A graduate student’s passion for steelheading hooked him into doing serious research on the sea-going salmonid.
Carl Ostberg, who is earning a master’s degree at Washington State University, discovered distinct genetic variations among Washington’s West Side steelhead.
Steelhead originating in Puget Sound rivers have 60 chromosomes compared with 58 chromosomes in steelhead from Washington coastal rivers to the west and south.
Ostberg believes the last Ice Age may have separated the fish in evolutionary development, and that caused the variation. The fish with the extra chromosomes are found in the Strait of Juan de Fuca and Puget Sound from the Elwah River eastward. The fish with 58 chromosomes are found west and south of there.
In the Elwah River area, some fish have 59 chromosomes, indicating the region is a transition zone.
The findings were presented to the Western Region of the American Fisheries Society and could influence future management decisions for steelhead runs.