Migratory Fishes

In addition to the direct effects of sea ice loss on walrus ( Odobenus rosmarus divergens ) and polar bears ( Ursus maritimus ) that use ice as a platform, the decline of Arctic sea ice is predicted to promote a fundamental ecosystem shift from benthic animals that forage on the sea floor to pelagic animals that forage near the sea surface.

Permafrost thaw is leading to a myriad of changes in physical and chemical conditions throughout the Arctic.

The potential for invasive species introductions in Arctic and Subarctic ecosystems is growing as climate change manifests and human activity increases in high latitudes.

Invertebrate communities provide food for several economically and ecologically important fish and waterbird species in coastal estuaries. Scientists at the WERC San Francisco Bay Estuary Field Station specialize in studying foraging ecology of waterbirds and fishes, general food web dynamics across estuaries, and the effects of habitat restoration and other factors on waterbird prey availability.

Adult sea lamprey abundance in Lake Erie increased during the past decade, exceeding pre-control levels and causing extensive mortality on some strains of stocked lake trout (Markham 2015). Control agents speculate that this increase may be due to an uncontrolled larval sea lamprey population in the St. Clair River because other known sources of larval sea lampreys are regularly treated with...

The near shore waters along the coast of southern California host one of the most productive marine ecosystems on earth: giant kelp forests. These complex environments provide habitat, food, and hiding places for more than 1,000 species of plants and animals, but are easily disturbed by both natural events and human activities. Strong storms, fluctuating water temperatures, coastal development...

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.

Unexplained heterogeneity in statistical models of animal responses to their physical environment is reasonable to expect because the measured habitat resources are a constraint on—but not the sole determinant of—abundance, survival, fecundity, or fitness. The ecological understanding and reliability of management predictions based on animal habitat models can be improved by shifting focus from...

It's hard to imagine a better job than doing fieldwork with the USGS Coastal Ecology crew as they work to keep tabs on the Gulf sturgeon population.

Marine reserves and protected areas in the U.S. Virgin Islands and Puerto Rico encompass a variety of tropical ecosystems, including coral reefs, mangroves, and seagrass beds, but questions remain regarding how effective these areas are at preserving and protecting the habitats and species they encompass. USGS and collaborators address this question by examining the biodiversity and food web...

The decline of freshwater animals has resulted in an increase in the number of imperiled species and extinctions. USGS scientists use genetics to determine if these species truly are gone forever.