My bad on mortality. For me mortality is not just dead fish but eggs. The fish can live but the eggs will not be viable. In the Chehalis Chinook the first 10% of run will have about 15% of the hens ending up sour. Sour is when you pick up the hen the ovarian fluid will have a odor that is not normal and when you smell it you separate it into a separate bucket. Prior to doing that we ended up with trays ( incubator ) with a huge % of blank eggs. So we we learned to simply discard those fish or separate them and identify them so we could kinda track it. Thing is anything that adds stress or physically impacts the body of the female will be detrimental to the eggs that she will produce. Fact is everything that the female experiences after leaving the ocean will effect the viability of spawning. No pluses only minuses from any encounter be it nature ( critters ) or human.