If you’ve ever been trolling behind a wing dike on the Missouri or down the Mississippi and had a big silver fish jump like it is going to slam dunk the boat, you know what a problem silver and bighead (Asian) carp can be. Two stories: one good, one possibly very bad, appeared this morning.

Photo by Jason Jenkins, courtesy www.missouri.edu

On the good side, the biological division of the United States Geological Survey may have a lead on how to control these critters:

“Invasive carp and the secret language of scent: The chemical language of invasive Asian carp may eventually be turned against them in the fight to help eradicate these harmful invaders from the Mississippi River. Asian carp, introduced into the Mississippi River in the 1970s and 80s, are now abundant throughout the lower Missouri, the Mississippi and Ohio rivers, posing a threat to native species. Carp seem to have a chemical language effective for predator defense and reproduction in murky environments, so researchers put this language to the test by subjecting young carp to extracts prepared from the skins of other carp. The result: the young carp, upon detecting the extracts, significantly avoided them by moving from the area, becoming immobile, and schooling. This “alarm substance” may be effective in repelling carp from habitat critical to native species. Young carp were also attracted to the chemical stimuli of schooling carp, which can assist in conventional eradication methods.”

Followup information has been requested.

Jake Allman holding Missouri River silver carp. Note low-set eyes. Photo by Jo Schaper

On the bad side, The Detroit Free Press and other sources report that Asian carp DNA has been reported in the Cal-Sag Channel, one of the Chicago shipping channels which leads from the Illinois River to Lake Michigan. Fisheries officials had been hopeful that an electrical curtain barrier would prevent the fish from migrating from the Mississippi River system to the Great Lakes.

Stay tuned.