Cormorant colonies growing out of control
BY DALE BOWMAN firstname.lastname@example.org August 11, 2012 12:34AM
Hundreds of cormorants, a fraction of those found at the ArcelorMittal plant in East Chicago, take off this summer. | Dale Bowman~For Sun-Times Media
Updated: September 13, 2012 6:14AM
EAST CHICAGO — Memories came back for a veteran steelworker as we walked to the fishing spot by the steel-plant discharge. He remembered when he could walk all the way to the point end of the Inland Steel wall and would catch so many perch that he lugged them back in a 5-gallon bucket, a fish basket and another two bags stuffed under his coat.
Those days are gone. What is known as the ‘‘Hole in the Wall’’ is now part of the ArcelorMittal plant. In terms of the natural world in this most unnatural setting, there has been a dramatic change: A colony with thousands of cormorants is exploding around the landfill area.
Fishermen have complained for several years that the fish-eating birds were affecting nearby fisheries. Now both bird and fisheries biologists agree something needs to be done.
That is easier thought than done. Cormorants are protected under the Migratory Bird Treaty Act. With protection since 1972 and the ban on DDT, cormorant populations recovered and have reached historic highs in many areas. In 2003, the U.S. Fish and Wildlife Service began ‘‘allowing more flexibility in the control of double-crested cormorants where they are causing damage to aquaculture and public resources such as fisheries, vegetation or other birds.’’
So far, Indiana hasn’t officially filed written justification to the USFWS for that.
This summer, the veteran steelworker was checking for perch or early Chinook when he noticed more than 10,000 cormorants lining the shorelines and near-shore waters. He called me to come to document them.
I long had wanted to fish the discharge area from shore. To access it, you need to be an employee or a guest. We made a few casts first — to make sure that no kings had arrived (none had) — then we went looking at cormorants. We estimated more than 3,000. Work being done in one area likely kept thousands away.
Fishermen have been on the front lines of documenting the effect of the cormorants. Capt. Chuck Weis used to operate Ace Charters out of East Chicago, but he had such a dramatic decline in perch catches (from 1,500 to 2,000 annually to around 100) that he moved to Portage this year.
The decline in perch catches mirrors the dramatic rise in cormorants around the colony. Kenneth Brock, whose birding CD ‘‘Brock’s Birds of Indiana’’ is the definitive work, pulled up the reporting data for the last 20 years for cormorants along Lake Michigan. In 1993, 996 cormorants were reported. There has been a steady increase almost every year. So far in 2012, 8,181 have been reported. There was a statistical blip to 24,293 in 2009.
In recent years, the nest counts keep increasing. The 2011 survey yielded 2,633 nests.
‘‘We did a nest count on 22 May 2012 and counted 2,800 double-crested cormorant nests at the nearby steel mill,’’ emailed John Castrale, a non-game bird biologist for the Indiana Division of Fish and Wildlife. ‘‘We do have concerns about cormorant numbers and how they may be impacting fisheries and other colonial-nesting birds.’’
‘‘I support some type of control measures [because] the population has expanded considerably since 2008,’’ Lake Michigan fisheries biologist Brian Breidert emailed.
Last summer, Breidert and Janel Palla helped with a survey of stomach samples. Of 50 nests assessed, 503 ‘‘identifiable diet items’’ were of four fish: yellow perch, alewives, spottail shiners and round gobies.
‘‘Are they impacting the environment? I certainly believe so,’’ Breidert said.
Waves of more cormorants returned as the steelworker and I walked out.