Suspect profiling is a commonly used technique in the fight against crime. Now scientists are using species profiling to help prevent further introductions of invasive fish into the Great Lakes and other waterways.

"Once an invasive species becomes established in a new environment, its impact often is irreversible," said David Lodge, biologist at University of Notre Dame. But, not all exotic species present a threat to the balance of an ecosystem. Many introduced species simply do not survive or do not become a nuisance.

"If we knew which ones would be likely to present problems in the future, we could focus our efforts on preventing those particular species from taking hold," said Lodge, who is a member of the Federal Invasive Species Advisory Committee. To provide some answers, Lodge and fellow researcher Cindy Kolar, developed a risk-assessment "decision tree" that environmental agencies and managers can use to predict possible culprits of tomorrow. This computer model correctly identified nuisance fish with a high degree of accuracy.

"Ideally, environmental managers might choose to prevent all species from being introduced into an ecosystem under the credo that exotics are guilty until proven innocent, but from an economic point of view, that's not practical. Some industries, such as horticulture, depend on importing new species. We need to achieve a reasonable balance between commerce and the environment."

Lodge and Kolar studied the history of exotic species to find a common thread in those that succeed in their new environments. Funded by Illinois-Indiana Sea Grant, they focused their efforts on fishes in the Great Lakes and the Illinois River. These results have been published recently in the journal Science.

Using data from as far back as the glacial age, the researchers gathered information on a range of species characteristics to identify those that are likely to be adaptive in new environments. They looked to examples from as early as the 1600s and found 24 nonindigenous fish species that have firmly established themselves in the Great Lakes. How were they able to thrive so well with native fish?

"Introduced species that are successful have several traits in common," said Lodge. "More so than unsuccessful invaders, they tolerate a wide range in temperature and salinity. These fishes are also smaller at maturity and have higher reproduction rates."

By applying the profile to fishes that have not yet been introduced to the Great Lakes, Lodge and Kolar have identified 22 species that one day may pose problems. One example is the monkey goby, which is native to the Caspian Sea. Monkey gobies are in the same family as round gobies, which have proven to be quite successful after their introduction into the Great Lakes. On the other hand, tubenose gobies have not.

With this sort of information, prevention efforts can be targeted. "The first line of defense in preventing these potential nuisance species from making their way into our waterways is to work with aquaculture, bait, aquarium and other industries to stop any intentional introductions of these fishes," explained Lodge.

"Unintentional introductions, such as in the ballast of ships, can be difficult to completely prevent, but by carefully selecting when and where ballast water is taken in, we can lower the probability of these fishes being transported. The use of toxins and other eradication technologies in ballast water can also prove effective. And, with increased monitoring we can take strong action to eliminate these species if they are discovered," added Lodge.

"An immediate rapid response to a species that is a likely threat-even if it is fairly expensive-might save a great deal of money and effort, and reduce environmental effects, down the road," said Lodge.

If you would like more information about invasive species, visit the Sea Grant Web site on this topic at www.sgnis.org.

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The Illinois-Indiana Sea Grant College Program is one of 30 National Sea Grant College Programs. Created by Congress in 1966, Sea Grant combines university, government, business and industry expertise to address coastal and Great Lakes needs. Funding is provided by the National Oceanic Atmospheric Administration (NOAA), U. S. Department of Commerce, the University of Illinois at Urbana-Champaign and Purdue University at West Lafayette, Indiana.

Irene Miles
Illinois-Indiana Sea Grant
376 NSRC
1101 W. Peabody Dr.
Urbana, Il 61801
Phone:  217-333-8055
Fax:  217-333-8046
miles@illinois.edu