It's hard to talk about salmon overfishing for two reasons. One, salmon fishermen are not villians, and two, I'm part of the problem. But integrity demands a few words.
It's important to say that salmon fishermen bust a** in protecting salmon habitat. I've rarely seen stronger conservation advocates than angry fishermen seeing salmon killed by dams or water diversions or anything else. But salmon fishermen have a blind spot when it comes to killing salmon directly, with a line, net, or whatever, believing that fishermen are the "good guys" that would never overdo it.
So is salmon overfishing a problem? Salmon fishermen routinely killed up to 50% of adult salmon in recent years and sometimes up to 80%, in many different places (see pp. 18-22 of this link for data). That's killing too many fish, and it's hard for me to believe that anyone seriously thought that was a biologically acceptable kill rate (we can go into this more later, if anyone asks for it--there's a lot to say).
Things are better now, overfishing of salmon is much less of a problem. But unfortunately, some salmon fishermen continue to push for higher salmon fishing rates, even when salmon are so depleted that they should be left alone.
I understand this problem. I fished commercially for salmon in 1976 when I was young, and I didn't think we were the ones harming salmon. Only later did I see data showing that we killed over 80% of the adult coho salmon that returned to Oregon that year. We helped drive Oregon coho into listing as "threatened" under the Endangered Species Act (see page 6 of this link for data). I refuse to hide behind ignorance, I feel bad even though I didn't know what was happening.
Fishermen and other conservationists are now united in saving salmon. But let's keep our own house in order while we criticize those that kill salmon using dams or water pipes or chain saws. It wasn't that long ago that we killed 80% or more of adult salmon, and criticized everyone else for their impacts. Integrous? I think not.