Invasive Silver Carp Confirmed in Chickamauga Lake

Tennessee fisheries officials have confirmed the discovery of Silver carp, also known as Asian or jumping carp, in Chickamauga Lake.

Invasive Silver Carp Confirmed in Chickamauga Lake

Invasive Asian carp species including Silver and Bighead carp have established populations in the Tennessee River, adding to the concerns of state officials in Tennessee, Alabama, Mississippi and Kentucky. (Photo: Tennessee Wildlife Resources Agency)

Tennessee fisheries officials have confirmed the discovery of Silver carp in Chickamauga Lake after an angler had one of the invasive fish leap into his boat.

Also known as Asian carp or jumping carp, it's the first known confirmation of the exotic species in the famed bass lake near Chattanooga and any east Tennessee waterway. They are prolific in Kentucky Lake, part of the Tennessee River in western Tennessee and Kentucky. They were introduced in the 1960s and 70s before escaping due to flooding and releases. Since then the different carp species have been found in the Mississippi, Tennessee, Ohio, Missouri and Illinois river systems. 

Officials with the Tennessee Wildlife Resources Agency received a report January 10 from angler Dustin Hinkle, who said the fish “jumped into the boat as I deployed my trolling motor.” Hinkle was fishing near the Sequoyah Nuclear Plant, and told TWRA officials he “saw 15-20 more fish near the surface” exhibiting a feeding behavior.

“No additional reports have been made since this occurrence,” Cole Harty, TWRA’s Aquatic Nuisance Species Coordinator, said in a press release. “This is an excellent reminder to report carp sightings from east Tennessee, where carp are not already known to be established. We encourage anyone reporting to include photos, location information, and if possible keep a fish frozen to share with TWRA.” Reports can be made by contacting the nearest TWRA regional office. It is likely that these fish traveled up the Tennessee River through navigation locks, ultimately finding their way to Chickamauga Lake. “TWRA has been working with multiple partners to limit the spread and impact of invasive Asian carp in Tennessee,” said Frank Fiss, TWRA Fisheries Chief. “This new observation demonstrates the urgency of the issue.”

Where are Silver Carp?

Stretching more than 640 miles, the Tennessee River flows from east Tennessee near Knoxville southwest and across north Alabama before hanging a right up through western Tennesse and Kentucky.

Reservoirs created by a series of hydroelectric dams have giant locks for barges and watercraft. These locks move millions of gallons of water — and fish — thorugh the system. Migrating fish, such as carp, sturgeon, paddlefish or other species, often move from one reservoir to another though the locks.

Grass carp have been known within the system for decades. Bighead carp, part of the four known Asian carp species, have been shot by bowfishermen in Guntersville Lake and others. Silver carp are so prolific in Kentucky Lake they have negatively altered its famed bass fishingdied in massive numbers and are easy to catch via electrofishing for biological study.

Along with the Tennessee, silver carp have been found in the Cumberland and Duck rivers. They were confirmed in Pickwick Lake in northwest Alabama in 2016. That the fish have been discovered in Chickamauga leads, logically, to the belief they also would be in Wilson, Wheeler and Guntersville lakes — the three reservoirs between the Tennessee impoundment and Pickwick. State officials continue to monitor for the species and request anglers to help with sightings or any captured fish, as Hinkle did with TWRA.

Devastating Feeders

Silver carp can destroy an aquatic ecosystem due to their prolific feeding on phytoplankton, the base of the food chain and primary food for shad. Because shad are a primary food source for bass, catfish and other predators, the loss of plankton sets off a chain reaction with terrible impacts.

“They’re like the feral hogs of the water,” former Alabama DCNR fisheries chief Nick Nichols said in this press release. “At least, silver carp are as big a threat.”

“The silver carp is a filter feeder. It filters not only zooplankton but also phytoplankton, the microscopic plants. So they’re feeding right at the bottom of the food chain. By doing so, they’re competing with every other fish species in that body of water for the food supply. If they’re cropping off that zooplankton, that’s taking food out of the mouths of the native species, like the shad and bluegills.

"Once the silver carp establish a heavy population in an area, they literally eat themselves out of house and home. There won’t be anything left but silver carp.”

A study on the Yazoo River in Mississippi reveals the impact silver carp have on the backwater areas, which are vital for the recruitment of the native species like sunfish and black bass. In that study, rotenone was applied to sample the population a couple of decades ago. All the native species like crappie, bream and black bass were present. About a year ago, fisheries biologists went in and sampled those same areas with stunning results.

“Well over 90 percent of the biomass in the most recent study was silver carp,” Nichols said. “Basically, the only thing left was silver carp. They can literally take over the habitat. That’s what has happened in some places in the Mississippi basin.

How Silver Carp Spawn

According to the Mississippi Department of Wildlife, Fisheries and Parks, silver carp could survive in some brackish or saltwater situations and are prolific spawners if the right conditions are present:

Silver carp can reach three feet in length and weigh up to 80 pounds. They grow rapidly, reaching nearly 12 pounds in their first year of life, and they can live for 20 years. They school in open water, swim just beneath the surface, and are usually found from 1-5 meters deep in the water column. Because they tolerate a wide range of water temperatures and turbidities, they could potentially spread to all of the lower 48 states, parts of Alaska, Canada, and Mexico. They can even tolerate up to 12 parts per thousand (ppt) salinity.

They mature in two to four years and produce between 314,000-4.3 million eggs, depending on body weight. They spawn near the water surface in late summer to early fall in the United States. Rising water levels and increasing water temperatures trigger spawning. Because Silver carp eggs are semi-buoyant, they must be carried for about 60 miles by river currents ranging from 0.3-3 meters/second for several days to allow them to hatch. The eggs usually hatch in 15-50 hours depending on water temperature, with less time required to hatch in warmer water. In soft water with less than 200 parts per million (ppm) hardness, the eggs absorb water, swell, and burst before successfully hatching.



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