N:
NISbase: Nonindigenous Species Database Network - NISbase is a distributed database providing information concerning nonindigenous species. [Ad Hoc Organizations, Smithsonian Institution]

National River Restoration Science Synthesis - A scientific synthesis of river restoration projects, with a searchable database. [Department of the Interior, U.S. Geological Survey (USGS), National Biological Information Infrastructure]

National Wildlife Research Center (NWRC) Research Library - Locate hard to find reports on species profiles, habitat suitability index, and community profiles [Department of the Interior, U.S. Geological Survey (USGS)]

R:
Regulatory Fish Encyclopedia (RFE) - Compilation of data in several formats that assists with the accurate identification of fish species [Department of Health and Human Services (HHS), Food and Drug Administration (FDA), Center for Food Safety and Applied Nutrition (CFSAN)]