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| FishTails |
Carp Kill Blamed on Bacterial Infection
By Chris Lawrence
Increasing reports of dead carp noticed by fishermen on the Ohio River have been traced to naturally occurring
bacteria within the water. DNR Fisheries Biologist Frank Jernejcic says samples taken from fish on the Ohio indicate
the cause of death is the obscure bacteria Columnaris.
"We first noticed dead fish on the Monongahela River about the second week of May." Says the Fairmont
based biologist. "Since then they've been reported all up and down the Ohio River and up into Pennsylvania."
Columnaris is a common bacteria in the waters of the larger rivers and can affect all species of fish. However,
Jernejcic says for now they're only noticing carp being impacted.
"A couple of years ago we had a situation in the summer when only Red Horse suckers were being killed and
at the time we hypothesized it was related to spawning."
Jernejcic is convinced the kill may include large numbers of the bottom feeding creatures, but can't say for sure
until later this year.
"When you see a few fish dead it's an indication there are a lot more dead. Our best indication of the magnitude
of this kill will come later this year when we do the lock surveys on the Ohio River. Normally we get a large number
of carp in those and if that number drops significantly, we'll know what caused it."
At this point, few are shedding a lot of tears over the loss of carp-since their numbers are already nearing a
level of diminishing returns.
"Given the reproductive capacity of carp, it's unlikely it's going to affect them significantly."
While the bacteria could easily spread to bass, it so far has not. Biologists are unable to say with any degree
of certainty what triggers the bacteria to infect fish. Jernejcic says while the bacteria could impact bass as
well as other game fish-an overabundance of carp isn't helping their cause either.
"They stir up the bottom and make it more turbid and also compete for food with other species." Notes
Jernejcic, "They may not compete for food with gamefish, but they do compete with forage fish-which the game
fish prey on."
An overpopulation of carp can also be lethal to nesting bass. As carp root in the area near nests the eggs tend
to be covered with layers of silt stirred up by the carp activities-this can keep the eggs from being fertilized.
Male bass guarding the nest are also forced to drive off the nuisance fish-leaving the nest vulnerable to a host
of predators.
Jernejcic, always the one to look on the positive side of everything, laughs if you could bottle up the stuff -you
could sell it.
"I've got a couple of lakes in the district where carp are too abundant, I've been trying to figure out what
to do about it. I've thought about collecting some of the diseased fish from the Ohio River and taking them over
to some of those lakes." |
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