Improvement Project Annual Report 1999.  

SciTech Connect

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of the lake and its fishery have been limited. Early studies indicate that natural reproduction within the lake and tributaries are not sufficient to support a rainbow trout (Onchoryhnchus mykiss) fishery (Scholz et. al., 1988). These studies indicate that the rainbow trout population may be limited by lack of suitable habitat for spawning and rearing (Scholz et. al., 1988). The initial phase of this project (Phase I, baseline data collection- 1990-91) was directed at the assessment of limiting factors such as quality and quantity of available spawning gravel, identification of passage barriers, and assessment of other limiting factors. Population estimates were conducted using the Seber/LeCren removal/depletion method. After the initial assessment of stream parameters, several streams were selected for habitat/passage improvement projects (Phase II, implementation-1992-96). At the completion of project habitat improvements, the final phase (Phase III, monitoring) began. This phase will assess changes and gauge the success achieved through the improvements. The objective of the project is to correct passage barriers and improve habitat conditions of selected tributaries to Lake Roosevelt for adfluvial rainbow trout that utilize tributary streams for spawning and rearing. Streams with restorable habitats were selected for improvements. Completion of improvement efforts should increase the adfluvial rainbow trout contribution to the resident fishery in Lake Roosevelt. Three co-operating agencies, the Confederated Tribes of the Colville Reservation (CCT), the Spokane Tribe of Indians (STI) and the Washington Department of Fish and Wildlife initiated the project fieldwork in 1990. Phase II included only the Confederated Tribes of the Colville Reservation and the Spokane Tribe of Indians. Phase III is being completed by the Confederated Tribes of the Colville Reservation.

Jones, Charles D.

2000-02-01

152

Lake Roosevelt Rainbow Trout : Habitat/Passage Improvement Project : Annual Report 1998.  

SciTech Connect

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of the lake and its fishery have been limited. Early studies indicate that natural reproduction within the lake and tributaries are not sufficient to support a rainbow trout (Onchoryhnchus mykiss) fishery (Scholz et. al., 1988). These studies indicate that the rainbow trout population may be limited by lack of suitable habitat for spawning and rearing (Scholz et. al., 1988). The initial phase of this project (Phase I, baseline data collection) was directed at the assessment of limiting factors such as quality and quantity of available spawning gravel, identification of passage barriers, and assessment of other limiting factors. Population estimates were conducted using the Seber/LeCren removal/depletion method. After the initial assessment of stream parameters, several streams were selected for habitat/passage improvement projects (Phase II, implementation). At the completion of project habitat improvements, the final phase (Phase III, monitoring) began. This phase will assess changes and gauge the success achieved through the improvements. The objective of the project is to correct passage barriers and improve habitat conditions of selected tributaries to Lake Roosevelt for adfluvial rainbow trout that utilize tributary streams for spawning and rearing. Streams with restorable habitats were selected for improvements. Completion of improvement efforts should increase the adfluvial rainbow trout contribution to the resident fishery in Lake Roosevelt. Personnel of three co-operating agencies, the Confederated Tribes of the Colville Reservation (CCT), the Spokane Tribe of Indians (STI) and the Washington Department of Fish and Wildlife initiated the project fieldwork in 1990. Phase II included only the Confederated Tribes of the Colville Reservation and the Spokane Tribe of Indians. Phase III is being done by the Confederated Tribes of the Colville Reservation.

Jones, Charles D.

1999-02-01

153

Polybrominated diphenyl ethers in whitefish from Swiss lakes and farmed rainbow trout.  

PubMed

A method for trace analysis of polybrominated diphenyl ethers (PBDE) in fish based on gas chromatography/electron ionization high resolution mass spectrometry (GC/EI-HRMS) was developed, and levels of PBDE were determined in whitefish (Coregonus sp.) from eight Swiss lakes and in rainbow trout (Oncorhynchus mykiss) from four Swiss fish farms. PBDE concentrations (sum of PBDE congeners BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) in filet from whitefish between 36 and 165 ng/g lipid weight (lw) were found, corresponding to wet weight (ww) concentrations of 1.6-7.4 ng/gww. PBDE contents in filet from farmed rainbow trout were significantly lower than in wild whitefish (12-24 ng/glw, 0.74-1.3 ng/gww), and the PBDE congener patterns were different for both species (a higher BDE-47 to BDE-99 ratio for farmed rainbow trout compared to wild whitefish was found). Whitefish PBDE levels [ng/glw] correlate better with the surface/volume ratio of the respective lakes (r(2)=0.70) than with other lake properties such as catchment area (size or number of inhabitants) or residence time, suggesting atmospheric deposition as an input pathway for PBDE. Based on an average daily consumption of 20 g whitefish (Switzerland) with a PBDE content of 7.4 ng/gww (highest PBDE concentration detected in this study), a maximum daily intake of 0.15 microg PBDE was estimated (0.026 microg/day for farmed trout). This number corresponds to the lower end of the estimate for the total PBDE intake of the Nordic consumer of 0.2-0.7 microg/day. PMID:12615108

Zennegg, Markus; Kohler, Martin; Gerecke, Andreas C; Schmid, Peter

2003-05-01

154

Acute toxicities to larval rainbow trout of representative compounds detected in Great Lakes fish  

SciTech Connect

In recent years the National Fisheries Research Center-Great Lakes has ranked the potential hazard to fish and invertebrates of various chemical compounds detected in two Great Lakes fishes - lake trout, Salvelinus namaycush, and walleye. Stizostedion vitreum vitreum. This hazard assessment has included the identification of the potential sources of the compound, determination of the occurrence and abundance of the compounds in Great Lakes fish, and the determination of acute toxicities of representative compounds of 19 chemical classes. The author focuses on four of the classes. The PAHs are products of fuel combustion and components of fossil fuels. The other three classes principally originate from industrial applications (alkyl halides), as fossil fuels, insecticides, solvents, and in perfumes (cyclic alkanes); and as herbicides and insecticides (heterocyclic nitrogen compounds). The authors purpose is to report results of static acute toxicity tests in which larval rainbow trout (Oncorhynchus mykiss) were used as the test fish and to compare results of acute toxicity tests with previous studies.

Edsall, C.C. (National Fisheries Research Center-Great Lakes, Ann Arbor, MI (United States))

1991-02-01

155

Juvenile rainbow trout production in New York tributaries of Lake Ontario: implications for Atlantic salmon restoration  

USGS Publications Warehouse

Three Pacific salmonid species Onchorynchus spp. have replaced the extirpated Atlantic salmon Salmo salar as the main migratory salmonid in the Lake Ontario drainage. One of those species, the nonnative rainbow trout O. mykiss, has become widely distributed within the historical Atlantic salmon habitat, occupying an ecological niche similar to that of juvenile Atlantic salmon. Consequently, both a tributary's carrying capacity for Atlantic salmon and competition from established nonnative species are important when considering the feasibility of Atlantic salmon restoration. Estimation of juvenile rainbow trout production will help evaluate the capacity of tributaries to produce salmonids that occupy similar niches. Geostatistical methods were applied to standardized and efficiency-corrected electrofishing data from three of New York's best salmonid-producing streams to precisely estimate juvenile rainbow trout populations. Results indicated that each study stream could produce 20,000-40,000 age-0 and 4,000-10,000 age-1 and older rainbow trout per year. Statistical interpolation indicated areas of significantly different production potential and points of significant changes in productivity. Closer examination of the niche similarity and competitive potential of these two species is needed to properly interpret these estimates with regard to Atlantic salmon restoration.

McKenna, James E., Jr.; Johnson, James H.

2005-01-01

156

Lower fitness of hatchery and hybrid rainbow trout compared to naturalized populations in Lake Superior tributaries.  

PubMed

We have documented an early life survival advantage by naturalized populations of anadromous rainbow trout Oncorhynchus mykiss over a more recently introduced hatchery population and outbreeding depression resulting from interbreeding between the two strains. We tested the hypothesis that offspring of naturalized and hatchery trout, and reciprocal hybrid crosses, survive equally from fry to age 1+ in isolated reaches of Lake Superior tributary streams in Minnesota. Over the first summer, offspring of naturalized females had significantly greater survival than offspring of hatchery females in three of four comparisons (two streams and 2 years of stocking). Having an entire naturalized genome, not just a naturalized mother, was important for survival over the first winter. Naturalized offspring outperformed all others in survival to age 1+ and hybrids had reduced, but intermediate, survival relative to the two pure crosses. Averaging over years and streams, survival relative to naturalized offspring was 0.59 for hybrids with naturalized females, 0.37 for the reciprocal hybrids, and 0.21 for hatchery offspring. Our results indicate that naturalized rainbow trout are better adapted to the conditions of Minnesota's tributaries to Lake Superior so that they outperform the hatchery-propagated strain in the same manner that many native populations of salmonids outperform hatchery or transplanted fish. Continued stocking of the hatchery fish may conflict with a management goal of sustaining the naturalized populations. PMID:15487997

Miller, L M; Close, T; Kapuscinski, A R

2004-11-01

157

Use of cover habitat by bull trout, Salvelinus confluentus , and lake trout, Salvelinus namaycush , in a laboratory environment  

Microsoft Academic Search

Lacustrine-adfluvial bull trout, Salvelinus confluentus, migrate from spawning and rearing streams to lacustrine environments as early as age 0. Within lacustrine environments,\\u000a cover habitat provides refuge from potential predators and is a resource that is competed for if limiting. Competitive interactions\\u000a between bull trout and other species could result in bull trout being displaced from cover habitat, and bull trout

Michael H. Meeuwig; Christopher S. Guy; Wade A. Fredenberg

2011-01-01

158

Chemosensory cues attract lake trout Salvelinus namaycush and an egg predator to the spawning substratum.  

PubMed

A field experiment was conducted to determine whether chemosensory cues emanating from lake trout Salvelinus namaycush spawning substratum attract breeding S. namaycush. Substrata from either a spawning site or a control site were randomly placed in trap nets around an isolated spawning shoal; those containing spawning substratum caught significantly more S. namaycush, as well as a greater proportion in breeding condition. White sucker Catostomus commersoni were a major predator of S. namaycush eggs and were also captured in greater numbers in nets with spawning substratum. PMID:23557313

Wasylenko, B A; Blanchfield, P J; Pyle, G G

2013-02-25

159

Factors Affecting Survival Rates of a Recovering Lake Trout Population Estimated by Mark–Recapture in Lake Superior, 1969–1996  

Microsoft Academic Search

We used data from a long-term Wisconsin Department of Natural Resources mark–recapture study to examine the dynamics of survival in a recovering population of lake trout Salvelinus namaycush in western Lake Superior from 1969 to 1996. Survival rates were estimated using the Cormack–Jolly–Seber method, and a series of models were constructed to examine the effect of year, size, sex, and

Kenneth H. Pollock; Jun Yoshizaki; Mary C. Fabrizio; Stephen T. Schram

2007-01-01

160

Distinguishing wild vs. stocked lake trout (Salvelinus namaycush) in Lake Ontario: Evidence from carbon and oxygen stable isotope values of otoliths  

USGS Publications Warehouse

We investigated the potential for using carbon and oxygen isotope values of otolith carbonate as a method to distinguish naturally produced (wild) lake trout (Salvelinus namaycush) from hatchery-reared lake trout in Lake Ontario. We determined ??13C(CaCO3) and ?? 18O(CaCO3) values of otoliths from juvenile fish taken from two hatcheries, and of otoliths from wild yearlings. Clear differences in isotope values were observed between the three groups. Subsequently we examined otoliths from large marked and unmarked fish captured in the lake, determining isotope values for regions of the otolith corresponding to the first year of life. Marked (i.e., stocked) fish showed isotope ratios similar to one of the hatchery groups, whereas unmarked fish, (wild fish or stocked fish that lost the mark) showed isotope ratios similar either to one of the hatchery groups or to the wild group. We interpret these data to suggest that carbon and oxygen isotope values can be used to determine the origin of lake trout in Lake Ontario, if a catalogue of characteristic isotope values from all candidate years and hatcheries is compiled.

Schaner, T.; Patterson, W. P.; Lantry, B. F.; O'Gorman, R.

2007-01-01

161

A 14-year study of habitat use and diet of brown trout (Salmo trutta) and Arctic charr (Salvelinus alpinus) in Lake Atnsjøen, a subalpine Norwegian lake  

Microsoft Academic Search

We studied the spatial and temporal variation in relative abundance (CPUE), habitat use, and diet of Arctic charr (Salvelinus alpinus (L.)) and brown trout (Salmo trutta L.) in Lake Atnsjøen in southern Norway over a period of 14 years (1985–1998). Fish were sampled with gill nets in epibenthic and pelagic habitats in August each year. Stratified sampling in the epibenthic

Randi Saksgård; Trygve Hesthagen

2004-01-01

162

Environmental and Population Strain Effects on Survival of Lahontan Cutthroat Trout in Walker Lake, Nevada: A Bayesian Approach  

Microsoft Academic Search

Lahontan cutthroat trout Oncorhynchus clarkii henshawi are listed as threatened under the U.S. Endangered Species Act. Populations inhabiting terminal lakes in the Great Basin of Utah and adjacent states face increasing salinity associated with increased anthropogenic use of water and climate change. We used tag recovery models and Markov chain–Monte Carlo methods to assess models of variation in annual survival

James S. Sedinger; Erik J. Blomberg; Amanda W. VanDellen; Stephanie Byers

2012-01-01

163

Growth and mortality of fry of Lake Michigan lake trout during chronic exposure to PCB's and DDE  

USGS Publications Warehouse

Fry hatched from eggs of Lake Michigan lake trout (Salvelinus namaycush) were exposed (beginning about 1 week after hatching) to contaminant concentrations of PCB's and DDE similar to those in water and plankton in southeastern Lake Michigan (1X level), and to concentrations about 5 (5X) and 25 (25X) times greater. Body concentrations of contaminants in fry (I?g/g) decreased at 1X levels of PCB's and at 1X and 5X levels of DDE, but generally increased at all other contaminant exposure levels. Uptake of PCB's and DDE was evident from increases in body burden (I?g/fish) of the contaminants at all exposure levels and the controls. Growth was not significantly affected by any of the contaminant exposures. Mortalities of fry exposed to the lower concentrations (1X and 5X) were significantly less than those of control fry before day 56; however, between days 57 and 136, mortality rates increased dramatically and were significantly higher in all nine exposed groups than in the control group. For the last 40-day period (days 137-176), mortality was low and leveled off, but continued to be significantly higher in all exposed fry (except those in 1X and 5X PCB's) than in control fry. By the end of the 176-day study, the total cumulative mortality ranged from 30.5 to 46.5% in the exposed groups and was 21.7% in the control group.

Berlin, William H.; Hesselberg, Robert J.; Mac, Michael J.

1981-01-01

164

The importance of size and growth rate in determining mercury concentrations in European minnow ( Phoxinus phoxinus ) and brown trout ( Salmo trutta ) in the subalpine lake, Øvre Heimdalsvatn  

Microsoft Academic Search

The alien fish species, European minnow (Phoxinus phoxinus), was recorded in the mountain lake, Øvre Heimdalsvatn, southern Norway, for the first time in 1969. After some years minnows\\u000a were observed in the diet of brown trout (Salmo trutta). In 2006, brown trout had significantly higher ?15N values than European minnow, indicating that brown trout holds the top trophic position in

Marthe T. Solhaug Jenssen; Reidar Borgstrøm; Brit Salbu; Bjørn Olav Rosseland

2010-01-01

165

Impact of thiamine deficiency on T-cell dependent and T-cell independent antibody production in lake trout  

USGS Publications Warehouse

Lake trout Salvelinus namaycush on thiamine-replete and thiamine-depleted diets were evaluated for the effects of thiamine status on in vivo responses to the T-dependent antigen trinitophenol (TNP)-keyhole limpet hemocyanin (TNP-KLH), the T-independent antigen trinitrophenol-lipolysaccaharide (TNP-LPS), or Dulbecco's phosphate-buffered saline (DPBS; negative control fish). Plasma antibody concentrations were evaluated for possible differences in total anti-TNP activity as well as differences in response kinetics. Associations between anti-TNP activity and muscle and liver thiamine concentrations as well as ratios of muscle-to-liver thiamine to anti-TNP activity were also examined. Thiamine-depleted lake trout that were injected with TNP-LPS exhibited significantly more anti-TNP activity than thiamine-replete fish. The depleted fish injected with TNP-LPS also exhibited significantly different response kinetics relative to thiamine-replete lake trout. No differences in activity or kinetics were observed between the thiamine-replete and -depleted fish injected with TNP-KLH or in the DPBS negative controls. Anti-TNP activity in thiamine-depleted lake trout injected with TNP-KLH was positively associated with muscle thiamine pyrophosphate (thiamine diphosphate; TPP) concentration. A negative association was observed between the ratio of muscle-to-liver TPP and T-independent responses. No significant associations between anti-TNP activity and tissue thiamine concentration were observed in the thiamine-replete fish. We demonstrated that thiamine deficiency leads to alterations in both T-dependent and T-independent immune responses in lake trout.

Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

2012-01-01

166

Perfluoroalkyl contaminants in Lake Ontario Lake Trout: detailed examination of current status and long-term trends.  

PubMed

Perfluoroalkyl contaminants (PFCs) were determined in Lake Ontario Lake Trout sampled annually between 1997 and 2008 in order to assess how current trends are responding to recent regulatory bans and voluntary phase-outs. We also combined our measurements with those of a previous study to provide an updated assessment of long-term trends. Concentrations of PFCs generally increased from the late 1970s until the mid-1980s to mid-1990s, after which concentrations either remained unchanged (perfluorooctane sulfonate (PFOS) and perfluorocarboxylates) or declined (perfluorodecanesulfonate (PFDS)). The temporal trends were assessed using three models, quadratic, exponential rise to maximum, and two-segment linear piecewise function, and then evaluated for best fit using Akaike Information Criteria. For PFOS and perfluorocarboxylates, the exponential rise to maximum function had the best fit. This is particularly interesting for PFOS as it suggests that although concentrations in Lake Ontario Lake Trout may have stopped increasing in response to voluntary phase-outs in 2000-2002, declines have yet to be observed. This may be due to continuing input of PFOS from products still in use and/or slow degradation of larger precursor molecules. A power analysis of PFOS suggested that 15 years of data with a within-year sample size of 10 is required to obtain sufficient power (80%) to detect a 5% decreasing trend. However, the length of the monitoring program had a greater influence on the ability to detect a trend compared to within-year sample size. This provides evidence that additional sampling years are required to detect a response to bans and phase-outs, given the variability in the fish data. The lack of observed declines of perfluorocarboxylate residues in fish may be expected as regulations for these compounds were only recently enacted. In contrast to the other compounds, the quadratic model had the best fit for PFDS. The results of this study emphasize the importance of long-term monitoring for assessing the effectiveness of bans and phase-outs on PFCs in the environment. PMID:22553902

Gewurtz, Sarah B; De Silva, Amila O; Backus, Sean M; McGoldrick, Daryl J; Keir, Michael J; Small, Jeff; Melymuk, Lisa; Muir, Derek C G

2012-05-17

167

Total and Methyl Mercury in 1994-5 Lake Michigan Lake Trout and Forage Fish  

EPA Science Inventory

Total and methyl mercury were analyzed in Lake Michigan fish collected in 1994 and 1995 as part of the Lake Michigan Mass Balance project (LMMB). One predator fish species and five forage fish species were analyzed to determine the bioaccumulative nature of mercury. These data ...

168

Comparison of lake trout-egg survival at inshore and offshore and shallow-water and deepwater sites in Lake Superior  

USGS Publications Warehouse

We incubated lake trout (Salvelinus namaycush) eggs over winter at shallow (10 m) and deep locations (20 m) on Gull Island Shoal, Lake Superior; at a shallow-water (10 m) site off the mainland (bark point); and in flowing great lakes water at two laboratories. Survival to hatch was significantly higher in the laboratories and averaged 80.9%. In Lake Superior, egg survival among incubators at all sites was significantly higher (p < 0.0001) For incubators that remained buried in spawning substrates (15.1-21.0%) than for incubators that were partially or completely exposed to water currents (1.0-12.6%). Egg survival for incubators that remained buried at the shallow-water sites was significantly higher at bark point (44.6%) than at Gull Island Shoal (21.0%). Egg survival among incubators that remained buried at the deep (14.4%) and shallow-water sites (21.0%) on Gull Island Shoal was not significantly different. Because incubators that were completely buried or partially exposed only appeared to differ in their degree of exposure, we concluded that survival of eggs in the lake was reduced by mechanical stress associated with water turbulence. Lower egg survival at Gull Island Shoal, a known lake trout-spawning site, was not expected and appeared to have been caused by a strong gale that occurred when these eggs were in late epiboly, a sensitive embryological stage. We present a hypothesis suggesting that lake trout recruitment in the Great Lakes is limited by availability of spawning habitat.

Eshenroder, Randy L.; Bronte, Charles R.; Peck, James W.

1995-01-01

169

Embryotoxicity of extracts from Lake Ontario rainbow trout (Oncorhynchus mykiss) to Japanese medaka (Oryzias latipes)  

SciTech Connect

Various preparative techniques were used to extract nonpolar organic compounds from the muscle tissue of Lake Ontario rainbow trout (Oncorhynchus mykiss). In this extract, PCBs and organochlorine compounds were detected in nanogram-per-milliliter quantities, and polychlorinated dibenzo-p-dioxins and dibenzofurans were detected in picogram-per-milliliter quantities. The extract and various subfractions of the extract were tested for embryotoxicity in a bioassay with embryos of Japanese medaka (Oryzias latipes). The whole extract was embryotoxic to medaka, as were an extract fraction containing PCBs (fraction A) and extract fractions containing nonpolar organochlorine compounds (fractions B and C). When subfractions prepared from fraction A were tested for embryotoxicity, a subfraction containing non-ortho-substituted PCB congeners was embryo-toxic, whereas subfractions containing mono-ortho- and di-ortho-substituted PCB congeners were relatively nontoxic. Pathological lesions characteristic of exposure to planar halogenated aromatic hydrocarbons were observed only in embryos exposed to the non-ortho-PCB subfraction. The non-ortho-PCB subfraction of fraction A was more toxic than the original fraction A, which indicates that nontoxic PCBs reduce the toxicity of the non-ortho-PCBs through some unknown mechanism. This study indicates that organochlorine compounds and non-ortho-substituted PCBs have the potential to be embryotoxic to early life stages of Great lakes fish, but nontoxic contaminants can modify this toxic response. These data are relevant to the interpretation of correlations between embryo mortalities and concentrations of persistent organic contaminants in Great Lakes salmonids.

Harris, G.E.; Metcalfe, T.L.; Metcalfe, C.D. (Trent Univ., Peterborough, Ontario (Canada). Environmental and Resources Studies Program); Huestis, S.Y. (Canada Centre for Inland Waters, Burlington, Ontario (Canada))

1994-09-01

170

Management of Commercial Fisheries Bycatch, with Emphasis on Lake Trout Fisheries of the Upper Great Lakes.  

National Technical Information Service (NTIS)

The purposes of this paper were to: (1) investigate the collective published record on the global significance and management of commercial fisheries bycatch; (2) identify elements of Great Lakes ecosystems that are especially vulnerable as bycatch; and (...

J. E. Johnson J. L. Jonas J. W. Peck

2004-01-01

171

Classifying sea lamprey marks on Great Lakes lake trout: Observer agreement, evidence on healing times between classes, and recommendations for reporting of marking statistics  

USGS Publications Warehouse

In 1997 and 1998 two workshops were held to evaluate how consistent observers were at classifying sea lamprey (Petromyzon marinus) marks on Great Lakes lake trout (Salvelinus namaycush) as described in the King classification system. Two trials were held at each workshop, with group discussion between trials. Variation in counting and classifying marks was considerable, such that reporting rates for A1-A3 marks varied two to three-fold among observers of the same lake trout. Observer variation was greater for classification of healing or healed marks than for fresh marks. The workshops highlighted, as causes for inconsistent mark classification, both departures from the accepted protocol for classifying marks by some agencies, and differences in how sliding and multiple marks were interpreted. Group discussions led to greater agreement in classifying marks. We recommend ways to improve the reliability of marking statistics, including the use of a dichotomous key to classify marks. Laboratory data show that healing times of marks on lake trout were much longer at 4??C and 1??C than at 10??C and varied greatly among individuals. Reported A1-A3 and B1-B3 marks observed in late summer and fall collections likely result from a mixture of attacks by two year classes of sea lamprey. It is likely that a substantial but highly uncertain proportion of attacks that occur in late summer and fall lead to marks that are classified as A1-A3 the next spring. We recommend additional research on mark stage duration.

Ebener, M. P.; Bence, J. R.; Bergstedt, R. A.; Mullett, K. M.

2003-01-01

172

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

USGS Publications Warehouse

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.

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

2008-01-01

173

Variability of kokanee and rainbow trout food habits, distribution, and population dynamics, in an ultraoligotrophic lake with no manipulative management  

Microsoft Academic Search

Crater Lake is a unique environment to evaluate the ecology of introduced kokanee and rainbow trout because of its otherwise\\u000a pristine state, low productivity, absence of manipulative management, and lack of lotic systems for fish spawning. Between\\u000a 1986 and 2004, kokanee displayed a great deal of variation in population demographics with a pattern that reoccurred in about\\u000a 10 years. We

Mark W. Buktenica; Scott F. Girdner; Gary L. Larson; C. David McIntire

174

Efficacy of hydrogen peroxide versus formalin treatments to control mortality associated with saprolegniasis on lake trout eggs  

USGS Publications Warehouse

We compared the efficacy of hydrogen peroxide versus formalin treatments to control fungal infections on eggs of lake trout Salvelinus namaycush incubated at a hatchery in Wisconsin. Four strains of lake trout eggs were incubated in six vertical-flow Heath incubators; three replicate incubators for each chemical. Each incubator had 13 trays containing approximately 25,000-30,000 eggs/tray. Formalin (1,667 mg/L) or hydrogen peroxide (1,000 mg/L) treatments were administered once daily for 15 min up to the development of visible eye spots in the eggs (eyed egg stage). Eyed and dead eggs were separated using a photoelectric egg sorter, and the number of live and dead eggs was determined volumetrically. In the hydrogen peroxide test group, the bottom trays of each incubator had fungus present on the eggs, whereas no fungus was observed on eggs treated with formalin. The mean percentage of eyed eggs for an incubator treated with formalin (75%) was significantly greater than an incubator treated with hydrogen peroxide (70%). Formalin was the most efficacious therapeutant; however, both therapeutants were effective in increasing lake trout egg survival up to the eyed egg stage. ?? Copyright by the American Fisheries Society 2005.

Rach, J. J.; Redman, S.; Bast, D.; Gaikowski, M. P.

2005-01-01

175

Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project, Annual Report 2002-2003.  

