Skip to main content
U.S. flag

An official website of the United States government

During seasonal low flow in streams, survival of fish is low and predation risk is high, which could be explained by a lack of available cover.

Federal researchers studied how coastal cutthroat trout use in-stream cover, both in Oregon streams and in an experimental study, where they controlled flow, depth, and cover availability to test multiple hypotheses about cover use. Trout showed behavioral plasticity, concealing under cover and emigrating as first options, followed by grouping, then habitat shifting. Trout selected boulders as the main cover in natural streams and disproportionately used cover near deeper water, selecting larger-sized cover in shallower water, and emigrating at higher levels when there was less cover available. Lack of feeding and growth suggested that perceived threat of predation was a more important driver of behavior than foraging. Collectively, findings indicate that cover can be considered a critical limiting resource for stream-living fish. 

 

Penaluna, B.E., Dunham, J.B., Andersen, H.V., 2020, Nowhere to hide: The importance of instream cover for stream-living Coastal Cutthroat Trout during seasonal low flow: Ecology of Freshwater Fish, https://doi.org/10.1111/eff.12581

Get Our News

These items are in the RSS feed format (Really Simple Syndication) based on categories such as topics, locations, and more. You can install and RSS reader browser extension, software, or use a third-party service to receive immediate news updates depending on the feed that you have added. If you click the feed links below, they may look strange because they are simply XML code. An RSS reader can easily read this code and push out a notification to you when something new is posted to our site.