As I posted, whatever the limiting factors are, and that includes corresponding salmon escapements, most Puget Sound and coastal rivers are presently producing wild steelhead at their current carrying capacities. Harvest hasn't been a limiting factor for years now.

Muck Creek certainly added to the Nisqually's steelhead (and coho and chum salmon) production base. Even without it, the mainstem Nisqually and Mashel Rivers contain a lot of good to high quality steelhead habitat. The problem for steelhead appears to be the heavily increased marine mammal (harbor seals and sea lions) predation on smolts in the estuary and throughout Puget Sound. With the Nisqually being at the southern extreme of PS, the predation rate on smolts is higher than for any other PS river system. Tagging studies indicate that fewer than 20% of Nisqually steelhead smolts survive past Point-No-Point. Couple that with the low ocean survival rates for steelhead since 1990 and you have a nearly perfect storm of very low adult steelhead returns even with good freshwater habitat and no significant fishing harvest.

In Lk WA primary productivity and zooplankton density decreased drastically after King County approved METRO in 1968 and stopped sending untreated sewage into the lake. And since that time the number and species of salmonid predators has drastically increased in the lake and below the Ballard Locks. There are a lot of factors limiting Lk WA sockeye production. However, the sockeye population is at the present day carrying capacity, given all those factors. And it can't make its escapement goal because the escapement goal is not tied to the ecology and productivity of the population.