Silver carp

Silver carp jump out of the Illinois River.

Alien flying fish have invaded our Mississippi River waters.

These scaly aviators are not raiders from Mars, they came from Asia. Silver carp are notoriously known as flying fish that leap out of the water when disturbed by passing watercraft.

Individuals and large numbers of fish jump towards the sky in unison, hurdling 10 feet high and 20 feet horizontally and weighing up to 15 pounds. The U.S. Fish and Wildlife Service is asking boaters to report any sightings of these aerial aquanauts.

Researchers have stalked silver carp for several years based upon catch reports from local commercial fishermen. Recent catches and sightings of silvers and its cousin, the bighead carp, have confirmed that these flying fish are becoming more common in our area.

Studies have documented the Asian carp migration, identified feeding behaviors, and determined what factors may limit their spread. Hundreds of carp were surgically implanted with radio transmitters. These fish are being tracked with acoustic receivers placed underwater on buoys.

In addition, water samples are undergoing eDNA genetics testing to forensically determine carp presence in areas where there are no physical sightings. Eggs and larvae have also been collected to confirm areas where Asia carp are successfully reproducing.

Why is there so much interest in these invaders? The bighead and silver carp are not native fish. They are physically adapted to live in the Upper Mississippi River due to large size, massive body weight, high reproductive potential and voracious appetite. Asian carp invaded the Illinois River over 20 years ago and now are the most abundant fish species in many areas.

Due to the Illinois River invasion, three underwater electric barriers were installed in the Chicago Sanitary & Ship Canal to prevent Asian carp from entering the Great Lakes. Steel electrodes at the bottom of the canal emit an electric field that discourages fish passage and hopefully protects the multi-billion dollar fishing industry in the Great Lakes.

Asian carp began their trek upriver 40 years ago and a thousand miles away. They were imported by commercial catfish farmers in Arkansas in the early 1970s to remove algae from their ponds. Flood waters in the 1980s provided access into the Lower Mississippi River.

Their trek north was assisted by the Great Flood of 1993 allowing expansion into the Middle Mississippi River, Illinois River and Missouri River. Subsequent floods in 1997 and 2001 allowed passage past locks and dams to near Lake Michigan by 2002. The first report of Asian carp in our area was 2005. Low numbers are currently being caught in nets by commercial fishermen. These carp have been reported as far north as Canada.

Some anglers dream of catching a monster fish. A whopper 73 pound bighead carp estimated to be 20-25 years old was caught by a commercial fisherman in lower Sabula Lake in summer 2012. However, hook-and-line fishermen will be disappointed to know that Asian carp are unlikely to be captured by anglers due to their filter feeding habits. Conversely, silvers may jump into your boat without having to bait a hook or drown a worm.

A growing Asian carp population in our Mississippi River waters is reason for concern not only due to competition with native fish but also a safety hazard to river users. Recreationists on the Illinois River have sustained broken bones, lacerations, concussions, and knocked unconscious after flying fish encounters. Sightings of flying fish should be reported to the U.S. Fish and Wildlife Service office in Thomson, Illinois at (815) 273-2732, Ext. 111.

Ed Britton is a Wildlife Refuge Manager at the Upper Mississippi River National Wildlife & Fish Refuge and a volunteer at Bickelhaupt Arboretum.