SciTech Connect

The construction of Chief Joseph and Grand Coulee Dams completely and irrevocably blocked anadromous fish migrations to the Upper Columbia River. Historically this area hosted vast numbers of salmon returning to their natal waters to reproduce and die. For the native peoples of the region, salmon and steelhead were a principle food source, providing physical nourishment and spiritual sustenance, and contributing to the religious practices and the cultural basis of tribal communities. The decaying remains of spawned-out salmon carcasses contributed untold amounts of nutrients into the aquatic, aerial, and terrestrial ecosystems of tributary habitats in the upper basin. Near the present site of Kettle Falls, Washington, the second largest Indian fishery in the state existed for thousands of years. Returning salmon were caught in nets and baskets or speared on their migration to the headwater of the Columbia River in British Columbia. Catch estimates at Kettle Falls range from 600,000 in 1940 to two (2) million around the turn of the century (UCUT, Report No.2). The loss of anadromous fish limited the opportunities for fisheries management and enhancement exclusively to those actions addressed to resident fish. The Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project is a mitigation project intended to enhance resident fish populations and to partially mitigate for anadromous fish losses caused by hydropower system impacts. This substitution of resident fish for anadromous fish losses is considered in-place and out-of-kind mitigation. Upstream migration and passage barriers limit the amount of spawning and rearing habitat that might otherwise be utilized by rainbow trout. The results of even limited stream surveys and habitat inventories indicated that a potential for increased natural production exists. However, the lack of any comprehensive enhancement measures prompted the Upper Columbia United Tribes Fisheries Center (UCUT), Colville Confederated Tribes (CCT), Spokane Tribe of Indians (STI) and Washington Department of Fish and Wildlife (WDFW) to develop and propose a comprehensive fishery management plan for Lake Roosevelt. The Rainbow Trout Habitat/Passage Improvement Project (LRHIP) was designed with goals directed towards increasing natural production while maintaining genetic integrity among current tributary stocks. The initial phase of the Lake Roosevelt Habitat Improvement Project (Phase I, baseline data collection: 1990-91) was focused on the assessment of limiting factors, including the quality and quantity of available spawning gravel, identification of passage barriers, and assessment of other constraints. After the initial assessment of stream parameters, five streams meeting specific criteria were selected for habitat/passage improvement projects (Phase II, implementation -1992-1995). Four of these projects were on the Colville Indian Reservation South Nanamkin, North Nanamkin, Louie and Iron Creeks and one Blue Creek was on the Spokane Indian Reservation. At the completion of project habitat improvements, the final phase (Phase III, monitoring-1996-2000) began. This phase assessed the changes and determined the success achieved through the improvements. Data analysis showed that passage improvements are successful for increasing habitat availability and use. The results of in-stream habitat improvements were inconclusive. Project streams, to the last monitoring date, have shown increases in fish density following implementation of the improvements. In 2000 Bridge Creek, on the Colville Reservation was selected for the next phase of improvements. Data collection, including baseline stream survey and population data collection, was carried out during 2001 in preparation for the design and implementation of stream habitat/passage improvements. Agencies cooperating on the project include the Colville Confederated Tribes (CCT), Natural Resource Conservation Service (NRCS, Ferry County District), Ferry County Conservation District, and Ferry County. The Bonneville Power Administration (BPA) provided

Sears, Sheryl

2004-01-01

176

Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project, Annual Report 2001-2002.  

SciTech Connect

The construction of Chief Joseph and Grand Coulee Dams completely and irrevocably blocked anadromous fish migrations to the Upper Columbia River. Historically this area hosted vast numbers of salmon returning to their natal waters to reproduce and die. For the native peoples of the region, salmon and steelhead were a principle food source, providing physical nourishment and spiritual sustenance, and contributing to the religious practices and the cultural basis of tribal communities. The decaying remains of spawned-out salmon carcasses contributed untold amounts of nutrients into the aquatic, aerial, and terrestrial ecosystems of tributary habitats in the upper basin. Near the present site of Kettle Falls, Washington, the second largest Indian fishery in the state existed for thousands of years. Returning salmon were caught in nets and baskets or speared on their migration to the headwater of the Columbia River in British Columbia. Catch estimates at Kettle Falls range from 600,000 in 1940 to two (2) million around the turn of the century (UCUT, Report No.2). The loss of anadromous fish limited the opportunities for fisheries management and enhancement exclusively to those actions addressed to resident fish. The Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project is a mitigation project intended to enhance resident fish populations and to partially mitigate for anadromous fish losses caused by hydropower system impacts. This substitution of resident fish for anadromous fish losses is considered in-place and out-of-kind mitigation. Upstream migration and passage barriers limit the amount of spawning and rearing habitat that might otherwise be utilized by rainbow trout. The results of even limited stream surveys and habitat inventories indicated that a potential for increased natural production exists. However, the lack of any comprehensive enhancement measures prompted the Upper Columbia United Tribes Fisheries Center (UCUT), Colville Confederated Tribes (CCT), Spokane Tribe of Indians (STI) and Washington Department of Fish and Wildlife (WDFW) to develop and propose a comprehensive fishery management plan for Lake Roosevelt. The Rainbow Trout Habitat/Passage Improvement Project (LRHIP) was designed with goals directed towards increasing natural production while maintaining genetic integrity among current tributary stocks. The initial phase of the Lake Roosevelt Habitat Improvement Project (Phase I, baseline data collection: 1990-91) was focused on the assessment of limiting factors, including the quality and quantity of available spawning gravel, identification of passage barriers, and assessment of other constraints. After the initial assessment of stream parameters, five streams meeting specific criteria were selected for habitat/passage improvement projects (Phase II, implementation -1992-1995). Four of these projects were on the Colville Indian Reservation South Nanamkin, North Nanamkin, Louie and Iron Creeks and one Blue Creek was on the Spokane Indian Reservation. At the completion of project habitat improvements, the final phase (Phase III, monitoring-1996-2000) began. This phase assessed the changes and determined the success achieved through the improvements. Data analysis showed that passage improvements are successful for increasing habitat availability and use. The results of in-stream habitat improvements were inconclusive. Project streams, to the last monitoring date, have shown increases in fish density following implementation of the improvements. In 2000 Bridge Creek, on the Colville Reservation was selected for the next phase of improvements. Data collection, including baseline stream survey and population data collection, was carried out during 2001 in preparation for the design and implementation of stream habitat/passage improvements. Agencies cooperating on the project include the Colville Confederated Tribes (CCT), Natural Resource Conservation Service (NRCS, Ferry County District), Ferry County Conservation District, and Ferry County. The Bonneville Power Administration (BPA) provided

Sears, Sheryl

2003-01-01

177

Classifying sea lamprey marks on Great Lakes lake trout: observer agreement, evidence on healing times between classes and recommendations for reporting of marking statistics  

USGS Publications Warehouse

In 1997 and 1998 two workshops were held to evaluate how consistent observers were at classifying sea lamprey (Petromyzon marinus) marks on Great Lakes lake trout (Salvelinus namaycush) as described in the King classification system. Two trials were held at each workshop, with group discussion between trials. Variation in counting and classifying marks was considerable, such that reporting rates for A1-A3 marks varied two to three-fold among observers of the same lake trout. Observer variation was greater for classification of healing or healed marks than for fresh marks. The workshops highlighted, as causes for inconsistent mark classification, both departures from the accepted protocol for classifying marks by some agencies, and differences in how sliding and multiple marks were interpreted. Group discussions led to greater agreement in classifying marks. We recommend ways to improve the reliability of marking statistics, including the use of a dichotomous key to classify marks. Laboratory data show that healing times of marks on lake trout were much longer at 4A?C and 1A?C than at 10A?C and varied greatly among individuals. Reported A1-A3 and B1-B3 marks observed in late summer and fall collections likely result from a mixture of attacks by two year classes of sea lamprey. It is likely that a substantial but highly uncertain proportion of attacks that occur in late summer and fall lead to marks that are classified as A1-A3 the next spring. We recommend additional research on mark stage duration.

Ebener, Mark P.; Bence, James R.; Bergstedt, Roger A.; Mullet, Katherine M.

2003-01-01

178

Sample size requirements and analysis of tag recoveries for paired releases of lake trout  

USGS Publications Warehouse

A simple chi-square test can be used to analyze recoveries from a paired-release experiment to determine whether differential survival occurs between two groups of fish. The sample size required for analysis is a function of (1) the proportion of fish stocked, (2) the expected proportion at recovery, (3) the level of significance (a) at which the null hypothesis is tested, and (4) the power (1-I?) of the statistical test. Detection of a 20% change from a stocking ratio of 50:50 requires a sample of 172 (I?=0.10; 1-I?=0.80) to 459 (I?=0.01; 1-I?=0.95) fish. Pooling samples from replicate pairs is sometimes an appropriate way to increase statistical precision without increasing numbers stocked or sampling intensity. Summing over time is appropriate if catchability or survival of the two groups of fish does not change relative to each other through time. Twelve pairs of identical groups of yearling lake trout Salvelinus namaycush were marked with coded wire tags and stocked into Lake Ontario. Recoveries of fish at ages 2-8 showed differences of 1-14% from the initial stocking ratios. Mean tag recovery rates were 0.217%, 0.156%, 0.128%, 0.121%, 0.093%, 0.042%, and 0.016% for ages 2-8, respectively. At these rates, stocking 12,100-29,700 fish per group would yield samples of 172-459 fish at ages 2-8 combined.

Elrod, Joseph H.; Frank, Anthony

1990-01-01

179

Lake Roosevelt Volunteer Net Pens, Lake Roosevelt Rainbow Trout Net Pens, 2002-2003 Annual Report.  

SciTech Connect

The completion of Grand Coulee Dam for power production, flood control, and irrigation resulted in the creation of a blocked area above the dam and in the loss of anadromous fish. Because of lake level fluctuations required to meet the demands for water release or storage, native or indigenous fish were often threatened. For many years very little effort was given to stocking the waters above the dam. However, studies by fish biologists showed that there was a good food base capable of supporting rainbow and kokanee (Gangmark and Fulton 1949, Jagielo 1984, Scholz etal 1986, Peone etal 1990). Further studies indicated that artificial production might be a way of restoring or enhancing the fishery. In the 1980's volunteers experimented with net pens. The method involved putting fingerlings in net pens in the fall and rearing them into early summer before release. The result was an excellent harvest of healthy fish. The use of net pens to hold the fingerlings for approximately nine months appears to reduce predation and the possibility of entrainment during draw down and to relieve the hatcheries to open up available raceways for future production. The volunteer net pen program grew for a few years but raising funds to maintain the pens and purchase food became more and more difficult. In 1995 the volunteer net pen project (LRDA) was awarded a grant through the Northwest Power Planning Council's artificial production provisions.

Smith, Gene

2003-11-01

180

Lake Roosevelt Fisheries Evaluation Program; Evaluation of Limiting Factors for Stocked Kokanee and Rainbow Trout in Lake Roosevelt, Washington, 1999 Annual Report.  

SciTech Connect

Hatchery supplementation of kokanee Oncorhynchus nerka and rainbow trout O. mykiss has been the primary mitigation provided by Bonneville Power Administration for loss of anadromous fish to the waters above Grand Coulee Dam (GCD). The hatchery program for rainbow trout has consistently met management goals and provided a substantial contribution to the fishery; however, spawner returns and creel survey results for kokanee have been below management goals. Our objective was to identify factors that limit limnetic fish production in Lake Roosevelt by evaluating abiotic conditions, food limitations, piscivory, and entrainment. Dissolved oxygen concentration was adequate throughout most of the year; however, levels dropped to near 6 mg/L in late July. For kokanee, warm water temperatures during mid-late summer limited their nocturnal distribution to 80-100 m in the lower section of the reservoir. Kokanee spawner length was consistently several centimeters longer than in other Pacific Northwest systems, and the relative weights of rainbow trout and large kokanee were comparable to national averages. Large bodied daphnia (> 1.7 mm) were present in the zooplankton community during all seasons indicating that top down effects were not limiting secondary productivity. Walleye Stizostedion vitreum were the primary piscivore of salmonids in 1998 and 1999. Burbot Lota lota smallmouth bass Micropterus dolomieui, and northern pikeminnow Ptychocheilus oregonensis preyed on salmonids to a lesser degree. Age 3 and 4 walleye were responsible for the majority (65%) of the total walleye consumption of salmonids. Bioenergetics modeling indicated that reservoir wide consumption by walleye could account for a 31-39% loss of stocked kokanee but only 6-12% of rainbow trout. Size at release was the primary reason for differential mortality rates due to predation. Entrainment ranged from 2% to 16% of the monthly abundance estimates of limnetic fish, and could account for 30% of total mortality of limnetic fishes, depending on the contribution of littoral zone fishes. Inflow to GCD forebay showed the strongest negative relationship with entrainment whereas reservoir elevation and fish vertical distribution had no direct relationship with entrainment. Our results indicate that kokanee and rainbow trout in Lake Roosevelt were limited by top down impacts including predation and entrainment, whereas bottom up effects and abiotic conditions were not limiting.

Baldwin, Casey; Polacek, Matt

2009-03-01

181

Genetic and Phenotypic Catalog of Native Resident Trout of the interior Columbia River Basin : FY-2001 Report : Populations in the Wenatchee, Entiat, Lake Chelan and Methow River Drainages.  

SciTech Connect

The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat trout has been petitioned for listing under the U. S. Endangered Species Act (American Wildlands et al. 1997). Before at-risk populations can be protected, their presence and status must be established. Where introgression from introduced species is a concern, as in the case of both westslope cutthroat trout and redband rainbow trout, genetic issues must be addressed as well. As is true with native trout elsewhere in the western United States (Behnke 1992), most of the remaining pure populations of these species in the Columbia River Basin are in relatively remote headwater reaches. The objective of this project was to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique. FY-2001 was year three (and final year) of a project in which we conducted field visits to remote locations to seek out and catalog these populations. In FY-2001 we worked in collaboration with the Wenatchee National Forest to catalog populations in the Wenatchee, Entiat, Lake Chelan, and Methow River drainages of Washington State.

Trotter, Patrick C.

2001-10-01

182

Nearshore Habitat and Fish Community Associations of Coaster Brook Trout in Isle Royale, Lake Superior  

Microsoft Academic Search

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

Owen T. Gorman; Seth A. Moore; Andrew J. Carlson; Henry R. Quinlan

2008-01-01

183

Genotypic Characterization of an MHC Class II Locus in Lake Trout (Salvelinus namaycush) from Lake Superior by Single-Stranded Conformational Polymorphism Analysis and Reference Strand–Mediated Conformational Analysis  

Microsoft Academic Search

This study compares the genotypic information provided by reference strand–mediated conformational analysis and single-stranded confirmational polymorphism (SSCP) analysis for the major histocompatibility complex (MHC) II locus in lake trout. For this study 80 wild-caught animals from the Apostle Islands of Lake Superior were genotyped using both RSCA and SSCP analysis. Their genotypes were recorded using both methods and compared. The

Marc A. Noakes; Tara Reimer; Ruth B. Phillips

2003-01-01

184

Lake Roosevelt Rainbow Trout : Habitat\\/Passage Improvement Project Annual Report 1999  

Microsoft Academic Search

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of

Charles D

2000-01-01

185

Lake Roosevelt Rainbow Trout : Habitat\\/Passage Improvement Project : Annual Report 1998  

Microsoft Academic Search

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of

Charles D

1999-01-01

186

Lake Roosevelt Rainbow Trout : Habitat\\/Passage Improvement Project Annual Report 2000  

Microsoft Academic Search

Lake Franklin D. Roosevelt was created with the completion of the Grand Coulee Dam in 1942. The lake stretches 151 miles up-stream to the International border between the United States and Canada at the 49th parallel. Increased recreational use, subsistence and sport fishing has resulted in intense interest and possible exploitation of the resources within the lake. Previous studies of

Sear; Sheri

2001-01-01

187

The brown trout ( Salmo trutta ) in the lake, Øvre Heimdalsvatn: long-term changes in population dynamics due to exploitation and the invasive species, European minnow ( Phoxinus phoxinus )  

Microsoft Academic Search

Studies of the brown trout (Salmo trutta) population in the Norwegian subalpine lake, Øvre Heimdalsvatn, over a 50-year period have revealed major changes in population\\u000a dynamics. In 1958, the population density was high, with individuals stagnating in growth at lengths below 30 cm. After heavy\\u000a exploitation during the years 1958–1969, the number of older fish declined substantially, and growth rates increased

Reidar Borgstrøm; Jon Museth; John E. Brittain

2010-01-01

188

Radionuclides and heavy metals in rainbow trout from Tsichomo, Nana Ka, Wen Povi, and Pin De Lakes in Santa Clara Canyon  

Microsoft Academic Search

Radionuclide (³H, ⁹°Sr, ¹³⁷Cs, ²³⁸Pu, ²³⁹Pu, and total uranium) and heavy metal (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, and TI) concentrations were determined in rainbow trout collected from Tsichomo, Nana Ka, Wen Povi, and Pin De lakes in Santa Clara Canyon in 1997. Most radionuclide and heavy metal concentrations in fish collected from these four

P. R. Fresquez; D. R. Armstrong; L. Jr. Naranjo

1998-01-01

189

Variability of kokanee and rainbow trout food habits,distribution, and population dynamics, in an ultraoligotrophic lake with no manipulative management  

Microsoft Academic Search

Crater Lake is a unique environment to evaluate the ecology of introduced kokanee and rainbow trout because of its otherwise\\u000a pristine state, low productivity, absence of manipulative management, and lack of lotic systems for fish spawning. Between\\u000a 1986 and 2004, kokanee displayed a great deal of variation in population demographics with a pattern that reoccurred in about\\u000a 10 years. We believe

Mark W. Buktenica; Scott F. Girdner; Gary L. Larson; C. David McIntire

2007-01-01

190

DIAGNOSIS OF 20TH CENTURY LAKE ONTARIO LAKE TROUT POPULATION TRENDS IN A CONSTANTLY CHANGING, MULTI-STRESSOR ENVIRONMENT  

EPA Science Inventory

Early mortality syndrome (EMS) in Great Lakes salmonids is thought to reduce recruitment through a thiamine deficiency in embryos that is related to dietary input of thiaminase by the female. This may be complicated......

191

Census (N C) and genetically effective (N e) population size in a lake-resident population of brown trout Salmo trutta.  

PubMed

Census (N(C)) and effective population size (N(e)) were estimated for a lake-resident population of brown trout Salmo trutta as 576 and 63, respectively. The point estimate of the ratio of effective to census population size (N(e):N(C)) for this population is 0.11 with a range of 0.06-0.26, suggesting that N(e):N(C) ratio for lake-resident populations agree more with estimates for fishes with anadromous life histories than the small ratios observed in many marine fishes. PMID:22141907

Charlier, J; Palmé, A; Laikre, L; Andersson, J; Ryman, N

2011-11-01

192

Radionuclides and heavy metals in rainbow trout from Tsichomo, Nana Ka, Wen Povi, and Pin De Lakes in Santa Clara Canyon  

SciTech Connect

Radionuclide ({sup 3}H, {sup 90}Sr, {sup 137}Cs, {sup 238}Pu, {sup 239}Pu, and total uranium) and heavy metal (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, and TI) concentrations were determined in rainbow trout collected from Tsichomo, Nana Ka, Wen Povi, and Pin De lakes in Santa Clara Canyon in 1997. Most radionuclide and heavy metal concentrations in fish collected from these four lakes were within or just above upper limit background concentrations (Abiquiu reservoir), and as a group were statistically (p < 0.05) similar in most parameters to background.

Fresquez, P.R.; Armstrong, D.R.; Naranjo, L. Jr.

1998-04-01

193

Landscape influences on genetic differentiation among bull trout populations in a stream-lake network  

USGS Publications Warehouse

This study examined the influence of landscape heterogeneity on genetic differentiation between migratory bull trout (Salvelinus confluentus) populations in Glacier National Park, Montana. An information-theoretic approach was used to compare different conceptual models of dispersal associated with barriers, different models of isolation by distance, and the combined effects of barriers, waterway distance, patch size, and intra- and inter-drainage distribution of populations on genetic differentiation between bull trout populations. The effect of distance between populations on genetic differentiation was best explained by partitioning the effects of mainstem and tributary stream sections. Models that categorized barriers as having a one-way effect (i.e. allowed downstream dispersal) or a two-way effect were best supported. Additionally, patch size and the distribution of populations among drainages influenced genetic differentiation. Genetic differentiation between bull trout populations in Glacier National Park is linked to landscape features that restrict dispersal. However, this analysis illustrates that modelling variability within landscape features, such as dispersal corridors, will benefit landscape genetic analyses. Additionally, the framework used for evaluating the effects of barriers must consider not just barrier presence, but also potential asymmetries in barrier effects with respect to the organism under investigation.

Meeuwig, M. H.; Guy, C. S.; Kalinowski, S. T.; Fredenberg, W. A.

2010-01-01

194

Ecology, Evolution, and Conservation of Lake-Migratory Brook Trout: A Perspective from Pristine Populations  

Microsoft Academic Search

Reintroduction or rehabilitation plans for fish populations in many systems (e.g., lakes) are complicated by limited data on ecological and genetic characteristics before human disturbances occurred. While no two lakes have identical physical and biological characteristics, a growing body of empirical evidence nevertheless indicates that parallel patterns of population structuring may evolve within northern temperate fish species. Examining the population

Dylan J. Fraser; Louis Bernatchez

2008-01-01

195

Lake Michigan Mass Balance Study Post Audit: Integrated, Multi-media PCB Modeling and Forecasting for Lake Trout, Presentation  

EPA Science Inventory

The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

196

An Improved Method to Estimate Sea Lamprey Wounding Rate on Hosts with Application to Lake Trout in Lake Huron  

Microsoft Academic Search

To better estimate wounding rates on hosts of sea lamprey (Petromyzon marinus) in the Great Lakes, methods were developed to fit a logistic model for the mean number of wounds per host as a function of host length. These methods were applied to the number of wounds (the sum of type A-I to A-III marks on hosts collected in spring)

Michael A. Rutter; James R. Bence

2003-01-01

197

Genetic monitoring reveals temporal stability over 30 years in a small, lake-resident brown trout population  

PubMed Central

Knowledge of the degree of temporal stability of population genetic structure and composition is important for understanding microevolutionary processes and addressing issues of human impact of natural populations. We know little about how representative single samples in time are to reflect population genetic constitution, and we explore the temporal genetic variability patterns over a 30-year period of annual sampling of a lake-resident brown trout (Salmo trutta) population, covering 37 consecutive cohorts and five generations. Levels of variation remain largely stable over this period, with no indication of substructuring within the lake. We detect genetic drift, however, and the genetically effective population size (Ne) was assessed from allele-frequency shifts between consecutive cohorts using an unbiased estimator that accounts for the effect of overlapping generation. The overall mean Ne is estimated as 74. We find indications that Ne varies over time, but there is no obvious temporal trend. We also estimated Ne using a one-sample approach based on linkage disequilibrium (LD) that does not account for the effect of overlapping generations. Combining one-sample estimates for all years gives an Ne estimate of 76. This similarity between estimates may be coincidental or reflecting a general robustness of the LD approach to violations of the discrete generations assumption. In contrast to the observed genetic stability, body size and catch per effort have increased over the study period. Estimates of annual effective number of breeders (Nb) correlated with catch per effort, suggesting that genetic monitoring can be used for detecting fluctuations in abundance.

Charlier, J; Laikre, L; Ryman, N

2012-01-01

198

Genetic monitoring reveals temporal stability over 30 years in a small, lake-resident brown trout population.  

PubMed

Knowledge of the degree of temporal stability of population genetic structure and composition is important for understanding microevolutionary processes and addressing issues of human impact of natural populations. We know little about how representative single samples in time are to reflect population genetic constitution, and we explore the temporal genetic variability patterns over a 30-year period of annual sampling of a lake-resident brown trout (Salmo trutta) population, covering 37 consecutive cohorts and five generations. Levels of variation remain largely stable over this period, with no indication of substructuring within the lake. We detect genetic drift, however, and the genetically effective population size (N(e)) was assessed from allele-frequency shifts between consecutive cohorts using an unbiased estimator that accounts for the effect of overlapping generation. The overall mean N(e) is estimated as 74. We find indications that N(e) varies over time, but there is no obvious temporal trend. We also estimated N(e) using a one-sample approach based on linkage disequilibrium (LD) that does not account for the effect of overlapping generations. Combining one-sample estimates for all years gives an N(e) estimate of 76. This similarity between estimates may be coincidental or reflecting a general robustness of the LD approach to violations of the discrete generations assumption. In contrast to the observed genetic stability, body size and catch per effort have increased over the study period. Estimates of annual effective number of breeders (N(b)) correlated with catch per effort, suggesting that genetic monitoring can be used for detecting fluctuations in abundance. PMID:22828900

Charlier, J; Laikre, L; Ryman, N

2012-07-25

199

Introgression of domesticated alleles into a wild trout genotype and the impact on seasonal survival in natural lakes  

PubMed Central

We tested the fitness consequences of introgression of fast-growing domesticated fish into a wild population. Fry from wild and domesticated rainbow trout (Oncorhynchus mykiss) crosses, F1 hybrids, and first- and second-generation backcrosses were released into two natural lakes. Parentage analysis using microsatellite loci facilitated the identification of survivors, so fitness was estimated in nature from the first-feeding stage. Results indicated that under certain conditions, domesticated fish survived at least as well as wild fish within the same environment. Relative growth and survival of the crosses, however, were highly dependent on environment. During the first summer, fastest-growing crosses had the highest survival, but this trend was reversed after one winter and another summer. Although the F1 hybrids showed evidence of outbreeding depression because of the disruption of local adaptation, there was little evidence of outbreeding depression in the backcrosses, and the second-generation backcrosses exhibited a wild-type phenotype. This information is relevant for assessing the multigenerational risk of escaped or released domesticated fish should they successfully interbreed with wild populations and provides information on how to minimize detrimental impacts of a conservation breeding and/or management programme. These data also further understanding of the selection pressures in nature that maintain submaximal rates of growth.

Vandersteen, Wendy; Biro, Pete; Harris, Les; Devlin, Robert

2012-01-01

200

The relative contribution of drift and selection to transcriptional divergence among Babine Lake tributary populations of juvenile rainbow trout.  

PubMed

Fine-scale population structure has been widely described for salmonid populations using neutral genetic markers, but whether that structure reflects adaptive differences among the populations remains of interest to evolutionary biologists and conservation managers alike. The use of transcriptomics to quantify population differences in genetically controlled functional gene expression traits holds promise for investigating this divergence associated with possible local adaptation. We use custom microarrays to characterize population divergence in transcription at functionally relevant (metabolic and immune function) genes among tributary populations of rainbow trout from Babine Lake, BC and compare it to neutral divergence estimated from microsatellite markers. Transcriptional divergence (PST ) was determined at resting state and in response to metabolic and immune challenges, two major sources of mortality and thus selective forces on juvenile salmonids. Results indicate that the majority of selected genes [56 genes (65%), 64 genes (63%) and 38 genes (78%) under control, temperature and immune challenges respectively] show transcriptional divergence (PST  > FST ) that is consistent with the action of divergent selection. Patterns of pairwise PST among populations are inconsistent with evolution by drift. In general, it appears that the magnitude and pattern of population divergence in transcription reflect the action of natural selection and identify selection on transcription as a mechanism for local adaptation. These results reinforce the need to conserve salmonids on a tributary basis and provide insight into genetic mechanisms that facilitate local adaptation. PMID:24118678

Wellband, K W; Heath, D D

2013-10-01

201

Concentrations of mercury and other trace elements in walleye, smallmouth bass, and rainbow trout in Franklin D. Roosevelt Lake and the upper Columbia River, Washington, 1994  

USGS Publications Warehouse

Three species of sportfish--walleye, smallmouth bass, and rainbow trout--were collected from Franklin D. Roosevelt Lake and the upstream reach of the Columbia River within the state of Washington, to determine the concentrations of mercury and other selected trace elements in fish tissue. Concentrations of total mercury in walleye fillets ranged from 0.11 to 0.44 milligram per kilogram, with the higher concentrations in the larger fish. Fillets of smallmouth bass and rainbow trout also contained mercury, but generally at lower concentrations. Other selected trace elements were found in fillet samples, but the concentrations were generally low depending on species and the specific trace element. The trace elements cadmium, copper, lead, and zinc were found in liver tissue of these same species with zinc consistently present in the highest concentration.

