Why would the ocean be selectively bad for Snake Rive salmon and steelhead?
Conclusion: Ocean conditions influence smolt-to-adult survival of salmon and steelhead. However, there have been no hypotheses advanced or evidence presented to explain why the estuary or ocean would be selectively bad for Snake River fish. The following material is adapted from Schaller et al. (1996) The conclusion by Schaller et al. (1996) that hydropower was a primary cause of productivity and survival rate declines of Snake River and upper Columbia river stocks was conditioned on evidence that the estuary and early ocean conditions do not have a systematically different effect on survival for interior Columbia River basin stream-type chinook stocks. This is reasonable in view of the similarity of these stocks, the overlap in time and space of these stocks during their early ocean residence (and beyond), and the broad-scale nature of climatic influences described in the literature. There are several lines of evidence suggesting that the interior Columbia Basin stocks are exposed to
