Scientists removed 70% of lake logs; yellow perch nearly vanished in 2 years

From the surface a lake might look like it is not changing at all but underneath it is a very different story. Scientists demonstrated how important fallen trees and submerged logs can be to freshwater ecosystems in an unusual whole-lake experiment under calm waters of Wisconsin’s Little Rock Lake. In the study, ‘The rapid effects of a whole-lake reduction of coarse woody debris on fish and benthic macroinvertebrates’, researchers removed over 70% of the coarse woody habitat from one basin of the lake, and the effects were quickly seen in its fish. Yellow perch, which was once the lake’s most abundant fish, plummeted to very low numbers within two years, the study adds. The study was conducted in Little Rock Lake, an 18-hectare undeveloped, unfished lake in Vilas County, Wisconsin. A large curtain divides the lake into 2 similar basins. Fish and water cannot pass between the basins.