Fish Health

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...

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...

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.

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...

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.

Black basses (Micropterus spp) are enigmatic North American sportfishes that support the most economically valuable freshwater sport fishery in the United States and serve as keystone predators within aquatic ecosystems. Hyperpigmented melanistic lesions on the surface of black basses have been observed in a number of waterbodies across the country in increasing frequency. We have recently...

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.

Changes in the body condition of a key forage fish species, Pacific sand lance ( Ammodytes personatus ), are examined to understand how energy transfer to predators may have been disrupted during the recent marine heatwave in the North Pacific (late 2013 to mid 2016).

Small streams in forests are likely to see dramatic shifts as global climate change influences air temperature and rain patterns. We have already seen warmer stream temperatures as air temperatures increase in summer in the Northeastern US. The intensity and duration of floods and droughts are also expected to magnify as future rain patterns shift. This project will evaluate how stream temperature...