By Carol Stiffler
Officials with the Animal and Plant Health Inspection Service (APHIS) killed 470 double-breasted cormorants on Big Manistique this April in multiple visits and destroyed 50 cormorant nests.
With 350 active nests counted on the island, and two breeding adults per nest, there were an estimated 700 adult cormorants on Gull Island, and 67% of them were killed.
Cormorants, a migratory bird species that is native to Michigan, have been increasing in number on Big Manistique Lake, and are cited by the Michigan Department of Natural Resources (DNR) as one of the reasons that walleye fishing on the big lake has been difficult in recent years.
Cormorants have found Gull Island a decent place to lay a nest, and APHIS counted 350 active nests – both on the ground and in trees. The birds lay eggs once a year, averaging 2-4 eggs per clutch. According to a study published by the National Institute of Health, double-breasted cormorant chicks have a first-year mortality rate that ranges from 25-48%. The higher figure includes human disturbance, which has been largely impossible on the uninhabited Gull Island.
Anglers are noticing the reduction in birds, said Betsy Pollaski, president of the Portage Anglers Club.
“I am hearing reports of there being a dramatic difference,” Pollaski said. “Just sitting at Mick’s Bait Shop the other day, we feel like people are catching more fish this year than last year. Word of mouth has been ‘Well I’m getting some good fish this year, where last year I didn’t’.”
“It sounds like it was successful,” said Doug Schultz, the Lake Huron Basin Coordinator for the Michigan Department of Natural Resources. “We’re going to have to wait and see how many birds choose to backfill that open habitat next year. Whether or not this becomes a relatively recurring need on an annual basis or not, we’re going to have to wait and see.”
There are other factors affecting the quality of Big Manistique Lake fishery, including warmer water temperatures due to climate change, clearer lake water thanks to the invasive zebra mussels, and lack of habitat for baby fish to hide in.
“Walleye are very sensitive to that kind of stuff. With the clearer waters, they can see these boats coming and they’re getting out of the territory before people are dropping a line,” Pollaski said.
As a migratory bird species, cormorants are protected by law. They cannot be killed by civilians, and APHIS was granted a special permit to cull cormorants from Big Manistique Lake. Illegally killing a cormorant in Michigan violates both state and federal law with penalties that can include imprisonment.
Safe methods of discouraging cormorant populations include hazing, like scaring the birds away with loud sounds or moving objects. Curtis residents may recall a cannon sound going off at regular intervals a few years ago; that was an attempt at cormorant hazing.
Pollaski said volunteers from the Portage Anglers Club are hazing the cormorants on Gull Island harder than ever before. Using supplies from the DNR, people are traveling to the island and shooting “bangers” to startle them away.
Club members are encouraging others to communicate with local legislators to make sure funds for cormorant control are secured for future years. The Portage Angler’s Club is also in the midst of a fundraising effort. They’re selling long sleeve UPF 50 shirts online at https://bit.ly/PortageAnglers (case sensitive), with all proceeds going to restocking Big Manistique Lake with fingerling walleye.
“Every year or other year we will need to buy those,” Pollaski said. That costs upwards of $30,000. “It’s a continued effort for years to come.”