Munn, M. D.; Cox, S. E.; Dean, C. J.

1995-01-01

202

Mixed-function oxidase enzyme activity and oxidative stress in lake trout (Salvelinus namaycush) exposed to 3,3â²,4,4â²5-pentachlorobiphenyl (PCB126)  

Microsoft Academic Search

Juvenile lake trout were intraperitoneally injected with corn oil containing nominal concentrations of 0, 0.6, 6.3, or 25 μg [¹⁴C]-3,3â²,4,4â²,5-pentachlorobiphenyl (PCB-126) per gram of body weight. The PCB-126 accumulated in liver in a dose-dependent manner to a sustained concentration by 6 weeks and remained elevated for the 30-week experimental period. Mixed-function oxidase (MFO) enzyme activity was elevated in the two

Vince P. Palace; Jack F. Klaverkamp; W. Lyle Lockhart; Don A. Metner; Derek C. G. Muir; Scott B. Brown

1996-01-01

203

Evolutionary Ecology of Redband Trout  

Microsoft Academic Search

We examined genetic differences at 29 enzyme encoding loci among 10,541 rainbow trout Oncorhynchus mykiss from 240 collections throughout the species' range, including redband trout (i.e., several rainbow trout subspecies) in pluvial lake basins of the northern Great Basin that have had largely internal drainage with no connection to the Pacific Ocean. Differences among groups accounted for 29.2% of the

Kenneth P. Currens; Carl B. Schreck; Hiram W. Li

2009-01-01

204

Environmental associations with gene transcription in Babine Lake rainbow trout: evidence for local adaptation  

PubMed Central

The molecular genetic mechanisms facilitating local adaptation in salmonids continue to be poorly characterized. Gene transcription is a highly regulated step in the expression of a phenotype and it has been shown to respond to selection and thus may be one mechanism that facilitates the development of local adaptation. Advances in molecular genetic tools and an increased understanding of the functional roles of specific genes allow us to test hypotheses concerning the role of variable environments in shaping transcription at known-function candidate loci. To address these hypotheses, wild rainbow trout were collected in their first summer and subjected to metabolic and immune challenges. We assayed gene transcription at candidate loci that play a role in the molecular genetic response to these stresses, and correlated transcription with temperature data from the streams and the abundance and diversity of bacteria as characterized by massively parallel pyrosequencing. Patterns of transcriptional regulation from resting to induced levels varied among populations for both treatments. Co-inertia analysis demonstrated significant associations between resting levels of metabolic gene transcription and thermal regime (R2 = 0.19, P = 0.013) as well as in response to challenge (R2 = 0.39, P = 0.001) and resting state and challenged levels of cytokine gene transcription with relative abundances of bacteria (resting: R2 = 0.25, P = 0.009, challenged: R2 = 0.65, P = 0.001). These results show that variable environments, even within a small geographic range (<250 km), can drive divergent selection among populations for transcription of genes related to surviving stress.

Wellband, Kyle W; Heath, Daniel D

2013-01-01

205

Some bioaccumulation factors and biota-sediment accumulation factors for polycyclic aromatic hydrocarbons in Lake Trout  

SciTech Connect

Bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/triphenylene were calculated using the tissue data of Zabik et al. for Salvelinus namaycush siscowet with a 20.5% lipid content, the water data of Baker and Eisenreich, and the sediment data of Baker and Eisenreich for the Lake Superior ecosystem. Log BAFs, both lipid normalized and based on the freely dissolved concentration of the chemical in the water, of 1.95, 3.22, 4.72, 4.73, and 3.61 were calculated for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/triphenylene, respectively. The BSAFs for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/tripenylene were 0.00011, 0.00016, 0.0071, 0.0054, and 0.00033, respectively.

Burkhard, L.P.; Lukasewycz, M.T.

2000-05-01

206

Genotypic characterization of an MHC class II locus in lake trout ( Salvelinus namaycush) from Lake Superior by single-stranded conformational polymorphism analysis and reference strand-mediated conformational analysis.  

PubMed

This study compares the genotypic information provided by reference strand-mediated conformational analysis and single-stranded confirmational polymorphism (SSCP) analysis for the major histocompatibility complex (MHC) II locus in lake trout. For this study 80 wild-caught animals from the Apostle Islands of Lake Superior were genotyped using both RSCA and SSCP analysis. Their genotypes were recorded using both methods and compared. The genotypic information provided by the 2 methods was essentially the same although some inconsistencies were observed. Both methods detected approximately 65 genotypes, and both were able to distinguish heterozygous and homozygous animals. The analyses determined that only approximately 20% of alleles were shared between 2 morphologically different populations within the sample set, and identified the dominant alleles. SSCP analysis was quicker, simple, and more robust than RSCA. SSCP analysis using fluorescence technologies could be the method of choice for future genotypic analysis of the MHC II locus in salmonids. PMID:14502399

Noakes, Marc A; Reimer, Tara; Phillips, Ruth B

207

77 FR 33230 - Notice of Intent To Prepare an Environmental Impact Statement for Proposed Strategies for Lake...  

Federal Register 2010, 2011, 2012, 2013

...during the scoping process may include, but not be limited to: Biological resources (lake trout, bull trout, westslope cutthroat trout, lake whitefish, pygmy whitefish, yellow perch, and invertebrates including Mysis shrimp),...

2012-06-05

208

Lean production  

Microsoft Academic Search

“Lean production”, or rather “lean management”, is an intellectual approach consisting of a system of measures and methods which when taken all together have the potential to bring about a lean and therefore particularly competitive state in a company. The main fields of activity concerned are product development, the chain of supply, shop floor management and to a lesser extent

H. J. Warnecke; M. Hüser

1995-01-01

209

Mixed-function oxidase enzyme activity and oxidative stress in lake trout (Salvelinus namaycush) exposed to 3,3{prime},4,4{prime}5-pentachlorobiphenyl (PCB-126)  

SciTech Connect

Juvenile lake trout were intraperitoneally injected with corn oil containing nominal concentrations of 0, 0.6, 6.3, or 25 {micro}g [{sup 14}C]-3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB-126) per gram of body weight. The PCB-126 accumulated in liver in a dose-dependent manner to a sustained concentration by 6 weeks and remained elevated for the 30-week experimental period. Mixed-function oxidase (MFO) enzyme activity was elevated in the two highest dose groups relative to the control group, but not in the low-dose group throughout the 30 weeks. Oxidative stress, measured by the thiobarbituric acid reactive substances test, was correlated with ethoxyresorufin O-deethylase and was elevated in liver of the two highest PCB dose groups but not the low-dose group. The activities of the enzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB-126 exposure. The nonenzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB-126 exposure. The nonenzymatic antioxidant tocopherol was depleted to approximately 75% of the control concentration in liver of all three PCB-dosed groups. Hepatic ascorbic acid levels were not different in any of the treatment groups. Retinol was depleted by greater than an order of magnitude in liver of the two highest dose groups but not in the los-dose group. This study demonstrates a correlation between hepatic MFO activity and oxidative stress in PCB-exposed lake trout. Tocopherol and retinol may be important mediators of oxidative stress but additional study is required to confirm the antioxidant activity of retinol.

Palace, V.P. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Zoology; Klaverkamp, J.F.; Lockhart, W.L. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Zoology]|[Department of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.; Metner, D.A.; Muir, D.C.G.; Brown, S.B. [Department of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.

1996-06-01

210

Open-Water Movements of the Cutthroat Trout (Salmo Clarki) in Yellowstone Lake after Displacement from Spawning Streams.  

National Technical Information Service (NTIS)

Cutthroat trout were taken from their spawning streams (June-August 1964 and 1965). A Styrofoam float was attached and fish were tracked from two release points. They moved generally shoreward (eastward). Of 120 fish tracked when the sun was visible, 68% ...

L. A. Jahn

1966-01-01

211

Food Intake and Feed Conversion Ratios in Abant Trout (Salmo trutta abanticus T., 1954) and Rainbow Trout (Oncorhynchus mykiss W., 1792) in Pond Culture  

Microsoft Academic Search

This study was carried out at DSI-Gölköy Fish Production Station in Bolu and lasted for 350 days. Food consumption (FC) and feed conversion ratios (FCR) in Abant and rainbow trout in pond culture were compared. Abant trout larvae obtained from eggs of wild Abant trout broodstocks in Lake Abant and rainbow trout larvae obtained from eggs of the cultured broodstocks

Atilla ALPBAZ

212

Management of Lake Taneycomo, Missouri. Job 2: Problem Identification.  

National Technical Information Service (NTIS)

Lake Taneycomo, a 766-ha reservoir, receives hypolimnetic water from an upstream impoundment, Table Rock Lake, and has supported a rainbow trout (Oncorhynchus mykiss) fishery since 1958. Recently, the number of large rainbow trout in this fishery has decl...

M. Kruse

1999-01-01

213

Low levels of aluminium causing death of brown trout (salmo trutta fario, L.) in a Swiss alpine lake  

Microsoft Academic Search

Several attempts to stock fish in acidified alpine lakes have so far proven unsuccessful. In an effort to investigate the problems associated with the stocking of fish, the Swiss alpine Lake Laiozza was chosen for experimentation. An analysis of Lake Laiozza water revealed low ion concentrations (0.5 mg Ca\\/L, 0.13 mg Na\\/L, 0.02 mg Cl\\/L), moderate aluminium concentrations (121 ±

Daniel Dietrichl; Ch. Schlatter

1989-01-01

214

Changes in the diet of lake trout (Salvelinus namaycush) in near-shore Lake Michigan with the invasion of the Round Goby (Neogobius melanostomus): 1995-2005  

Microsoft Academic Search

The predator-prey base of the Great Lakes has been altered since the early 1900's, with the majority of these changes occurring due to invasive species such as the sea lamprey (Petromyzon marin us), alewife (A los a pseudoharangus ), and rainbow smelt (Osmerus mordax). These changes have forced large piscivorous fish to find alternate prey species. One predator, the lake

Marybeth K. Brey

2006-01-01

215

Ulcer disease of trout  

USGS Publications Warehouse

During the summer of 1933, lesions of a disease were noted among some fingerling brook, rainbow, blackspotted, and lake trout at the Cortland (New York) trout hatchery. Although these lesions bore a marked superficial resemblance to those of furunculosis, they were sufficiently atypical to warrant further investigation. A more detailed examination of the lesions proved them to be of a distinct disease, which for lack of a better name is herein called "ulcer disease," for the lesions closely resemble those described by Calkins (1899) under this name. Because of the marked resemblance to furunculosis, ulcer disease has not been generally recognized by trout culturists, and any ulcer appearing on fish has been ascribed by them to furunculosis without further question.

Fish, F. F.

1934-01-01

216

Prairie Pothole Ecology and the Feasibility of Growing Rainbow Trout (Salmo Gairdneri Richardson) in Prairie Potholes.  

National Technical Information Service (NTIS)

Commercial rainbow trout production is not feasible in four North Dakota pothole lakes studied, although trout growth did reach commercial size in one season. Mortality was due to a combination of factors: Initial stocking mortality, diurnal dissolved oxy...

G. L. Myers

1973-01-01

217

Phylogenetic status of brown trout Salmo trutta populations in five rivers from the southern Caspian Sea and two inland lake basins, Iran: a morphogenetic approach.  

PubMed

Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes. PMID:23020557

Hashemzadeh Segherloo, I; Farahmand, H; Abdoli, A; Bernatchez, L; Primmer, C R; Swatdipong, A; Karami, M; Khalili, B

2012-10-01

218

Wisconsin's 1996 open water sportfishing effort and catch from Lake Michigan and Green Bay  

Microsoft Academic Search

This paper documents the sport fishery in Wisconsin waters of Lake Michigan and Green Bay in 1996. Unlike naturally reproducing species such as yellow perch and smallmouth bass the salmonid sport fishery was sustained through the continued stocking of rainbow trout ( Oncorhynchus mykiss), lake trout (Salvelinus namaycush), brook trout (S. fontinalis), brown trout (Salmo trutta), coho salmon (O. kisutch),

Bradley T. Eggold

1996-01-01

219

Round Goby and Mottled Sculpin Predation on Lake Trout Eggs and Fry: Field Predictions from Laboratory Experiments  

Microsoft Academic Search

The accidental introduction of round gobies (Neogobius melanostomus) into the North American Great Lakes has raised concerns about their potential impacts on local fauna. Gobies have similar habitat and spawning requirements to mottled sculpins (Cottus bairdi) and slimy sculpins (C. cognatus), and may already be displacing sculpins where the ranges of the species overlap. Like sculpins, gobies are capable of

Michael A. Chotkowski; J. Ellen Marsden

1999-01-01

220

Measuring groundwater surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA  

Microsoft Academic Search

Measurements of groundwater surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes Water, Energy and Biogeochemical Budgets (NTL WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) site. Large upward

Randall J. Hunt; Mac Strand; John F. Walker

2006-01-01

221

Near-field loading dynamics of total phosphorus and short-term water quality variations at a rainbow trout cage farm in Lake Huron.  

PubMed

Aquatic total phosphorus (Tot-P) is measured at fish-cages in Lake Huron for environmental regulatory compliance. An improved understanding of how Tot-P is manifested in the near-field (trout (Oncorhynchus mykiss) cage-farm in the North Channel of Lake Huron was intensively sampled for six multi-day periods of differing environmental and fish production scenarios. Current profiles were measured by acoustical Doppler current profilers for five periods, and multi-probes continuously measured temperature, pH and dissolved oxygen, at the farm centre and 30 m north/south for two sampling periods. Near-field Tot-P data was non-normally distributed. Differences between parametric and non-parametric measures were minor. Phosphorus depth profiles appeared to be influenced by the locations of cages, manure collectors and the lake bottom. Near-field lateral Tot-P concentrations were elevated above background only in down-current locations except during one period of high production and slow current velocity; suggesting adequately flushed cages will have background concentrations at up-current locations. Variation of DO, pH and Tot-P and the correlations among these parameters, increased from the up-current, down-current and the site centre locations, respectively. These relationships suggest some limited utility for the use multi-probes deployed around fish cages to determine nutrient flow direction, thereby inferring short-term trends of Tot-P concentrations adjacent to the farm. Implications for present monitoring practices are discussed. PMID:16951755

Reid, Gregor K; McMillan, Ian; Moccia, Richard D

2006-06-13

222

Measuring groundwater–surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA  

Microsoft Academic Search

Measurements of groundwater–surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes–Water, Energy and Biogeochemical Budgets (NTL–WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) site. Large upward vertical gradients at

Randall J. Hunt; Mac Strand; John F. Walker

2006-01-01

223

An Attempt to Rehabilitate a Collapsed Brook Trout Population by Introducing F1 Splake to Control Yellow Perch  

Microsoft Academic Search

Historically, brook trout Salvelinus fontinalis provided an outstanding sport fishery and lived sympatrically with yellow perch Perca flavescens in East Lake, a 30-ha water body in central Ontario. The fishery collapsed when lake access was improved and cottages were built around the shore in the early 1960s. Annual stocking of brook trout did not improve the brook trout fishery. During

Charles R. Rumsey Retired; Nicholas E. Jones; Hugh H. Banks

2007-01-01

224

Potency of 3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB 126), alone and in combination with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), to produce lake trout early life-stage mortality  

SciTech Connect

Newly fertilized lake trout (Salvelinus namaycush) eggs were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB 126), or their combination, and sac fry mortality was used to determine toxic potencies. The toxic equivalency factor (TEF) for PCB 126 was 0.0030. The dose-response curve for the PCB 126/TCDD mixture based on TCDD toxic equivalents was not significantly different from that for TCDD alone, suggesting additivity between the two congeners in causing sac fry mortality.

Zabel, E.W.; Peterson, R.E. [Univ. of Wisconsin, Madison, WI (United States); Cook, P.M. [Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.

1995-12-01

225

Genetic and Phenotypic Catalog of Native Resident Trout of the interior Columbia River Basin : FY2001 Report : Populations in the Wenatchee, Entiat, Lake Chelan and Methow River Drainages  

Microsoft Academic Search

The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat

Trotter; Patrick C

2001-01-01

226

Lean manufacturing: a perspective of lean suppliers  

Microsoft Academic Search

The main thrust of this paper empirically examines the connection between lean production and various aspects of the logistics system. This paper performs a comparison analysis to find whether significant performance\\/practice differences exist between lean suppliers and non-lean suppliers. The research findings indicate that, even given the same organizational constraints and resources, lean suppliers gain significant competitive advantages over non-lean

Yen Chun Wu

2003-01-01

227

Failure of Total Body Electrical Conductivity to Predict Lipid Content of Brook Trout  

Microsoft Academic Search

We found that a noninvasive procedure that used total body electrical conductivity (TOBEC) failed to estimate lean mass and whole body lipid content of brook trout Salvelinus fontinalis. We explored two approaches using TOBEC, the inverse-regression approach, in which lipid mass is predicted from the relationship between TOBEC, and lean mass and the multiple-regression approach, in which lipid is predicted

Douglas C. Novinger; Carlos Martinez Del Rio

1999-01-01

228

Ninespine Stickleback Abundance in Lake Michigan Increases After Dreissenid Mussel Invasion  

USGS Publications Warehouse

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

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

2010-01-01

229

DEVELOPMENT OF A CARBON-BASED PHYTOPLANKTON MODEL FOR LAKE MICHIGAN AS PART OF A SEQUENCE OF MODELS USED IN THE LAKE MICHIGAN MASS BALANCE PROJECT  

EPA Science Inventory

Different from earlier Great Lakes models, our objective is to link autochthonous carbon production to the toxic chemical concentration within the lake and ultimately to components of the foodchain, such as Lake Trout and Coho Salmon....

230

The Sea Lamprey in the Great Lakes  

Microsoft Academic Search

The sea lamprey was inadvertently introduced above Niagara Falls by the development of the Welland Canal between Lakes Ontario and Erie. A major population did not develop in Lake Erie but the species rapidly established itself as a highly significant predator in all three upper lakes. Its most obvious effect was the virtual extermination of the lake trout which had

A. H. Lawrie

1970-01-01

231

Habitat use and life history of brown trout (Salmo trutta) and Arctic charr (Salvelinus alpinus) in some low acidity lakes in central Norway  

Microsoft Academic Search

Habitat utilization and the life history of browntrout Salmo trutta and Arctic charr Salvelinus alpinus were investigated in fivesympatric populations and five allopatric brown troutpopulations in Høylandet catchment, a atmosphaericlow deposition area in Mid Norway. There was asignificant inverse correlation in abundance ofepibenthic Arctic charr and brown trout in theselakes, indicating that the latter species is dominant.The largest numbers of

Trygve Hesthagen; Bror Jonsson; Ola Ugedal; Torbjørn Forseth

1997-01-01

232

Genetic Structure of Columbia River Redband Trout Populations in the Kootenai River Drainage, Montana, Revealed by Microsatellite and Allozyme Loci  

Microsoft Academic Search

We describe the genetic divergence among 10 populations of redband trout Oncorhynchus mykiss gairdneri from the upper Columbia River drainage. Resident redband trout from two watersheds in the Kootenai River drainage and hatchery stocks of migratory Kamloops redband trout from Kootenay Lake, British Columbia, were analyzed using allele frequency data from microsatellite and allozyme loci. The Kamloops populations have significantly

Kathy L. Knudsen; Clint C. Muhlfeld; George K. Sage; Robb F. Leary

2002-01-01

233

Genetic Structure of Columbia River Redband Trout Populations in the Kootenai River Drainage, Montana, Revealed by Microsatellite and Allozyme Loci  

Microsoft Academic Search

We describe the genetic divergence among 10 populations of redband trout Onco­ rhynchus mykiss gairdneri from the upper Columbia River drainage. Resident redband trout from two watersheds in the Kootenai River drainage and hatchery stocks of migratory Kamloops redband trout from Kootenay Lake, British Columbia, were analyzed using allele frequency data from microsatellite and allozyme loci. The Kamloops populations have

Kathy L. Knudsen; Clint C. Muhlfeld; George K. Sage; Robb F. Leary

2002-01-01

234

Bull Trout Distribution and Abundance in the Waters on and Bordering the Warm Springs Reservation : 2002 Annual Report  

Microsoft Academic Search

The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be healthy in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et

Christopher V. Brun; Rebekah Dodson

2003-01-01

235

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2001  

Microsoft Academic Search

Bull trout Salvelinus confluentus exhibit a number of life history strategies. Stream-resident bull trout complete their life cycle in their natal tributaries. Migratory bull trout spawn in tributary streams where juvenile fish usually spend from one to four years before migrating to either a larger river (fluvial) or lake (adfluvial) where they rear before returning to the tributary stream to

Alan R. Hemmingsen; Stephanie L. Gunckel; Paul M. Sankovich; Philip J. Howell

2002-01-01

236

Bull Trout Distribution and Abundance in the Waters on and Bordering the Warm Springs Indian Reservation, 2000 Annual Report  

Microsoft Academic Search

The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be stable in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et

Brun

2000-01-01

237

Bull Trout Distribution and Abundance in the Waters on and Bordering the Warm Springs Indian Reservation, 2001 Annual Report  

Microsoft Academic Search

The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be stable in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et

Brun; Christopher V

2002-01-01

238

Hybridization and Introgression in a Managed, Native Population of Yellowstone Cutthroat Trout: Genetic Detection and Management Implications  

Microsoft Academic Search

Since the mid-1920s, the Idaho Department of Fish and Game has cultured Yellowstone cutthroat trout Oncorhynchus clarki bouvieri at Henrys Lake to offset declines in natural production and for use in stocking programs throughout Idaho. Since the mid-1970s, they have also produced F1 hybrids: female Yellowstone cutthroat trout × male rainbow trout O. mykiss. The ability of fishery managers, when

Matthew R. Campbell; Jeff Dillon; Madison S. Powell

2002-01-01

239

Lean and Chemicals Toolkit.  

National Technical Information Service (NTIS)

This Lean and Chemicals Toolkit describes practical strategies for using Lean manufacturingthe production system developed by Toyotato reduce chemical wastes while improving the operational and environmental performance of manufacturing and industrial bus...

2009-01-01

240

Lean blowoff detection sensor  

DOEpatents

Apparatus and method for detecting incipient lean blowoff conditions in a lean premixed combustion nozzle of a gas turbine. A sensor near the flame detects the concentration of hydrocarbon ions and/or electrons produced by combustion and the concentration monitored as a function of time are used to indicate incipient lean blowoff conditions.

Thornton, Jimmy (Morgantown, WV); Straub, Douglas L. (Morgantown, WV); Chorpening, Benjamin T. (Morgantown, WV); Huckaby, David (Morgantown, WV)

2007-04-03

241

LEAN LEADERSHIP IN CONSTRUCTION  

Microsoft Academic Search

Lean leadership is the missing link between theoretical solutions and application in practice. This is the difference between superficial attempts at implementing Lean, where the tools and techniques are evident, but the behaviors haven't changed, and the results are disappointing or not sustained beyond a few brief weeks of enthusiasm. The key to understanding how to implement Lean successfully is

Cameron Orr

242

Changes in Wisconsin's Lake Michigan salmonid sport fishery, 1969-1985  

USGS Publications Warehouse

The modern sport fishery for salmonids in Wisconsin waters of Lake Michigan was begun during 1963-1969 with the stocking of rainbow trout (Oncorhynchus mykiss), lake trout (Salvelinus namaycush), brook trout (S. fontinalis), brown trout (Salmo trutta), coho salmon (O. kisutch), and chinook salmon (O. tshawytscha). The fishery grew rapidly during 1969-1985 as angler effort increased 10-fold, catch rate doubled, and catch increased 20-fold. The stocking and catch became increasingly dominated by chinook salmon, with coho salmon and lake trout of secondary importance and brown, rainbow, and brook trout of least importance. Trolling dominated the fishery, particularly by launched-boat anglers and, more recently, by moored-boat anglers. Charter boat trolling grew the most continuously and had the highest catch rates. The catch by trollers was dominated by chinook and coho salmon and lake trout. Pier, stream, and shore anglers fished less overall, but had catch rates that were similar to launched-boat anglers. The catch by pier and shore anglers was spread among chinook and coho salmon, and lake, brown and rainbow trout. The catch by stream anglers was dominated by chinook salmon. The percentage of stocked fish that were subsequently caught (catch ratio) was highest for fingerling chinook salmon (12.9%). Yearling brook trout, brown trout, coho salmon, lake trout, and rainbow trout had intermediate catch ratios (5.1-9.8%). Fingerling brook trout, brown trout, and lake trout had the lowest catch ratios (2.5-3.5%). The catch ratio for rainbow trout dropped from 9.8 to 5.1% after stocking with a different strain (the Shasta strain). Fingerling rainbow trout produced the lowest returns (<0.5%). We derived stocking recommendations for each species and life stage based on these catch ratios, and catch objectives based on maintaining catch levels recorded during 1983-1985.

Hansen, Michael J.; Schultz, Paul T.; Lasee, Becky A.

1990-01-01

243

Changes in Wisconsin's Lake Michigan Salmonid Sport Fishery, 1969-1985  

Microsoft Academic Search

The modern sport fishery for salmonids in Wisconsin waters of Lake Michigan was begun during 1963–1969 with the stocking of rainbow trout Oncorhynchus mykiss, lake trout Salvelinus namaycush, brook trout S. fontinalis, brown trout Salmo trutta, coho salmon O. kisutch, and chinook salmon O. tshawytscha. The fishery grew rapidly during 1969-1985 as angler effort increased 10-fold, catch rate doubled, and

Michael J. Hansen; Paul T. Schultz; Becky A. Lasee

1990-01-01

244

77 FR 38043 - Great Lakes Hydro America, LLC; Notice of Application Accepted for Filing and Soliciting Comments...  

Federal Register 2010, 2011, 2012, 2013

...Request: Great Lakes Hydro America...eliminate the water level management...reservoir levels in compliance...reservoir level requirements for lake trout would...fishery. Great Lakes Hydro...modification to its Water Quality...

2012-06-26

245

Water Quality (2000-08) and Historical Phosphorus Concentrations from Palelimnological Studies of Swamp and Speckled Trout Lakes, Grand Portage Reservation, Northeastern Minnesota.  

National Technical Information Service (NTIS)

A paleolimnological approach was taken to aid the Grand Portage Reservation, in northeastern Minnesota, in determining reference conditions for lakes on the reservation. The U.S. Geological Survey, in cooperation with the Grand Portage Band of Chippewa In...

