Coeur d’Alene Basin Bull Trout

This story was written by Graham Freeman on behalf of the Our Gem Collaborative team for the CDA Press on Sunday, April 23, 2023. Read the original article.

The Idaho Governor’s Office of Species Conservation (OSC) is dedicated to planning, coordinating and implementing the State’s actions to preserve, protect and restore species listed as candidate, threatened or endangered under the federal Endangered Species Act (ESA). This work is done in coordination with the State’s natural resource agencies and with input from the citizens of Idaho while taking into consideration the economic vitality of the State. In northern Idaho, OSC works with aquatic ESA species including Bull trout (Salvelinus confluentus), Chinook salmon (Oncorhynchus tshawytscha), Kootenai river white sturgeon (Acipenser transmontanus), and steelhead trout (Oncorhynchus mykiss). Specific to the Our Gem Collaborative and the Coeur d’Alene Lake, the threatened bull trout are found within the Coeur d’Alene Lake Subbasin.

Bull trout are a native fish to California, Montana, Nevada, Oregon, Washington and are found throughout Idaho. Bull trout express resident and migratory life history strategies. Resident bull trout complete their entire life cycle in streams, or near streams, where they spawn and rear. Migratory bull trout will spend one to four years in their natal streams before migrating to large rivers or lakes. Fluvial bull trout migrate to rivers and adfluvial bull trout migrate to large lakes or reservoirs to access foraging and overwintering sites. Migratory bull trout can move hundreds of miles from their spawning tributaries to access foraging and overwintering sites. In general, migratory bull trout have access to better food resources and are typically much larger than resident bull trout. Migratory bull trout return to small tributaries to spawn and may make multiple migrations over the course of their life.

Bull trout are highly sensitive to changes in their habitat and typically require water cooler than 60 degrees Fahrenheit; clean spawning substrate (minimal fine sediment); complex habitat including pools, woody debris and overhanging banks; and connection between spawning/rearing habitat to foraging/overwintering habitat. Due to these habitat requirements, bull trout are sensitive to habitat modification. Bull trout no longer inhabit 60% of their native range, largely due to habitat loss and fragmentation.

In 1999, bull trout within the coterminous United States were listed as threatened pursuant to the ESA. This listing included bull trout within the Coeur d’Alene Lake geographic area. Historically, bull trout were found in the Coeur d’Alene and the St. Joe River systems and expressed adfluvial life history strategies. Currently, there are five populations of bull trout in the St. Joe watershed. Bull trout are no longer found in the Coeur d’Alene River, largely due to poor water quality. The populations of bull trout in the St. Joe River are relatively small and are threatened by limited access to foraging/overwintering habitat and nonnative fish which may prey on juvenile/subadult migratory bull trout.

In 2018, the United States Fish and Wildlife Service (USFWS) published the final Recovery Plan for the Coterminous United States Bull Trout Population (Recovery Plan). The Recovery Plan outlines the actions necessary to manage and ameliorate threats, work cooperatively to implement bull trout recovery actions and adaptively manage bull trout. The goal of the Recovery Plan is to ensure sufficient distribution and abundance of bull trout in the coterminous United States which would no longer require protection under the ESA. Later in 2018, the USFWS released a 5-Year Status Review of the threatened bull trout. The 5-year status review found that populations of Bull Trout are generally stable range-wide, but some populations of bull trout are decreasing. Thus, the 2018 5-Year Status Review determined the threatened ESA listing for bull trout was still appropriate. In 2020, the USFWs initiated the next 5-Year Status Review of bull trout and should be finalized within the next year.

Bull trout are a dynamic fish species occupying a variety of habitats from small tributaries to large lakes and rivers. Their complex requirements make them sensitive to changes in water quality, habitat alterations and interactions with non-native fish. Bull trout populations in the Coeur d’Alene Lake geographic area could benefit from actions that reduce water quality pollutants, including temperature and metals, and reduce interactions with non-native fish.

Additional information on bull trout can be found on the USWFS’s webpage here. If you have a question related to bull trout in Idaho or services provided by the Idaho Governor’s Office of Species Conservation, you can contact Graham Freeman, the office’s Aquatic Species Manager/Policy Advisor at graham.freeman@osc.idaho.gov.

Graham Freeman is the Aquatic Species Manager and Policy Advisor for the Office of Species Conversation.
The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach and stewardship. Our Gem includes local experts from the University of Idaho Community Water Resource Center, Coeur d’Alene Tribe Lake Management Department, Idaho Department of Environmental Quality, Kootenai Environmental Alliance, Coeur d’Alene Regional Chamber of Commerce, and Connect Kootenai.