Pelicans gobble Idaho trout, anger fishermen

A cunning predator that hunts in packs, corners prized game species and devours them whole is angering sportsmen in this eastern Idaho RV hamlet on the Blackfoot Reservoir’s wind-whipped shores.

In a twist to the predator-prey debate of the West, where hunters accuse wolves of eating too many elk and Pacific Coast states bemoan federally protected sea lions eating endangered salmon, a fresh menace has emerged: the American white pelican, which anglers say gobbles hatchery-raised rainbow trout and native Yellowstone cutthroats.

To deal with the problem, state wildlife managers are reviewing a plan that could include destroying some pelican eggs on islands commandeered by the giant birds. But they would first need approval from the federal U.S. Fish and Wildlife Service, which protects the pelican under the Migratory Bird Treaty Act of 1918.

Wildlife managers are increasingly being challenged to weigh competing interests in the West, where the natural balance has been altered by humans. Just as the Columbia River’s dams make spawning salmon easy pickings for sea lions, eastern Idaho’s reservoirs created predator-free islands for pelicans to multiply.

“They’re just like a gang of horse thieves,” said retired eastern Idaho rancher Don Allen, who launches his 15 1/2 -foot fishing boat from Henry, where a shuttered 100-year-old store is the sole reminder of the area’s once-famous cattle roundups. “They get a group of them together, circle an area, then go to work.”

Anglers have taken matters into their own hands, illegally releasing pigs or even badgers on the islands to eat the eggs, state officials say.

Wildlife advocates are concerned that sportsmen may have the upper hand in this species-on-species drama, because proceeds from fishing licenses help cover state Department of Fish and Game operations. They say federally protected pelicans play a vital role in keeping nongame carp and Utah chubs in check.

“I hate to see pelicans treated like vermin,” said Chuck Trost, a retired Idaho State University biology professor in Pocatello and president of the local Audubon Society chapter. “Yes, you may be able to save some trout. But there are subtle things that can go on that I’m not sure that fishermen think about.”

Bird experts say pelicans probably have been in Idaho since before European settlement, though the creation of vast reservoirs in the early 1900s produced ideal island habitat for the ground-nesting birds. Idaho now has two colonies on islands behind the Snake River’s Minidoka Dam near Rupert and in the Blackfoot Reservoir just west of the Idaho-Wyoming border.

In 2003, state biologists counted 1,450 nests between the two colonies, or about 2,900 adult birds. In 2007, the number of nests had risen to 3,665, or more than 7,200 birds. This year, that has dropped to 2,730 nests, or 5,400 pelicans. The decline is probably a result of predation from night herons or ravens, said Colleen Moulton, a Department of Fish and Game nongame species biologist.

“If you look at pelican colonies around the West, they’re kind of boom and bust,” Moulton said. “These two colonies have had a lot of growth over the years, but it was just a matter of time before they crashed.”

Pelicans may be getting a bad rap from fishermen who blame the birds for their struggles to catch limits of fat, hatchery-raised rainbows, she said.

“From the data we have, 80[%] to 90% of their diet is trash fish” like carp and Utah chubs, Moulton said. “It kind of boils down to a fight between what’s most important: managing a species of greatest conservation need, and appeasing the sportsmen that pay for managing the sport fish.”

Still, David Teuscher, the regional Fish and Game fisheries biologist in Pocatello, said opportunistic pelicans along the gantlet of the Blackfoot River where it flows into the reservoir are skilled anglers, especially in drought years, when low water gives foraging birds the upper hand over Yellowstone cutthroats.

More than 4,700 spawning cutthroats were counted in 2001; the number dropped to just 14 in 2005, before rebounding to 540 this spring. Anglers must release cutthroats because their numbers are so low.

“The pelicans have really lined up on the banks and rocks of the Blackfoot River,” Teuscher said, adding that 70% of surviving fish showed scarring from birds. Hazing efforts, including the use of rumbling all-terrain vehicles, have proved largely ineffective. Teuscher has begun stocking rainbow trout after pelicans migrate south in the fall.

“It’s not the ideal time to stock rainbow trout, but it’s the only time to stock them and survive,” he said.

Last year, state wildlife biologists began tagging hundreds of the season’s pelican chicks to determine whether they return after wintering south and whether wide-ranging pelicans from the Snake River and Blackfoot Reservoir are the same ones anglers at lakes and reservoirs elsewhere in the region say are making a dent in their fish populations.

Tagging was repeated in mid-July, targeting 600 more birds.

As part of the effort, the Department of Fish and Game assembled a team of three fisheries biologists and three wildlife biologists, including Moulton and Teuscher, to work on a pelican management plan.

If the agency’s commissioners opt this year for lethal control measures, the plan would need approval of the Fish and Wildlife Service. That agency has approved other measures to protect fish, including a 1990s effort in the Columbia River to relocate a population of Caspian terns that were decimating endangered salmon and steelhead numbers, though only after extensive environmental review.

Brad Bortner, the agency’s Portland, Ore.-based chief of the division of migratory birds and habitat, said he probably would meet with Idaho officials this month or in October to discuss the state’s pelican plan, which he has yet to see.

“There undoubtedly will be public review and comment,” Bortner said. “These birds and these fish evolved together, but they’re in a somewhat altered ecosystem. Whatever happens, we’ll have to weigh all the competing interests.”