Geology topics

Research about British Columbia, Idaho, Montana

Source-linked reports with geographic coverage including British Columbia, Idaho, Montana.

3 recordsLinked to original sources

USGS2025

Population structure and movement dynamics of Redband Trout in the Kootenai River basin

Redband Trout Oncorhynchus mykiss gairdneri is a species of high conservation concern in the Kootenai River basin, United States and Canada. However, identifying the specific mechanisms influencing Redband Trout is difficult as its life history structure is largely unknown. Using otolith microchemistry analysis, we found that 18.5% ( n = 66) of the fish sampled ( n = 329) were a product of mainstem Kootenai River spawning. The remainder were fish ( n = 264) that originated from one of 31 tributaries throughout the basin. Redband Trout were captured between 0 and 153 km from their assigned natal tributaries. Most migratory fish originated from tributaries in the uppermost portion of the study area and had migratory mothers. However, a diversity of life history types (e.g., multi-year resident, migratory) was observed in the population. Redband Trout were estimated to outmigrate from natal habitats at a variety of ages (0–3 years) and lengths (12–430 mm). Our results highlight diversity in the population structure of Redband Trout and provide information valuable to conservation efforts in the Kootenai River system. Interestingly, several tributaries identified as natal habitats of Redband Trout contain substantial obstacles originally considered barriers to upstream fish passage. In addition, some streams in the lower portion of the Kootenai River basin with degraded habitat that were not expected to contribute Redband Trout had natal assignments. These observations indicate previously unknown sources of Redband Trout and support the notion that improved fish passage in disconnected and degraded streams could increase production of Redband Trout throughout the Kootenai River basin. Restoration efforts in the mainstem that include considerations for spawning and natal habitat may also aid in conservation efforts for Redband Trout. Our research demonstrates the value of microchemistry in planning and evaluating habitat restoration to recover fishes in large rivers.

British Columbia, Idaho, Montana↗

USGS2024

An evaluation of fin ray microchemistry to describe movement of White Sturgeon in the Kootenai River basin: Insights and limitations

Introduction: White Sturgeon Acipenser transmontanus in the Kootenai River basin is listed as endangered in the United States and Canada. Declines have been mainly attributed to poor recruitment exacerbated by the environmental effects of Libby Dam in Montana. Reduced primary production downstream of Libby Dam has been identified as one factor limiting growth of White Sturgeon, thereby limiting natural reproduction through delayed sexual maturity. However, estimating changes in growth over time without knowledge of fish location (i.e., Kootenai River vs. Kootenay Lake) is difficult. The objective of this project was to use microchemistry analysis to describe the movement of White Sturgeon within the Kootenai River basin. Methods: Water samples ( n = 27) and White Sturgeon fin rays ( n = 162) collected in the Kootenai River basin were measured for strontium isotope ( 87 Sr: 86 Sr) ratios using laser ablation multicollector inductively coupled plasma mass spectrometry. All water samples and a subset of fin rays ( n = 8) were also analyzed for trace elements (e.g., Sr, Ba, Mg). Fin ray annuli were measured and tested using knowledge of known age; known locations from physical capture events were assigned to age at capture. Results: Strontium isotope analysis was unable to detect differences in the Kootenai River and Kootenay Lake using water or fin ray samples. The Kootenai River and Kootenay Lake were distinguishable using trace element data from water samples, but not fin rays. The discrepancy with trace elements appears to be associated with the physiology of fin ray growth. Discussion: Although this study did not meet its original objective of describing the movement of White Sturgeon in the Kootenai River basin from fin ray microchemistry, our results provide insight into the potential influence of physiology on microchemistry analysis. In particular, fin ray microchemistry of slow-growing fishes may be possible in freshwater systems with further investigation into the physiological processes associated with growth and the incorporation of elements into calcified structures.

British Columbia, Idaho, Montana↗

USGS2022

Selenium in the Kootenai River Basin, Montana and Idaho, United States, and British Columbia, Canada

Selenium entering the 90-mile long transboundary Koocanusa Reservoir (also called Lake Koocanusa) in southeastern British Columbia, Canada, and northwestern Montana, United States, has been measured at concentrations above State and Federal water-quality and aquatic life standards. The reservoir is within the international Kootenai (or “Kootenay” in Canada) drainage basin, which contains critical habitat for native fish species and is impounded by Libby Dam 16 miles upstream from Libby, Montana. Since 1984, selenium concentrations have ranged from below detection to greater than 8 micrograms per liter in the Elk River, measured 2.2 miles above its discharge into Koocanusa Reservoir at a British Columbia environmental monitoring station (site 0200016). Selenium is a required micro-nutrient, but elevated concentrations in water bioaccumulate in egg-laying fish and birds, causing various sublethal effects and death. One possible source of selenium in the Kootenai River Basin is the excavation of bedrock in the Elk River Valley to access coal seams for metallurgical steelmaking and coal production. Five open-pit coal mines are operating in this region of southeastern British Columbia that produce about 21 million tons of metallurgical coal annually. Site-specific selenium standards were established for the reservoir in 2020 following collaborative work by the U.S. Geological Survey, Montana Department of Environmental Quality, the British Columbia Ministry of Environment and Climate Change Strategy, the Lake Koocanusa Monitoring and Research Working Group, and the Selenium Technical Subcommittee. The standards of 0.8 microgram per liter for dissolved selenium in the water column and 15.1 milligrams per kilogram dry weight for fish egg (ovary) tissue (in addition to the muscle and wholebody standards) were adopted into Montana State law in 2020 and approved by the U.S. Environmental Protection Agency in 2021.

British Columbia, Idaho, Montana↗