Fish Health

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.

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...

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

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...

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...

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.

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...

The Winged Mapleleaf mussel ( Quadrula fragosa) is only known to inhabit five locations in the U.S., and the population in the St. Croix National Scenic Riverway is isolated both physically and genetically from the other populations. In 2000, the U.S. Fish and Wildlife Service (USFWS) issued Reasonable and Prudent Measures, which required the U.S. Army Corps of Engineers (USACE) to establish...

Our research experience spans geography (estuaries, tributary and mainstem habitats and reservoirs); topics (fish passage, aquatic invasive species, climate change); and, encompasses a diverse range of activities such as telemetry, physiological studies, and regional scale ecological modeling. Many of our research findings are relevant to issues affecting the Nation.

Researchers are investigating the influence of Antimycin A on invasive carp and non-target fishes by measuring the effects of a novel species-specific bait formulation.