TRAVERSE CITY, Mich. — Inadequate regulation of the bait fish trade and carelessness on the part of anglers may be allowing invasive species — including widely feared Asian carp — to reach the Great Lakes and inland waterways, according to a scientific paper released Thursday.
Researchers with Central Michigan University and the University of Notre Dame said they tested water samples from tanks containing small fish for sale as bait at more than 500 shops across the eight states on the lakes and found that 27 tested positive for invasive species’ DNA. Positive hits for silver carp, one of the Asian varieties threatening to reach the Great Lakes, were recorded in three water samples from shops on the Lake Erie shore in Ohio.
The team also detected genetic material from round goby, tubenose goby, and Eurasian rudd, which are already in the Great Lakes although authorities hope to prevent them from reaching inland lakes and other waters. They also found traces of goldfish, which are classified as an invasive foreign species despite being widely available for purchase at pet stores.
‘‘While overall only a small percentage of bait shops had evidence of invasive species, it is nevertheless alarming that at least some invaders are being spread by anglers, the very group of people that value the Great Lakes fishery the most,’’ said Andrew Mahon, one of the paper’s co-authors and a molecular ecologist at Central Michigan’s Institute for Great Lakes Research.
The report was being published in the journal Conservation Biology.
Many states urge anglers to not dump unused bait into the water but not everyone obeys, Notre Dame scientist Christopher Jerde said. A study in Canada found that more than 30 percent of anglers were releasing unwanted minnows into waterways rather than tossing them in trash cans or freezing them for future use.