Hybrid salmon discovered by scientists on Vancouver Island

CBC –

Two salmon researchers say a surprising discovery has been made on Vancouver Island.

Andres Araujo, a biologist at the Department of Fisheries and Oceans, and Will Duguid, a PhD biology student at the University of Victoria, recently found fish in the Cowichan River, north of Victoria, B.C., that have the genes of both coho and chinook salmon.

Tissue samples revealed the fish are second-generation hybrids, meaning they are the spawn of hybrids.

The hybrid fish, according to Araujo and Duguid, are a rare find in Canada and are likely the result of drought in the Cowichan watershed, which has impacted when and where coho and chinook spawn.

“For a hybrid to exist we need overlapping spawning grounds and timing,” said Araujo, noting that chinook usually spawn in September and October, whereas coho traditionally spawn toward the end of October until December. He said when summer droughts extend into fall it can push chinook spawning season back into when coho are also starting to spawn.

Duguid said there are some fish that routinely generate hybrids — such as rainbow trout and cutthroat trout — but not wild salmon.

“Apparently, it rarely occurred in the past and there has never been documentation of hybridization into the second generation,” said Duguid.

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