Native Fish

As droughts become more frequent and severe, freshwater ecosystems and the valuable fisheries they support face increasing challenges. Drought reduces streamflows, raises water temperatures, and stresses fish populations, particularly cold-water species like trout. These impacts can lead to declines in trout populations, threatening biodiversity, ecosystem health, and local economies. To address...

The USGS has developed the Rapid environmental (e)DNA Assessment and Deployment Initiative & Network (READI-Net) to accelerate the implementation of environmental DNA (eDNA) analysis as a best practice for the early detection of aquatic biological threats. READI-Net provides tools and a strategy to collect and deliver early detection data for natural resource managers and public health protection...

For more than a decade, researchers around the world have shown that sampling a water body and analyzing for DNA (a method known as eDNA) is an effective method to detect an organism in the water. The challenge is that finding organisms that are not very abundant requires a lot of samples to locate this needle in a haystack. Enter the "lab in a can", the water quality sampling and processing robot...

After 14,000 years of dominance, Glacier National Park’s (GNP) greatest native aquatic predator is at high risk of extirpation (local extinction) in several lakes on the western slopes of the Continental Divide. The decline of threatened bull trout in GNP is directly attributed to the invasion and establishment of nonnative lake trout, which consistently displace bull trout in systems where lake...

Glacier National Park (GNP) is considered a stronghold for a large diversity of plant and animal species and harbors some of the last remaining populations of threatened and endangered species such as grizzly bear and bull trout, as well as non threatened, yet ecologically important species such as bighorn sheep and black bear. The mountain ecosystems of GNP that support these species are dynamic...

These Frequently Asked Questions and responses were developed by USGS and their partners with the Lake Trout Suppression Scientific Review Panel *. The purpose of these FAQs is to provide answers to several of the more common questions concerning the lake trout suppression program in Yellowstone Lake, within Yellowstone National Park, and provide information about the current status of the program...

Researchers at the Northern Rocky Mountain Science Center's Western Waters Invasive Species and Disease Research Program work extensively with federal, state, tribal, regional, and local partners to deliver science to improve early detection and prevention of invasive species and disease; understand complex interactions that promote invasive species and disease, and their impacts (and associated...

Fishery biologists and managers are increasingly consumed with the recovery and restoration of native trout and salmon throughout the western United States. These fish historically inhabited a variety of freshwater habitats, but have declined due to habitat degradation, fragmentation and introduction of nonnative species. Introduced fishes constitute a major threat to the persistence of native...

Bob Gresswell's Past Projects

The topographic diversity and extensive area of protected public land within the Greater Yellowstone demonstrate the importance of this region as a natural resource reserve. Understanding the effects of anticipated changes in climate on aquatic resources and means for managing these resources will ultimately require accurate linkages between empirical data and regional climatic patterns. This...

Beyond large-scale climate models, it is becoming increasingly important to quantify how regional climate patterns link with in situ stream temperatures and hydrologic regimes and concomitantly, fish behavior, growth, and survival. Here, we are using comprehensive mark-recapture techniques to evaluate how changing climatic conditions are likely to influence native westslope cutthroat trout and non...

In 2010, Congress established ten decade-long Collaborative Forest Landscape Restoration Program projects to carry out fuel reduction and ecological restoration treatments on public lands across the country. The Southwest Crown of the Continent was selected as one of the locations under this initiative, given the importance of this region to the economic vitality of local communities and the...