Ice Fishing on Lake Superior (IMAGE) Michigan Technological University Caption Fishing on Keweenaw Bay is an all-seasons endeavor and is an important source for food the local indigenous community. However, because of the landscape's sensitivity, mercury levels remain higher than the tribe considers safe in key species like lake trout and whitefish. Credit Sarah Bird/Michigan Tech Usage Restrictions Please credit the photographer. 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.