The oceans simply need to be managed like any other resource on our planet.
Absolutely, but it isn't. It's being decimated by huge corporations with no greater aim than profit. Same thing is happening to farm agriculture. We can't keep poisoning the hell out of the ground and then propping it back up with fertilizer. Organic small scale farming has been shown to work, and work well.
FWIW a single AWARE and KNOWLEDGEABLE diver is probably one of the better ways to harvest fish. What you are competing with really is massive fish trawlers with nets miles long that take EVERYTHING in their path, and stupidly discard the by-catch.....because it's illegal. How wasteful and stupid is that?
They now have to use more technological tools, go deeper, wider, and longer than they ever have before. They are still losing ground and desirable species faster than they are replenished.
A young man I know who just graduated from Marine Biology got his first job as a surveyor on the ships in AK. His report on that experience is really disturbing. The claim is that this is a sustainable fishery. What is the government going to say, "Everybody stop for say about 20-50 years and we'll see what happens.?" That just won't happen.
There used to be salmon in abundance on the west coast. Now there are few. Same thing is happening in AK, and fast. Sustainable.....not likely unless a whole lot of people are willing to go broke and not eat fish, which also seems unlikely.
Sad, I loved to fish when I was a teen. It was mostly lake and river trout but even back in the 60's as a kid could tell that fishery was about long gone. All we could catch was skinny 8" hatchery trout most of the time. People pay thousands of dollars to go where the fishing is still pristine. You have to be freaking rich and dedicated to do that anymore.