Sorting Out the Effects of Dams and the Ocean on Salmon Survival

<ombumedia data-ombumedia="{"fid":"6379","link":"","link_options":0,"position":"default","view_mode":"full","title":"Fall Chinook BON WA Side Sept . 2013 -2","type":"image"}"></ombumedia>

David Welch, Kitama Research Services, presented the findings of a paper he coauthored on dam passage and salmon survival. The research, which used acoustic tags, compared the survival of Snake River salmon smolts (that pass through hydrosystem dams) to migrating Yakima River smolts in the estuary and coastal ocean environments. Their research found no evidence for delayed mortality from dam passage, as commonly assumed. Welch speculated that the survival difference in adult returns may be ocean related. As the paper notes, "Columbia River salmon managers will need to recognize that the survival problem may be on a scale far larger than that of the Columbia River basin."

As a counterpart to this research, Dr. Steve Haesecker, U.S. Fish and Wildlife Service, and Margaret Filardo, Fish Passage Center, presented the results of a long-term salmon life-cycle study that includes data on smolt-to-adult return rates and experimental spill management at the eight federal mainstem dams on the Snake and Columbia rivers. According to Dr. Haesecker, their analyses support additional spill to improve salmon survival.