Weather Forecast


Fish stocks decline in Lake Superior due to warming according to study

DULUTH/SUPERIOR - Lake Superior has lost about 20-percent of its most abundant large fish over the last 30 years, as the average water temperature has warmed by two-and-a-half percent.

Scientists at UW-Madison say the siscowet lake trout love colder temperatures, and their numbers have dwindled while other fish like walleye and Chinook salmon thrive in the warmer water.

The research was funded by the UW's Sea Grant program. It builds on previous studies from Minnesota-Duluth, which found that the average surface temperatures on Lake Superior grew by two-and-a-half degrees Celsius from 1979-2006. It was said to be among the most graphic examples of global warming in North America. In 2010, the average temperature on Lake Superior was the highest in 31 years of record-keeping.

The author of the new study says the warming has already caused changes in Lake Superior's fish population. Tim Cline says the lake deserves attention because it's had some of the largest temperatures increases seen anywhere.