J. M. Ramstack M. B. Edlund P. M. Jones V. G. Christensen

2006-01-01

246

Seasonal Patterns in Growth, Blood Consumption, and Effects on Hosts by Parasitic-Phase Sea Lampreys in the Great Lakes: An Individual-Based Model Approach  

Microsoft Academic Search

An individual-based model (IBM) was developed for sea lamprey (Petromyzon marinus) populations in the Laurentian Great Lakes. The IBM was then calibrated to observed growth, by season, for sea lampreys in northern Lake Huron under two different water temperature regimes: a regime experienced by Seneca-strain lake trout (Salvelinus namaycush) and a regime experienced by Marquettestrain lake trout. Modeling results indicated

Charles P. Madenjian; Philip A. Cochran; Roger A. Bergstedt

2003-01-01

247

Effects of Temperature and Density on Consumption of Trout Eggs by Orconectes propinquus and O. rusticus  

Microsoft Academic Search

Using laboratory experiments, we assessed the effect of temperature and predator density on consumption of trout eggs by crayfish. We quantified the effect of four temperature ranges (2–3, 4–5, 7–8, and 10–12°C) on consumption of lake trout (Salvelinus namaycush) and rainbow trout (Oncorhynchus mykiss) eggs by a native (Orconectes propinquus) and an exotic (Orconectes rusticus) crayfish found in the Great

Brian J. Ellrott; J. Ellen Marsden; John D. Fitzsimons; Jory L. Jonas; Randall M. Claramunt

2007-01-01

248

Population dynamics of daphnia pulex and utilization by the rainbow trout (salmo gairdneri)  

Microsoft Academic Search

The effect of rainbow trout (Salmo gairdneri) predation on the population dynamics of the water flea,Daphnia pulex, was examined during 1976 and 1977 in Becker Lake, a small, shallow, productive reservoir in northeastern Arizona.\\u000a \\u000a \\u000a Rainbow trout were size-biased feeders, utilizing daphnids which were 1.3 mm in size or larger. Trout predation uponDaphnia pulex occurred mainly during winter and early spring

William W. Taylor; Shelby D. Gerking

1980-01-01

249

Lake Michigan Steelhead Fisheries Management Plan, 1999.  

National Technical Information Service (NTIS)

Wisconsin began its Lake Michigan rainbow/steelhead trout fishery in 1963 when rainbow trout were stocked in a Door County stream. During the years following the original stocking, many changes in the fishery have occurred, including changes in the strain...

T. Burzynski

1999-01-01

250

Genetic diversity of infectious hematopoietic necrosis virus from Feather River and Lake Oroville, California, and virulence of selected isolates for Chinook salmon and rainbow trout.  

PubMed

Infectious hematopoietic necrosis virus (IHNV) is a significant pathogen of young salmonid fishes worldwide but particularly within the historical range of the Pacific Northwest and California. In the Sacramento and San Joaquin River drainages of California, IHNV outbreaks in juvenile Chinook salmon Oncorhynchus tshawytscha have been observed regularly at large production hatcheries, including Coleman National Fish Hatchery (established in 1941) and Feather River State Fish Hatchery (FRH; established in 1967), since facility operations began. Recent severe epidemics at the FRH in 1998 and 2000-2002 prompted investigations into the characteristics and potential sources of virus at this facility. Both phylogenetic analyses of a variable portion of the glycoprotein gene and serologic comparisons based on neutralization with three polyclonal rabbit sera were used to characterize 82 IHNV isolates from the Feather River watershed between 1969 and 2004. All isolates examined were in the L genogroup and belonged to one of three serologic groups typical of IHNV from California. The IHNV isolates from the Feather River area demonstrated a maximum nucleotide sequence divergence of 4.0%, and new isolates appeared to emerge from previous isolates rather than by the introduction of more diverse subgroups from exogenous sources. The earliest isolates examined from the watershed formed the subgroup LI, which disappeared coincidently with a temporal shift to new genetic and serologic types of the larger subgroup LII. Experimental challenges demonstrated no significant differences in the virulence for juvenile Chinook salmon and rainbow trout O. mykiss from selected isolates representing the principal types of IHNV found historically and from recent epidemics at FRH. While most isolates were equally virulent for both host species, one isolate was found to be more virulent for Chinook salmon than for rainbow trout. PMID:18333482

Bendorf, Christin M; Kelley, Garry O; Yun, Susan C; Kurath, Gael; Andree, Karl B; Hedrick, Ronald P

2007-12-01

251

Reproductive Abnormalities in Trout from Western U.S. National Parks  

Microsoft Academic Search

Reproductive disruption is well documented in polluted areas, such as below sewage treatment plants, but not in ecologically protected environments, such as national parks. In a majority of subalpine lakes sampled in Rocky Mountain and Glacier National parks, we observed intersex male cutthroat trout Oncorhynchus clarkii and brook trout Salvelinus fontinalis at frequencies of 9-33%. Intersexuality, one form of reproductive

Adam R. Schwindt; Michael L. Kent; Luke K. Ackerman; Staci L. Massey Simonich; Dixon H. Landers; Tamara Blett; Carl B. Schreck

2009-01-01

252

Ecotypic differentiation of native rainbow trout ( Oncorhynchus mykiss ) populations from British Columbia  

Microsoft Academic Search

We sampled 34 native rainbow trout (Oncorhynchus mykiss) populations over a wide geographic area of British Columbia to determine whether variation in morphology is related to differences in habitat or fish community characteristics experienced by a population. After correcting for differences in body size, the most dramatic differences occurred in external characteristics between stream- and lake-dwelling populations. Rainbow trout from

E. R. Keeley; E. A. Parkinson; E. B. Taylor

2005-01-01

253

Lean project management  

Microsoft Academic Search

Projects are temporary production systems. When those systems are structured to deliver the product while maximizing value and minimizing waste, they are said to be ‘lean’ projects. Lean project management differs from traditional project management not only in the goals it pursues, but also in the structure of its phases, the relationship between phases and the participants in each phase.

Glenn Ballard; Gregory Howell

2003-01-01

254

lean-ISD.  

ERIC Educational Resources Information Center

Explains lean instructional systems design/development (ISD) as it relates to curriculum architecture design, based on Japan's lean production system. Discusses performance-based systems; ISD models; processes for organizational training and development; curriculum architecture to support job performance; and modular curriculum development. (LRW)

Wallace, Guy W.

2001-01-01

255

Healthy Lean through HRD  

Microsoft Academic Search

The paper reports on findings from the initial, exploratory phase of a longitudinal research study aimed at developing a framework for implementing lean while ensuring employee well-being. Data from observations and in-depth dialogues with persons involved in lean implementation, along with relevant theory, are used to construct a tentative framework for implementing \\

Frances Jørgensen

256

Lean health care.  

PubMed

Principles of Lean management are being adopted more widely in health care as a way of improving quality and safety while controlling costs. The authors, who are chief executive officers of rural North Carolina hospitals, explain how their organizations are using Lean principles to improve quality and safety of health care delivery. PMID:23802475

Hawthorne, Henry C; Masterson, David J

257

lean-ISD.  

ERIC Educational Resources Information Center

|Explains lean instructional systems design/development (ISD) as it relates to curriculum architecture design, based on Japan's lean production system. Discusses performance-based systems; ISD models; processes for organizational training and development; curriculum architecture to support job performance; and modular curriculum development. (LRW)|

Wallace, Guy W.

2001-01-01

258

Why Lean Needs Simulation  

Microsoft Academic Search

Lean methods have become the standard approach to the resolution of design and operational issues in production and other systems. However, the lean approach has deficiencies. The deficiencies that simulation can address are presented, discussed and illustrated. These deficiencies include modeling and assessing the effects of variation, making use of all available data, validating the effects of proposed changes before

Charles R. Standridge; Jon H. Marvel

2006-01-01

259

Why lean needs simulation  

Microsoft Academic Search

Lean methods have become the standard approach to the resolution of design and operational issues in production and other systems. However, the lean approach has deficiencies. The deficiencies that simulation can address are presented, discussed and illustrated. These deficiencies include modeling and assessing the effects of variation, making use of all available data, validating the effects of proposed changes before

Charles R. Standridge; Jon H. Marvel

2006-01-01

260

Mountain Lake Non-native Fish Eradication Pretreatment Planning Reconnaissance Surveys of Kettling, Skymo, and Sourdough Lakes at North Cascades National Park Service Complex, Washington: Data Summary, 2010.  

National Technical Information Service (NTIS)

Ninety- three naturally fishless mountain lakes found in the park complex have been stocked with non-native trout, and currently 33 of these lakes contain naturally reproducing populations. These self-sustaining fish populations have the ability to overpo...

A. Rawhouser L. Bodensteiner R. Glesne

2013-01-01

261

Bull Trout Distribution and Abundance in the Waters on and Bordering the Warm Springs Indian Reservation, 2000 Annual Report.  

SciTech Connect

The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be stable in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et al. 1997). Little was known about bull trout in the lower Deschutes basin until BPA funded project No.9405400 began during 1998. In this progress report we describe the findings from the third year (2000) of the multi-year study aimed at determining the life history, genetics, habitat needs and limiting factors of bull trout in the lower Deschutes subbasin. Juvenile bull trout and brook trout (Salvelinus fontinalis) relative abundance was assessed in the Warm Springs River and Shitike Creek by night snorkeling. In the Warm Springs R. juvenile bull trout were slightly more numerous than brook trout, however, both were found in low densities. Relative densities of both species declined from 1999 observations. Juvenile bull trout vastly out numbered brook trout in Shitike Cr. Relative densities of juvenile bull trout increased while brook trout abundance was similar to 1999 observations in eight index reaches. The utility of using index reaches to monitor trends in juvenile bull trout and brook trout relative abundance was assessed in the Warm Springs R. for the second year. Mean relative densities of both species, within the index reaches was slightly higher than what was observed in a 2.4 km control reach. Mill Creek was surveyed for the presence of juvenile bull trout. The American Fisheries Society ''Interim protocol for determining bull trout presence'' methodology was field tested. No bull trout were found in the 2 km survey area.

Brun, Christopher

2000-01-01

262

Duckling response to changes in the trophic web of acidified lakes  

Microsoft Academic Search

We reared American Black Duck (Anas rubripes Brewster) and Common Goldeneye (Bucephala clangula Linnaeus) ducklings on two Quebec laurentian lakes in which we manipulated brook trout populations (Salvelinus fontinalis Mitchill), lake acidity and lake productivity to relate waterfowl foraging to trophic status of lakes. We developed a preliminary model to assess the effects of lake acidity and productivity, fish predation

Jean-Luc DesGranges; Christian Gagnon

1994-01-01

263

Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration  

Microsoft Academic Search

Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for

Jae-Soon Choi; Vitaly Y Prikhodko; William P Partridge Jr; II Parks; James E; Kevin M Norman; Shean P Huff; Paul H Chambon; John F Thomas

2010-01-01

264

COMBINING PREDICTION AND MONITORING FOR REDUCTION OF TOXICS: THE LAKE MICHIGAN MASS BALANCE STUDY  

EPA Science Inventory

This presentation will focus on PCBs and the primary findings of mathematical modeling including the mass balance of PCBs for Lake Michigan and forecasts of future concentrations of PCBs in lake trout....

265

Lean Manufacturing Engineering Certification  

NSDL National Science Digital Library

This website from Best Practice Research features online business training courses including lean manufacturing and six sigma certification training courses. The courses are available for purchase and may be taken online.

2012-12-10

266

Sustainability of the Lake Superior Fish Community: Interactions in a Food Web Context  

Microsoft Academic Search

The restoration and rehabilitation of the native fish communities is a long-term goal for the Laurentian Great Lakes. In Lake\\u000a Superior, the ongoing restoration of the native lake trout populations is now regarded as one of the major success stories\\u000a in fisheries management. However, populations of the deepwater morphotype (siscowet lake trout) have increased much more substantially\\u000a than those of

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

2000-01-01

267

Long-term impacts of invasive species on a native top predator in a large lake system  

USGS Publications Warehouse

1.?Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2.?We measured stable isotopes of carbon (?13C) and nitrogen (?15N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3.?Relationships between ?15N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, ?13C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4.?Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where ?13C values of the lake trout population were dominated by a reliance on offshore carbon production. 5.?These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways.

Rush, Scott A.; Paterson, Gordon;Johnson, Tim B.; Drouillard, Ken G.; Haffner, Gordon D.; Hebert, Craig E.; Arts, Michael T.; McGoldrick, Daryl J.; Backus, Sean M.; Lantry, Brian F.; Lantry, Jana R.; Schaner, Ted; Fisk, Aaron T.

2012-01-01

268

Resource Partitioning in Summer by Salmonids in South-Central Lake Ontario  

Microsoft Academic Search

During the summers of 1981 and 1982, we studied resource partitioning by stocked lake trout Salvelinus namaycush, brown trout Salmo trutta, and chinook salmon Oncorhynchus tshawytscha by fishing vertical gill nets at six distances from shore in south-central Lake Ontario. The nets were set at depths of approximately 15–45 m (nearshore stations, <4 km offshore) and more than 55 m

Robert A. Olson; Jimmy D. Winter; David C. Nettles; James M. Haynes

1988-01-01

269

Resource Partitioning in Summer by Salmonids in South-Central Lake Ontario  

Microsoft Academic Search

During the summers of 1981 and 1982, we studied resource partitioning by stocked lake trout Salvelinus namaycush, brown trout Salmo trutta, and chinook salmon Oncorhynchus tshawytscha by fishing vertical gill nets at six distances from shore in south-central Lake Ontario. The nets were set at depths of approximately 15-45 m (nearshore stations, <4 km offshore) and more than 55 m

ROBERT A. OLSON; JIMMY D. WINTER; DAVID C. NETTLES; James M. Haynes

1988-01-01

270

Arizona Trout (Apache Trout) Recovery Plan.  

National Technical Information Service (NTIS)

Arizona trout were recognized as a unique species many years before they were officially described in 1972. Their distribution la centered in the White Mountains of east Central Arizona, on lands administered by the White Mountain Apache Tribe and adjacen...

1983-01-01

271

Development of Rainbow Trout Brood Stock by Selective Breeding  

Microsoft Academic Search

Management programs to maintain and increase the sports fishery require large numbers of strong, healthy, acclimatized fingerlings for restocking the lakes and streams. To produce the fingerling trout needed, stocks of fish are first developed and selected at fishery laboratories, then tested in the field. At the University of Washington over a period of 23 years of intensive selective breeding,

Lauren R. Donaldson; Paul R. Olson

1957-01-01

272

Fish community change in Lake Superior, 1970–2000  

Microsoft Academic Search

Abstract: Changes,in Lake Superior’s fish community,are reviewed,from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus,clupeaformis) stocks have increased substantially and may,be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea

Charles R. Bronte; Mark P. Ebener; Donald R. Schreiner; David S. DeVault; Michael M. Petzold; Douglas A. Jensen; Carl Richards; Steven J. Lozano

2003-01-01

273

Evidence for natural hybridization between Dolly Varden ( Salvelinus malma ) and bull trout ( Salvelinus confluentus ) in a northcentral British Columbia watershed  

Microsoft Academic Search

Morphological and molecular analyses were used to identify sympatric Dolly Varden ( Salvelinus malma) and bull trout (Salvelinus confluentus) and their hybrids from streams tributary to Thutade Lake, Peace River drainage, northcentral British Columbia. Morphological analysis identified two groups of char resembling allopatric Dolly Varden and bull trout as well as a small number of morphologically intermediate fish. One of

James S. Baxter; Eric B. Taylor; Robert H. Devlin; John Hagen; J. Donald McPhail

1997-01-01

274

Fragmentation of riverine systems: the genetic effects of dams on bull trout (Salvelinus confluentus) in the Clark Fork River system  

Microsoft Academic Search

Migratory bull trout ( Salvelinus confluentus ) historically spawned in tributaries of the Clark Fork River, Montana and inhabited Lake Pend Oreille as subadult and adult fish. However, in 1952 Cabinet Gorge Dam was constructed without fish passage facilities dis- rupting the connectivity of this system. Since the construction of this dam, bull trout popu- lations in upstream tributaries have

Lukas P. Neraas; Paul Spruell

2001-01-01

275

The Use of Rotenone to Restore Native Brook Trout in the Adirondack Mountains of New York—An Overview  

Microsoft Academic Search

The brook trout Salvelinus fontinalis is endemic to the eastern United States, and historically was abundant in the lakes and ponds of the Adirondack Mountain region of New York State. Anthropogenic impacts have caused drastic declines in brook trout populations. A major cause of the decline has been introduction of competing fishes such as nonnative yellow perch Perca flavescens, bass

Leo Demong

276

The origin of introduced rainbow trout ( Oncorhynchus mykiss ) in the Santa Cruz River, Patagonia, Argentina, as inferred from mitochondrial DNA  

Microsoft Academic Search

Rainbow trout (Oncorhynchus mykiss) was first introduced into Argentinean Patagonia, the southernmost region of South America, from the United States in 1904 and at present constitutes the most conspicuous freshwater fish in lakes and rivers of the region. The Santa Cruz River in Southern Patagonia is the only river in the world where a self-sustained population of introduced rainbow trout

Carla M. Riva Rossi; Enrique P. Lessa; Miguel A. Pascual

2004-01-01

277

Lake Pend Oreille Predation Research, Annual Report 2002-2003.  

SciTech Connect

During August 2002 we conducted a hydroacoustic survey to enumerate pelagic fish >406 mm in Lake Pend Oreille, Idaho. The purpose of this survey was to determine a collective lakewide biomass estimate of pelagic bull trout Salvelinus confluentus, rainbow trout Oncorhynchus mykiss, and lake trout S. namaycush and compare it to pelagic prey (kokanee salmon O. nerka) biomass. By developing hydroacoustic techniques to determine the pelagic predator to prey ratio, we can annually monitor their balance. Hydroacoustic surveys were also performed during December 2002 and February 2003 to investigate the effectiveness of autumn and winter surveys for pelagic predators. The inherent problem associated with hydroacoustic sampling is the inability to directly identify fish species. Therefore, we utilized sonic tracking techniques to describe rainbow trout and lake trout habitat use during our winter hydroacoustic survey to help identify fish targets from the hydroacoustic echograms. During August 2002 we estimated there were 39,044 pelagic fish >406 mm in Lake Pend Oreille (1.84 f/ha). Based on temperature and depth utilization, two distinct groups of pelagic fish >406 mm were located during August; one group was located between 10 and 35 m and the other between 40 and 70 m. The biomass for pelagic fish >406 mm during August 2002 was 73 t (metric ton). This would account for a ratio of 1 kg of pelagic predator for every 2.63 kg of kokanee prey, assuming all pelagic fish >406 mm are predators. During our late fall and winter hydroacoustic surveys, pelagic fish >406 mm were observed at lake depths between 20 and 90 m. During late fall and winter, we tracked three rainbow trout (168 habitat observations) and found that they mostly occupied pelagic areas and predominantly stayed within the top 10 m of the water column. During late fall (one lake trout) and winter (four lake trout), we found that lake trout (184 habitat observations) utilized benthic-nearshore areas 65% of the time and were found in the pelagic area only 35% of the time. Lake trout were found at depths between 10 and 90 m (average was approximately 30 m). Based on hydroacoustic surveys of pelagic fish >406 mm and habitat use of sonic tagged rainbow trout and lake trout during late fall and winter, we conclude that hydroacoustic sampling during those times would be ineffective at acquiring an accurate pelagic predator population estimate and recommend conducting abundance estimates for pelagic predators when Lake Pend Oreille is thermally stratified (i.e. August).

Bassista, Thomas

2004-02-01

278

Fish and fisheries of the Prespa lakes  

Microsoft Academic Search

Twenty-three taxa of fish have been identified fromthe Prespa lakes. Eleven of these have been introducedor translocated, and 7 of the remaining 12 are endemicto the Prespa lakes. This high proportion of endemismrequires confirmation because the systematic positionof several of the species and subspecies remainsuncertain. The absence of a predatory fish in MikriPrespa, the occurrence of trout in Megali Prespa,

A. J. Crivelli; G. Catsadorakis; M. Malakou; E. Rosecchi

1997-01-01

279

Relative Contribution and Comparative Life History Characteristics of Hatchery and Wild Steelhead Trout in the Betsie River, Michigan.  

National Technical Information Service (NTIS)

Spawning runs of wild, naturalized steelhead trout occur in northern tributaries of Lake Michigan including the Betsie River. Management of Betsie River steelhead has focused on supplemented wild stocks with hatchery fish though little is known about natu...

J. R. Harbeck

1999-01-01

280

Ecology and Life History of Coaster Brook Trout and Potential Bottlenecks in Their Rehabilitation  

Microsoft Academic Search

Lake Superior once supported abundant lake-dwelling brook trout Salvelinus fontinalis called coasters; however, only scattered remnant populations remained by the early 20th century. Owing to their early decline, there is little information about their ecology and life history, yet such information is vital for the ecologically based rehabilitation and management of coasters. This study reviews the ecology of coaster brook

Casey J. Huckins; Edward A. Baker; Kurt D. Fausch; Jill B. K. Leonard

2008-01-01

281

Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears  

USGS Publications Warehouse

Spawning cutthroat trout (Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears (Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized (i) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ?? 93 ppb) and its virtual absence in all other bear foods (???6 ppb), (ii) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, (iii) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, (iv) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and (v) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

Felicetti, L. A.; Schwartz, C. C.; Rye, R. O.; Gunther, K. A.; Crock, J. G.; Haroldson, M. A.; Waits, L.; Robbins, C. T.

2004-01-01

282

Performance and Developmental Stability of Triploid Tiger Trout (Brown Trout ? X Brook Trout ?)  

Microsoft Academic Search

Triploid fish hybrids frequently survive better than diploid hybrids. Tiger trout are a sterile hybrid between female brown trout Salmo trutta and male brook trout Salvelinus fontinalis; they have a poor early survival rate but a good growth rate. We produced triploid tiger trout by heat shock treatments of fertilized eggs and examined their survival and growth under hatchery conditions.

Paul D. Scheerer; Gary H. Thorgaard; James E. Seeb

1987-01-01

283

Lean staged combustion assembly  

Microsoft Academic Search

This patent describes a lean staged combustion assembly. It comprises: means for channeling compressed air including a pilot portion and a main portion. This patent also describes an annular combustor outer liner having an upstream end and a downstream end; an annular combustor inner liner having an upstream end and a downstream end and spaced from the outer liner; means

P. E. Sabla; W. J. Dodds; T. M. Tucker

1992-01-01

284

The Lean Woman  

Microsoft Academic Search

Objective: In the current obesity epidemic, the ability to remain lean is beginning to be uncommon. Therefore, it was considered of interest to characterize such subjects.Research Methods and Procedures: From a population of premenopausal women (n = 270), all 40 years of age, those with a similar body mass index (BMI) as women at the age of 21 years, born

Fariba Baghaei; Roland Rosmond; Lars Westberg; Monica Hellstrand; Mikael Landén; Elias Eriksson; Göran Holm; Per Björntorp

2002-01-01

285

Lean: Rx for Hospitals  

Microsoft Academic Search

Lean has been slowly but steadily gaining acceptance in the healthcare field based on its proven success in the industry helping the bottom line while improving the quality. Two trillion dollar healthcare industry needs help on both counts i.e. bottom line and quality. US hospitals are gradually decreasing as are their profit margins; therefore requiring cost reductions. Reports from the

Andrew R. Ganti; Anita G. Ganti

286

Transferring Lean into government  

Microsoft Academic Search

Purpose – This paper evaluates the transfer of a Lean approach developed by a global manufacturing and logistics company into a large UK Government department. The purpose of this paper is to examine which tools and techniques are transferred and implemented into the government department together with their impact as viewed by the staff within the department in order to

Zoe Radnor

2010-01-01

287

Introduced trout sever trophic connections in watersheds: consequences for a declining amphibian.  

PubMed

Trophic linkages between terrestrial and aquatic ecosystems are increasingly recognized as important yet poorly known features of food webs. Here we describe research to understand the dynamics of lake food webs in relation to a native riparian amphibian and its interaction with introduced trout. The mountain yellow-legged frog Rana muscosa is endemic to alpine watersheds of the Sierra Nevada Mountains and the Transverse Ranges of California, but it has declined to a small fraction of its historical distribution and abundance. Although remaining frogs and introduced trout feed in different habitats of alpine lakes, our stable-isotope analyses clearly show that the same resource base of benthic invertebrates sustains their growth. During one period, insect emergence from naturally fishless lakes was nearly 20-fold higher compared to adjacent lakes with trout, showing that fish reduce availability of aquatic prey to amphibious and terrestrial consumers. Although trout cannot prey on adult frogs due to gape limitation, foraging post-metamorphic frogs are 10 times more abundant in the absence of trout, suggesting an important role for competition for prey by trout in highly unproductive alpine watersheds. Most Sierran lakes contain fish, and those that do not are usually small isolated ponds; in our study, these two lake types supported the lowest densities of post-metamorphic frogs, and these frogs were less reliant on local, benthic sources of productivity. Since Rana muscosa was formerly the most abundant vertebrate in the Sierra Nevada, the reduction in energy flow from lake benthos to this consumer due to fish introductions may have had negative consequences for its numerous terrestrial predators, many of which have also declined. We suggest that disruptions of trophic connections between aquatic and terrestrial food webs are an important but poorly understood consequence of fish introduction to many thousands of montane lakes and streams worldwide and may contribute to declines of native consumers in riparian habitats. PMID:17918397

Finlay, Jacques C; Vredenburg, Vance T

2007-09-01

288

Effects of Partially Anadromous Arctic Charr ( Salvelinus alpinus ) Populations on Ecology of Coastal Arctic Lakes  

Microsoft Academic Search

Little research has been conducted on effects of iteroparous anadromous fishes on Arctic lakes. We investigated trophic ecology,\\u000a fish growth, and food web structure in six lakes located in Nunavut, Canada; three lakes contained anadromous Arctic charr\\u000a (Salvelinus alpinus) whereas three lakes did not contain Arctic charr. All lakes contained forage fishes and lake trout (Salvelinus namaycush; top predator). Isotope

Heidi K. Swanson; Karen A. Kidd; James D. Reist

2010-01-01

289

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to brook trout (salvelinus fontinalis) during early development  

SciTech Connect

The sensitivity of early life stages of brook trout (Salvelinus fontinalis) to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity was investigated. Newly fertilized eggs were exposed for 48 h to water containing either acetone or a range of concentrations of [[sup 3]H]TCDD dissolved in acetone. Eggs were then transferred to TCDD-free water and observed through development. TCDD concentrations of 101 to 470 pg/g in the eggs caused dose-related increases in sac-fry mortality associated with yolk-sac edema, hemorrhages, and arrested development. These signs of TCDD-induced toxicity resemble blue-sac disease. The NOELs and LOELs for sac-fry mortality were 135 and 185 pg TCDD/g egg, respectively, whereas the LD50 and LD100 were 200 and 324 pg/g egg, respectively. The time course and signs of TCDD toxicity to brook trout during early development are essentially identical to those observed in both rainbow trout and lake trout following TCDD exposure of their eggs via water or injection, and in lake trout exposed to maternally derived TCDD. Brook trout sac fry are intermediate in sensitivity to TCDD-induced lethality compared to lake trout and rainbow trout.

Walker, M.K.; Peterson, R.E. (Univ. of Wisconsin, Madison, WI (United States))

1994-05-01

290

Molecular analysis of population genetic structure and recolonization of rainbow trout following the Cantara spill  

USGS Publications Warehouse

Mitochondrial DNA (mtDNA) sequence and allelic frequency data for 12 microsatellite loci were used to analyze population genetic structure and recolonization by rainbow trout, Oncorhynchus mykiss, following the 1991 Cantara spill on the upper Sacramento River, California. Genetic analyses were performed on 1,016 wild rainbow trout collected between 1993 and 1996 from the mainstem and in 8 tributaries. Wild trout genotypes were compared to genotypes for 79 Mount Shasta Hatchery rainbow trout. No genetic heterogeneity was found 2 years after the spill (1993) between tributary populations and geographically proximate mainstem fish, suggesting recolonization of the upper mainstem directly from adjacent tributaries. Trout collections made in 1996 showed significant year-class genetic variation for mtDNA and microsatellites when compared to fish from the same locations in 1993. Five years after the spill, mainstem populations appeared genetically mixed with no significant allelic frequency differences between mainstem populations and geographically proximate tributary trout. In our 1996 samples, we found no significant genetic differences due to season of capture (summer or fall) or sampling technique used to capture rainbow trout, with the exception of trout collected by electrofishing and hook and line near Prospect Avenue. Haplotype and allelic frequencies in wild rainbow trout populations captured in the upper Sacramento River and its tributaries were found to differ genetically from Mount Shasta Hatchery trout for both years, with the notable exception of trout collected in the lower mainstem river near Shasta Lake, where mtDNA and microsatellite data both suggested upstream colonization by hatchery fish from the reservoir. These data suggest that the chemical spill in the upper Sacramento River produced significant effects over time on the genetic population structure of rainbow trout throughout the entire upper river basin.

