Study reveals the evolutionary history of imperiled salmon stocks

Aug 16, 2017 at 6:00pm

PHYS.ORG

These technologies can be applied to a wide range of species around the world—from mushrooms to walruses—but the study focuses on two iconic species of Pacific salmon: steelhead and chinook. While steelhead are a legendary sport fish, chinook are considered the workhorse of the West Coast salmon industry.

Using an inexpensive, efficient DNA analysis method called RAD (restriction-site associated DNA), developed by UC Davis Assistant Professor Mike Miller, the authors found that early migrating salmon populations (called spring chinook and summer steelhead) depend on a single gene. The version of the gene that makes them migrate early evolved only once in each species.  

The study's findings carry significant management implications. In most watersheds, spring chinook and summer steelhead are currently not protected independently from their later-migrating counterparts (fall chinook and winter steelhead) even though early migrating populations are on the brink of extinction in most locations where they haven't already been lost. Fall chinook and winter steelhead populations are relatively healthy in most watersheds.

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