It wasn’t necessarily Herschel the sea lion outside the locks with a very hungry tummy; the decline of steelhead salmon in Puget Sound in the last couple of decades could be due to many factors including whales, hake, pollock, and sculpins, though as Katharine Gammon reports at Hakai, humans needed someone to blame for depleting fish stocks.
The sea lions kept on coming and kept on eating. In 1986, the Seattle Times trumpeted, “It’s the return of ‘Herschel’ and the good old boys—those wandering California sea lions that are arriving earlier, staying later, and dining out more frequently. Pass the salmon and steelhead, please.” In 1982, 2,575 steelhead, Washington’s state fish, had swum through the locks; in the fall of 1988, only 686 were counted.
It’s undeniable that sea lions impacted the steelhead population by capitalizing on the advantage afforded by the locks. Wildlife managers estimate the animals consumed between 42 and 65 percent of the total steelhead run between 1986 and 1992. Yet steelhead had been in decline in parts of Puget Sound long before Herschel boldly poked his whiskered snout up to the foreign structure and discovered nirvana. Models suggest that the historical steelhead run in Puget Sound maxed out somewhere between 409,000 and 930,000 fish. The fishery likely peaked in 1895 with 204,600 steelhead caught, but such a heavy harvest was unsustainable. Just three years later, the Washington State Fish Commission estimated that the run had dropped by half.
When predatory animals go from being a rarity to a commonplace, people struggle to adjust—and it’s especially hard if we watch them compete for depleting resources. Sea lions often consume their meals on the surface, which is unfortunate for their public image. “We tend to want to blame things on the surface, but would anyone think to start blaming hake, pollock, sculpins?” says Andrew Trites, director of the Marine Mammal Research Unit in the Institute for the Oceans and Fisheries at the University of British Columbia. Those are all species that may be feeding on juvenile fish. “We tend to come up with simple narratives: when salmon are down, it must be the fault of something we see.”