Nielsen, J. L.; Heine, E. L.; Gan, C. A.; Fountain, M. C.

2000-01-01

291

Diurnal stream habitat use of juvenile Atlantic salmon, brown trout and rainbow trout in winter  

USGS Publications Warehouse

The diurnal winter habitat of three species of juvenile salmonids was examined in a tributary of Skaneateles Lake, NY to compare habitat differences among species and to determine if species/age classes were selecting specific habitats. A total of 792 observations were made on the depth, velocity, substrate and cover (amount and type) used by sympatric subyearling Atlantic salmon, subyearling brown trout and subyearling and yearling rainbow trout. Subyearling Atlantic salmon occurred in shallower areas with faster velocities and less cover than the other salmonid groups. Subyearling salmon was also the only group associated with substrate of a size larger than the average size substrate in the study reach during both winters. Subyearling brown trout exhibited a preference for vegetative cover. Compared with available habitat, yearling rainbow trout were the most selective in their habitat use. All salmonid groups were associated with more substrate cover in 2002 under high flow conditions. Differences in the winter habitat use of these salmonid groups have important management implications in terms of both habitat protection and habitat enhancement.

Johnson, J. H.; Douglass, K. A.

2009-01-01

292

Spawning Demographics and Juvenile Dispersal of an Adfluvial Bull Trout Population in Trestle Creek, Idaho  

Microsoft Academic Search

We utilized a screw trap, trap-box weir, remote passive integrated transponder tag (PIT) detection weir, and otolith microchemistry to evaluate (2000–2004) spawning demographics and migration patterns of adfluvial bull trout Salvelinus confluentus in Trestle Creek, Idaho, a tributary to Lake Pend Oreille. Annual repeat spawning was more common than alternate-year spawning. Annual growth, estimated from adult bull trout PIT-tagged in

Christopher C. Downs; Dona Horan; Erin Morgan-Harris; Robert Jakubowski

2006-01-01

293

Comparison of Hatchery and Field Performance between a Whirling-Disease-Resistant Strain and the Ten Sleep Strain of Rainbow Trout  

Microsoft Academic Search

A whirling-disease-resistant strain of rainbow trout Oncorhynchus mykiss (GRHL strain) derived from a backcross of an F1 hybrid of two strains (German strain × Harrison Lake strain) with German strain females, was compared with the Ten Sleep (TS) strain of rainbow trout. The GRHL strain had consistently superior growth and feed conversion in two consecutive hatchery trials. Hatching and mortality

Eric J. Wagner; Matt Bartley; Ronney Arndt; Randall W. Oplinger; M. Douglas Routledge

2012-01-01

294

Effects of Fish-farm Activity on the Limnetic Community Structure of Brown Trout, Salmo trutta, and Arctic Charr, Salvelinus alpinus  

Microsoft Academic Search

Establishment of four fish-farms during the period 1971 to 1994 in the oligotrophic lake Skogseidvatnet affected Arctic charr, Salvelinus alpinus, but not brown trout, Salmo trutta. From 1971 to 1987, an increase in mean individual size of Arctic charr was recorded, while the mean individual size of brown trout remained stable. Arctic charr were found to use deeper benthic areas

Sven-Erik Gabrielsen

1999-01-01

295

Diet and food resource partitioning in koaro, Galaxias brevipinnis (Günther), and juvenile rainbow trout, Oncorhynchus mykiss (Richardson), in two Taupo streams, New Zealand  

Microsoft Academic Search

This study examined the diet of sympatric populations of migratory juvenile rainbow trout and landlocked koaro in the Waipehi and Omori Streams, Lake Taupo, New Zealand. In both species, diet was dominated, both numerically and by weight, by aquatic prey: Ephemeroptera, Trichoptera, and Diptera larvae were the most numerous prey items. Adult koaro and juvenile rainbow trout both fed on

Ian A. Kusabs; Stephen Swales

1991-01-01

296

Organizational change through Lean Thinking.  

PubMed

In production and manufacturing plants, Lean Thinking has been used to improve processes by eliminating waste and thus enhancing efficiency. In health care, Lean Thinking has emerged as a comprehensive approach towards improving processes embedded in the diagnostic, treatment and care activities of health-care organizations with cost containment results. This paper provides a case study example where Lean Thinking is not only used to improve efficiency and cost containment, but also as an approach to effective organizational change. PMID:18647948

Tsasis, Peter; Bruce-Barrett, Cindy

2008-08-01

297

Wigwam River Juvenile Bull Trout and Fish Habitat Monitoring Program : 2000 Data Report.  

SciTech Connect

The Wigwam River bull trout (Salvelinus confluentus) and fish habitat monitoring program is a trans-boundary initiative implemented by the British Columbia Ministry of Environment, Lands and Parks (MOE), in cooperation with Bonneville Power Administration (BPA). The Wigwam River is an important fisheries stream located in southeastern British Columbia that supports healthy populations of both bull trout and Westslope cutthroat trout (Figure 1.1). This river has been characterized as the single most important bull trout spawning stream in the Kootenay Region (Baxter and Westover 2000, Cope 1998). In addition, the Wigwam River supports some of the largest Westslope cutthroat trout (Oncorhynchus clarki lewisi) in the Kootenay Region. These fish are highly sought after by anglers (Westover 1999a, 1999b). Bull trout populations have declined in many areas of their range within Montana and throughout the northwest including British Columbia. Bull trout were blue listed as vulnerable in British Columbia by the B.C. Conservation Data Center (Cannings 1993) and although there are many healthy populations of bull trout in the East Kootenays they remain a species of special concern. Bull trout in the United States portion of the Columbia River were listed as threatened in 1998 under the Endangered Species Act by the U.S. Fish and Wildlife Service. The upper Kootenay River is within the Kootenai sub-basin of the Mountain Columbia Province, one of the eleven Eco-provinces that make up the Columbia River Basin. MOE applied for and received funding from BPA to assess and monitor the status of wild, native stocks of bull trout in tributaries to Lake Koocanusa (Libby Reservoir) and the upper Kootenay River. This task is one of many that was undertaken to ''Monitor and Protect Bull Trout for Koocanusa Reservoir'' (BPA Project Number 2000-04-00).

Cope, R.S.; Morris, K.J.

2001-03-01

298

Wigwam River Juvenile Bull Trout and Fish Habitat Monitoring Program : 2002 Data Report.  

SciTech Connect

The Wigwam River bull trout (Salvelinus confluentus) and fish habitat monitoring program is a trans-boundary initiative implemented by the British Columbia Ministry of Water, Land, and Air Protection (MWLAP), in cooperation with Bonneville Power Administration (BPA). The Wigwam River is an important fisheries stream located in southeastern British Columbia that supports healthy populations of both bull trout and Westslope cutthroat trout (Figure 1). This river has been characterized as the single most important bull trout spawning stream in the Kootenay Region (Baxter and Westover 2000, Cope 1998). In addition, the Wigwam River supports some of the largest Westslope cutthroat trout (Oncorhynchus clarki lewisi) in the Kootenay Region. These fish are highly sought after by anglers (Westover 1999a, 1999b). Bull trout populations have declined in many areas of their range within Montana and throughout the northwest including British Columbia. Bull trout were blue listed as vulnerable in British Columbia by the B.C. Conservation Data Center (Cannings 1993) and although there are many healthy populations of bull trout in the East Kootenay they remain a species of special concern. Bull trout in the United States portion of the Columbia River were listed as threatened in 1998 under the Endangered Species Act by the U.S. Fish and Wildlife Service. The upper Kootenay River is within the Kootenai sub-basin of the Mountain Columbia Province, one of the eleven Eco-provinces that make up the Columbia River Basin. MWLAP applied for and received funding from BPA to assess and monitor the status of wild, native stocks of bull trout in tributaries to Lake Koocanusa (Libby Reservoir) and the upper Kootenay River. This task is one of many that were undertaken to ''Monitor and Protect Bull Trout for Koocanusa Reservoir'' (BPA Project Number 2000-04-00).

Cope, R.S. [Westslope Fisheries, Cranbrook, BC, Canada

2003-03-01

299

Potential Effects of Climate Warming on Fish Habitats in Temperate Zone Lakes with Special Reference to Lake 239 of the Experimental Lakes Area (ELA), North-Western Ontario  

Microsoft Academic Search

We used simple statistics (e.g. mean temperature, degree days, cumulative volume days) to describe present thermal habitats for cool water (yellow perch, Perca flavescens) and cold water (lake trout, Salvelinus namaycush) fish of a small boreal lake. We then modelled changes in the vertical and temporal extent of these habitats under various scenarios of climatic change that included increases in

Wolfgang Jansen; Raymond H. Hesslein

2004-01-01

300

A Simulation of Lean Manufacturing: The Lean Lemonade Tycoon 2  

ERIC Educational Resources Information Center

|This article discusses the functions and effectiveness of games and simulations in the learning processes, in particular as an experiential learning methodology. The application of the game Lemonade Tycoon in the development of lean manufacturing concepts is described. This article addresses the use of the game to teach the principles of lean…

Ncube, Lisa B.

2010-01-01

301

Evaluation of a Chrysler Lean Burn Vehicle.  

National Technical Information Service (NTIS)

Lean mixture combustion engines are attractive because of the low emissions and good fuel economy that are possible with a properly controlled lean burn engine. Chrysler Corporation has conducted research into engine operation at lean air-fuel ratios and ...

1975-01-01

302

Bull Trout Population Assessment in the White Salmon and Klickitat Rivers, Columbia River Gorge, Washington, 2001 Annual Report.  

SciTech Connect

We utilized night snorkeling and single pass electroshocking to determine the presence or absence of bull trout Salvelinus confluentus in 26 stream reaches (3,415 m) in the White Salmon basin and in 71 stream reaches (9,005 m) in the Klickitat River basin during summer and fall 2001. We did not find any bull trout in the White Salmon River basin. In the Klickitat River basin, bull trout were found only in the West Fork Klickitat River drainage. We found bull trout in two streams not previously reported: Two Lakes Stream and an unnamed tributary to Fish Lake Stream (WRIA code number 30-0550). We attempted to capture downstream migrant bull trout in the West Fork Klickitat River by fishing a 1.5-m rotary screw trap at RM 4.3 from July 23 through October 17. Although we caught other salmonids, no bull trout were captured. The greatest limiting factor for bull trout in the West Fork Klickitat River is likely the small amount of available habitat resulting in a low total abundance, and the isolation of the population. Many of the streams are fragmented by natural falls, which are partial or complete barriers to upstream fish movement. To date, we have not been able to confirm that the occasional bull trout observed in the mainstem Klickitat River are migrating upstream into the West Fork Klickitat River.

Thiesfeld, Steven L.; McPeak, Ronald H.; McNamara, Brian S. (Washington Department of Fish and Wildlife); Honanie, Isadore (Confederated Tribes and Bands, Yakama Nation)

2002-01-01

303

Dynamics of CFCs in northern temperate lakes and adjacent groundwater  

USGS Publications Warehouse

[1] Three dimictic lakes and one meromictic lake in and near the Trout Lake, Wisconsin, watershed were sampled to determine the variation of chlorofluorocarbon (CFC) concentrations within the lakes. The lakes were sampled during stratified conditions, during fall turnover, and during ice cover. The results demonstrate a considerable variation in CFC concentrations and corresponding atmospheric mixing ratios in the lakes sampled, both with depth and season within a given lake, and across different lakes. CFC profiles and observed degradation were not related to the groundwater inflow rate and hence are likely the result of in-lake processes influenced by CFC degradation in the (lake) water column, CFC degradation in the lake-bed sediments, and gas exchange rates and the duration of turnover (turnover efficiency).

Walker, J. F.; Saad, D. A.; Hunt, R. J.

2007-01-01

304

HOW TO SUCCESSFULLY IMPLEMENT LEAN  

Microsoft Academic Search

ABSTRACT In major industrialised countries, manufacturing is considered to be the most important driving force towards a nation’s riches and success. Lean manufacturing, also known as the Toyota Production System (TPS), has proved to be a valuable aid towards achieving competitiveness among manufacturers all over the world. In the UK, the transformation of manufacturers towards Lean started in the late

MUHAMMAD AL-SHAMMRI

2007-01-01

305

Lean indicators and manufacturing strategies  

Microsoft Academic Search

Develops and tests an integrated check-list to assess manufacturing changes towards lean production. Using the results from a survey to manufacturing plants located in the Spanish region of Aragon, analyzes which lean production indicators are more used to assess the company’s improvements in their production systems, and the determinants on the use of these indicators.

Angel Martínez Sánchez; Manuela Pérez Pérez

2001-01-01

306

Introducing lean manufacturing at ESI  

Microsoft Academic Search

Summary form only given. Lean production is a collection of techniques to identify and reduce waste in the manufacturing process. By reducing waste, enormous gains in throughput and reductions in WIP inventory and cycle time can be achieved with no increase in resources. It was the promise of these advantages that caused ESI to begin the move to lean manufacturing

D. Mottershead

2001-01-01

307

The genealogy of lean production  

Microsoft Academic Search

Lean production not only successfully challenged the accepted mass production practices in the automotive industry, significantly shifting the trade-off between productivity and quality, but it also led to a rethinking of a wide range of manufacturing and service operations beyond the high-volume repetitive manufacturing environment. The book ‘The machine that changed the World’ that introduced the term ‘lean production’ in

Matthias Holweg

2007-01-01

308

Is Lean Production the Solution?  

Microsoft Academic Search

The Japanese system of lean production is the most efficient way for manufacturing cars argue Womack et al. in their MIT study The Machine that Changed the World (1990). They strongly recom- mend Western companies to learn and adapt to it, if they want to survive in the 1990s. This paper shows that lean production per se is not sufficient

Christos Papahristodoulou

1994-01-01

309

Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report.  

National Technical Information Service (NTIS)

Pelagic fishes, such as kokanee and rainbow trout, provide an important fishery in Lake Roosevelt; however, spawner returns and creel results have been below management goals in recent years. Our objective was to identify factors that potentially limit pe...

C. Baldwin M. Polacek S. Bonar

2002-01-01

310

The missing link: Lean leadership.  

PubMed

People often equate "Lean" with the tools that are used to create efficiencies and standardize processes. However, implementing tools represents at most 20 percent of the effort in Lean transformations. The other 80 percent of the effort is expended on changing leaders' practices and behaviors, and ultimately their mindset. Senior management has an essential role in establishing conditions that enable that 80 percent of the effort to succeed. Their involvement includes establishing governance arrangements that cross divisional boundaries, supporting a thorough, long-term vision of the organization's value-producing processes, and holding everyone accountable for meeting Lean commitments. This is accomplished through regular, direct involvement. When upper management sets the example, durable Lean success and an increasingly Lean leadership mindset follow. PMID:19791484

Mann, David

2009-01-01

311

Mt. St. Helens ash in lakes in the Lower Grand Coulee, Washington State  

SciTech Connect

In 1979, an experiment to assess the effects of an introduced predator, cutthroat trout (Salmo clarki henshawi), on the biota of two alkaline lakes, Soap Lake and Lake Lenore, in Washington was initiated. This report discusses the effects of the Mt. St. Helens eruption and associated ash fall on the experiment. (ACR)

Edmondson, W.T.; Litt, A.H.

1983-01-01

312

AGE DEPENDENT MODEL OF PCB IN A LAKE MICHIGAN FOOD CHAIN  

EPA Science Inventory

An age-dependent food chain model that considers species bioenergetics and toxicant exposure through water and food was developed. It was successfully applied to PCB contamination in the Lake Michigan lake trout food chain represented by phytoplankton, Mysis, alewife, and lake tr...

313

Biomass of deepwater demersal forage fishes in Lake Huron, 1994–2007: Implications for offshore predators  

Microsoft Academic Search

We estimated the biomass of deepwater demersal forage fishes (those species common in the diets of lake trout and Chinook salmon) in Lake Huron during the period 1994–2007. The estimated total lake-wide biomass of deepwater demersal fishes in 2007 was reduced by 87 percent of that observed in 1994. Alewife biomass remained near the record low observed in 2004. Biomass

Edward F. Roseman; Stephen C. Riley

2009-01-01

314

Control of the sea lamprey (Petromyzon marinus) in Lake Superior, 1953-70  

USGS Publications Warehouse

Although sea lamprey control and heavy plantings of hatchery-reared stock had restored lake trout abundance to prelamprey levels in many areas by 1970, the trout had not yet become self-sustaining. Additional effort will be required to further reduce the effects of lamprey predation.

Smith, Bernard R.; Tibbles, J. James; Johnson, B. G. H.

1974-01-01

315

Lean NOx Trap Catalysis for Lean Natural Gas Engine Applications  

SciTech Connect

Distributed energy is an approach for meeting energy needs that has several advantages. Distributed energy improves energy security during natural disasters or terrorist actions, improves transmission grid reliability by reducing grid load, and enhances power quality through voltage support and reactive power. In addition, distributed energy can be efficient since transmission losses are minimized. One prime mover for distributed energy is the natural gas reciprocating engine generator set. Natural gas reciprocating engines are flexible and scalable solutions for many distributed energy needs. The engines can be run continuously or occasionally as peak demand requires, and their operation and maintenance is straightforward. Furthermore, system efficiencies can be maximized when natural gas reciprocating engines are combined with thermal energy recovery for cooling, heating, and power applications. Expansion of natural gas reciprocating engines for distributed energy is dependent on several factors, but two prominent factors are efficiency and emissions. Efficiencies must be high enough to enable low operating costs, and emissions must be low enough to permit significant operation hours, especially in non-attainment areas where emissions are stringently regulated. To address these issues the U.S. Department of Energy and the California Energy Commission launched research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocating Internal Combustion Engines (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded by the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and <0.1 g/bhp-hr emissions of oxides of nitrogen (NOx). A summary of the goals for the ARES program is given in Table 1-1. ARICE 2007 goals are 45% thermal efficiency and <0.015 g/bhp-hr NOx. Several approaches for improving the efficiency and emissions of natural gas reciprocating engines are being pursued. Approaches include: stoichiometric engine operation with exhaust gas recirculation and three-way catalysis, advanced combustion modes such as homogeneous charge compression ignition, and extension of the lean combustion limit with advanced ignition concepts and/or hydrogen mixing. The research presented here addresses the technical approach of combining efficient lean spark-ignited natural gas combustion with low emissions obtained from a lean NOx trap catalyst aftertreatment system. This approach can be applied to current lean engine technology or advanced lean engines that may result from related efforts in lean limit extension. Furthermore, the lean NOx trap technology has synergy with hydrogen-assisted lean limit extension since hydrogen is produced from natural gas during the lean NOx trap catalyst system process. The approach is also applicable to other lean engines such as diesel engines, natural gas turbines, and lean gasoline engines; other research activities have focused on those applications. Some commercialization of the technology has occurred for automotive applications (both diesel and lean gasoline engine vehicles) and natural gas turbines for stationary power. The research here specifically addresses barriers to commercialization of the technology for large lean natural gas reciprocating engines for stationary power. The report presented here is a comprehensive collection of research conducted by Oak Ridge National Laboratory (ORNL) on lean NOx trap catalysis for lean natural gas reciprocating engines. The research was performed in the Department of Energy's ARES program from 2003 to 2007 and covers several aspects of the technology. All studies were conducted at ORNL on a Cummins C8.3G+ natural gas engine chosen based on industry input to simulate large lean natural gas engines. Specific technical areas addressed by the research include: NOx reduction efficiency, partial oxidation and reforming chemistry, and the effects of sulfur poisons on the partial oxidation

Parks, II, James E [ORNL; Storey, John Morse [ORNL; Theiss, Timothy J [ORNL; Ponnusamy, Senthil [ORNL; Ferguson, Harley Douglas [ORNL; Williams, Aaron M [ORNL; Tassitano, James B [ORNL

2007-09-01

316

Lake fisheries need lamprey control and research  

USGS Publications Warehouse

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.

Moffett, James W.

1953-01-01

317

What is the leanness level of your organisation in lean transformation implementation? An integrated lean index using ANP approach  

Microsoft Academic Search

We develop a lean index to assess the leanness level of the organisation in sustaining lean transformation. This ‘lean index’ is developed from theory, and is quantified using a multi-criteria approach i.e., analytic network process (ANP). This index provides a useful measure for sustainable lean performance because it adopts a holistic approach of performance measurement based on the socio-technical perspective

Wai Peng Wong; Joshua Ignatius; Keng Lin Soh

2012-01-01

318

Lean Six Sigma in a hospital  

Microsoft Academic Search

Abstract:Hospitals today face major challenges. Patients demand quality of care to be improved continuously. Health insurance companies demand the lowest possible prices. Lean Six Sigma is a program that can help healthcare providers to achieve these (seemingly) conflicting goals. Lean Six Sigma is an integration of Six Sigma and Lean Manufacturing, both quality improvement programs originating from industry. Lean and

Heuvel van den J; R. J. M. M. Does; Koning de H

2006-01-01

319

A leanness measure of manufacturing systems for quantifying impacts of lean initiatives  

Microsoft Academic Search

Various lean tools and techniques have been developed for process improvement. In order to track the progress, lean metrics were developed correspondingly. However, an integrated and quantitative measure of overall leanness level has not been established. This paper proposes a unit-invariant leanness measure with a self-contained benchmark to quantify the leanness level of manufacturing systems. Evolved from the concept of

Hung-da Wan; F. Frank Chen

2008-01-01

320

Universal Indicator Rainbow Trout  

NSDL National Science Digital Library

In this activity on page 2 of the PDF, learners discover how color changes can help scientists distinguish between acids and bases. Learners create colorful rainbow trout artwork using universal indicator solution and various household liquids. Safety note: learners must wear safety goggles.

Society, American C.

2001-01-01

321

Genetic variation at the mtDNA ND1 locus among North American wild and hatchery brown trout ( Salmo trutta)  

Microsoft Academic Search

Despite extensive knowledge of mitochondrial DNA (mtDNA) variation in European brown trout (Salmo trutta) populations, little is known about their nucleotide sequence variation in North America. The objective of this study was to quantify single nucleotide polymorphisms (SNPs) at the ND-1 mtDNA locus of 62 brown trout from hatcheries in Michigan and Wisconsin as well as Michigan streams and Lake

Shelby S. Johnson; Mark R. Luttenton; Alexey G. Nikitin

2009-01-01

322

Bull Trout Population Responses to Reductions in Angler Effort and Retention Limits  

Microsoft Academic Search

We compared historical (1977–1980) and recent (1997–2001) abundance, catch-per-unit-effort (CPUE), and growth data to assess whether the implementation of restrictive sportfishing regulatory regimes in the 1990s led to changes in abundance and population structure of bull trout Salvelinus confluentus in two small Rocky Mountain lakes in Alberta, Canada. For remote Harrison Lake, we used changes in gill-net CPUE to infer

Brian R. Parker; David W. Schindler; Frank M. Wilhelm; David B. Donald

2007-01-01

323

Defect reduction through Lean methodology  

NASA Astrophysics Data System (ADS)

Lean manufacturing is a systematic method of identifying and eliminating waste. Use of Lean manufacturing techniques at the IBM photomask manufacturing facility has increased efficiency and productivity of the photomask process. Tools, such as, value stream mapping, 5S and structured problem solving are widely used today. In this paper we describe a step-by-step Lean technique used to systematically decrease defects resulting in reduced material costs, inspection costs and cycle time. The method used consists of an 8-step approach commonly referred to as the 8D problem solving process. This process allowed us to identify both prominent issues as well as more subtle problems requiring in depth investigation. The methodology used is flexible and can be applied to numerous situations. Advantages to Lean methodology are also discussed.

Purdy, Kathleen; Kindt, Louis; Densmore, Jim; Benson, Craig; Zhou, Nancy; Leonard, John; Whiteside, Cynthia; Nolan, Robert; Shanks, David

2010-09-01

324

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

USGS Publications Warehouse

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.

Gorman, O. T.

2007-01-01

325

Population Structure and Genetic Divergence of Coastal Rainbow and Redband Trout in the Upper Klamath Basin  

Microsoft Academic Search

Freshwater-resident coastal rainbow trout Oncorhynchus mykiss irideus and the anadromous form of the subspecies, coastal steelhead (summer and winter runs), are present throughout the lower Klamath River–Trinity River system. Although coastal steelhead and other anadromous salmonids historically migrated into the Upper Klamath Basin (which encompasses the upper Klamath River and Upper Klamath Lake) and associated tributaries, the construction of Copco

Devon E. Pearse; Stephanie L. Gunckel; Steven E. Jacobs

2011-01-01

326

Size as a Determinant of Growth Rate in Rainbow Trout Salmo Gairdneri  

Microsoft Academic Search

Growth rates of rainbow trout have been calculated and compared for 27 British Columbia lakes. The use of absolute age as a reference point is unsatisfactory in many cases where comparisons involve fish of the same age but of dissimilar sizes. Changes in metabolic efficiency may be primarily a function of size and not of age. An alternative method is

P. A. Larkin; J. G. Terpenning; R. R. Parker

1957-01-01

327

Lean staged combustion assembly  

SciTech Connect

This patent describes a lean staged combustion assembly. It comprises: means for channeling compressed air including a pilot portion and a main portion. This patent also describes an annular combustor outer liner having an upstream end and a downstream end; an annular combustor inner liner having an upstream end and a downstream end and spaced from the outer liner; means for obtaining pilot stage combustion of a fuel-air pilot mixture for generating pilot stage combustion gases between the inner and outer liners using the pilot portion of compressed air channeled to the combustor by the channeling means, a pilot combustor first liner having an upstream end and a downstream end and spaced from the outer liner to define a first pilot combustion zone; a pilot combustor second liner having an upstream end and a downstream end and spaced from the inner liner to define a second pilot combustion zone; circumferentially spaced first fuel injectors and corresponding first air swirlers extending between the first and outer liners at the upstream ends thereof; and circumferentially spaced second fuel injectors and corresponding second air swirlers extending between the second and inner liners at the upstream ends thereof.

Sabla, P.E.; Dodds, W.J.; Tucker, T.M.

