Invasive species aren’t always pests

The havoc that aquatic invasive species like zebra mussels have wreaked on the Great Lakes and beyond has been well documented. They reproduce faster than rabbits, suck up plankton off lake floors, starving native species, and clog water intake pipes.

Zebra mussels, along with nasty critters like sea lamprey and those great flopping river acrobats Asian carp, have given invasive species a bad rap — often very deservedly so. But new research suggests that the most recent Great Lakes invader may actually help their new home.

The “bloody red shrimp” was discovered in Lake Michigan in 2006. They’ve spread to all of the Great Lakes except Lake Superior. Like zebra mussels, they likely hitched a ride from the Black and Caspian seas in eastern Europe in the ballast tanks of ocean-going freighters. Requirements for ships to exchange ballast water at sea have since slowed the introduction of non-native species to the Great Lakes.

New research shows that the little crustacean, so named for its bright red spots, has become food for native species like yellow perch and alewife.

Mike Yuille, a graduate student at Ontario’s Queens University, tells UPI that “forecasting how an invader will affect the growth and production of a specific native fish species is very relevant to conservation groups and government agencies hoping to conserve those fish.” Yuille’s findings will be published in the Journal of Great Lakes Research.

But the relationships among native and non-native species are complex. Yuille’s research also suggests that round gobies have incorporated the shrimp into their diet. Gobies are another aquatic invasive species, also brought over to the Great Lakes from far eastern Europe in ballast water.

  • Call ’em new natives, because they likely aren’t going away. I think the terminology needs to be reevaluated. Words like invasive, pests, and exotic give them a bad name right off the bat. While some native speices actually are/can be “invasive”.

    Don’t forget about time scales! At some point all plants and animals spread across the land and became what we call natives. Further reading: Mark Davis “Invasion Biology” or June Nature acticle “Don’t judge species on their origins”.

  • The war on non-native species is more out of control than any non-native species. Few non-native species are doing any more harm than the pesticides, prescribed burns, habitat destruction, etc. that is unleased on non-native species.

    Read 1493 to appreciate that the globatization of ecology has been going on for over 500 years. It’s only in the past 10-20 years that there has been a media-induced panic about non-native species, many of which have been here for hundreds of years.

    The “restoration” industry has become so large that it has a vested interest in scaring the public into funding their destructive activities. Case in point, the federal Invasive Plant Council recently appointed a new member who is an employee of Dow Chemical, the manufacturer of many of the pesticides used by these projects.

  • Matt Chew

    Note also that the once-threatened Lake Erie water snake population has rebounded because they are also eating round gobies.

  • Adam

    Quick Correction, but Alewives aren’t native to the Great Lakes. (They are an integral part of the “new” food web, but originally an Atlantic fish that entered when the Seaway opened)