Last month it was mealtime on the Lower Columbia. We could hear the excited barking of sea lions across the city of Longview, where I live, as they hauled themselves onto the rocks near the mouth of the Cowlitz and waited for dinner to arrive. Now the smelt have passed and Herschel and his friends are quiet. We expect them back as the adult Chinook salmon begin to return to their spawning grounds. I do hope some of the fish manage to escape.
At a time when salmon survival has become such a concern that we are talking about tearing down dams to improve their chances, fast-rising predation from sea lions has become an environmental emergency. Protected by federal law and with no real predators to worry about, the sea lion population off our coast has quadrupled over the last 50 years. Today they swarm the Lower Columbia and its tributaries from January to March, when the smelt are making their way downriver. Last year the sea lions were so aggressive that they swam 70 miles up the Cowlitz River to meet them, farther than ever before. The National Marine Fisheries Service conducted a study to estimate survival rates of returning spring Chinook on the Columbia River downriver of Bonneville Dam. One year it estimated losses due to sea lion predation at 20 percent; another it was a whopping 45%.
Nearly half? There’s nothing natural about losses at this level. If we want our fish runs to survive, we are going to have to step up our efforts to control sea lions – and we can’t be squeamish about it…