Cormorants as scapegoat for salmon's decline

Effort to reduce colony of fish-eating birds backfired, leading to a poop-smeared bridge and more predation; wildlife managers plan to scare birds back to island where they were shot and harassed

On any given sunny day, a small gathering of double-crested cormorants cling to a partially submerged log near the Japanese Garden Island at Lake Sacajawea in Longview. Sleek, velvety black and lined up on their perching limb, they resemble a bunch of justices holding court.

I don’t usually engage in such personifications — the attribution of human feelings and thoughts to objects and animals. But it’s apt here to invoke these birds for a judicial metaphor.

We humans should be indicted for mishandling and mistreating this species and the Columbia River ecosystem. If we were on trial, the indictment would be for our hubris — our misguided confidence that we can control and manage nature and ignore its great complexities just so we can exploit it.

Voracious fish eaters, cormorants have been shot, poisoned and reviled for centuries. Reflecting this hate,  English 17th-century poet John Milton disguises Satan as a cormorant so he can sneak into the Garden of Eden to corrupt Adam and Eve in the epic Paradise Lost.

“They are one of the  most persecuted birds in North America and around the world,” James Lawonn, a biologist for the Oregon Department of Fish and Wildlife, told me this week.

So this is an ancient story, but now it has a new and urgent twist.

In the summer, thousands of the four-pound birds perch and nest on the Astoria-Megler Bridge near the mouth of the Columbia. Their poop is causing a maintenance nightmare on the 4-mile, 58-year-old steel span. They pose a road hazard for motorists.  And they are eating more endangered juvenile salmon than ever.

These are all unintended consequences of a federal plan to reduce the size of the double-crested cormorant population on East Sand Island near the river’s mouth.

The cormorant colony there had swelled to about 13,000 breeding pairs in the early 1990s, just as the first of 13 Columbia River salmon and steelhead stocks were getting listed under the Endangered Species Act. Researchers estimated that the cormorants consume as many as 20 million juvenile salmonids annually, or about 10% of the ocean-bound salmon that make it to the river’s mouth.

In the hope of reducing the number of birds and salmon predation, federal fish and wildlife agencies last decade destroyed 6,200 cormorant nests and shot 5,600 birds. The goal was to reduce the population to about 5,600 breeding pairs, according to The Seattle Times.

The effort backfired — badly.

On a single day in 2016, the remaining birds abandoned East Sand Island and moved eight miles upriver to the Astoria-Megler Bridge, as some bird advocates predicted would happen. 

The cormorant population on the bridge today is only a third as large as the former colony on East Sand Island. But the colony likely is consuming just as much salmon because there is a smaller variety of marine fish to eat. Salmon are a bigger percentage of the birds’ diet now.

“When you go farther up river, you have fewer of those marine fish because the water salinity is different. And so you have a different fish community. So near the Astoria-Megler Bridge, when a cormorant is searching for food, it is much more likely to come across a juvenile salmon or steelhead than an anchovy, for example,” Lawonn explained to Oregon Public Broadcasting last fall.

 “We think that the 4,000 breeding pairs of cormorants on the bridge are having the same or even a slightly greater impact” on salmon than the former colony of 13,000 pairs on East Sand Island,  he said.

Now, agencies hope to chase the birds back to East Sand Island. That’s not a typo.  They plan to move the birds back to the same island where they were shot and harassed last decade.

The plan is to lure them with a fake colony and scare them off the bridge with water cannons, firecrackers and  lasers. The program is expected to cost $18 million over four years. This is on top of the $11.5 million the U.S. Army Corps of Engineers spent previously on cormorant control at East Sand Island. 

These costs contribute to the roughly $9.5 billion that local, state and federal agencies have spent attempting to restore Columbia River salmon runs — an expenditure that has not significantly boosted wild salmon runs, according to a 2023 Oregon State University study.

Columbia River salmon restoration has become the most complex and costly wildlife project in history.  Such is the cost of resource abuse.

There’s no assurance the bridge cormorant colony will move. A recent study found, for example,  that cormorants up and down the coast seem to prefer to nest on human-made structures such as bridges, which shelter them from predators such as bald eagles.

If they leave, where might they go? Will their reduced numbers remain in check? And will the project make a difference to the salmon and endangered salmon and steelhead?

“This is one of the great episodes of wildlife mismanagement of the last half-century,” Bill Sallinger,  executive director of Bird Conservation Oregon, told The Seattle Times recently.

Lawonn acknowledges that predicting the outcome of the new project is difficult, because any time you manipulate a predator you affect the food chain in unknown ways. But the project is justified because of the critical condition of the salmon stocks as well as a need to protect the bridge, he said.

Still, it’s good to recognize how we got to this fiasco, in which cormorants — just like sea lions — have become scapegoats for human failures.

Cormorants and salmon co-existed for centuries. What upset the balance?

Why, for example, did cormorant populations at the mouth of the Columbia rise even while salmon runs were declining? Some possible explanations: the 1972 ban on the pesticide DDT likely improved cormorant reproduction. Shooting them was outlawed that same year by amendments to the Migratory Bird Treaty Act. And the Army Corps  of Engineers, in its effort to protect shipping, stabilized East Sand Island,  making the historically shifting, flood-prone island an ideal nesting site.

Regulation of the river’s flow by the system of  Columbia River dams no doubt affects predation. Juvenile salmonids were once sluiced to sea by a free-flowing river. Now they exhaust themselves swimming there  and are easier easier pickings for fish-chomping birds.

The birds are not a problem. We made them one by bringing salmon to the brink of extinction.  (I don’t have room to discuss it here, but is it ethical to shoot one species to save another when humans are causing its decline?)

Remember,  a century ago an estimated 16 million adult salmon returned to the river annually.  By last decade,  their numbers plummeted to an average of only 1.5 million, according to the OSU study. A robust salmon population in centuries and decades past provided cormorants, Caspian terns, sea lions and other fish-eaters with all the food they could eat. 

None of this is to suggest that we tear out the dams or stop dredging the river. Our economies are too dependent on these projects.  Somehow we must muddle through this problem.

This sorry episode reminds us that we need the humility to understand nature and its complexities before we manipulate, trash and exploit earth’s resources. More than anything, humans needs to recognize that “resources”  are not exclusively ours— and that our actions often boomerang, resulting in high costs and wrecked human and wildlife communities when we treat them that way.

We must be guided by the dictum of Aldo Leopold, the famous naturalist and philosopher of  the early 20th century: “The first rule of intelligent tinkering is to keep all the pieces.”

We threw away or disrupted pieces of the ecosystem that supported the world’s greatest salmon run, which in turn supported humans and myriad other wildlife. We, and the cormorants, are having to pay the price and the penalties.

It would be apt for that perched, judicial-looking row of cormorants to hand down a guilty verdict.