USGS: Biology arrow iconStatus & Trends Home arrow iconEcosystems arrow iconInland Waters arrow iconRivers and Streams+Lakes
Have a suggestion for new material?


Evaluation of Potentially Nonlethal Sampling Methods for Monitoring Mercury Concentrations in Smallmouth Bass (Micropterus dolomieu)

This project is an evaluation of three potentially nonlethal alternatives to fillet sampling for the determination of mercury (Hg) concentrations in smallmouth bass (Micropterus dolomieu) to monitor mercury concentrations in smallmouth bass (micropterus dolomieu) from six sites in southern Missouri were captured by electrofishing. Blood samples More...

  • blank image

Ecological Interactions between Aquatic Macrophytes and Fish in Lake Onalaska, Pool 7, Upper Mississippi River

In the Upper Mississippi River, more than 80 species of fish use vegetated habitats during some portion of their life cycle. Fish depend on aquatic vegetation for abundant, high-quality food resources (plant-associated invertebrates) and refuge from predators. Vegetation abundance in the Upper Mississippi River substantially declined in the late More...

  • Image of a map from Pool 7 lock and dam 7, located near Dresbach, Minnesota upstream to Lock & Dam 6

Bioaccumulation of Mercury by Fish and Fish-forage Organisms in Camp Far West Reservoir, Yuba and Placer Counties, California

Mercury contamination from historic gold mining operations is widespread in many rivers, lakes, and reservoirs on the western slopes of the Sierra Nevada. A multidisciplinary investigation by USGS is attempting to better understand mercury dynamics and to identify hot spots within Camp Far West Reservoir in order to determine if remediation More...

  • blank image

Eurasian Ruffe

Eurasian Ruffe pose a threat to native fish because they(1) mature quickly, (2) have a high reproductive capacity, and (3) easily adapt to new environments. Ruffe were first detected in western Lake Superior in 1986. UMESC scientists are conducting research on various types of piscicides (chemicals that kill fish). They are attempting to develop More...

  • Eurasian ruffe (Gymnocephalus cernuus)

Genetic population structure of the green floater (Lasmigona subviridis): Identification of management units and associated fish hosts

Freshwater bivalves, which are among the most threatened animals in North America, present significant challenges to conservation biologists that attempt to maintain ecological and evolutionary processes within and among populations. Effective management of this rare fauna is often complicated because inadequate information exists for More...

  • blank image

Zebra Mussels

Zebra mussels have caused drastic declines in native clam and mussel populations in some locations. Zebra mussels compete with other invertebrates and young fish for plankton, the primary food source for these groups. UMESC scientists are investigating the effects zebra mussels are having on the riverine ecosystem. This study examines the effects More...

  • blank image

Community Structure and Adaptive Strategies of Fungi in Geothermal Soils

There are approximately 500,000 abandoned mines in the western US. Collectively, these mines pollute rivers, streams, and western reservoirs with millions of tons of metals annually that degrade aquatic habitat and water used by humans for drinking, recreation, and irrigation. However, there is great potential in decreasing or eliminating the flow More...

  • blank image

Evaluation of sampling designs to monitor populations of freshwater mussels in small- to mid-sized drainages in the northeastern ecoregion

Freshwater mussels are declining rapidly in response to habitat degradation associated with anthropogenic changes. Williams et. al. (1993) reported that 213 of the 297 recognized taxa are considered endangered, threatened, or of special concern. There is a documented need for BRD centers to provide guidance on freshwater mussel ecology in general, More...

  • blank image

Silent Streams? Escalating Endangerment for North American Freshwater Fish: Nearly 40 Percent Now At-Risk

Nearly 40 percent of fish species in North American streams, rivers and lakes are now in jeopardy, according to the most detailed evaluation of the conservation status of freshwater fishes in the last 20 years. The 700 fishes now listed represent a staggering 92 percent increase over the 364 listed as "imperiled" in the previous 1989 study More...

  • blank image

Swimming Performance of Bull Trout (Salvelinus confluentus)

Bull trout in the western United States are now listed as threatened under the Endangered Species Act. One cause of bull trout population declines is fish passage issues caused by dams and diversion structures. In order to best design or modify culverts and other fish passage structures in watersheds where bull trout are present, baseline swimming More...

  • Bull trout (Salvelinus confluentus)

Bioassessment of the Finger Lakes Habitat Rehabilitation and Enhancement Project: Responses of Fish and Aquatic Invertebrates

The Upper Mississippi River System has been highly modified for human use since the late 1800s. One effect of these modifications is that many side channels and backwaters are slowly filling with sediment. The Finger Lakes area of the Upper Mississippi River is a system of six connected backwater lakes just below Dam 4 near Kellogg, Minnesota. More...

  • Image of Lock & Dam 5 located near Whitman, Minnesota

Estimating Survival Estimates for Migrant Juvenile Salmonids Passing Through the Dalles Dam Using Radio-telemetry

As anadromous juvenile salmonids migrate from freshwater rearing habitats to the ocean, they are vulnerable to a host of factors that affect their survival. Direct effects associated with dam passage (e.g., instantaneous mortality, injury, loss of equilibrium, etc.) and indirect effects (e.g., predation, disease, and physiological stress) More...

  • blank image