Fish Health

Nearshore systems provide habitat to a unique community of marine and diadromous (lives in both fresh and saltwater) fish and support high fish abundance.

Fish and aquatic habitats in Alaska support important commercial, sport, and subsistence fisheries and provide forage fish that support wildlife populations. The USGS Alaska Science Center conducts interdisciplinary research to inform local, state, federal, and international policy makers regarding conservation of fish, aquatic species, and their habitats. We work collaboratively with hydrologists...

The USGS Eastern Ecological Science Center (EESC) provides world-class science to inform natural resource decisions on aquatic ecosystems, species populations and management, disease, and invasive species. Our scientific products represent critical contributions that enhance the ecological and economic sustainability of recreational and commercial fishing. In the United States, anglers contribute...

The USGS Eastern Ecological Science Center (EESC) is rooted in a proud tradition of service to the nation—advancing science that informs the conservation and management of fish, wildlife, and habitats across the eastern United States and beyond. Our mission is clear: deliver reliable, partner-driven science that supports natural resource decisions today, while ensuring these resources remain...

Forage fish are small pelagic schooling fish that play a key role in transferring energy between plankton and top marine predators. Many seabirds, marine mammals, and commercial fish species depend on forage fish to grow and survive.

Alaska's coastal and offshore waters provide foraging habitat for an estimated 100 million birds comprising more than 90 different species; from loons and seaducks that nest inland, to petrels and puffins that breed on islands off shore. All these birds depend on the sea to provide a wide variety of food types— from clams, crabs and urchins nearshore— to krill, forage fish, and squid offshore. The...

The Gulf sturgeon, Acipenser oxyrinchus desotoi, has been listed as Threatened since 1991. Beginning in 1986, USGS has been investigating sturgeon population abundance and ecology throughout its range, but mostly in the Suwannee River.

USGS scientists are studying American shad ( Alosa sapidissima), blueback herring ( Alosa aestivalis), and alewife ( Alosa pseudoharengus; collectively “alosines”) to develop robust genetic baselines that will inform management practices for individual species.

Rainbow trout are a desirable sport fish that have been introduced in many locations around the world, including the Colorado River. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they can also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying...

USGS' and Loyola University New Orleans' innovative research techniques played a role in the decision to downlist the Okaloosa Darter, a freshwater fish endemic to northwest Florida, from Endangered to Threatened in 2011, and the removal of the fish from the U.S. Endangered Species Act in 2023.

The mission brings together state, federal, tribal, Canadian provincial, private, and non-profit partners using advanced fishery research approaches to enhance fishery assessment methods.

Algae, phytoplankton, and rooted macrophytes represent the base of many aquatic food webs and are known as primary producers. Through photosynthesis, these organisms convert sunlight energy into chemical energy (i.e., carbon) that in turn fuels the growth of animals such as macroinvertebrates and fish. This project uses high frequency measurements of dissolved oxygen, which is a by-product of...