Alien flying fish have invaded our Mississippi River waters. These scaly aviators are not raiders from Mars; they came from Asia. The silver carp is notoriously known as the flying fish that leaps out of the water when disturbed by passing watercraft. Hundreds of fish may jump towards the sky in unison, hurdling 10 feet high and 20 feet horizontally, and many weigh between 10 and 15 pounds.
Researchers have stalked these aerial aquanauts for several years based upon catch reports from local commercial fishermen. Recent catches and sightings of silvers and its cousin, the bighead carp, by commercial fishermen near Bellevue in Pool 13 have confirmed that the flying fish have landed.
Several studies are ongoing to document the Asian carp migration, identify feeding behaviors, and determine what factors may limit their spread. Hundreds of Asian carp, primarily in Pools 16 to 19, have been surgically implanted with radio transmitters. These fish are 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 are also being collected to confirm whether Asia carp are successfully reproducing.
Why is there so much interest in these invaders? The bighead and silver carp are Asian species, they 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 have been 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 30 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 to 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 received broken bones, lacerations and concussions, and have been knocked unconscious, after flying fish encounters. Who would have ever thought that we may soon be ducking to avoid being hit by a flying fish?
Ed Britton is a Wildlife Refuge Manager at the Upper Mississippi River National Wildlife & Fish Refuge and a volunteer at Bickelhaupt Arboretum.