Commercial fishing along the Upper Mississippi River has been sustainable over the past 60 years and hasn't negatively influenced fish populations or recreational fisheries, according to a University of Idaho-led study published in the journal Fisheries.
Commercial overfishing is often the primary cause of declines in marine fish stock, but few studies have looked at the link between commercial fishing and the health of inland fisheries. To investigate how inland fisheries function, U of I Department of Fish and Wildlife Sciences doctoral student Zachary Klein and U of I Associate Professor Michael Quist studied fishery data from the upper Mississippi, which extends from Lake Itasca, Minnesota, to Cairo, Illinois. Quist is also the assistant unit leader of the U.S. Geological Survey Idaho Cooperative Fish and Wildlife Research Unit.
The total annual harvest from 1953 to 2013 fluctuated around a steady average, according to the study. Specifically, annual harvests ranged from 2,509 tons to 6,037 tons and averaged 4,358 tons. The annual harvest was valued at $1.5 million to $13.2 million and averaged $5 million. Bullhead catfish, non-bullhead catfish, shovelnose sturgeon and American eel counted for more than half of the market value of fish harvested from the section of river.
Those analyses indicate commercial fishing has not substantially altered the upper Mississippi's fish populations, the types of fish present, the food chain or recreational harvests. The authors largely contribute the fishery's sustainability to active and informed management of the system by state natural resource agencies. In addition, they suggest the low harvests—compared to other large rivers like the Ob-Irtysh, Mekong and Parana—may be responsible for the upper Mississippi remaining a productive and sustainable commercial inland fishery.
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Zachary B. Klein et al. Commercial Fisheries of the Upper Mississippi River: A Century of Sustained Harvest, Fisheries (2018). DOI: 10.1002/fsh.10176