Wildlife Resources fisheries technician holds a Flathead catfish caught during a fish survey. The size of these fishes is probably they were artificially introduced to local waters by anglers.
Wildlife Resources Commission surveys have confirmed numbers of this popular local game fish, known as the bullhead, mud cat or yellow catfish has decreased dramatically. Fish biologists believe it is due to non-native Flathead catfish preying on them.
Local anglers are reporting to wildlife resource officers a decline in Snail and Flat bullhead catfish, tough local species that have provided recreation and food for Surry County fishermen.
According to North Carolina Wildlife Resources Commission fisheries biologist Kin Hodges, their observation is true and is due to the artificial introduction of Flathead catfish to local waters.
“The bullhead is traditionally one of the main fish taken on the Yadkin,” said Hodges. “Even in previous years when the Yadkin was dirtier it tended to favor these little catfish over bass or trout.”
He said buffer zones of vegetation along rivers and creeks and efforts coordinated by the N.C. Soil and Water Conservation District and the Natural Resources Conservation Service have resulted in less runoff and better agricultural practices that have helped make the Yadkin cleaner. He said the water quality has not improved to the point that this is a factor hurting the bullheads.
Hodges indicated fisheries biologists with the commission recently completed a series of electro-fishing surveys in Surry, Yadkin and Wilkes counties and found that catch rates near Elkin had declined from a high of 120 fish collected per hour in 2005 to less than three fish collected per hour this year. Similar collection rates at an upstream site in the Ronda community have decreased from nearly 300 fish per hour in 2005 to 20 fish per hour.
He reported an even more extreme decline of bullheads in the Yadkin River below Idols Dam near Winston-Salem. Hodges said no bullheads have been collected from this section of the Yadkin since the commission began its surveys in 2005.
“In my opinion the game changer occurred with the introduction of the non-native species of Flathead catfish in bodies of water that drain into the Atlantic. Flatheads are native in waters such as the New River which drains into the Mississippi. Hodges offered some hope in ongoing studies to find out why Flatheads have not impacted local fish populations as they have here.
Hodges explained that Flathead catfish are the dominant predator in waters they inhabit, eating mainly life fish. Although they prey heavily on bullheads, shad and sunfishes studies have shown they also will eat carp and crayfish. Flatheads commonly reach weights of 20 to 30 pounds in North Carolina. The state record, caught in the Cape Fear River, tips the scales at 78 pounds.
He said bass have not eaten bullhead catfish. Their numbers have increased recently because more periods of clear water favor bass’ hunting behaviors and lead to more bass being produced. He said Snail and Flat bullheads typically are 12- to 16-inches in length and weigh a pound or less. They were valued for being plentiful, easy to catch and good to eat.
One phenomenon noted by both fish and game biologists is an overabundance of prey animals or predators will offset each other. It is a boom or bust cycle that occurs in many ecosystems. Flatheads preference for slower, deep waters could offer the bullheads a niche to fill to lessen the impact of Flathead predation, so the little catfish could escape extinction.
Hodges said the department had stocked some Flatheads in High Rock Lake in the 1960s and quickly noticed their mistake. This is an area where Idols Dam served as a barrier to help keep Flatheads out of the upper Yadkin until recently.
“Sharp declines in bullhead abundance have been documented in other river systems in North Carolina and throughout the southeast where Flatheads have been introduced,” said Hodges.
Biologists speculate this has led to anglers who wanted to increase fishing opportunities for a large and hard-fighting fish in their areas, to slip them in local waters. He said that while it might seem like a good idea to replace a population of small bullheads the result will be less fishing opportunities.
“As a general rule, only 10 percent of the weight of a prey item is converted into body weight of the predator that eats it,” continued Hodges. “If a stretch of river now contains a single Flathead catfish weighing 50 pounds and ate bullheads exclusively, up to 500 pounds of bullheads could have been eaten by that Flathead to grow that big.”
The food chain mathematics gets worse from there.
“Taking that scenario one step further, if you assume an average bullhead weighs about half a pound it means that for each 500 pounds of bullheads that are eaten, anglers fishing the Yadkin River are losing opportunities to catch 1,000 half-pound bullheads and replacing them with a chance to catch one trophy-sized Flathead catfish.”
He said the commission passed a regulation in 2005 that requires anyone interested in stocking a public, inland fishing water to obtain a stocking permit first. Hodges noted that unwanted species continue to appear across the state.
“To prevent episodes like this one from playing out in other water bodies across the state it is imperative that anglers do not release any species of fish into streams, rivers or lakes where they currently do not exist,” stressed Hodges. “This is one of the most significant threats to populations of both game and non-game fish. Once a non-native species becomes established within a river system, very little can be done.”
Persons interested in more information on fishing in public, inland waters can obtain more information at the website www.ncwildlife.org/fishing.
Reach David Broyles at dbroyles@heartlandpublications.com or 719-1952.
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