Good article about the locks and steelhead decimated by the sea lions, not salmon. Sure, there are other factors, but it is undeniable that Herschel and buddies were a critical cause of the elimination of the steelhead. no mention of the salmon run through there, but it must have been negatively affected by the lions also.
It’s dangerous to blame the decline of one species on a single predator. We humans like to do it anyway.
hakaimagazine.com
This if from a while ago talking about how the southern pods won’t eat seals and sea lions.
Marine mammals on the U.S. West Coast are now so numerous they are taking more chinook salmon than fishermen, posing a new threat for Puget Sound’s critically endangered killer whales.
www.seattletimes.com
A couple of things I see from these…
The Ballard locks run was basically insignificant. The article says about 2,500 fish before Herschel showed up. That’s nothing (yet they still have the obligatory mention of the viewing window packed with fish). In addition to that, it’s not even a natural run. The ship channel didn’t exist before 1916, so neither did that run. It’s also running through a very tight channel that’s pretty easy for a small number of predators to block almost completely. Like the article suggests, we created an almost perfect sea lion feeding facility.
The bigger thing that’s at the root of both articles - our protection of the sea lions has gone too far. We’ve made their lives so easy that their population has reached an unsustainable level. Unsustainable because the food supply isn’t big enough to support it. Whatever the reason - overfishing, pollution, predation (or all of the above) - there aren’t as many salmon as there used to be. When a prey population declines, the predator population
has to follow. If it doesn’t, the prey will continue to decline rapidly, eventually collapsing. Then the predator will collapse too, and the ecosystem will be in upheaval.
We’ve created this issue, by encouraging the seal/sea lion population to increase past the point that can be supported. We’re working against our own salmon recovery efforts by guaranteeing and protecting an increase in predation. I know this isn’t going to happen, but our best move is likely to just get out of the way. That’ll likely lead to a seal/sea lion collapse in the short term, but that might be what’s needed to give salmon a chance.
As for the orcas, I wonder…if the southern pod has been focused on salmon for that long, have they “forgotten” how to hunt and eat seals? It’s strange that they’ve gotten so particular about what’s a lower quality, lower availability, higher effort prey. There must be something that keeps them from eating seals, I don’t see it being a simple preference issue.