As in all things fish traps are no different, it is location location! Let me share my experience with you all. LLTK had a contract to capture Chinook brood for the hatchery on the Hump and utilized a tidewater area. Getting fish not that difficult but keeping them alive was something else. After a bit in the hatchery a full wedding band of fungus from gripping the fish showed on many as the stomach with a hand print! Even worse on the Wishkah and it was well documented. Seems we hit the salt fresh thing that tidewater gives you so any effort in tide water got dumped.

On the Chehalis we found that the water temp has to drop or the females do not do well. Satsop not so much but by the time they reach that far they are slimed up and sturdy as h===.

Bottom line is traps can work but not everywhere. Rain driven streams on the coast not so much UNLESS you can release the fish without touching it. Frankly fish wheels would work best and the technology exist now to hit a pedal and clipped one way fin the other.

So traps or other methods can work but it is about release, water temp, and location. It can be done but it ain't cheap and is difficult to site. Then the coastal streams can go up to flood stage in a few hours so construction cost are likely be high as a bunch of net strung up in pilings will not work on the coast.