1992-03-31

328

Species succession and fishery exploitation in the Great Lakes  

USGS Publications Warehouse

The species composition of fish in the Great Lakes has undergone continual change since the earliest records. Some changes were caused by enrichment of the environment, but others primarily by an intensive and selective fishery for certain species. Major changes related to the fishery were less frequent before the late 1930's than in recent years and involved few species. Lake sturgeon (Acipenser fulvescens) were overexploited knowingly during the late 1800's because they interfered with fishing for preferred species; sturgeon were greatly reduced in all lakes by the early 1900's. Heavy exploitation accompanied sharp declines of lake herring (Leucichthys artedi) in Lake Erie during the 1920's and lake whitefish (Coregonus clupeaformis) in Lake Huron during the 1930's. A rapid succession of fish species in Lakes Huron, Michigan, and Superior that started about 1940 has been caused by selective predation by the sea lamprey (Petromyzon marinus) on native predatory species, and the resultant shifting emphasis of the fishery and species interaction as various species declined. Lake trout (Salvelinus namaycush) and burbot (Lota lota), the deepwater predators, were depleted first; this favored their prey, the chubs (Leucichthys spp.). The seven species of chubs were influenced differently according to differences in size. Fishing emphasis and predation by sea lampreys were selective for the largest species of chubs as lake trout and burbot declined. A single slow-growing chub, the bloater, was favored and increased, but as the large chubs declined the bloater was exploited by a new trawl fishery. The growth rate and size of the bloater increased, making it more vulnerable to conventional gillnet fishery and lamprey predation. This situation in Lakes Michigan and Huron favored the small alewife (Alosa pseudoharengus) which had recently become established in the upper Great Lakes, and the alewife increased rapidly and dominated the fish stocks of the lakes. The successive 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.

Smith, Stanford H.

1968-01-01

329

Temporary Restoration of Bull Trout Passage at Albeni Falls Dam  

SciTech Connect

This study was designed to monitor movements of bull trout that were provided passage above Albeni Falls Dam, Pend Oreille River. Electrofishing and angling were used to collect bull trout below the dam. Tissue samples were collected from each bull trout and sent to the U. S. Fish and Wildlife Service Abernathy Fish Technology Center Conservation Genetics Lab, Washington. The DNA extracted from tissue samples were compared to a catalog of bull trout population DNA from the Priest River drainage, Lake Pend Oreille tributaries, and the Clark Fork drainage to determine the most probable tributary of origin. A combined acoustic radio or radio tag was implanted in each fish prior to being transported and released above the dam. Bull trout relocated above the dam were able to volitionally migrate into their natal tributary, drop back downstream, or migrate upstream to the next dam. A combination of stationary radio receiving stations and tracking via aircraft, boat, and vehicle were used to monitor the movement of tagged fish to determine if the spawning tributary it selected matched the tributary assigned from the genetic analysis. Seven bull trout were captured during electrofishing surveys in 2008. Of these seven, four were tagged and relocated above the dam. Two were tagged and left below the dam as part of a study monitoring movements below the dam. One was immature and too small at the time of capture to implant a tracking tag. All four fish released above the dam passed by stationary receivers stations leading into Lake Pend Oreille and no fish dropped back below the dam. One of the radio tags was recovered in the tributary corresponding with the results of the genetic test. Another fish was located in the vicinity of its assigned tributary, which was impassable due to low water discharge at its mouth. Two fish have not been located since entering the lake. Of these fish, one was immature and not expected to enter its natal tributary in the fall of 2008. The other fish was large enough to be mature, but at the time of capture its sex was unable to be determined, indicating it may not have been mature at the time of capture. These fish are expected to enter their natal tributaries in early summer or fall of 2009.

Paluch, Mark; Scholz, Allan; McLellan, Holly [Eastern Washington University Department of Biology; Olson, Jason [Kalispel Tribe of Indians Natural Resources Department

2009-07-13

330

Temporary Restoration of Bull Trout Passage at Albeni Falls Dam, 2008 Progress Report.  

SciTech Connect

The goal of this project is to provide temporary upstream passage of bull trout around Albeni Falls Dam on the Pend Oreille River, Idaho. Our specific objectives are to capture fish downstream of Albeni Falls Dam, tag them with combination acoustic and radio transmitters, release them upstream of Albeni Falls Dam, and determine if genetic information on tagged fish can be used to accurately establish where fish are located during the spawning season. In 2007, radio receiving stations were installed at several locations throughout the Pend Oreille River watershed to detect movements of adult bull trout; however, no bull trout were tagged during that year. In 2008, four bull trout were captured downstream of Albeni Falls Dam, implanted with transmitters, and released upstream of the dam at Priest River, Idaho. The most-likely natal tributaries of bull trout assigned using genetic analyses were Grouse Creek (N = 2); a tributary of the Pack River, Lightning Creek (N = 1); and Rattle Creek (N = 1), a tributary of Lightning Creek. All four bull trout migrated upstream from the release site in Priest River, Idaho, were detected at monitoring stations near Dover, Idaho, and were presumed to reside in Lake Pend Oreille from spring until fall 2008. The transmitter of one bull trout with a genetic assignment to Grouse Creek was found in Grouse Creek in October 2008; however, the fish was not found. The bull trout assigned to Rattle Creek was detected in the Clark Fork River downstream from Cabinet Gorge Dam (approximately 13 km from the mouth of Lightning Creek) in September but was not detected entering Lightning Creek. The remaining two bull trout were not detected in 2008 after detection at the Dover receiving stations. This report details the progress by work element in the 2008 statement of work, including data analyses of fish movements, and expands on the information reported in the quarterly Pisces status reports.

Bellgraph, Brian J. [Pacific Northwest National Laboratory

2009-03-31

331

Status of Yellowstone Cutthroat Trout in Idaho  

Microsoft Academic Search

In this study, we electrofished 961 study sites to estimate the abundance of trout (in streams only) throughout the upper Snake River basin in Idaho (and portions of adjacent states) to determine the current status of Yellowstone cutthroat trout Oncorhynchus clarkii bouvierii and other nonnative salmonids and to assess introgressive hybridization between Yellowstone cutthroat trout and rainbow trout O. mykiss.

Kevin A. Meyer; Daniel J. Schill; James A. Lamansky Jr; Matthew R. Campbell; Christine C. Kozfkay

2006-01-01

332

Long-term effects of a trophic cascade in a large lake ecosystem  

PubMed Central

Introductions or invasions of nonnative organisms can mediate major changes in the trophic structure of aquatic ecosystems. Here we document multitrophic level impacts in a spatially extensive system that played out over more than a century. Positive interactions among exotic vertebrate and invertebrate predators caused a substantial and abrupt shift in community composition resulting in a trophic cascade that extended to primary producers and to a nonaquatic species, the bald eagle. The opossum shrimp, Mysis diluviana, invaded Flathead Lake, Montana, the largest freshwater lake in the western United States. Lake trout had been introduced 80 y prior but remained at low densities until nonnative Mysis became established. The bottom-dwelling mysids eliminated a recruitment bottleneck for lake trout by providing a deep water source of food where little was available previously. Lake trout subsequently flourished on mysids and this voracious piscivore now dominates the lake fishery; formerly abundant kokanee were extirpated, and native bull and westslope cutthroat trout are imperiled. Predation by Mysis shifted zooplankton and phytoplankton community size structure. Bayesian change point analysis of primary productivity (27-y time series) showed a significant step increase of 55 mg C m?2 d?1 (i.e., 21% rise) concurrent with the mysid invasion, but little trend before or after despite increasing nutrient loading. Mysis facilitated predation by lake trout and indirectly caused the collapse of kokanee, redirecting energy flow through the ecosystem that would otherwise have been available to other top predators (bald eagles).

Ellis, Bonnie K.; Stanford, Jack A.; Goodman, Daniel; Stafford, Craig P.; Gustafson, Daniel L.; Beauchamp, David A.; Chess, Dale W.; Craft, James A.; Deleray, Mark A.; Hansen, Barry S.

2011-01-01

333

Long-term effects of a trophic cascade in a large lake ecosystem.  

PubMed

Introductions or invasions of nonnative organisms can mediate major changes in the trophic structure of aquatic ecosystems. Here we document multitrophic level impacts in a spatially extensive system that played out over more than a century. Positive interactions among exotic vertebrate and invertebrate predators caused a substantial and abrupt shift in community composition resulting in a trophic cascade that extended to primary producers and to a nonaquatic species, the bald eagle. The opossum shrimp, Mysis diluviana, invaded Flathead Lake, Montana, the largest freshwater lake in the western United States. Lake trout had been introduced 80 y prior but remained at low densities until nonnative Mysis became established. The bottom-dwelling mysids eliminated a recruitment bottleneck for lake trout by providing a deep water source of food where little was available previously. Lake trout subsequently flourished on mysids and this voracious piscivore now dominates the lake fishery; formerly abundant kokanee were extirpated, and native bull and westslope cutthroat trout are imperiled. Predation by Mysis shifted zooplankton and phytoplankton community size structure. Bayesian change point analysis of primary productivity (27-y time series) showed a significant step increase of 55 mg C m(-2) d(-1) (i.e., 21% rise) concurrent with the mysid invasion, but little trend before or after despite increasing nutrient loading. Mysis facilitated predation by lake trout and indirectly caused the collapse of kokanee, redirecting energy flow through the ecosystem that would otherwise have been available to other top predators (bald eagles). PMID:21199944

Ellis, Bonnie K; Stanford, Jack A; Goodman, Daniel; Stafford, Craig P; Gustafson, Daniel L; Beauchamp, David A; Chess, Dale W; Craft, James A; Deleray, Mark A; Hansen, Barry S

2011-01-03

334

Status of Oregon's Bull Trout.  

SciTech Connect

Limited historical references indicate that bull trout Salvelinus confluentus in Oregon were once widely spread throughout at least 12 basins in the Klamath River and Columbia River systems. No bull trout have been observed in Oregon's coastal systems. A total of 69 bull trout populations in 12 basins are currently identified in Oregon. A comparison of the 1991 bull trout status (Ratliff and Howell 1992) to the revised 1996 status found that 7 populations were newly discovered and 1 population showed a positive or upgraded status while 22 populations showed a negative or downgraded status. The general downgrading of 32% of Oregon's bull trout populations appears largely due to increased survey efforts and increased survey accuracy rather than reduced numbers or distribution. However, three populations in the upper Klamath Basin, two in the Walla Walla Basin, and one in the Willamette Basin showed decreases in estimated population abundance or distribution.

Buchanan, David V.; Hanson, Mary L.; Hooton, Robert M.

1997-10-01

335

Field study of Ra accumulation in trout with assessment of radiation dose to man  

SciTech Connect

The purpose of this study was to determine the concentrations of /sup 226/Ra in edible fish from surface ponds near an open pit U mine. Because one reclamation plan for the U mine proposed formation of an artificial lake in the open pit, potential radiation dose to man from ingestion of fish needed to be investigated. Trout were collected from four existing ponds which varied in mean /sup 226/Ra concentration from 12-33 pCi/l and in Ca concentration from 30-330 mg Ca/l. Radium and Ca accumulation in trout flesh, skin, fins and bone were measured. Geometric mean concentrations of /sup 226/Ra in trout flesh from four ponds ranged from 6.3-30 pCi/kg wet weight. The distribution of Ra in the trout body was similar to that of Ca. The calculated dose equivalent commitment to human endosteal tissue range from 0.2-2 mrem per fish consumed, depending on the assumed dietary and environmental parameters. Neglecting the consumption of trout skin underestimated the ingestion dose from /sup 226/Ra by a factor of 5-10. Estimated annual dose equivalent rates to human endosteal tissue ranged from 1.0-83 mrem/yr for an individual who consumed one fish per week for a 50-yr period. The dose to man from ingestion of /sup 226/Ra in fish would not likely preclude the establishment of a recreational lake at this site.

Ropes, S.K.; Whicker, F.W.

1985-08-01

336

Learning Lean: A Survey of Industry Lean Needs  

ERIC Educational Resources Information Center

The authors examined business practitioners' preferences for higher education curricula design in general and for what graduates should know about Lean, or waste-reduction efforts. The authors conducted a Web-based survey and found that practitioners are not as concerned about graduates' possessing specific technical skills as they are about them…

Fliedner, Gene; Mathieson, Kieran

2009-01-01

337

Lean Six Sigma in a hospital  

Microsoft Academic Search

Abstract: Hospitals today face major challenges. Patients demand ,quality of care to be ,improved ,continuously. Health insurance companies ,demand ,the lowest possible prices. Lean Six Sigma is a programme,that can help healthcare providers to achieve,these (seemingly) conflicting goals. Lean Six Sigma is an integration of Six Sigma and Lean Manufacturing, both quality improvement programmes,originating from ,industry. Lean and ,Six Sigma

Jaap Van Den Heuvel; Canisius Wilhelmina Hospital

2006-01-01

338

Intra-strain dioxin sensitivity and morphometric effects in swim-up rainbow trout (Oncorhynchus mykiss)  

USGS Publications Warehouse

Inter and intra-specific differences in sensitivity of early life stage salmonids to 2,3,7,8-TCDD exposure have been reported, but intra-strain differences have not been found in the literature. Our results indicate that intra-strain variability in terms of embryo mortality (LD50) is small in Eagle Lake strain of rainbow trout, LD50 values ranging from 285 to 457 pg TCDD egg g-1. These results confirm Eagle Lake as a less sensitive strain within rainbow trout, and do not indicate overlap with reported LD50 values for brook or lake trout. Our results also demonstrate that although generalized edema in regions including the yolk-sac are frequently associated with mortality following dioxin exposure, not all edematous fish die. We detected dose-dependent decreases in cranial length, eye diameter, mass, and total length (P<0.05) in viable swim-up rainbow trout. These effects are presumed to indicate more subtle dose-dependent disruptions of the viteline vein vasculature and, therefore, in access to energy sources. A tendency for dose-dependent decrease in liver glycogen reserves concurred with previous results on salmonids and with the well described TCDD-induced alterations in intermediate metabolism of rats and chicken embryos (wasting syndrome). This syndrome could be contributing to the reduced growth that we observed. ?? 2004 Elsevier Inc. All rights reserved.

Carvalho, P. S. M.; Noltie, D. B.; Tillitt, D. E.

2004-01-01

339

Classification scheme for lean manufacturing tools  

Microsoft Academic Search

For the past few years almost every manufacturing industry has been trying to get 'lean'. A headlong rush to become lean also resulted in many misapplications of existing lean manufacturing tools often due to inadequate understanding of the purpose of tools. While tool descriptions abound, there is no way systematically to link a manufacturing organization to its problems and to

S. J. Pavnaskar; J. K. Gershenson; A. B. Jambekar

2003-01-01

340

Computer simulation to manage lean manufacturing systems  

Microsoft Academic Search

There is a difference between a lean manufacturing system and a manufacturing system that just applies lean techniques. This paper addresses the previous statement through using computer simulation to explore the impact of applying just in time lean policy on a traditional inventory based production system. A system dynamics model is introduced to capture the different components of the production

Ahmed Deif

2010-01-01

341

LEAN VALUE CREATION METRICS FOR NETWORKED ORGANISATIONS  

Microsoft Academic Search

Research about lean has been mainly focused on process or product innovation. Innovation should not on ly be applied on product level but also on the way the va lue chain and system are organised. This research t akes the lean principles to a higher aggregation; to an orga nisation level. Adoption of lean principles and the 3C model -

Wouter W. A. Beelaerts; Sakyi O. B. Amo; Sicco C. Santema

342

Trends and approaches in lean healthcare  

Microsoft Academic Search

Purpose – The aim of this paper is to provide a review of the existing literature on lean healthcare. It seeks to describe how this concept has being applied and to assess how trends and methods of approach in lean healthcare have evolved over the years. Design\\/methodology\\/approach – The paper surveys the applications of lean healthcare in the current literature

Luciano Brandao de Souza

2009-01-01

343

Downsizing: is it always lean and mean?  

Microsoft Academic Search

Discusses how downsizing has been associated with the move towards lean working in organisations and with having negative consequences for employees. Considers the extent to which downsizing is lean and mean drawing on an extensive review of the available literature. Concludes that downsizing is rarely lean since it usually takes the form of quantitative changes in employment rather than qualitative

Nicholas Kinnie; Sue Hutchinson; John Purcell

1998-01-01

344

The missing arguments of lean construction  

Microsoft Academic Search

The emerging concept of lean construction is concerned with the application of lean thinking to the construction industry. The ideas of lean thinking seem set to dominate the UK construction industry's quest to improve quality and efficiency. However, the current debate is based on a highly selective interpretation of the available literature. The extent to which the Japanese model of

S. D. Green

1999-01-01

345

Lean management methods for complex projects  

Microsoft Academic Search

This paper reviews the principles, history, applications and current research issues associated with lean construction, in order to provide a foundation for future research in this area. Lean is a management approach that emerged in the automobile industry and spread initially to other forms of repetitive manufacturing and ultimately to service industries. Despite its success in practice, the lean philosophy

Glenn Ballard; Iris Tommelein

2012-01-01

346

IMPLEMENTING LEAN IN CONSTRUCTION: HOW TO SUCCEED  

Microsoft Academic Search

Implementing lean means an organization (project or enterprise) transforms itself from a current state to a future state vision that incorporates a lean ideal. This paper proposes a strategy for organizations to increase the likelihood of success when going through a lean transformation. This approach considers construction projects as the basis for transformation, and proposes a narrow and deep implementation

Roberto Arbulu; Todd Zabelle

347

Applying Lean Principles to Production Scheduling  

Microsoft Academic Search

When exploring the Lean issue, literature appears to have countless definitions to describe that individual topic, causing misinterpretations between academics and professionals alike. The mainstream Lean implementation ventures are merely a compilation of tools and methods that are forced down the organisational hierarchy from higher tiers, due to other organisations publicising lean in improving their enterprise\\

Mustafa Ramzi Salman; Roman van der Krogt; James Little; John Geraghty

348

Fragmentation of riverine systems: the genetic effects of dams on bull trout (Salvelinus confluentus) in the Clark Fork River system.  

PubMed

Migratory bull trout (Salvelinus confluentus) historically spawned in tributaries of the Clark Fork River, Montana and inhabited Lake Pend Oreille as subadult and adult fish. However, in 1952 Cabinet Gorge Dam was constructed without fish passage facilities disrupting the connectivity of this system. Since the construction of this dam, bull trout populations in upstream tributaries have been in decline. Each year adult bull trout return to the base of Cabinet Gorge Dam when most migratory bull trout begin their spawning migration. However, the origin of these fish is uncertain. We used eight microsatellite loci to compare bull trout collected at the base of Cabinet Gorge Dam to fish sampled from both above and further downstream from the dam. Our data indicate that Cabinet Gorge bull trout are most likely individuals that hatched in above-dam tributaries, reared in Lake Pend Oreille, and could not return to their natal tributaries to spawn. This suggests that the risk of outbreeding depression associated with passing adults over dams in the Clark Fork system is minimal compared to the potential genetic and demographic benefits to populations located above the dams. PMID:11380874

Neraas, L P; Spruell, P

2001-05-01

349

The Classification and Scientific Names of Rainbow and Cutthroat Trouts  

Microsoft Academic Search

Two unambiguous discoveries involving rainbow trout require scientific name changes. First, the rainbow trout has been demonstrated to be the same species as the Kamchatka trout. Second, studies of osteology and biochemistry of trout and salmon show that rainbow and cutthroat trout, and their close relatives, the golden, Mexican golden, Gila, and Apache trouts, are more closely related to Pacific

Gerald R. Smith; Ralph F. Stearley

1989-01-01

350

Customer focused lean production development  

Microsoft Academic Search

This research concerns changing a factory into a lean organization. The main issues treated are as follows: what are the features of the solution, how the change is conducted, what it requires and what is the role of the researcher\\/consultant in the change process. The research was conducted in a Finnish elevator factory. It was started in the fall of

K. Kosonen; P. Buhanist

1995-01-01

351

Lean production and the Internet  

Microsoft Academic Search

In this paper, the implications for lean production systems of the Internet are explored. Does the World Wide Web facilitate the implementation of Just-In-Time (JIT) production systems, or alternatively, can it serve as a substitute for JIT? The possible effects on supply chains, production scheduling, inventory control, procurement, quality improvement, and the workforce are some of the issues addressed. Some

Peter Bruun; Robert N Mefford

2004-01-01

352

Assessing changes towards lean production  

Microsoft Academic Search

Develops a model which operationalizes the different principles in lean production, with a focus on those that concern the work organization in the manufacturing part of a company. The model has been developed using available theory and has also been tried out in a clinical field study. The model has implications both for research and practice. For research, it can

Christer Karlsson; Pär Åhlström

1996-01-01

353

Explore it! Fish  

NSDL National Science Digital Library

Species profiles of 10 common, and often less-publicized, Great Lakes fishes. Each profile describes the fish's length, weight, coloring, common names, and preferred habitat. Site also discusses its creator, Cliff Kraft, and why he selected these 10 particular species. Profiles include: the lake sturgeon, lake herring, brook stickleback, brook trout, longnose sucker, deepwater sculpin, spottail shiner, siscowet, logperch, and lean lake trout.

354

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

USGS Publications Warehouse

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.

Hoff, Michael H.

2004-01-01

355

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

USGS Publications Warehouse

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.

Hoff, M. H.

2004-01-01

356

Trends of legacy and emerging-issue contaminants in Lake Simcoe fishes  

Microsoft Academic Search

The temporal trends of legacy contaminants (i.e., mercury, PCBs, and DDT) and the current status of both legacy and emerging-issue (polybrominated diphenyl ethers (PBDEs) and polychlorinated naphthalenes (PCNs)) chemicals were examined in sport fishes from Lake Simcoe. Mercury concentrations decreased statistically significantly with time in lake trout, cisco, smallmouth bass, and yellow perch, consistent with assumed loading patterns. In contrast,

Sarah B. Gewurtz; Satyendra P. Bhavsar; Donald A. Jackson; Emily Awad; Jennifer G. Winter; Terry M. Kolic; Eric J. Reiner; Rusty Moody; Rachael Fletcher

2011-01-01

357

An Inexpensive Modified Emergent-Fry Trap for Lake-Spawning Salmonids  

Microsoft Academic Search

Emergent-fry traps, designed for sampling salmonid fry, have been particularly valuable for evaluating the reproductive success of stocked lake trout Salvelinus namaycush in the Great Lakes. Traditional fry traps are constructed with a welded iron base and riveted walls and are therefore heavy and bulky as well as expensive. We describe an inexpensive new design with a semi-rigid base and

Michael A. Chotkowski; J. Ellen Marsden; Brian J. Ellrott

2002-01-01

358

An Ecosystem Perspective on Re-establishing Native Deepwater Fishes in the Laurentian Great Lakes  

Microsoft Academic Search

Herein we examine scientific questions related to successful re-establishment of native deepwater fish communities in the Laurentian Great Lakes, and we (1) propose a conceptual model for native deepwater fish communities; (2) review current research and identify research hypotheses for lake trout Salvelinus namaycush, pelagic ciscoes Coregonus spp., and sculpins (Cottus spp. and Myoxocephalus spp.); (3) pose research questions emerging

Mara S. Zimmerman; Charles C. Krueger

2009-01-01

359

LEAN MANUFACTURING MEASUREMENT: THE RELATIONSHIP BETWEEN LEAN ACTIVITIES AND LEAN METRICS  

Microsoft Academic Search

Lean Manufacturing was developed by Toyota Motor company to address their specific needs in a restricted market in times of economic trouble. These concepts have been studied and proven to be transferrable and applicable to a wide variety of indus- tries. This paper aims to integrate a set of metrics that have been pro- posed by different authors in such

DIEGO FERNANDO; MANOTAS DUQUE; LEONARDO RIVERA CADAVID

360

Bull Trout Distribution and Abundance in the Waters on and Bordering the Warm Springs Reservation : 2002 Annual Report.  

SciTech Connect

The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be healthy in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et al. 1997). Little was known about bull trout in the lower Deschutes basin until BPA funded project No.9405400 began during 1998. In this progress report we describe the findings to date from this multi-year study aimed at determining the life history, habitat needs and limiting factors of bull trout in the lower Deschutes subbasin. Juvenile bull trout and brook trout (Salvelinus fontinalis) relative abundance has been assessed in the Warm Springs River and Shitike Creek since 1999. In the Warm Springs R. the relative densities of juvenile bull trout and brook trout were .003 fish/m{sup 2} and .001 fish/m{sup 2} respectively during 2002. These densities were the lowest recorded in the Warm Springs River during the period of study. In Shitike Cr. the relative densities of juvenile bull trout and brook trout were .025 fish/m{sup 2} and .01 fish/m{sup 2} respectively during 2002. The utility of using index reaches to monitor trends in juvenile bull trout and brook trout relative abundance in the Warm Springs R. has been assessed since 1999. During 2002 the mean relative densities of juvenile bull trout within the 2.4 km study area was higher than what was observed in four index reaches. However, the mean relative densities of brook trout was slightly higher in the index reaches than what was observed in the 2.4 km study area. Habitat use by both juvenile bull trout and brook trout was determined in the Warm Springs R. Juvenile bull trout and brook trout were most abundant in pools and glides. However pools and glides comprised less than 20% of the available habitat in the study area during 2002. Multiple-pass spawning ground surveys were conducted during late August through October in the Warm Springs R. and Shitike Cr. during 2002. One-hundred and thirteen (113) redds were enumerated in the Warm Springs R. and 204 redds were found in Shitike Cr. The number of redds enumerated in both the Warm Springs R. and Shitike Cr. were the most redds observed since surveys began in 1998. Spatial and temporal distribution in spawning within the Warm Springs R. and Shitike Cr. is discussed. Juvenile emigration has been monitored in Shitike Creek since 1996. A total of 312 juveniles were estimated to have emigrated from Shitike Cr. during the spring, 2002. Adult escapement was monitored in the Warm Springs R. and Shitike Cr. Thirty adults were recorded at the Warm Springs National Fish Hatchery weir during 2002. This was the highest number of spawning adults recorded to date. A weir equipped with an underwater video camera near the spawning grounds was operated in the Warm Springs R. Thirty-one adults were recorded at the weir in day counts. The adult trap in Shitike Cr. was unsuccessful in capturing adult bull trout during 2002 due to damage from a spring high water event. Thermographs were placed throughout Warm Springs R. and Shitike Cr. to monitor water temperatures during bull trout migration, holding and spawning/rearing periods. During 1999-2002 water temperatures ranged from 11.8-15.4 C near the mouths during adult migration; 11.4-14.6 C during pre-spawning holding; and 6.5-8.4 C during adult spawning and juvenile rearing.

Brun, Christopher V.; Dodson, Rebekah

2003-03-01

361

Toxaphene in Great Lakes biota and air  

NASA Astrophysics Data System (ADS)

Toxaphene is a complex mixture of at least 600 hexa- through decachlorinated bornanes and bornenes, which was used as an insecticide in the United States from the 1950's until 1982, when it was banned. Toxaphene is ubiquitous in the environment, probably because of its atmospheric transport away from areas of use. Toxaphene's complex nature makes accurate quantitation difficult. I have developed a computer program to automate quantitation, thus decreasing the time required for analysis while maintaining precise quantitation. I have shown that toxaphene in lake trout (Salvelinus namaycush) and rainbow smelt (Osmerus mordax) taken from Lake Superior have not decreased as they have in the four other Great Lakes from the time of the ban though 1992. This result could be due to three possibilities: ( a) There had been a food chain perturbation that made the 1982 concentrations unusually low. (b) The physical properties of Lake Superior make the loss rate significantly lower than the other Great Lakes. (c) There are current sources of toxaphene entering the Lake Superior basin. I analyzed an extended time series of lake trout from Lake Superior and from northern Lake Michigan to test the first two hypotheses. The concentrations of toxaphene have been constant in trout from Lake Superior since the late 1970's, so hypothesis a can be negated. The northern Lake Michigan samples did not decline as greatly as the southern basin samples, so hypothesis b can not be disproved. To determine the atmospheric deposition of toxaphene to Lake Superior, I analyzed air samples collected every twelve days for sixteen months at Eagle Harbor, Michigan. The concentrations of toxaphene in these samples are similar to those found in recent studies of air collected at Traverse City, MI., but significantly lower than samples taken at a land based site in southern Ontario in 1988 and 1989. This difference in concentration may (or may not) be due to differences in sampling times or locations or in quantitation protocols. These finding imply that Lake Superior is not receiving a unique atmospheric burden, but, because I have not explored terrestrial inputs, I cannot fully nullify hypothesis c.

