Friday’s fireworks weren’t this year’s first big bangs along Lake Ontario. State natural resources agencies used “pyrotechnics” in April and May to haze double-crested cormorants out of Wilson and Olcott Harbors when releasing young trout and salmon.
“They’re mostly bottle rockets used to scare them off of the recently stocked fish,” said Jim Markham, Region 9 fisheries manager for the state Department of Environmental Conservation (DEC). The DEC contracted with the US Department of Agriculture’s Animal and Plant Health Inspection Service for the bird control measures, Markham said.
While it’s been an excellent spring fishing season, said Frank Campbell, sport fishing promotions coordinator for Niagara County, cormorants seriously undermine fishery stocking efforts by being efficient predators of young fish.
“The optimum time to stock the fish coincides with the cormorants’ migration,” Campbell said. “It will actually stop the cormorants in their tracks and they will stay here to feed. You have these fish that are stocked that are pretty much used to being in pens and tanks, and their instincts aren’t as good as naturally hatched fish. They will crowd up or linger in warmer water.”
For cormorants, it’s like shooting fish in a barrel.
“We’re not here to feed the birds,” said Town of Newfane Supervisor John Syracuse. “They like to hang out on the breakwater and busted-up pier off Olcott Beach. We’re raising 160,000 small fish and we’re releasing them. The birds are going up Eighteenmile Creek. They’ll hang in the foliage of the trees. You can tell where they’re at because their droppings turn all of that greenery white. It’s obnoxious. Right under that Route 18 bridge, they’ll go up the creek and roost up there and dive down.”
Markham said cormorants make a bigger impact on fish populations than gulls or wading birds.
“Gulls fish at the very surface,” Markham said. “But cormorants can dive down 40 feet. So they have a much greater range to go down. They’ll be on top of the water and move around and chase stuff. They’re a predator; there’s no doubt about that.”
Diving cormorants use their webbed feet and wings to fly through the water like penguins, Markham said. While cormorants will eat gobies, emerald shiners, and other fish species, Markham said they can swallow sizeable fish.
“It’s more efficient to eat larger prey items,” he said. “They would prefer to take an 8-inch trout. Chinooks are really small, we usually don’t have a problem. But our steelhead coming out of the stocked pens are all around the 6-inch mark.”
Campbell said there are videos of 5,000 newly released brown trout eaten by cormorants in Wilson a few years ago.
“The whole stocking was decimated by hundreds and thousands of cormorants,” he said. “They’ve done more hazing of the cormorants before they stock. We try to pen release right before dark, which gives fish an overnight of no cormorant predation.”
“These birds are smart and sometimes they realize that the pyrotechnics aren’t causing harm and they will come back,” Markham said. “The lethal is always the second part of that, if you can’t get them off the fish with pyrotechnics. The birds usually realize there’s danger after a couple of them are shot, and it will deter them.”
According to the Audubon website, after the pesticide DDT was banned in 1972 for damaging bird populations, double-crested cormorants began increasing and expanding their range. In some regions, wildlife management agencies have culled double-crested cormorant breeding flocks due to concern that cormorants would drive off other colony-nesting waterbirds, Audubon said.
“They had an eagle nest on Strawberry Island and there were so many cormorants in the nest with the eagles that the nest failed,” Campbell said.
“They are very damaging in the areas where they nest,” Markham said. “Their feces is very toxic and will kill trees and plants. They can destroy a whole island.”
Campbell said additional measures need to be taken to control local cormorant populations.
“It costs a lot of money to pen raise these fish to a certain point,” he said. “Cormorants may be eating $20,000 worth of fish. It’s not only future financial impact, but impact right then. There’s no natural enemies for them. They feed in clear water better than dirty water. Everything we’re doing is feeding into the cormorants’ growing numbers.”