Mentions field studies by University of Wisconsin-Madison researchers during 2004 and 2005 did not conclude the cormorant was responsible for the yellow perch population decline.
Graduate student Sarah Meadows, working with adviser Scott Craven, chairman of the department of wildlife ecology at UW-Madison, has found that cormorants are opportunistic birds that will eat all kinds of fish and aquatic life. Their dining habits change during a season and from year to year, she said.