In the 1970’s silver carp were accidentally introduced into the Illinois River after escaping from a fish farm. The fish mistake pressure waves from the propellers of the boat’s motors for the movements of predators and jump with fright. Each jumping fish scares its neighbor, causing a dangerous chain reaction.
The visuals of flying fish everywhere is fascinating for the non-fishing public. But anyone who has ever been hit knows there’s nothing funny about them.
“They’re here, they’re a problem and not going away soon. And they could potentially be life-threatening,” said Duane Chapman, a research fish biologist at the U.S. Geological Survey and national expert on invasive carp species.
Watch out especially along wing dikes where the waters are calm. Take care at night, when they can’t be seen flying at you. From rivers in South Dakota to the shores of Ohio, they fly out like popping corn without a lid.
“These fish can grow into 70 or 80 pounds,” warned scientist Tracey Hill at the U.S. Fish and Wildlife Service. So far, the silver carp in Missouri’s rivers average about 15 to 20 pounds. Eating 5 to 20 percent of their weight daily, they grow fast.
Hill recently returned to his Columbia office after studying the density of silver carp populations in the waterways near Chicago. Although few were found there, he knows how bad it can get. In a Missouri River tributary near Columbia, “more were in the air than in the water,” he said. He and his crew wore hockey helmets to protect themselves.
Asian carp are such a nuisance on the Missouri River that fishermen and other boaters protect themselves with barrier nets, not only to shield the passengers, but also to protect the boat motor’s throttle mechanism from damage.
“If they hit the throttle front or back, it’ll floor the engine in reverse or forward, and that’s dangerous,” Chapman said. “Someone could fall out and even be run over by his own boat. There are times when a fisherman doesn’t come home, and who knows what happened to him out there on the river?”
But the nets don’t eliminate all the hazards.
Fish biologists are studying whether the silver carp, which were introduced in the 1970s to Arkansas lakes to forage on troublesome algae, might also be sucking in the tiny young of Missouri’s native fish species. Other algae feeders clearly are losing the competition for the food, which means less for game fish to eat.
Asian carp are causing a big controversy in the Great Lakes region, where five states — Michigan, Wisconsin, Ohio, Minnesota and Pennsylvania — are asking a federal judge in Chicago to close two shipping locks and install additional barriers to prevent Asian carp from using the canals to reach the Great Lakes. One assistant attorney general dubbed the area “the carp highway.