Every year, millions of salmon make their way up the Columbia River to create the next generation of fish. They search for the spawning grounds in which they came into the world and procreate.
But human activities have not made it easy for salmon. Our voracious appetite for their pink meat, our hydroelectric dams and other forms of habitat destruction often prevent them from making it back to their breeding grounds. Those that manage to make it up river die shortly after breeding. Multiple strategies to help salmon get up river, like stairs or cannons to get them over dams have been developed, but the fact remains that human activity has made salmon endangered and there is more to their conservation than getting salmon over dams - we need to keep their spawn alive.
Like many baby animals, salmon spawn are extremely vulnerable to predators. They get snatched up by bears, bigger fish and birds. So the U.S. Army Corps of Engineers (USACE) decided to tackle the problem in a new way: a bird cull.
They're looking at a particular colony on the East Sand Island, where more than 60,000 shore birds breed. These birds are responsible for eating as many as 20 million salmon and trout smolts (youngsters) every year. USACE proposes shooting 16,000 double crested cormorants - more than half of the current cormorant population on the island.
"They're eating over 6 percent of all the wild steelhead that are passing through the lower Columbia River," Ritchie Graves, fisheries biologist with the National Oceanic and Atmospheric Administration, told National Geographic.
Culling is not an uncommon conservation strategy. Thousands of cowbirds were killed in the 70's to save Kirtland's Warblers and thousands of barred owls have been terminated on the west coast to save northern spotted owls. But this strategy has been opposed by many.
Part of the push back is that salmon are in trouble because of us - not because of the cormorants.
"The cormorants were there long before the dams were, and they coexisted perfectly fine with the fish," Bob Sallinger of the Audubon Society of Portland told National Geographic. "It's the dams and the habitat destruction that have truly brought things out of whack."
Cormorant species aren't doing so well themselves. Habitat loss and human disturbance has already impacted their populations and the proposed cull would reduce the total west coast cormorant population by 25 percent.
And besides, cormorants aren't the only species feeding on salmon smolt. Sea lions have been swimming upriver to meet the fish as they make their way down stream. So salmon populations would still be strongly impacted by other factors.
But some are convinced that mass killing is the only way. "[Culling] is slowly becoming a dominant conservation strategy," Michael Nelson, professor of environmental ethics and philosophy at Oregon State University, told National Geographic. "We are embracing this as the first line of defense."
What do you think?