If you do the math it is not hard to estimate even the minimal impact Pinnipeds (Seals/Sea Lions et...) have on the fisheries. If each one of a conservative estimate of 60,000 eats a conservative estimate of 30 lbs of fish per day that is a conservative estimate of 1,800,000 pounds just an average day or 657,000,000 pounds a year. These monsters voracious pigs. Have you wondered why the crabbing has gotten so good in the last ten to fifteen years? I believe one of the big reasons is because these pigs, when they don't have a huge appetite, and maybe just want a little dessert, eat just the bellies out of the fish. The rest goes to the bottom to feed the crabs.
I say we go back to using seal skin boats myself. That would be the natural thing to do.