The key focus of this paper is that the processes leading to speciation can happen much more quickly than anyone had previously supposed, he says. The sockeye studied were originally from Baker Lake, in northwest Washington state, and were introduced into Seattle's Lake Washington between 1937 and 1945. Today, runs of 100,000 to 350,000 fish spawn in the Cedar River, which starts in the Cascade Range southeast of Seattle and flows into Lake Washington. Another smaller group of descendents was first documented breeding along Pleasure Point Beach on Lake Washington, south of Bellevue, in 1957. The divergence scientists detected between these two populations came in response to conditions that favor different traits.
Flooding is absent from beaches, and females are correspondingly smaller.
The reproductive isolation of the two populations was established using genetic analysis conducted by UW's Marine Molecular Biotechnology Laboratory, which showed that fish hatched in the river but trying to spawn at the beach had little success. If the immigrants from the river had been equally successful in producing offspring, then the two populations would have been homogenous. Scientists involved in Columbia Basin processes intended to reverse salmon declines and ward off extinctions of 12 federally listed salmon and steelhead species found the study results intriguing. Major initiatives are under way to alter hatchery practices to avoid any negative influences non-native hatchery fish might pose to wild listed stocks. Those proposals would seek funding through innovative project and high priority project categories outlined in the Northwest Power Planning Council's Columbia Basin fish and wildlife program.