I was told today that fish hooks are designed to quickly dissolve if left in the fish…
Tell this idiot you believe him and you want to get the ones that dissolve the quickest so could he please point you to a hook manufacturer that has these dissolving hooks. Name even one.
Whether or not you leave a hook in a fish depends on the amount of handling required to remove it. You never “pull” a hook out because pulling is what keeps them firmly embedded. You have to twist them out or push back on them to get them to release and sometimes that just isn’t possible without serious handling, in which case you shouldn’t bother. It’s stress and loss of body slime you should worry about - hooks (dissolving or not) are not the issue. The fish may survive an embedded hook, he definitely won’t survive being manhandled and having his slime rubbed off.
I once caught a really nice spotted sand bass and managed to release him without even lifting him from the water and as he swam off, a little stunned, a seal came up and got him. It sucks to be a fish.
Worth mentioning that a hook fully immersed in water will corrode vastly slower than a wet hook in air. It isn’t water that rusts steel, it is oxygen. But water accelerates the rusting - if there is lots of oxygen to do the actual oxidising. Once you are fully immersed this doesn’t happen, and the rate of oxidisation drops massively.
Something made of a conventional high carbon steel will tarnish quite quickly if wet in air, but this isn’t the same thing as corroding down to nothing when fully immersed.
Yeah, a lot of the time, a barbless hook pops out as soon as the there is slack in the line. Once the fish hits the net, the hook often pops out and you can release the fish without ever touching him.