LL their are two types of moralities. One at the time of intercept and handling. Second is if they go on to spawn successfully. We found that captured brood if held for a time and then released failed to spawn naturally. A study I read some time back in Alaska ( or some place ) had really high mortality in the bay but as the intercept locations progressed up stream it dropped way down. Until at the hatchery you could seine them up, sort & toss, with almost no mortality. There seems to be a link of some sort ( I am not a Bio ) between when & where the stress occurs as the fish goes from salt to fresh and the changes in the creature with the length of time until spawning after handling. Pretty much a hard link to.

This is why many of us who live in GH have issues with sport C&R in the bay with Chinook the most vulnerable. It is a math thing with harvest always and it matters little as to who or what places the stress on the creature and if the access to harvest is viable. Conservation or harvest, how / where, always a gut check.