By the Numbers: A snapshot of our fishery


Lake Michigan whitefish.

The number of years it took a Lake Michigan whitefish to reach 17 inches in the early 1990s


The number of years it takes a Lake Michigan whitefish to reach that size today


Percent of the fish biomass that the invasive alewives represented in the mid-1960s


The year the Michigan Department of Natural Resources began stocking salmon, which eat alewives, in Lake Michigan


Percent reduction in zooplankton – the primary food of alewives, whitefish and chubs – in Lake Michigan since 2002, attributed largely to the arrival of the invasive quagga mussel

950 trillion

Quagga mussel shells on shore.

Estimated number of quagga mussels in Lake Michigan today


Percent cut in salmon stocking in 2013, the alewife’s chief predator, to help the now-dwindling alewife population rebound


Percent of Wisconsin adults who eat fish and shellfish

4 – 6

The average number of fish or shellfish consumed each month by Wisconsin adults

3.3 million

Cubic yards of PCB-contaminated sediment removed from the Fox River basin since remediation of contamination began in 2001

8 million

Cubic yards of PCB-contaminated sediment that will be removed by the time the project is completed in 2017

Sources: Wisconsin Department of Natural Resources; Great Lakes Fishery Commission; Alliance for the Great Lakes; Muskegon Chronicle; Brookings Institution; Environmental Protection Agency