If the problem is a lack of fish, the solution is proven and easy: MAKE MORE FISH!
This has been established with everything from mammals, birds, insects and even plants. Breed a whole bunch of them for release, and though the attrition is high, pretty soon you are up to your elbows in critters.
The technology for doing this with fish is fairly inexpensive, just needing a tug boat, pontoons, and a double or triple drop net. It’s called deep water aquaculture.
The tug takes the pontoons out to sea, far enough away from the coast to avoid polluting the “arable ocean” near the coast. Ideally in the lee of a rocky island. Then it drops its nets and put wild hatchlings of the desired type in them. The current cleans and aerates the water, and the fish are fed along with antibiotics.
When they are mature enough the nets are slowly dragged back to where wild populations of those fish live and they are released with the wild population.
The end result is that, again, attrition is high, but the newly released fish mature and mate with the wild fish, and are generally healthier and better fed, so the wild fish population is improved both in numbers and quality.
Other animals and fish eating them also improve because of a better diet.
Hardly anyone is going to read and digest that.
It makes way too much sense.