A dilemma sometimes presents itself to wildlife managers. When to allow culling of predators and when not?
Killing predators is fraught with controversy. Many environmental groups are opposed to culling such creatures as coyotes, wolves, bears, and sea lions. Others are happy to see predator populations reduced.
Wildlife managers face pressure from both sides, so they must carefully assess what actions to take. In some cases, what to do seems obvious. Male California sea lions have been picking off stocks of salmon and steelhead considered threatened under the Endangered Species Act. The sea lions are not threatened or endangered, so the rationale is that they must be culled to protect the fish.
The sea lions have been eating thousands of salmon and steelhead in the Columbia and Willamette rivers, which converge just below Vancouver,Washington. Oregon officials claim that about a quarter of the winter-run steelhead and spring-run chinook salmon are being picked off at the fish ladders at Bonneville Dam. Some sea lions have even learned to climb the ladders.
This problem is nothing new. Years ago, sea lions were gobbling up fish at Seattle’s Ballard Locks, leading into Lake Washington. Officials tried using firecrackers, rubber-tipped arrows, loud underwater noise, fish poisoned with a substance that made the animals vomit and nets to discourage them. Nothing worked.
In desperation, they captured the sea lions and transported them south to the mouth of the Columbia River. The same sea lions returned to Seattlein days.
Next, they moved the sea lions to Santa Barbara, so as director of the Santa Barbara Marine Mammal Center, I helped NOAA officials transport them to San Miguel Island by boat. The sea lions again returned to Seattle.
Officials got a permit to kill the sea lions, but Sea World in Orlando, Florida offered to take them. The Seattle problem was solved — temporarily.
Oregon state officials tried the usual means of discouraging the sea lions in the Columbia River, but these failed. The officials now have a permit to kill up to 93 sea lions interfering in the salmon and steelhead runs. They will capture them and humanely euthanize them. Some may possibly find homes on marine life parks, but others will not.
Some environmental groups point out that the problem is not with sea lions and fish, but with us. Humans have dammed and channeled rivers so the fish are more vulnerable to predation. Fish ladders amount to a fish-in-the-rain-barrel feeding opportunity for sea lions.
A Green Beret I knew called a bullet the 13-cent solution. Shooting sea lions is cheap compared to other means of control. On the other hand, we humans are supposed to be the most intelligent life forms.
NOAA Fisheries designed “excluders” to prevent the snaring of sea turtles in shrimp trawl nets and this proved very effective in reducing the catch of turtles without dramatically affecting the shrimp catch. They also required the use of acoustic pingers to discourage marine mammals from drift nets with some success.
The U.S. Fish and Wildlife Service has jurisdiction over California sea otters, which are threatened under the Endangered Species Act. But black-and-white abalones are listed as endangered, which means likely to become extinct. Sea otters eat endangered black and white abalones, so shouldn’t we control sea otters?
The popularity of the sea otter as one poster child of the environmental movement answers that question because politics are involved. The question has also become academic, since abalone populations were already reduced before the black and white abalones were listed as endangered.
Moreover, great white sharks, which have undergone a remarkable recovery since they became protected in 1992, are now a significant limiting factor in the southward migration of sea otters. Should we now start culling great whites? Some would say yes, others, no.
Peter Howorth has followed the sea for more than 50 years, first as a competitive free diver, surfer and professional diver. He captured marine mammals for sea life parks in the 1960s and founded the nonprofit Santa Barbara Marine Mammal Center in 1976. He serves as an environmental consultant for offshore projects, helping to prevent impacts to marine life. He has authored books and has been a columnist for the News-Press for more than 25 years. Any opinions are his and not necessarily the newspaper’s.