Humans, through overfishing and overpopulation, lie at the root of the problem. One of our major problems as a species is we can't see or think in a holistic manner.

Those seals, with their big brown eyes, are so cute and cuddly. Those anchovies, menhaden, herring, etc. make wonderful food for my chicken and so on. We see everything in pieces and really don't see, or want to see, the big picture.

Look at the recent threads here about how recs catch/kill so damn few fish in fresh water that they aren't a problem. The trawlers say the same thing; there is just a minuscule amount of Chinook in our catch. We are never the problem, they are.