DNR releases information on managing cormorants
LANSING – The Michigan Department of Natural Resources recently announced figures from its efforts with federal partners to actively manage cormorants in several parts of Michigan.
For years anglers have observed cormorants feeding in their favorite fishing spots, with substantial increases in bird numbers over the past few decades. These observations have concerned anglers about the potential effects cormorants may be having on the fish they are targeting. In response to these growing concerns, the federal government enacted a depredation order in 2003 that authorized states, tribes and the U.S. Department of Agriculture to conduct cormorant management, with the U.S. Fish and Wildlife Service overseeing the process. Under this authority, the DNR developed management goals at several cormorant breeding colonies across the state to determine what, if any, impacts cormorants were having on the state’s fishery resources. On-theground work to meet these goals is conducted by USDA’s Wildlife Services, which began oiling eggs and culling cormorants in the Les Cheneaux Islands in 2004.
Since that time, Wildlife Services has expanded its operations to include efforts at Thunder Bay (Alpena), Beaver Island, Ludington and Bays de Noc (Escanaba), with the culling of up to 10,000 birds per year for the past several years. Subsequently, cormorant nesting populations have been reduced anywhere from 54 percent to 94 percent at peak nesting counts at these locations. In colonies where management efforts have been conducted, the estimated cormorant nest count in Michigan waters has gone from more than 23,000 in 2007 to less than 10,000 in 2013.
In addition to these efforts, Wildlife Services has directed volunteer groups in harassment programs at many inland lakes and Great Lakes bays during spring migration periods. Volunteer groups also assisted in cormorant harassment programs during stocking events at many Great Lakes ports. Each year, management locations are mutually agreed-upon by a coordination committee composed of representatives of several federal, state and tribal agencies.
It’s difficult to evaluate the effects of cormorant management and its relationship to sport-fish populations due to constantly changing food-web dynamics, including the establishment of invasive species throughout the Great Lakes,” said Steve Scott, Michigan DNR fisheries biologist. “Fisheries surveys have shown an increase in sportfish populations during the same period cormorant populations were declining in areas where activities have been conducted. We are seeing some very encouraging results in fisheries at several locations, and anglers are reporting improvements. We are very pleased with the progress we are making through our partnership with Wildlife Services.”
Visit the USDA’s website for more information on cormorants: http:// www.aphis.usda. gov/ wildlife_ damage/ aquaculture/ aquaculture_ cormorant.shtml.