Those benefits accrue if you put more fish on the grounds. More spawners means more genes in the system which means more resilience and so on. The current practice of taking out a barrier and keeping the same goal puts less fish per unit area out there.

And, less fish on the grounds continues the myopic view that the ecosystem exists for the fish but the fish do not support the ecosystem. Plus, we need to take the holistic view and make sure that the food base is there for the fish to eat.

Plus, if we want to restore (say) grizzlies or resident Killer Whales we need to provide them with food. They're not going to be successful going vegan.