TOPEKA (KSNT) – Biologists are on the front lines of a battle on and beneath the Kansas River to take two invasive species down a peg.
Conservationists and members of the Kansas Department of Wildlife and Parks alike have been looking at the growing population of invasive carp species in the Kansas River with increasing worry in recent years. Their presence means that native and game species in the river face a greater level of competition for resources. Meanwhile, anglers and others who enjoy the water, consider them to be a nuisance.
KSNT 27 News spoke with the KDWP, a conservationist and a local angler to learn more about the threats posed by invasive carp in Kansas. They spoke on what is being done to help control their growth and expansion, not just in the Kansas River, but other waterbodies in the Sunflower State.
How did Asian Carp end up in Kansas?
Silver carp are one of four different varieties of invasive carp species found in Kansas waters. The others include bighead, grass and common carp. Each species is considered to be invasive in Kansas, according to KDWP Aquatic Invasive Species Coordinator Chris Steffen. While common carp have been in North American since the 1800s, silver and bighead found their way into U.S. rivers fairly recently.
Common carp were introduced to Kansas waterbodies in June 1878, according to the KDWP. While opinions were mixed on the fish being added among anglers and members of the KDWP, it is considered to be a part of Kansas waterbodies by one local angler.
“It’s also important to point out that the common carp are a naturalized species that were purposely stocked over 150 years ago as a food and game fish,” said local angler Kevin Zirjacks. “They are an important part of the ecosystem and people will lump them in with the invasive species just because of the ‘carp’ in the name.”
Originally coming from areas of East Asia and China, bighead and silver carp species were introduced to the U.S. during the 1970’s and 1980’s. They were placed in private fish farms and wastewater treatment facilities as a biological control agent to reduce algae growth and improve water-quality in some ponds, according to the U.S. Fish & Wildlife Service (USFWS). However, by the 1990’s these fish had escaped into the Mississippi River during floods and rapidly spread from there through the interconnected river system.
Silver and bighead carp eventually reached the Sunflower State through the Missouri River. The progress of these fish was checked thanks to barriers such as the Bowersock Dam in Lawrence and, initially, by the WaterOne Dam in the Kansas City area.
‘A very large threat’
Dawn Buehler, Kansas Riverkeeper and executive director of Friends of the Kaw, spoke with KSNT 27 News about the problems posed by silver and bighead carp. She said silver carp pose a nuisance to kayakers and boaters as they have a tendency to jump out of the water when frightened.
“They pose a very large threat to the river’s natural ecosystem,” Buehler said. “They’re very dangerous to boaters because they have this ability that they are easily startled and jump into the air. A boat motor or kayak paddle will cause them to jump in the air and they will wind up in your boat. Our members have been hit by flying carp many times in the lower part of the river.”
Silver carp can grow upwards of three feet long and regularly reach 20 pounds. Some adults weigh up to 60 pounds, according to the USFWS. A flying fish of this size could lead to injury and damage equipment for those on the river.
Bighead carp can also grow up to five feet in length and weigh up to 110 pounds, according to the KDWP. They are known to live up to 25 years in some instances, presenting a long-lasting problem to local wildlife in the water. The largest of this variety caught in the Kansas River weighed-in at 72 pounds while the world record was a 125 pound river monster caught from a Missouri lake, according to Steffen.
The carp also take away natural resources in the river, preventing native and game species from flourishing.
“They compete with natural fish for nutrients and habitat,” Buehler said. “They grow in such big numbers, they don’t leave much for our native fish to eat.”
Zirjacks was in agreement with Buehler, citing the damage that can be done by both bighead and silver carp when their populations increase unexpectedly.
“The biggest problem with the silver and bighead carp is that they are filter feeders,” Zirjacks said. “Silver and bighead carp in large numbers can strip huge amounts of plankton from the water. That directly affects all the native species that depend on that food source.”
Fish in the Kansas River, such as channel catfish, bass, walleye, crappie, all native game fish and bait fish are all threatened by the presence of silver and bighead carp, according to the KDWP.
Zirjacks said that both bighead and silver carp have the ability to reproduce at a “very high rate of speed,” leading to an explosion in their numbers. It was a large spawning event in 2010 that drastically increased the carp population’s numbers in the lower Kansas River, according to Steffen.
