Researchers look back more than 100 years using DNA from Skeena River salmon. A genetic analysis has found that the number of salmon returning each year to a river in British Columbia has declined more severely than previously estimated. Using genetic analysis, they found that the number of wild adult sockeye salmon that return to the river is about 75 percent lower in recent years than a century ago. Genetic Study of Sockeye Salmon in B.C. River Suggests 75% Decline Since 1913