Regarding the two photos I posted originally in this thread, I had some further discussions with my colleagues and determined a few more things.
Everyone's confident that the first fish was a male due to the distinct kype. This leads to the question, why would someone slit open a hatchery male coho salmon and left it on the bank? One illegal scenario is that, the angler caught and retained the fish, even though it was already a bit coloured, but encountered more hatchery-marked fish later on which were much fresher than this fish. He or she then decided to kill above his or her quota for the day, and abandoned this fish so when carrying the rest of the fish out to the car, it would be seen legal. It's high grading, which is a clear violation.
Another very possible scenario is that the fish was simply lost and washed away after it was cleaned. It has happened to me several times.
The second fish was clearly a violation if it was killed by an angler as it was a wild coho salmon. He or she may have been told off after it was killed, perhaps the angler did not know better, which is not unusual but unacceptable if new to fishing. He or she then decided to leave the fish behind so the officer would not issue a fine if checked.
For both cases, I guess the silver lining is that the carcasses remain in the watershed, which will fertilize it and support the offsprings next year.
While it was likely, I don't buy that someone cut open these fish after they had naturally died prior to spawning because of their condition. It's possible, but there were a few hundred other dead chum salmon around these, some looked like they did not spawn (but probably did), yet none of their abdomen were cut open. With that said, as I pointed out in the previous post, I am interested to find out whether slitting open carcasses on the river bank for roe is a legal practice. I shall have an answer within a few days.
I posted these photographs not with the intention to accuse anyone or user group, but to discuss possible scenarios,stimulate a topic which is rarely discussed yet quite important, and clear up some confusion. I'm glad to see three pages of opinions so far.