Glassmeyer, Susan Theresa

1998-11-01

362

Cooperation of Lean Enterprises - Techniques used for Lean Supply Chain  

Microsoft Academic Search

The paper presents the problems with integration of the companies within the supply chain. Usually the separate actions are\\u000a undertaken by the companies to implement lean tools for production systems and external logistics processes. This situation\\u000a leads to minor results or moving the costs between production and logistics processes instead of reduction. The purpose of\\u000a the paper is to present

Marek Eisler; Remigiusz Horbal; Tomasz Koch

2007-01-01

363

ACUTE TOXICITY OF KELTHANE, DURSBAN, DISULFOTON, PYDRIN, AND PERMETHRIN TO FATHEAD MINNOWS 'PIMEPHALES PROMELAS' AND RAINBOW TROUT 'SALMO GAIRDNERI'  

EPA Science Inventory

Flow-through acute lethal toxicity tests were conducted with kelthane, dursban, disulfoton, pydrin and permethrin using rainbow trout Salmo gairdneri and fathead minnows Pimephales promelas in Lake Superior water. Pydrin was the most toxic pesticide tested to both species of fish...

364

Survival Traits of Naturalized, Hatchery, and Hybrid Strains of Anadromous Rainbow Trout during Egg and Fry Stages  

Microsoft Academic Search

Two strains of anadromous rainbow trout Oncorhynchus mykiss, naturalized steelhead and “kamloops” (not the pure Kamloops strain from British Columbia, hence not capitalized) currently inhabit the Minnesota waters of Lake Superior and may have the potential to hybridize. This could compromise the genetic integrity of the naturalized steelhead population. Both strains are supplemented by annual stocking, despite the fact that

Mary T. Negus

1999-01-01

365

Genetic Differentiation of Rainbow Trout (Oncorhynchus mykiss) in the Kenai River, Alaska. Alaska Fisheries Technical Report Number 51, August 1999.  

National Technical Information Service (NTIS)

Population structure of rainbow trout (Oncorhynchus mykiss) in the Kenai River was examined by comparing two collection from the Kenai River mainstream-one collection from above and one from below Skilak Lake. Genetic variation in the Kenai River was also...

C. C. Krueger M. A. Cronin S. Miller W. J. Spearman

1999-01-01

366

Multiagent Framework for Lean Manufacturing  

Microsoft Academic Search

We have developed the manufacturing agent-based emulation system as an open framework for design and analysis of discrete manufacturing systems. MABES currently supports the transition from traditional to lean manufacturing in two major functions: analysis of alternative agent-based scheduling and control approaches that can be implemented across the extended enterprise; and real-time collaboration of design teams during manufacturing line design

Nenad Ivezic; Thomas E. Potok; Line Pouchard

1999-01-01

367

Lean six sigma in healthcare.  

PubMed

Healthcare, as with any other service operation, requires systematic innovation efforts to remain competitive, cost efficient, and up-to-date. This article outlines a methodology and presents examples to illustrate how principles of Lean Thinking and Six Sigma can be combined to provide an effective framework for producing systematic innovation efforts in healthcare. Controlling healthcare cost increases, improving quality, and providing better healthcare are some of the benefits of this approach. PMID:16749293

de Koning, Henk; Verver, John P S; van den Heuvel, Jaap; Bisgaard, Soren; Does, Ronald J M M

368

Acute Toxicity of Thiocyanate to Trout.  

National Technical Information Service (NTIS)

Acutely toxic effects of thiocyanate SCN(-) were studied in brook trout Salvelinus fontinalis and rainbow trout Salmo gairdneri exposed to concentrations of up to 518 mg/l SCN(-). These fishes were capable of accumulating thiocyanate against its concentra...

T. A. Heming R. V. Thurston E. L. Meyn R. K. Zajdel

1985-01-01

369

Universal Indicator Rainbow Trout  

NSDL National Science Digital Library

In this activity, learners cut out a fish and then "paint" it using universal indicator and acids and bases. The initial coat of indicator changes the color of the paper (it will turn a salmon color if the paper is acidic, and green if it is considered acid-free). From there, adding acids (such as lemon juice) and bases (such as laundry detergent) will further change the color. Universal indicator responds to a wide range of acids and bases, so other home chemicals (shampoo, vinegar, etc.) could be tried to create different colors. For older learners, a paper pattern other than a "rainbow trout" (such as a rainforest bird or other colorful animal) can be used.

Society, American C.

2008-01-01

370

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2001.  

SciTech Connect

Bull trout Salvelinus confluentus exhibit a number of life history strategies. Stream-resident bull trout complete their life cycle in their natal tributaries. Migratory bull trout spawn in tributary streams where juvenile fish usually spend from one to four years before migrating to either a larger river (fluvial) or lake (adfluvial) where they rear before returning to the tributary stream to spawn (Fraley and Shepard 1989). These migratory forms occur where conditions allow movement from spawning locations to downstream waters that provide greater foraging opportunities (Dunham and Rieman 1999). Resident and migratory forms may occur together, and either form can produce resident or migratory offspring (Rieman and McIntyre 1993). The ability to migrate is important to the persistence of local bull trout populations (Rieman and McIntyre 1993). The identification of migratory corridors can help focus habitat protection efforts. Determining the life history form(s) that comprise local populations, the timing of seasonal movements, and the geographic extent of these movements are critical to bull trout protection and recovery efforts. This section describes work accomplished in 2001 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In the Grande Ronde and Walla Walla basins, we continued to monitor the movements of bull trout with radio transmitters applied in 1998 (Hemmingsen, Bellerud, Gunckel and Howell 2001) and 1999 (Hemmingsen, Gunckel and Howell 2001). No new radio transmitters were applied to bull trout of the upper John Day River subbasin, Mill Creek (Walla Walla Basin), or the Grande Ronde Basin in 2001. In Mill Creek, we used traps for the fourth consecutive year to obtain data on migrant bull trout. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, and to determine the relative abundance and size of migrant fish. No traps were operated in the John Day Basin in 2001.

Hemmingsen, Alan R.; Gunckel, Stephanie L.; Sankovich, Paul M.; Howell, Philip J.

2002-12-01

371

33 CFR 117.337 - Trout River.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Trout River. 117.337 Section 117.337...Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville,...

2013-07-01

372

33 CFR 117.337 - Trout River.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Trout River. 117.337 Section 117.337...Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville,...

2010-07-01

373

Patterns of hybridization of nonnative cutthroat trout and hatchery rainbow trout with native redband trout in the Boise River, Idaho  

USGS Publications Warehouse

Hybridization is one of the greatest threats to native fishes. Threats from hybridization are particularly important for native trout species as stocking of nonnative trout has been widespread within the ranges of native species, thus increasing the potential for hybridization. While many studies have documented hybridization between native cutthroat trout Oncorhynchus clarkii and nonnative rainbow trout O. mykiss, fewer have focused on this issue in native rainbow trout despite widespread threats from introductions of both nonnative cutthroat trout and hatchery rainbow trout. Here, we describe the current genetic (i.e., hybridization) status of native redband trout O. mykiss gairdneri populations in the upper Boise River, Idaho. Interspecific hybridization was widespread (detected at 14 of the 41 sampled locations), but high levels of hybridization between nonnative cutthroat trout and redband trout were detected in only a few streams. Intraspecific hybridization was considerably more widespread (almost 40% of sampled locations), and several local populations of native redband trout have been almost completely replaced with hatchery coastal rainbow trout O. mykiss irideus; other populations exist as hybrid swarms, some are in the process of being actively invaded, and some are maintaining genetic characteristics of native populations. The persistence of some redband trout populations with high genetic integrity provides some opportunity to conserve native genomes, but our findings also highlight the complex decisions facing managers today. Effective management strategies in this system may include analysis of the specific attributes of each site and population to evaluate the relative risks posed by isolation versus maintaining connectivity, identifying potential sites for control or eradication of nonnative trout, and long-term monitoring of the genetic integrity of remaining redband trout populations to track changes in their status.

Neville, Helen M.; Dunham, Jason B.

2011-01-01

374

The promise of Lean in health care.  

PubMed

An urgent need in American health care is improving quality and efficiency while controlling costs. One promising management approach implemented by some leading health care institutions is Lean, a quality improvement philosophy and set of principles originated by the Toyota Motor Company. Health care cases reveal that Lean is as applicable in complex knowledge work as it is in assembly-line manufacturing. When well executed, Lean transforms how an organization works and creates an insatiable quest for improvement. In this article, we define Lean and present 6 principles that constitute the essential dynamic of Lean management: attitude of continuous improvement, value creation, unity of purpose, respect for front-line workers, visual tracking, and flexible regimentation. Health care case studies illustrate each principle. The goal of this article is to provide a template for health care leaders to use in considering the implementation of the Lean management system or in assessing the current state of implementation in their organizations. PMID:23274021

Toussaint, John S; Berry, Leonard L

2013-01-01

375

A comparison of susceptibility to Myxobolus cerebralis among strains of rainbow trout and steelhead in field and laboratory trials  

USGS Publications Warehouse

Three strains of rainbow trout and steelhead Oncorhynchus mykiss were evaluated for the presence of whirling disease in field and laboratory trials. In the field exposures, fingerling Salmon River steelhead and Cayuga Lake and Randolph strains of rainbow trout were placed in wire cages in an earthen, stream-fed pond in New York State that was known to harbor Myxobolus cerebralis. Control fish were held at another hatchery that was free of whirling disease. In the controlled trials at the National Fish Health Research Laboratory, fingerling steelhead and Cayuga Lake and Mount Lassen rainbow trout were exposed to triactinomyxons at low (200 triactinomyxons/fish) or high (2,000 triactinomyxons/fish) levels for 2 h. Controls of each group were sham-exposed. Following an incubation period of 154 d for laboratory trials and 180 d for field trials, cranial tissue samples were taken for spore enumeration (field and laboratory trials) and histological analyses (laboratory only). Clinical signs of disease, including whirling behavior, blacktail, and skeletal deformities, were recorded for each fish in the laboratory trial at the terminal sampling. No clinical evidence of disease was noted among fish in the field trials. Clinical signs were noted among all strains in the laboratory trials at both exposure levels, and these signs were consistently greatest for the Mount Lassen strain. Whirling and skeletal deformities were more evident in the steelhead than in the Cayuga Lake rainbow trout; blacktail was more common in the Cayuga Lake fish. In both field and laboratory trials, spore counts were significantly higher for Cayuga Lake rainbow trout than in steelhead. In laboratory trials, moderate to marked cranial tissue lesions predominated in all three strains.

Densmore, C. L.; Blazer, V. S.; Cartwright, D. D.; Schill, W. B.; Schachte, J. H.; Petrie, C. J.; Batur, M. V.; Waldrop, T. B.; Mack, A.; Pooler, P. S.

2001-01-01

376

A control framework: Insights from evidence on lean accounting  

Microsoft Academic Search

Lean manufacturing is a complete business system that combines advanced manufacturing techniques including just-in-time (JIT), total quality management (TQM), and total preventative maintenance (TPM). We investigate the control framework that results from a lean manufacturing strategic initiative. Our setting is the natural environment of a lean manufacturing firm which also implemented lean accounting and control practices. Lean accounting seeks to

Frances A. Kennedy; Sally K. Widener

2008-01-01

377

Fuzzy logic based leanness assessment and its decision support system  

Microsoft Academic Search

Manufacturing organisations have been witnessing a transition from mass manufacturing to lean manufacturing. Lean manufacturing is focused on the elimination of obvious wastes occurring in the manufacturing process, thereby enabling cost reduction. The quantification of leanness is one of the contemporary research agendas of lean manufacturing. This paper reports a study which is carried out to assess the leanness level

S. Vinodh; S. R. Balaji

2011-01-01

378

Bioaccumulation and trophic magnification of short- and medium-chain chlorinated paraffins in food webs from Lake Ontario and Lake Michigan.  

PubMed

Chlorinated paraffins (CPs) are complex mixtures of chlorinated alkanes used in a myriad of industrial applications as flame retardant plasticizers and additives. In this study, the distribution and bioaccumulation/biomagnification of short-chain CPs (C10-C13, SCCPs) and medium-chain CPs (C14-C17, MCCPs) were investigated in samples collected between 1999 and 2004 from Lake Ontario and northern Lake Michigan. Total (sigma) SCCPs and sigmaMCCPs concentrations in water from Lake Ontario were 1190 pg/L and 0.9 pg/L (data from 2004 only), respectively. CPs were also detected in invertebrates and fish from both lakes. SCCP predominated in organisms from Lake Michigan with the highest mean concentrations found in lake trout [Salvelinus namaycush, 123 +/- 35 ng/g wet weight (ww)]. In Lake Ontario, MCCPs predominated in most species with the highest levels detected in slimy sculpin (Cottus cognatus, 108 ng/g ww) and rainbow smelt (Osmerus mordax, 109 ng/g ww). Bioaccumulation and biomagnification of CPs was evaluated on an isomer basis (i.e., C10H17Cl5, C10H16Cl6, etc). Log bioaccumulation factors for lake trout (lipid based) ranged from 4.1 to 7.0 for SCCPs and 6.3 to 6.8 for MCCPs. SCCPs and MCCPs were found to biomagnify between prey and predators from both lakes with highest values observed for Diporeia-sculpin (Lake Ontario, C15Cl9 = 43; Lake Michigan, C10Cl5 = 26). Trophic magnification factors for the invertebrates-forage fish-lake trout food webs ranged from 0.41 to 2.4 for SCCPs and from 0.06 to 0.36 for MCCPs. Given the prominence of CPs, particularly in lake waters and in lower food web organisms, further investigation is needed to evaluate the magnitude of their distribution and accumulation/magnification in the Great Lakes environment. PMID:18546740

Houde, Magali; Muir, Derek C G; Tomy, Gregg T; Whittle, D Michael; Teixeira, Camilla; Moore, Serge

2008-05-15

379

Extreme acidification of a lake in southern Norway caused by weathering of sulphide-containing bedrock  

Microsoft Academic Search

In 1986 Lake Langedalstjenn in southern Norway was a weakly acidified lake with a pH of 5.2–5.6, and an average concentration of SO4 of 330 µeq L-1. The total Al concentration varied between 10 and 20 µeq L-1 (expressed as Al3+). The lake supported populations of brown trout and perch and had supplied about 100 people with drinking water until

Atle Hindar; Espen Lydersen

1994-01-01

380

Intensive fish predation: an obstacle to biological recovery following liming of acidified lakes?  

Microsoft Academic Search

Several thousand lakes have been limed inNorway and Sweden during the last threedecades. Most fishless lakes are stocked withsalmonid game fish after liming, predominantlybrown trout (Salmo trutta). Thecombination of intensive anthropogenic stockingand improved natural reproduction possibilitiesin brooks and rivers often leads to denselypopulated lakes and excess fish planktivory.Another major fish species in southern Norway,Eurasian perch (Perca fluviatilis),exhibits strong numerical increases

Jens Petter Nilssen; Svein Birger Wærvågen

2002-01-01

381

A lean route to manufacturing survival  

Microsoft Academic Search

Purpose – Aims to detail the ongoing implementation of lean manufacturing at a UK-based electronic product-manufacturing operation. Design\\/methodology\\/approach – Describes how and why a manufacturing operation, which had already seen major improvements that had made it a highly regarded plant, is adopting lean manufacturing as part of a manufacturing survival strategy. It also looks at some of the main Lean

Andrew Lee-Mortimer

2006-01-01

382

Differences in Organizational Factors by Lean Duration  

Microsoft Academic Search

The aim of this paper is to explore whether employees’ perceptions towards perceived organisational support and participative\\u000a decision-making vary by lean duration (i.e., the duration of lean production in operation), and whether managers’ perceptions\\u000a towards propensity for participative decision-making vary by the lean duration. For the study, quantitative research methodology\\u000a was used and data was collected from 616 shop-floor employees

Dharmasri Wickramasinghe; Vathsala Wickramasinghe

383

Beyond Lean Manufacturing: Combining Lean and the Theory of Constraints for Higher Performance  

Microsoft Academic Search

Summary Lean manufacturing (LM) evokes images of efficiency and minimizing unnecessary costs, an attractive value for many companies. But other companies are already as lean as they can be. Does LM have practical limits? This paper demonstrates how the Theory of Constraints (TOC) can take the business performance of those organizations currently pursuing lean to the next level.

H. William Dettmer

384

Selenium and mercury in native and introduced fish species of patagonian lakes, Argentina.  

PubMed

A survey of mercury (Hg) and selenium (Se) contents was performed in fish collected from lakes located in two National Parks of the northern patagonian Andean range. Two native species, catfish (Diplomystes viedmensis) and creole perch (Percichthys trucha), and three introduced species, brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), and brook trout (Salvelinus fontinalis), were caught from lakes Nahuel Huapi, Moreno, Traful, Espejo Chico, and Guillelmo belonging to Nahuel Huapi National Park and from lakes Futalaufquen and Rivadavia, Los Alerces National Park. In lake Moreno, fish diet items were analyzed and rainbow trout grown in a farm. Hg and Se were measured in muscle and liver tissues by instrumental neutron activation analysis. The average concentrations in muscle of Hg for all species, ages, and lakes are between 0.4 to 1.0 microg g(-1) dry weight (DW) with a few fish, mainly native, exceeding the United States Environmental Protection Agency health advisory for freshwater fish limited consumption, and from 0.8 to 1.5 microg g(-1) DW for Se. Average concentrations in liver of Hg in all species range from 0.4 to 0.9 microg g(-1) DW. Brown trout, the top predator in these lakes, showed the lowest average Hg burden in both tissues. Se concentrations in the liver of brown and rainbow trout, up to 279 microg g(-1) DW, are higher than those expected for nearly pristine lakes, exceeding 20 microg g(-1) DW, the threshold concentration associated with Se toxicity. These species show lower Hg contents in muscle, suggesting a possible detoxification of Hg by a Se-rich diet. Creole perch and velvet catfish livers have lower Se concentrations, with a narrower span of values (2.3 to 8.5 microg g(-1) and 3.3 to 5.5 microg g(-1) DW respectively). PMID:18214390

Arribére, M A; Ribeiro Guevara, S; Bubach, D F; Arcagni, M; Vigliano, P H

2008-01-23

385

Introgression among Apache, Cutthroat, and Rainbow Trout in Arizona  

Microsoft Academic Search

The Apache trout Oncorhynchus apache has become threatened through hybridization with introduced nonnative trouts, among other reasons. We used 10 isozyme locus polymorphisms, which were in the aggregate diagnostic for discrimination of alleles of Apache trout, rainbow trout Oncorhynchus mykiss, and cutthroat trout Oncorhynchus clarki, to assess extent and directionality of interspecific hybridization in 645 individuals from 31 wild populations

Gary J. Carmichael; James N. Hanson; Maureen E. Schmidt; Donald C. Morizot

1993-01-01

386

Rb-Cs ratio as an indicator of fish diet in lakes of the Patagonia, Argentina.  

PubMed

The ratios of Rb to Cs contents were studied in five fish species from seven lakes located in the Patagonia Andean Range, Argentina in order to trace fish diet. The species studied were native velvet catfish (Diplomistes viedmensis) and creole perch (Percichthys trucha), and exotic brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), and brook trout (Salvenilus fontinalis). Rainbow trout specimens from two farms were also studied, as well as fish food items and native mussels (Diplodon chilensis). Rb and Cs concentrations were determined by instrumental neutron activation analysis. A positive correlation of Cs concentration in the muscle of velvet catfish with fish length was observed, probably associated with the long biological half-life of this element in this species, whereas the Rb concentration remained constant, hence inhibiting the use of Rb-Cs ratios as a tracer in this case. Seasonal variations observed for rainbow trout and Cs concentration background bias in one of the lakes studied are also a limiting factor to the use of Rb-Cs ratios as a diet tracer. Rb-Cs ratios allowed clear differentiation of rainbow trout raised in farms from the natural specimens that lived in the same environment, in agreement with Rb-Cs ratios determined in both diets. Rb-Cs ratios in rainbow trout showed significant differences between Rivadavia and Futalaufquen lakes compared to Moreno and Nahuel Huapi lakes, which could be associated with a higher participation of plankton in the diet in the first case. No relevant variations in Rb-Cs ratios of brown trout were observed, probably because of the similarity in the diet. PMID:16943600

Guevara, S Ribeiro; Bubach, D; Macchi, P J; Vigliano, P; Arribére, M; Colombo, J C

2006-01-01

387

Monitor and Protect Wigwam River Bull Trout for Koocanusa Reservoir; White River Bull Trout Enumeration Project Summary, Progress Report 2003.  

SciTech Connect

This report summarizes the first year of a three-year bull trout (Salvelinus confluentus) enumeration project on the White River and is a co-operative initiative of the British Columbia Ministry of Water, Land, and Air Protection and Bonneville Power Administration. The White River has been identified as an important bull trout spawning tributary of the upper Kootenay River in southeastern British Columbia. The objective was to collect information on the returning adult spawning population to the White River through the use of a fish fence and traps, and to conduct redd surveys at the conclusion of spawning to provide an index of spawning escapement and distribution. The fence was installed on September 9th, 2003 and was operated continuously (i.e. no high-water or breaching events) until the fence was removed on October 9th, 2003. Estimation of the spawning population of White River bull trout was incomplete. This was due to a larger and more protracted out-migration than expected. As a result, the bull trout spawning population of the White River was estimated to be somewhere above 899 fish. In comparison, this represents approximately one third the population estimate of the 2003 Wigwam River bull trout spawning population. Based on redd index data, the number of bull trout per redd was over twice that of the Wigwam River or Skookumchuck Creek. This was expected as the index sites on the Wigwam River and Skookumchuck Creek cover the majority of the spawning area. This is not true on the White River. From previous redd counts, it is known that there are approximately twice as many redds in Blackfoot Creek as there are in the index site. Additionally, given the large size of the White River watershed and in particular, the large number of tributaries, there is a high likelihood that important bull trout spawning areas remain unidentified. Both floy tag and radio-telemetry data for the White River bull trout have identified extensive life history migrations. Similar data for the Wigwam River and Skookumchuck Creek populations illustrate there is considerable overlap and mixing among these three local populations within their over-wintering and feeding habitat. The upper Kootenay River, Lake Koocanusa and the lower Bull River provide overwintering and feeding habitat for the White River, Skookumchuck Creek and Wigwam River bull trout. Recommendations to improve escapement estimates and spawning distribution are provided. An accurate population estimate is especially important to provide baseline for any potential impacts due to wildfire and subsequent salvage logging that is currently underway immediately adjacent to and upstream of important spawning and rearing habitat in the Middlefork of the White River. Identification of important spawning habitat is important to meet management objectives for the White River.

Cope, R.

2004-02-01

388

Effects of Nonnative Fishes on Wilderness Lake Ecosystems in the Sierra Nevada and Recommendations for Reducing Impacts  

Microsoft Academic Search

Wilderness areas of the Sierra Nevada, California con- tain thousands of lakes and ponds, nearly all of which were histori- cally fishless. After more than a century of fish stocking, introduced trout are now present in up to 80% of larger lakes. These nonnative fishes have had profound impacts on native fishes, amphibians, and invertebrates. Several of these native species

R. A. Knapp; K. R. Matthews

2000-01-01

389

A case study of lean, sustainable manufacturing  

Microsoft Academic Search

A small furniture production company has integrated lean tools and sustainability concepts with discrete event simulation modeling and analysis as well as mathematical optimization to make a positive impact on the environment, society and its own financial success. The principles of lean manufacturing that aid in the elimination of waste have helped the company meet ever increasing customer demands while

Geoff Miller; Janice Pawloski; Charles Robert Standridge

2010-01-01

390

Lean Manufacturers' Transcendence to Green Manufacturing  

Microsoft Academic Search

A survey was administered to manufacturers recognized by the Shingo Prize as Lean to determine if they are transcending to a Greener state because of their commitment to Lean production. Results were compared with data published by Melnyk, et. al. (5) regarding the Greenness of over 1100 general manufacturing plants. The companies recognized by Shingo score significantly higher in Greenness

Gary G. Bergmiller; Paul R. McCright

2009-01-01

391

An implementation model for lean programmes  

Microsoft Academic Search

While lean programmes continue to be implemented in many companies, there is a rising concern regarding the failures of these programmes. Many of them fail because we do not know how to implement them. Using the experience with a lean programme in an aircraft maintenance and repair operation, the purpose of the research was to develop an implementation model which

Satya S. Chakravorty

2010-01-01

392

Lean production and sustainable competitive advantage  

Microsoft Academic Search

Today, “lean” may no longer be fashionable but its core principles (flow, value, pull, minimizing waste etc.) have become the paradigm for many manufacturing (and service) operations. Given this pre-eminence, the paper seeks to establish what impact it has had on the overall competitive positions of adopter firms. Combining normative and critical theory (from lean production and resource-based view of

Michael A. Lewis

2000-01-01

393

Lean healthcare: Rhetoric, ritual and resistance  

Microsoft Academic Search

This paper presents an ethnographic account of the implementation of Lean service redesign methodologies in one UK NHS hospital operating department. It is suggested that this popular management ‘technology’, with its emphasis on creating value streams and reducing waste, has the potential to transform the social organisation of healthcare work. The paper locates Lean healthcare within wider debates related to

Justin J. Waring; Simon Bishop

2010-01-01

394

Factors Predicting Employees' Approval of Lean Production  

Microsoft Academic Search

A number of influential studies advocate the adoption of a lean production system (LPS) in order to improve quality and efficiency in Western automotive plants. Critics argue that such systems place excessive demands upon employees. Very little survey data, however, is available on employees' attitudes toward lean production since companies are frequently reluctant to grant such access. Our survey of

Mark A. Shadur; John J. Rodwell; Greg J. Bamber

1995-01-01

395

Defining and developing measures of lean production  

Microsoft Academic Search

Our research addresses the confusion and inconsistency associated with “lean production.” We attempt to clarify the semantic confusion surrounding lean production by conducting an extensive literature review using a historical evolutionary perspective in tracing its main components. We identify a key set of measurement items by charting the linkages between measurement instruments that have been used to measure its various

Rachna Shah; Peter T. Ward

2007-01-01

396

Lean Production: Experience among Australian Organizations  

Microsoft Academic Search

Presents the findings of a study which investigated the adoption of lean production methods in Australian manufacturing industry. Data were gathered through a telephone survey from 51 companies representing a range of industry sectors. The study found that a large majority of the companies were practising lean production methods. Discusses the organizational changes which had occurred in the organizations as

Amrik S. Sohal; Adrian Egglestone

1994-01-01

397

PERFORMANCE IMPROVEMENT PROGRAMS AND LEAN CONSTRUCTION  

Microsoft Academic Search

The paper examines the relationship between Lean Construction and Performance Improvement programs in construction organizations. The authors argue that the structure and focus of existing performance improvement programs are a barrier to Lean Construction's entry into the organization. The paper first analyzes the characteristics of successful performance improvement programs, and develops a model that identifies three critical elements: 1) Time

Gregory Howell

398

TRIZ as a Lean Thinking Tool  

Microsoft Academic Search

Lean Thinking is a highly evolved method of managing an organization to improve the productivity, efficiency and quality of its products or services. The core principle it uses is that no work should be done unless it is going to create customer value. Traditionally Lean tools were Value Stream mapping, Quick Changeover\\/Setup Reduction, Single Minute Exchange of Dies (SMED), Kaizen,

Sergei Ikovenko; Jim Bradley

399

Contaminant Monitoring Strategy for Henrys Lake, Idaho  

SciTech Connect

Henrys Lake, located in southeastern Idaho, is a large, shallow lake (6,600 acres, {approx} 17.1 feet maximum depth) located at 6,472 feet elevation in Fremont Co., Idaho at the headwaters of the Henrys Fork of the Snake River. The upper watershed is comprised of high mountains of the Targhee National Forest and the lakeshore is surrounded by extensive flats and wetlands, which are mostly privately owned. The lake has been dammed since 1922, and the upper 12 feet of the lake waters are allocated for downriver use. Henrys Lake is a naturally productive lake supporting a nationally recognized ''Blue Ribbon'' trout fishery. There is concern that increasing housing development and cattle grazing may accelerate eutrophication and result in winter and early spring fish kills. There has not been a recent thorough assessment of lake water quality. However, the Department of Environmental Quality (DEQ) is currently conducting a study of water quality on Henrys Lake and tributary streams. Septic systems and lawn runoff from housing developments on the north, west, and southwest shores could potentially contribute to the nutrient enrichment of the lake. Many houses are on steep hillsides where runoff from lawns, driveways, etc. drain into wetland flats along the lake or directly into the lake. In addition, seepage from septic systems (drainfields) drain directly into the wetlands enter groundwater areas that seep into the lake. Cattle grazing along the lake margin, riparian areas, and uplands is likely accelerating erosion and nutrient enrichment. Also, cattle grazing along riparian areas likely adds to nutrient enrichment of the lake through subsurface flow and direct runoff. Stream bank and lakeshore erosion may also accelerate eutrophication by increasing the sedimentation of the lake. Approximately nine streams feed the lake (see map), but flows are often severely reduced or completely eliminated due to irrigation diversion. In addition, subsurface flows can occur as a result of severe cattle grazing along riparian areas and deltas. Groundwater and springs also feed the lake, and are likely critical for oxygen supply during winter stratification. During the winter of 1991, Henrys Lake experienced low dissolved oxygen levels resulting in large fish kills. It is thought that thick ice cover combined with an increase in nutrient loads created conditions resulting in poor water quality. The Idaho Department of Health and Welfare, DEQ is currently conducting a study to determine the water quality of Henrys Lake, the sources contributing to its deterioration, and potential remedial actions to correct problem areas.

