Pretty neat. Didn’t think they were keeping track of those saltwater fish.
Not sure what percentage they tag down south but up here we coded wire tag (CWT) a large percentage of our fish. Fish and game and the hatcheries use the information to extrapolate the data out to figure out survivals. Pretty sure Alaska only CWT kings and coho. Alaska fish and game has a whole website where you can track it all.
Here's some more info on this website-CWT data
The tags are tiny, about 1mm long and they are put into the fish when they are smolt usually, although you can tag them when they are about 6g.