For decades, federal, state, and nonprofit organizations have been working to restore freshwater habitat for Oregon coastal coho salmon (Oncorhynchus kisutch), a species listed as threatened under the federal Endangered Species Act. Much of the restoration, however, has been done without directly considering the availability and connectivity of seasonally important freshwater habitats.
Research by Rebecca Flitcroft, a research fish biologist with the U.S. Forest Service Pacific Northwest Research Station, and colleagues reveals that connectivity among different types of freshwater habitat is important for coastal coho salmon. In fact, salmon occupancy in rivers or streams over time is best explained by the level of connectivity among habitat used for spawning, summer rearing, and winter refuge. Juvenile fish benefit when they can move easily among these habitat types.
Restoration projects that focus on only individual habitat segments may not result in watershed-scale improvements. Targeted restoration that fills habitat gaps may be more effective when diversity, location, and proximity of seasonally important habitats already present in a watershed are considered.
Resource managers are using these findings to reevaluate how they think about coho salmon habitat, as well as habitat for other species such as trout and beaver.
Kirkland, John; Flitcroft, Rebecca. 2020. Location, location, location: For coho salmon, it’s all about the neighborhood. Science Findings 224. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.