Good question Dave, so I will take a guess. I have read or heard in the past that Puget Sound bound Salmon tend to run deeper because they have geneticly learned over time that going deeper helps them avoid the nets.

Perhaps the Snohomish Coho returning to this very urbanized area with lots of people fishing it have learned geneticly over time not to bite.

We have all read or heard those stories from many years ago when all one had to do was toss a chunk of herring into the Sound from the beach to catch a fish. It certainly has changed now.

It would be interesting to know if the Snohomish Coho of 30 or more years ago were as dificult to catch as they are today.