Great Lakes Whitefish Catch - Biggest Commercial Species - Down 2/3 In Past 15 Years
Lake whitefish are the most important commercial fish species in Michigan.
But in the last decade, state biologists say fishers are harvesting about a third of what they used to get. The catch dropped to 1.7 million pounds last year, down from five million pounds in the early 2000s. Agencies across the Great Lakes are trying to learn more about the population decline.
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Fisheries biologists say the main reason whitefish are declining is because of changes in the food web. Caroffino says, basically, invasive mussels – particularly quagga mussels – are blanketing the bottom of the lakes. Quagga basically filter nutrients out of the water, which don’t allow phytoplankton and zooplankton to really abound,” he says.
Juvenile whitefish eat zooplankton. So when there are fewer zooplankton, it’s harder for young whitefish to survive. Scientists say climate change might also be hurting whitefish, and lake trout are eating some of them, but the mussels are the main culprit.
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http://www.michiganradio.org/post/agencies-investigating-whitefish-decline-great-lakes
