At one time the sea lions were the top of the marine food chain, we can replace them, but there are not enough salmon to go around if we plan on sharing with them, up untill the 1960's the fisheries would machine gun them in their breeding grounds, I personally think that was an excellent idea albeit a tad politically incorrect in todays' world. Seriously there has to be some sort of control, we are the alpha predator now and there is no room for an over population of sea lions and seals there are just not enough fish to go around any more there are way too many humans living here to ever think there is some sort of balance of nature still.