A shock went through the Upper Midwest fishing industry and conservationist community last week as the Department of Natural Resources announced that tests for Asian carp came out positive above the Coon Rapids Dam.
The Coon Rapids Dam, located on the Mississippi to the North of the Twin Cities was previously thought to be a barrier to the fish as it expands its range northward after it has escaped fish farms further downstream. Asian carp are considered a threat to native fish species and the $2 billion Minnesota fishing industry that depends on them.
Calls from industry, recreational and environmental groups have been united for strong leadership in keeping the Asian carp out of northern waters, but suggestions for how to do so are varied. Shortly before the announcement that Asian carp were likely to have migrated past the dam, Minnesota had approved a $16 million plan to raise the height of the Coon Rapids Dam to keep the fish out.
Elsewhere in the Midwest varied technological strategies have been used and proposed to halt the Asian carp migration, ranging from metal sieves to sound and bubble barriers. Even an underwater electrical fence is in use in Chicago to keep invasive fish species out of the Great Lakes.
The Army Corps of Engineers is one of the main authorities who will respond to this imminent fish crisis, likely by modifying existing barriers on the Mississippi and other waterways.
It is rather ironic, however, that our commercial use of Mississippi downstream has now come back to influence another commercial use of the river upstream. Invasive fish species are not a problem that will disappear in the near future. Solutions that systematically tackle the ecological causes of the fish migration will be more effective and perhaps less costly than those which attempt to simply fence out Asian carp.