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Chinook salmon (Oncorhynchus tshawytscha) swimming upstream. Photo: Ingrid Taylar (CC BY-NC 2.0)
Chinook salmon (Oncorhynchus tshawytscha) swimming upstream. Photo: Ingrid Taylar (CC BY-NC 2.0)

‘Early migration gene’ tied to unique population of Chinook

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By Christopher Dunagan, Puget Sound Institute

Recent studies have shown that Chinook salmon that spawn in the spring are genetically distinct from varieties that spawn during fall months. Experts are confronting the resulting ecological, social and legal implications of that finding.

Each year, as the dark days of winter surrendered to the rebirth of spring, the Twana people earnestly waited for a unique type of salmon to return to the rushing rivers of Tuwa’duxq Si’dak, known today as Hood Canal.

Throughout the Northwest, bands of native people followed their own ancient traditions, greeting the mysterious spring Chinook that would show up after the mountain snowpack began to melt.

Now, such arrivals are rare. More than half the spring Chinook runs in Puget Sound streams — including those in Hood Canal — have gone extinct since settlers first appeared in the 1800s. Essential habitat in the higher elevations, where the spring Chinook like to spawn, was cut off or damaged by logging, farming, dams and development. Although fall Chinook generally fared better, they too have experienced severe declines.

In 1999, federal authorities placed Puget Sound Chinook — spring and fall runs together — on the Endangered Species List.

Over the past few years, thanks to extraordinary advances in genetics, scientists are beginning to understand the unique nature of these fish as well as the genetic losses that occurred when spring runs disappeared. Experts are now confronting the resulting ecological, social and legal implications of these losses while trying to save the remaining spring populations and possibly restore historic runs to some streams.

Read the full story in Salish Sea Currents on the Encyclopedia of Puget Sound.