Researchers have created a tool to assess the risk of hybridization among native and non-native fish, a development that could aid natural resource managers trying to protect threatened or endangered freshwater fish species.

The introduction of non-native species poses challenges to native species, including competition for resources and habitat, exposure to diseases carried by the introduced species and the risk of hybridization, which occurs naturally in wild populations as part of the evolutionary process.

The Oregon State research, just published in the journal Frontiers in Environmental Science, focused on two species: bull trout, a fish native to western North America that is protected under the Endangered Species Act; and brook trout, a native to eastern North America introduced in the West more than 100 years ago for recreational fishing purposes.

Bull trout were once abundant in Oregon, Washington, California, Nevada, Idaho and Montana but today are found in less than half of their historic range, and no longer exist in California. They are threatened by habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, the effects of climate change and fisheries management practices, including the introduction of brook trout.

While some studies have documented hybridization among bull and brook trout, there has not been enough research to allow natural resource managers to quantify hybridization risk, the Oregon State researchers said.

«The goal was to come up with a tool that allows managers to look at the potential long-term impacts when they are planning restoration or conservation projects,» said Michael Manning, the lead author of the paper who worked on the research as an Oregon State graduate student.

Story Source:
Materials provided by Oregon State University. Original written by Sean Nealon. Note: Content may be edited for style and length.