A Minnesota Department of Natural Resources roundtable this weekend heard warnings about two new invasive species that could make their way to Minnesota through Great Lakes ships.
Phyllis Green, superintendent for Isle Royale National Park, is working to develop technology for treating ballast water from ships.
Golden mussels could be on their way from southern China via Latin America and so-called "killer shrimp" are causing problems in Europe, she said.
"It actually kills more than it eats. My analogy was if you've ever watched sea lions in a lock that's full of fish, they take a bite here and a bite there. This thing shreds and kills small fish fry to other little critters that it likes to eat," said Green.
Preventing the spread of invasive species is much cheaper than fighting them once they arrive in the Great Lakes, she said.
She's seeking funding to test new technology on board ships in Duluth.