Be careful what you eat, says University of Notre Dame stream ecologist Gary Lamberti.
If you're catching and eating fish from a Lake Michigan tributary with a strong salmon run, the stream fish brook trout, brown trout, panfish may be contaminated by pollutants carried in by the salmon.
Research by Lamberti, professor and chair of biology, and his laboratory has revealed that salmon, as they travel upstream to spawn and die, carry industrial pollutants into Great Lakes streams and tributaries. The research was recently published in the journal Environmental Science and Technology.
It's a problem inadvertently created by people with good intentions, he notes.
"Most people don't realize that salmon are a non-native species in the Great Lakes," he says. "They were introduced to control alewives another non-native fish species."
Although salmon fed on and contained the alewives and have become important to sport fishingthere were unintended consequences. That's because of a lengthy history of industrial pollution of the Great Lakes.
"All the Great Lakes have some level of pollution," says Lamberti, "especially near cities Chicago, Detroit, Cleveland. There are far fewer pollutants now than over the past century, but many are persistent. There are hot spots, and Lake Michigan has a lot of them heavy metals, mercury, organic pollutants like PCBs."
PCBs (polychlorinated biphenyls) come from fluids in older electrical transformers. Also present is DDE (dichlorodiphenyldichloroethylene), a breakdown product of the banned insecticide DDT, and PBDEs (polybrominated diphenyl ethers). PBDEs, notes Lamberti, are flame retardants used in furniture, mattresses and children's clothing. "They wash out when you do the laundry."
Brook trout with salmon eggs pumped from its stomach Brook trout with salmon eggs pumped from its stomach
Even intentionally introduced species such as the Pacif
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University of Notre Dame