John S. Irving; R. P. Breckenridge

1992-12-01

400

Use of Otoliths to Separate Juvenile Steelhead Trout from Juvenile Rainbow Trout.  

National Technical Information Service (NTIS)

Otolith nuclei were investigated as a means of separating juvenile steelhead trout, Salmo gairdneri, from juvenile rainbow trout, S. gairdneri, in the lower Deschutes River, Oreg. An intensive recreational fishery necessitated development of a technique f...

J. T. Rybock H. F. Horton J. L. Fessler

1974-01-01

401

Temperature-mediated differences in bacterial kidney disease expression and survival in Renibacterium salmoninarum-challenged bull trout and other salmonids  

USGS Publications Warehouse

Resource managers considering restoration and reconnection of watersheds to protect and enhance threatened populations of bull trout Salvelinus confluentus have little information about the consequences of bacterial kidney disease (BKD) caused by Renibacterium salmoninarum. To better understand the response of bull trout to R. salmoninarum challenge, we conducted several laboratory experiments at two water temperatures. The extent, severity, and lethality of BKD in bull trout were compared with those of similarly challenged lake trout S. namaycush, Arctic char S. alpinus, Chinook salmon Oncorhynchus tshawytscha, and rainbow trout O. mykiss. The lethal dose of bacterial cells necessary to induce 50% mortality (LD50) was 10-fold lower at the 15??C challenge than at the 9??C challenge. Of the species tested, bull trout were relatively resistant to BKD, Arctic char were the most susceptible among Salvelinus species, and Chinook salmon were the most susceptible among Oncorhynchus species tested. Mean time to death was more rapid for all fish tested at 15??C than for fish challenged at 9??C. These results suggest that infection of bull trout with BKD likely poses a low risk to successful restoration of threatened populations. ?? Copyright by the American Fisheries Society 2007.

Jones, D. T.; Moffitt, C. M.; Peters, K. K.

2007-01-01

402

Feeding by Arizona trout ( Salmo apache ) and brown trout ( Salmo trutta ) at different light intensities  

Microsoft Academic Search

Synopsis Brown trout (Salmo trutta) were more efficient than Arizona trout (Salmo apache) in eating brine shrimp at starlight (10?4 fL) light levels. Arizona trout required light levels ? moonlight (10?3 fL) to feed. In bright light (50 fL), brown trout utilized cover to a much greater extent in both field and laboratory. Our study indicates that factors other than

Fredric W. Robinson; Jerry C. Tash

1979-01-01

403

Molecular Genetic Markers Identifying Hybridization between the Colorado River-Greenback Cutthroat Trout Complex and Yellowstone Cutthroat Trout or Rainbow Trout  

Microsoft Academic Search

We used polymerase chain reaction (PCR) primers that are complementary to interspersed nuclear DNA elements to identify genetic markers capable of detecting hybridization between native Colorado River cutthroat trout Oncorhynchus clarki pleuriticus (CRCT) or greenback cutthroat trout O. c. stomias (GCT) and introduced Yellowstone cutthroat trout O. c. bouvieri (YCT) or rainbow trout O. mykiss (RT). Using four different pair

Naohisa Kanda; Robb F. Leary; Paul Spruell; Fred W. Allendorf

2002-01-01

404

Diel Movement and Habitat Use of California Golden Trout in the Golden Trout Wilderness, California  

Microsoft Academic Search

I used radio transmitters to determine the diel habitat use and movement patterns of California golden trout Oncorhynchus mykiss aquabonita inside and outside cattle exclosures on the South Fork Kern River, Golden Trout Wilderness, California. Twenty-three golden trout were monitored from September 10 to 19, 1993, during 216 diel-tracking hours at four study sites in upper and lower Ramshaw Meadow.

KATHLEEN R. MATTHEWS

1996-01-01

405

Modelling competition and hybridization between native cutthroat trout and nonnative rainbow and hybrid trout  

Microsoft Academic Search

Native salmonid fish have been displaced worldwide by nonnatives through hybridization, competition, and predation, but the dynamics of these factors are poorly understood. We apply stochastic Lotka–Volterra models to the displacement of cutthroat trout by rainbow\\/hybrid trout in the Snake River, Idaho, USA. Cutthroat trout are susceptible to hybridization in the river but are reproductively isolated in tributaries via removal

Robert W. Van Kirk; Laurie Battle; William C. Schrader

2010-01-01

406

Regional Synchrony of Brown Trout and Brook Trout Population Dynamics among Michigan Rivers  

Microsoft Academic Search

The ability to describe regional patterns in trout density would be useful for biologists concerned with population status across large regions as well as managers of rivers at the local scale. Noting the importance of flow conditions at the time of emergence to trout year-class strength in Michigan streams and the influence of age-0 trout abundance on subsequent abundance of

Troy G. Zorn; Andrew J. Nuhfer

2007-01-01

407

Immunohistochemical localization of rainbow trout ladderlectin and intelectin in healthy and infected rainbow trout ( Oncorhynchus mykiss)  

Microsoft Academic Search

In the present study, the pattern of immuno-reactive ladderlectin and intelectin in healthy rainbow trout is compared to rainbow trout infected with a variety of infectious agents. In healthy rainbow trout, both proteins were localized to individual epithelial cells of the gill and intestine and both proteins were clearly demonstrated within cytoplasmic granules of polymorphonuclear leucocytes and macrophages\\/monocytes found in

S. Russell; M. A. Hayes; J. S. Lumsden

2009-01-01

408

An egg injection method for assessing early life stage mortality of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in rainbow trout, (Oncorhynchus mykiss)  

USGS Publications Warehouse

To characterize the risk that polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) pose to salmonid early life stage survival, we developed a method to expose rainbow trout (Oncorhynchus mykiss) eggs to graded doses of PCDD, PCDF, and PCB congeners, using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a prototype. Rainbow trout eggs were injected 24–50 h post-fertilization with 0.2 ?l of 50 mM phosphatidylcholine (PC) liposomes (control) or 0.2 ?l of 5–7 graded doses of TCDD incorporated into 50 mM PC liposomes. Injection volume never exceeded 0.6% egg volume. Immediately following injection, the injection site was sealed with Super glue®, resulting in 92–97% of TCDD dose retained by the egg. Following both egg injection and waterborne egg exposure. TCDD toxicity in rainbow trout was manifested by half-hatching mortality but predominantly by sac fry mortality associated with hemorrhages, pericardial edema, and yolk sac edema. TCDD LD50s, following injection and waterborne exposure of rainbow trout eggs, were 421 (331–489) and 439 (346–519) pg TCDD/g egg (LD50, 95% fiducial limits), respectively. As in rainbow trout, TCDD toxicity in lake trout (Salvelinus namaycush) following the same two routes of exposure was manifested by half-hatching mortality but predominantly by sac fry mortality preceded by hemorrhages and yolk sac edema. LD50s, based on the dose of TCDD in lake trout eggs, were 47 (21–65) and 65 (60–71) pg/g following injection and waterborne exposure, respectively. The egg injection method is ideal for assessing the relationship between early life stage mortality in rainbow trout and graded egg doses of individual PCDD, PCDF, or PCB congeners.

Walker, M. K.; Hufnagle, L. C., Jr.; Clayton, M. K.; Peterson, R. E.

1992-01-01

409

Elevated mercury concentrations in fish in lakes in the Mackenzie River Basin: The role of physical, chemical, and biological factors  

Microsoft Academic Search

During the mid-1990s and through the early 2000s, researchers determined that elevated mercury concentrations were a common occurrence in predatory fish in many lakes in the Mackenzie River Basin (MRB), located in northern Canada. Here we present the results of studies investigating factors contributing to higher mercury concentrations in fish in many of these lakes. Twenty-two percent of lake trout,

M. S. Evans; W. L. Lockhart; L. Doetzel; G. Low; D. Muir; K. Kidd; G. Stephens; J. Delaronde

2005-01-01

410

Leading Lean: a Canadian healthcare leader's guide.  

PubMed

Canadian healthcare organizations are increasingly asked to do more with less, and too often this has resulted in demands on staff to simply work harder and longer. Lean methodologies, originating from Japanese industrial organizations and most notably Toyota, offer an alternative - tried and tested approaches to working smarter. Lean, with its systematic approaches to reducing waste, has found its way to Canadian healthcare organizations with promising results. This article reports on a study of five Canadian healthcare providers that have recently implemented Lean. We offer stories of success but also identify potential obstacles and ways by which they may be surmounted to provide better value for our healthcare investments. PMID:19553764

Fine, Benjamin A; Golden, Brian; Hannam, Rosemary; Morra, Dante

2009-01-01

411

Trace elements as fingerprint of lake of Provenance and of species of some native and exotic fish of northern Patagonian lakes.  

PubMed

A survey of trace element contents in fish muscle and liver was performed in different lakes of two northern Patagonian national parks: Nahuel Huapi and Los Alerces national parks. The aim of the work was to obtain the first set of reference data on elements that are not liable to be disturbed by human activities and to identify compositional patterns related to the species and site of collection. The species studied are native creole perch and velvet catfish and exotic brown trout, rainbow trout, and brook trout. The elements analyzed are Br, Cs, Fe, Rb, Se, Na, and Zn. Trace elements in muscle of brown trout, rainbow trout, and creole perch showed statistical patterns that allow one to identify the national park of origin, as well as which of the lakes (Traful, Espejo Chico, or the Nahuel Huapi-Moreno system) of the Nahuel Huapi National Park from which they come. Contents in the liver provide similar but less clear patterns than contents in muscle; however, in some particular cases, they provide additional information. Trace element contents in muscle are also good indicators of the species collected within a lake. PMID:16943599

Arribére, M A; Guevara, S Ribeiro; Bubach, D F; Vigliano, P H

2006-01-01

412

The impact of lean practices on inventory turnover  

Microsoft Academic Search

Lean manufacturing (LM) is currently enjoying its second heyday. Companies in several industries are implementing lean practices to keep pace with the competition and achieve better results. In this article, we will concentrate on how companies can improve their inventory turnover performance through the use of lean practices. According to our main proposition, firms that widely apply lean practices have

Krisztina Demeter; Zsolt Matyusz

2011-01-01

413

Lean hospitals: a new challenge for facility designers  

Microsoft Academic Search

This article presents a literature review of a wide array of implementation studies of Lean healthcare practices, performed worldwide. Firstly, we review some fundamentals of Lean thinking. Second, we describe the continuous work improvement cycle along with some commonly used Lean tools. We then examine how the implementation of Lean practices has affected hospitals and their users. Furthermore, we review

Jori Reijula; Iris D. Tommelein

2012-01-01

414

An application of Lean Six Sigma in a hospital  

Microsoft Academic Search

Abstract:Healthcare today faces major challenges. Patients demand quality of care to be improved continuously. Insurance companies demand the lowest possible prices. Lean Six Sigma is a tool that can help healthcare providers to achieve these at least partly conflicting goals. Lean Six Sigma is an integration of Six Sigma and Lean Manufacturing, both quality improvement programs originating from industry. Lean

Heuvel van den J; R. J. M. M. Does; Koning de H

2006-01-01

415

Using Simulation to Understand and Optimize a Lean Service Process  

Microsoft Academic Search

This paper describes the application of discrete event simulation to understand and optimize a lean service process. Simulation is being used increasingly in the design and improvement of lean manufacturing systems. We now apply simulation to the emerging notion of lean service. We use the case study of a lean auto repair facility to demonstrate the significant role that simulation

Kumar Venkat; Wayne W. Wakeland

2006-01-01

416

Leanness assessment using multi-grade fuzzy approach  

Microsoft Academic Search

The manufacturing organisations have been witnessing a transition from mass manufacturing to lean manufacturing. Lean operations are characterised by the elimination of obvious wastes occurring in the manufacturing process, thereby facilitating cost reduction. This paper reports a research carried out to assess the leanness of an organisation using multi-grade fuzzy approach. During this research, a leanness measurement model incorporated with

S. Vinodh; Suresh Kumar Chintha

2011-01-01

417

Garter Snake Distributions in High-Elevation Aquatic Ecosystems: Is There a Link with Declining Amphibian Populations and Nonnative Trout Introductions?  

Microsoft Academic Search

The dramatic amphibian population declines reported worldwide likely have important ef- fects on their predators. In the Sierra Nevada, where amphibian declines are well documented and some are closely tied to the introduction of nonnative trout, the mountain garter snake, Thamnophis elegans elegans, preys predominately on amphibians. We surveyed 2103 high-elevation lakes in the Sierra Nevada, quantified the distributional relationship

Kathleen R. Matthews; Roland A. Knapp; Karen L. Pope

2002-01-01

418

A Web-Based Lean Simulation Game for Office Operations: Training the Other Side of a Lean Enterprise  

ERIC Educational Resources Information Center

This research proposes a Web-based version of a lean office simulation game (WeBLOG). The game is designed to be used to train lean concepts to office and administrative personnel. This group belongs to the frequently forgotten side of a lean enterprise. Over four phases, the game presents the following seven lean tools: one-piece flow,…

Kuriger, Glenn W.; Wan, Huang-da; Mirehei, S. Moussa; Tamma, Saumya; Chen, F. Frank

2010-01-01

419

A Web-Based Lean Simulation Game for Office Operations: Training the Other Side of a Lean Enterprise  

ERIC Educational Resources Information Center

|This research proposes a Web-based version of a lean office simulation game (WeBLOG). The game is designed to be used to train lean concepts to office and administrative personnel. This group belongs to the frequently forgotten side of a lean enterprise. Over four phases, the game presents the following seven lean tools: one-piece flow,…

Kuriger, Glenn W.; Wan, Huang-da; Mirehei, S. Moussa; Tamma, Saumya; Chen, F. Frank

2010-01-01

420

CONNECTICUT LAKES  

EPA Science Inventory

This is a 1:24,000-scale datalayer of named lakes in Connecticut. It is a polygon Shapefile that includes all lakes that are named on the U.S. Geologicial Survey (USGS) 7½ minute topographic quadrangle maps that cover the State of Connecticut, plus other officially named lakes i...

421

Value Engineering Synergies with Lean Six Sigma.  

National Technical Information Service (NTIS)

Lean Six Sigma (LSS), its Design for Six Sigma (DFSS) variant, and Value Engineering (VE) were developed as business process improvement initiatives. This paper explores synergies between LSS, DFSS, and VE by identifying opportunities where they can be us...

A. C. Hermes H. W. Williams J. Mandelbaum

2010-01-01

422

Use of similar habitat by cutthroat trout and brown trout in a regulated river during winter  

USGS Publications Warehouse

Few differences in habitat use were observed between cutthroat trout and brown trout during winter in the Shoshone River, a regulated river in northwestern Wyoming. Radio-tagged fish of 20-30 cm total length were found in pool habitat five to six times more frequently than would be expected if they were using pools in proportion to pool availability. Nevertheless, run habitat was most frequently used by both species. The microhabitat characteristics at locations of each species were similar when in both pools and runs, however, habitat use was variable suggesting that a variety of microhabitats were suitable over-wintering habitat. Brown trout were more frequently associated with boulder cover than were cutthroat trout. Cutthroat trout used large pools that provided refuge from high water velocities more frequently that brown trout. Cutthroat trout and brown trout were found at similar distances from the bank except in late February when cutthroat trout were farther from the bank. Both species moved frequently during the winter, but cutthroat trout showed a greater propensity than brown trout to move long distances. This study suggests that during a mild winter in a stable environment, these species were able to overwinter successfully in a variety of habitats.

Dare, M. R.; Hubert, W. A.

2003-01-01

423

Mercury temporal trends in top predator fish of the Laurentian Great Lakes.  

PubMed

Mercury (Hg) contamination is widespread in the Laurentian Great Lakes region and is a serious environmental concern. In anaerobic environments such as lake sediments, mercury is transformed into methylmercury (MeHg) and can biomagnify up the food chain to toxic concentrations. The Great Lakes Fish Monitoring Program (GLFMP), administered by the US EPA Great Lakes National Program Office (GLNPO), aims to monitor temporal trends of mercury in the five Great Lakes using top predator fish as biomonitors. Total Hg (THg) concentrations were measured in Great Lake fish collected between 1999 and 2009. Single factor ANOVA determined that average fish THg concentrations over this time period in the five lakes were significantly different from one another in the order of Superior > Huron > Michigan > Ontario > Erie. By fitting the data to three different models (linear, quadratic, and two-segment piecewise), it was determined that Hg concentrations in top predator fish (lake trout, or walleye in Lake Erie) are currently increasing in Lake Erie and the Apostle Island sampling site in Lake Superior. Significant decreasing trends are evident in Lakes Michigan, Ontario, and the Rockport sampling site in Lake Huron, although all of the lakes exhibit elevated concentrations in fish compared to historic concentrations. As new Hg emission controls are implemented in the US, continued monitoring of Hg in Great Lakes fish will be needed to determine if they influence the current concentrations and trends. PMID:21792660

Zananski, Tiffany J; Holsen, Thomas M; Hopke, Philip K; Crimmins, Bernard S

2011-07-27

424

Hybridization and Cytonuclear Associations among Native Westslope Cutthroat Trout, Introduced Rainbow Trout, and Their Hybrids within the Stehekin River Drainage, North Cascades National Park  

Microsoft Academic Search

Historic introductions of nonnative rainbow trout Oncorhynchus mykiss into the native habitats of cutthroat trout O. clarkii have impacted cutthroat trout populations through introgressive hybridization, creating challenges and concerns for cutthroat trout conservation. We examined the effects of rainbow trout introductions on the native westslope cutthroat trout O. c. lewisii within the Stehekin River drainage, North Cascades National Park, Washington,

Carl O. Ostberg; Rusty J. Rodriguez

2006-01-01

425

Effect of Thiamine Status on Probability of Lake Ontario Chinook Salmon Spawning in the Upper or Lower Sections of Salmon River, New York  

Microsoft Academic Search

Consumption of thiaminase-containing forage fishes reduces egg and muscle thiamine content and impairs the spawning migration of Cayuga Lake (New York) rainbow trout Oncorhynchus mykiss. Because some Chinook salmon O. tshawytscha from Lake Ontario have been shown to produce eggs low in thiamine, we examined the relationship between the migration of Chinook salmon and the thiamine content of their eggs

H. George Ketola; James H. Johnson; Jacques Rinchard; Francis J. Verdoliva; Mary E. Penney; Andreas W. Greulich; Russell C. Lloyd

2009-01-01

426

Measurement of Lake Roosevelt Biota in Relation to Reservoir Operations : Final Report 1993.  

SciTech Connect

The purpose of this study was to collect biological data from Lake Roosevelt to be used in the design of a computer model that will predict biological responses to reservoir operations as part of the System Operation Review Program. This study worked in conjunction with Lake Roosevelt Monitoring Project which investigated the effectiveness of two kokanee salmon hatcheries. This report summarized the data collected from Lake Roosevelt from 1993 and includes limnological, reservoir operation, zooplankton, benthic macroinvertebrate, experimental trawling, and net-pen rainbow trout tagging data. Major components of the Lake Roosevelt model include quantification of impacts to zooplankton, benthic macroinvertebrates, and fish caused by reservoir drawdowns and low water retention times.

Voeller, Amy C.

1993-01-01

427

Incidence of Pathogenic Microorganisms in Aquacultured Rainbow Trout (Oncorhynchus mykiss)  

Microsoft Academic Search

Quantitative levels of six known pathogens (Listeria monocytogenes, Clostridium botulinum, Salmonella species, Vibrio cholerae, Yersinia enterocolitica, and Y. pseudotuberculosis) and aerobic plate counts were measured at five aquaculture facilities. The farmed rainbow trout (Oncorhynchus mykiss) and trout fillets were sampled at two different growing seasons to monitor for microbial hazards. Listeria spp. was identified in both whole trout and trout

T. James McAdams; Robert G. Reinhart; Custy F. Fernandes; George J. Flick Jr; Stephen A. Smith; Cameron R. Hackney; George S. Libey; L. Ankenman Granata

2005-01-01

428

Reproductive Isolation with Little Genetic Divergence in Sympatric Populations of Brown Trout (SALMO TRUTTA)  

PubMed Central

Two reproductively isolated demes of brown trout coexist in a small Swedish mountain lake, Lake Bunnersjöarna. We electrophoretically examined 102 specimens from that lake for 27 enzymes encoded by 54 loci. The two demes are fixed for different alleles at a lactate dehydrogenase locus (LDH-1); statistically significant allele frequency differences at five other loci further support the complete lack of gene flow between these demes. There are significant differences in growth rates between fish in the two demes, but no further morphological differentiation has been detected.——In light of these findings, the genetic distance between these populations is surprisingly small (Nei's I = 0.975). These demes represent one of the least genetically divergent, reproductively isolated sympatric pair of vertebrate populations that have been identified. The results are discussed from both an evolutionary and ecological perspective.

Ryman, Nils; Allendorf, Fred W.; Stahl, Gunnar

1979-01-01

429

Redband Trout and the Endangered Species Act  

Microsoft Academic Search

Redband trout Oncorhynchus mykiss and the Endangered Species Act (ESA) have been linked since 1982, when the fish first appeared as a candidate species. Petitions to list populations of redband trout under the ESA were filed with the U.S. Fish and Wildlife Service (USFWS) in 1994, 1995, and 1997. USFWS found that the listing action requested in the first two

RONALD RHEW

430

33 CFR 117.337 - Trout River.  

Code of Federal Regulations, 2010 CFR

...Navigable Waters 1 2009-07-01 2009-07-01 false Trout River. 117.337 Section 117.337 Navigation and Navigable...REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the Seaboard System Railroad bridge,...

2009-07-01

431

Have brook trout ( Salvelinus fontinalis ) displaced bull trout ( Salvelinus confluentus ) along longitudinal gradients in central Idaho streams?  

Microsoft Academic Search

Invasions of non-native brook trout (Salvelinus fontinalis) have the potential for upstream displacement or elimination of bull trout (Salvelinus confluentus) and other native species already threatened by habitat loss. We sum- marized the distribution and number of bull trout in samples from 12 streams with and without brook trout in central Idaho and used hierarchical regression analysis to consider whether

Bruce E. Rieman; James T. Peterson; Deborah L. Myers

2006-01-01

432

Innocent until proven guilty? Stable coexistence of alien rainbow trout and native marble trout in a Slovenian stream  

Microsoft Academic Search

To understand the consequences of the invasion of the nonnative rainbow trout Oncorhynchus mykiss on the native marble trout Salmo marmoratus, we compared two distinct headwater sectors where marble trout occur in allopatry (MTa) or sympatry (MTs) with rainbow trout\\u000a (RTs) in the Idrijca River (Slovenia). Using data from field surveys from 2002 to 2009, with biannual (June and September)

Simone Vincenzi; Alain J. Crivelli; Dusan Jesensek; Gianluigi Rossi; Giulio A. De Leo

2011-01-01

433

A Lean Toolbox—Using Lean Principles and Techniques in Healthcare  

Microsoft Academic Search

The Lean principles derived from the Toyota Production System have been revolutionizing manufacturing and service industries worldwide for many years. Lean can create a balance between quality and finance by developing the most efficient and effective method of providing value to the customer. The Toyota Production System grew out of a disheartening situation, similar in some ways to the experience

Thomas G. Zidel

2006-01-01

434

Effects of Water Chemistry and Habitat on the Density of Young Brown Trout Salmo trutta in Acidic Streams  

Microsoft Academic Search

We examined the relationship between young brown trout ( Salmo trutta) density in lake tributaries, and water chemistry and habitat variables. The study was carried out during the autumn in three acidic, softwater river systems in western and southwestern Norway; Gaular and Vikedal (1987–1993) and Bjerkreim (1988–1993). The streams had mean calcium concentrations of 0.35 mg L-1 (Gaular), 0.52 mg

T. Hesthagen; J. Heggenes; B. M. Larsen; H. M. Berger; T. Forseth

1999-01-01

435

Comparison of Hatchery Performance, Agonistic Behavior, and Poststocking Survival between Diploid and Triploid Rainbow Trout of Three Different Utah Strains  

Microsoft Academic Search

The hatchery performance (growth, feed conversion, and survival) of rainbow trout Oncorhynchus mykiss was compared between diploid and triploid fish from three Utah strains: Fish Lake-DeSmet (FD), Sand Creek (SC), and Ten Sleep (TS). For FD, specific growth rates were slightly higher for triploids (2.79%\\/d) than for diploids (2.60%\\/d), but final mean weight at 108 d did not significantly differ.

Eric J. Wagner; Ronney E. Arndt; M. Douglas Routledge; David Latremouille; Roger F. Mellenthin

2006-01-01

436

Effect of pH on the bioaccumulation of low level, dissolved methylmercury by rainbow trout (Oncorhynchus mykiss)  

Microsoft Academic Search

An inverse relationship has been observed between pH and McHg concentration in freshwater fish. Many hypotheses exist regarding\\u000a the mechanisms which lead to elevated levels of organic Hg in fish from low pH lakes. To determine if pH has a direct effect\\u000a on the rate of McHg bioaccumulation in fish, rainbow trout fingerlings (Oncorhynchus mykiss) were exposed to a low

R. A. Ponce; N. S. Bloom

1991-01-01