From the Olympian:

The Nisqually Tribe has closed its coho fishery nearly a month early to protect a weak run of adult fish returning to the river.

It marks the second consecutive year the fishery has closed early, raising questions about what’s happening to the fish when they leave the river for saltwater.’

“It’s alarming,” said David Troutt, the tribe’s natural resources director. “The habitat couldn’t be any better in the river. It seems to be a matter of poor survival in Puget Sound.”
The 50 or so tribal fishers landed about 3,200 coho, about 1,000 fewer than last year, before the emergency closure Oct. 28. Typically, the tribe would fish for coho until Thanksgiving, Troutt said.

The pre-season run size was predicted at 30,000, which would have been a record return, Troutt said. But it never materialized, suggesting something is happening to the fish in Puget Sound when they leave the river as young fish and return as adults.