It certainly could be one piece of the puzzle! The prey species like herring I think are important too. It doesn't seem a coincidence that seals in the Salish Sea became smolt eaters the same time we were vacuuming up herring stocks to commercial extinction in many areas of the SS. Howe Sound stocks were almost wiped out, hopefully now that they are rebuilding a wasteful herring fishery isn't restarted there . Will rebounding herring stocks help ease the pressure on seals eating smolts? Maybe not now that SS seals have learned to key on the hatchery smolt releases, but there are clearly other forces at play as well. Allowing for seal predation there are still 20 million more Chinook smolts venturing out into the SS than there were in 1975 but less adults returning. If some proportion of the 20+ million smolts seals eat in the SS were saved through hunts, they may just die other ways (disease, starvation, parasites, predation by other species) as all the rest of the increased smolt production does compared to the dynamics in the 1975 ecosystem.