Major Die-Off of Fish along Lakefront
ENVIRONMENT, 24 Jan 2011
Dale Bowman – Chicago Sun-Times
A bizarre scene is evolving on the Chicago lakefront, with Canada geese and mallard ducks gulping down dead or dying gizzard shad.
A major die-off of what appears to be the 2010 class is happening in Chicago harbors. Thousands, perhaps far more than that, of dead gizzard shad in the 3- to 5-inch range are frozen in the ice of Chicago harbors or floating around in open patches of water.
“Gizzard shad are pretty sensitive,’’ Lake Michigan Program biologist Dan Makauskas said. “On the toughness scale, the herrings are pretty soft.’’
Gizzard shad, members of the herring family, are more sensitive to drops in oxygen levels than most fish. And thick ice came early to Chicago harbors in December.
The massive die-off was first documented Thursday by Carl Vizzone, a North Side fisherman who sits on the board of Perch America. What caught his eye was Canada geese and mallards eating dying shad at open water by DuSable and Diversey harbors. “This is not normal,’’ he said.
He’s right, agreed naturalist Joel Greenberg, author of A Natural History of the Chicago Region. Canada geese and mallards normally don’t eat fish, but, Greenberg said, “They are opportunistic.”
Other species of fish do not appear to be involved in the die-off.
Makauskas, who speculated that the young shad may not have built up enough reserves to survive the early onslaught of extreme cold, agreed the die-off is abnormal.
___________________
Dale Bowman is the outdoors columnist for the Sun-Times.
DISCLAIMER: The statements, views and opinions expressed in pieces republished here are solely those of the authors and do not necessarily represent those of TMS. In accordance with title 17 U.S.C. section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. TMS has no affiliation whatsoever with the originator of this article nor is TMS endorsed or sponsored by the originator. “GO TO ORIGINAL” links are provided as a convenience to our readers and allow for verification of authenticity. However, as originating pages are often updated by their originating host sites, the versions posted may not match the versions our readers view when clicking the “GO TO ORIGINAL” links. This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a ‘fair use’ of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. For more information go to: http://www.law.cornell.edu/uscode/17/107.shtml. If you wish to use copyrighted material from this site for purposes of your own that go beyond ‘fair use’, you must obtain permission from the copyright owner.