Fishwerks (1 of 3) (IMAGE) University of Wisconsin-Madison Caption Breeding migrations of native Great Lakes fishes, like the suckers shown here, are often blocked by impassable road crossings and dams. Credit Evan Childress Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.