Use the slider below to see photos of bighead (left) and silver (right) carp:
Steffen said that KDWP data on the extent of damage being done by silver and bighead carp is limited but the severity of the impact can be roughly correlated to how many carp are in the river. He said the United States Geological Survey (USGS) summarizes the impacts of these carp and indicate that their presence has been recorded in 12 states.
What’s being done to stop them?
While the presence of silver and bighead carp have caused problems for boaters, anglers and native wildlife, recent efforts by the KDWP have resulted in some positive change. Steffen detailed the long history the KDWP has had with counteracting silver and bighead carp in Kansas.
Beginning in 1978, the KDWP prohibited the possession of live bighead and silver carp in Kansas by adding them to the Prohibited Species List. This designation means that it is illegal to import or possess bighead and silver carp without proper documentation under KAR 115-18-10. The KDWP later completed the Kansas Aquatic Nuisance Species Management Plan in 2005 to help guide the management of invasive species.
In 2007, silver carp were placed on the injurious species list by the USFWS while bighead were added in 2011. This designation means that these species are considered injurious to the interests of humans, agriculture, horticulture, forestry, wildlife or wildlife resources in the U.S. The USFWS also created a control and management plan for carp species in the U.S. in the same year.
Steffen said the KDWP began two initiatives in 2011 that it continues to use today. One involves the inspection of bait shops to verify live carp are not being spread through the live bait trade while the other focused on actively sampling waterbodies for silver and bighead carp distribution.
Most recently, members of the KDWP have been taking a more proactive approach to carp removal from the Kansas River. Steffen said there are two techniques used to remove carp: using a gillnet to trap a school of carp or by using a method known as electrofishing which stuns the fish, allowing them to be collected and removed. These efforts, which began in 2022 and continue today, have resulted in more than 25,000 pounds of silver and bighead carp being removed from the Kansas River.
Steffen said the big worry now is that another flood will give the carp the opportunity to cross over the Bowersock Dam. A flood could also allow the carp to enter other waterbodies such as Clinton Lake through the Wakarusa River which connects back to the Kansas River.
“Obviously these things are bad, we want to limit their reach in the state,” Steffen said. “The Bowersock Dam does that unless there is a flood. We want to reinforce that.”
One idea that is being considered is the installment of an acoustic deterrent on the Bowersock Dam. This would activate in the event of a flood and prevent the carp from traveling further upriver, according to Steffen. However, this technology has not been installed yet. Steffen cited a need for more data before the deterrent could be installed in Kansas.
The USGS reported in 2021 that it was testing an underwater Acoustic Deterrent System at a dam on the Mississippi River in Iowa to see how carp respond to acoustic signals. The USGS said the same technology could be used at other locations to control the movement of invasive carp.
Steffen said that studies conducted by the KDWP have found no trace of the carp above the Bowersock Dam so far. He said most of the carp in between the Lawrence dam and the Kansas City dam are “resident” fish that do not migrate and are distinct from Missouri River fish.
“This resident fish situation, created by the combination of these two barriers, creates a scenario where bighead/silver carp removal is likely to both benefit native species and river users in that stretch of river and also provide some protection against upstream range expansion should a very large flood create an opportunity for bighead/silver carp to attempt to move upstream of the Bowersock Dam,” Steffen said.
What you can do
Average anglers can help prevent the spread of silver and bighead carp in Kansas. If you catch one of these fish, you are encouraged to follow the standards of the American Fisheries Society for spinal cord dislocation or decapitation methods on the carp. It is illegal to return them to the water alive or possess them in Kansas, according to Steffen.
By returning the body of the carp back to the water, it returns the nutrients they contain back to the water from where they were caught, according to Steffen. He also advised against leaving their bodies on the bank as it constitutes as littering and makes the site unpleasant for other people.
Steffen encouraged people to avoid moving the fish to new waterbodies as well.
“Don’t move live fish,” Steffen said. “These things are kind of constrained by the barriers in place. The biggest worry is people moving them to different locations.”
Recommendations from the KDWP online encourage people who catch a silver or bighead carp anywhere other than the Kansas, Missouri, Big Blue or Wakarusa Rivers, are to keep it. You are then encouraged to freeze the carp and place it in in a sealed plastic bag. Write down the date and location of the capture, and call the Emporia Research Office at 620-342-0658 or send an email to email@example.com.
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