"If the problem was in the ocean or the estuary, both populations would have been in trouble, " Bosse said.

CNN: Dam removal: Too little, too late for salmon?

"A model is only as accurate as the assumptions that go into it, " said Scott Bosse, a fisheries biologist at Idaho Rivers United.

CNN: Dam removal: Too little, too late for salmon?

According to Bosse, there is scant proof that egg-to-smolt survival, which occurs during the first year of life, has decreased since the four lower Snake River dams were constructed.

CNN: Dam removal: Too little, too late for salmon?