USGS: Biology arrow iconStatus & Trends Home arrow iconIssues arrow iconThreatened and Endangered Species+Fish
Have a suggestion for new material?


Development of a Bioassay to Quantify Vitellogenin in the Endangered Razorback Sucker followed by Annual Cycle Characterization of Vitellogenin and Steroid Hormones as a Measure of Reproductive Health

This research project objective is to measure vtg and steroid hormones in sexually mature, adult razorback sucker over one annual -estradiol,ß reproductive cycle. We will measure vtg and steroid hormones (17 11-ketotestosterone, and testosterone) in blood plasma of razorback suckers once a month for one year to document concentrations throughout More...

  • Razorback Sucker (Xyrauchen texanus)

Assessment of Smolt Condition: Biological and Environmental Interactions

Salmonid species in the Pacific Northwest continue to decline despite management efforts to mitigate the effects of development of the Columbia River basin and power system. Altered fish species diversity and changes in the aquatic habitat have created the need for research to determine the status, life history, and habitat requirements of at risk More...

  • Photo of salmon eggs, alevin, and smolt

Near-Shore Habitat Use by Endangered Juvenile Suckers

The objectives of this study are 1) to determine how and when juvenile suckers use near-shore habitat with emergent vegetation, 2) determine how the distribution and abundance of juvenile suckers varies between near shore and offshore areas as well as between different areas of the lake over time, 3) determine if water quality conditions affect More...

  • Juvenile sucker captured in emergent vegetation.

Evaluating the Role of Wetlands to Endangered Salmonids at Toppenish and Tualatin River National Wildlife Refuge

Threatened and endangered salmonids in the Pacific Northwest often use backwaters and wetlands as they migrate toward the ocean, however our understanding of the role of wetlands to juvenile salmonids is limited. The major Objective of this study was to determine whether juvenile steelhead were being tapped on the wetland during spring, and More...

  • blank image

Investigating Passage of ESA-listed Juvenile Fall Chinook Salmon at Lower Granite Dam During Winter When the Fish Bypass System is Not Operated

Fall chinook salmon (Oncorhynchus tshawytscha) in the Snake River are currently listed as threatened under the Endangered Species Act (ESA). Although fish bypass systems reduce the mortality of fish entering turbine intakes at mainstem hydroelectric dams, they are only operated during the spring, summer, and early fall during the peaks of seaward More...

  • blank image

Paddlefish Study Project

Paddlefish (Polyodon spathula) have been lost from four states and Canada, and 11 of 22 states within the remaining species range now list the paddlefish as endangered, threatened, or a species of special concern. Restoration of paddlefish populations is a shared goal of many state and federal agencies. UMESC scientists, in collaboration with the More...

  • Image of a Paddlefish (Polyodon spathula)

Rescuing the Razorback Sucker

The razorback sucker (Xyrauchen texanus) is a fish few people recognize. Once abundant in the turbulent and unpredictable Colorado River, the razorback sucker is now restricted to a few remnant populations, the largest being found in Lake Mohave, Arizona-Nevada. Habitat loss due to channelization and reservoir construction, along with competition More...

  • Image of the razorback sucker (Xyrauchen texanus)

Beulah Reservoir (2001) - Food-Based Studies for Bull Trout

Bull trout were listed by the U.S. Fish and Wildlife Service as a threatened species throughout the Columbia and Klamath river basins in 1998, and Oregon has listed the North Fork Malheur River population "Of Special Concern". Reasons for the decline of bull trout in the Malheur River likely include habitat degradation, habitat fragmentation, and More...

  • Catch and release of bull trout at Beulah Reservoir.

Evaluate Status of Coastal Cutthroat Trout in the Columbia River Basin Above Bonneville Dam

The goal of this project is to provide vital information on the current status of cutthroat trout (Oncorhynchus clarkii) populations as a necessary prerequisite to determining need and type of future recovery efforts. Coastal cutthroat trout were petitioned for listing under the Endangered Species Act in 1997.

  • cutthroat trout (Oncorhynchus clarkii)

Water Quality and Other Environmental Variables Associated With Variations in Population Densitites of the Santa Ana Sucker

The Santa Ana sucker (Catostomus santaanae), was recently identified by the U.S. Fish and Wildlife Service (FWS) as a species of special concern. This sucker is endemic to the Los Angeles, San Gabriel, and Santa Ana river drainages of southern California. The purpose of this study was to develop a better understanding of environmental factors More...

  • blank image

American Fisheries Society Imperiled Freshwater and Diadromous Fishes of North America

This website provides access to the list of imperiled freshwater and diadromous fishes of North America as determined by the 2008 American Fisheries Society (AFS) Endangered Species Committee (ESC) on Fishes. At this website, one can view lists of imperiled fishes by freshwater ecoregion, by state or province boundary, and plot distributions of More...

  • blank image

Post-release Behavior and Survival of Hatchery and Natural Juvenile Fall Chinook Salmon

Fall chinook salmon (Oncorhynchus tshawytscha) in the Snake River are currently listed as threatened under the Endangered Species Act (ESA). Because fall chinook salmon migrate seaward during the summer when flows are low and water temperatures are high, their survival rate is lower. The goal of this study is to more clearly identify the More...

  • Image of scientist surgically implanting a radio tag.