There used to be a lot of news stories about a sea lion that was eating salmon at the Ballard Locks in Seattle. A lot of money was spent to move the sea lion to San Diego or someplace like that but he knew where he had a good thing going and swam all the way back. But I could never figure out how one sea lion could be putting a serious dent in the salmon population.
It's not just one sea lion, I believe they're over a hundred of them at Bonneville Dam.
If the above stats are true that's a heck of a dent and that's just at one spot.
There’s also quite a few at Bonneville that return every year that they have names and/or numbers for, those will probably be the first to go.
You must be remembering Herschel.