COLUMNARIS DISEASE, CATFISH - USA: (ALABAMA)
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Date: 22 Aug 2011
Source: Times Daily [edited]
<http://www.timesdaily.com/article/20110823/ARTICLES/308239994/1011/NEWS?Title=Bacterial-disease-blamed-for-fish-deaths>
Bacterial disease blamed for dead fish on Wilson, Wheeler
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A bacterial disease related to high water temperatures is being blamed for the deaths of thousands of catfish on Wheeler and Wilson lakes in recent weeks, conservation officials said Monday [22 Aug 2011].
Keith Floyd, a supervising fisheries biologist for the Alabama Department of Conservation and Natural Resources, said he began receiving reports of dead catfish on Wheeler Lake near Decatur about a month ago. He received a report Monday about dead catfish found during the weekend in Wilson Lake, in the Shoals.
Killen resident Mike Zacharski said about 300 dead catfish floated past his home on Wilson Lake on Monday morning.
"They were spread out over about a mile and stretched almost from bank-to-bank. It's was pretty spooky looking," Zacharski said. "There were some huge fish. Several looked like they weighed more than 20 pounds."
Zacharski said he began noticing dead catfish along the shoreline and floating in the lake about 3 weeks ago. Monday was the 1st time he saw hundreds floating in a group. Floyd said the fish are dying from columnaris disease [_Flavobacterium columnare_], which is caused by a bacteria that becomes more active when water temperatures are high.
"We usually see this when the water is very warm," Floyd said. "The warm water helps the bacteria multiply, plus it causes stress for the fish. The combination of more bacteria and heat stress makes the fish more susceptible to being infected."
Water temperatures in local lakes were in the lower 90s earlier this month. Those temperatures are now in the upper 80s.
Barry Ray, who lives on Wilson Lake, said he began noticing dead catfish floating in the lake about 3 weeks ago. "At 1st, it was just big catfish, 20- to 30-pounders, but lately I've been seeing a lot of small catfish, too," Ray said. "They're real scattered; you see a few here and then a few there, perhaps 10 to 15 in a 1/4-mile circle."
So far, catfish are the only fish reportedly dying. Floyd said blue catfish make up a majority of those killed to this point. "This disease can be very species specific," Floyd said. "When we see it around here, it usually hits catfish." Floyd is unsure why catfish are typically targeted by the disease in the Tennessee River. He said the disease can kill any species of fish.
Fish infected with columnaris disease often have sores on their skin and gills.
Now that water temperatures are cooling, Floyd said the problem should being winding down. "It's already gone on longer than we expected," he said. "It's kind of like the flu bug going through a school where a few kids get sick at 1st and then more and more until it peaks and starts winding down. Hopefully we're seeing the peak of the fish kills and they are going to start tapering off."
Floyd said he does not expect long-term damage to the catfish populations on either lake. "I had a friend who went fishing over the weekend close to Browns Ferry and was catching catfish left and right," Floyd said. "So far, it does not seem to have hurt the catfish population."
The disease is not known to infect humans who swim in lakes where the bacteria is present, conservation officials said.
Zacharski continues to go swimming in Wilson Lake, but finds it increasingly difficult because of the dead fish. "When I'm out there swimming, I'm having to duck and dodge the dead catfish that are floating by," he said.
[Byline: Dennis Sherer
<dennis.sherer@TimesDaily.com>]
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Communicated by:
ProMED-mail from HealthMap alerts
<promed@promedmail.org>
[Columnaris disease is the 2nd leading cause of mortality in pond raised catfish in the southeastern United States. It is 2nd only to enteric septicemia of catfish (ESC) caused by the bacterium _Edwardsiella ictaluri_. Most species of fish are susceptible to columnaris following some type of environmental stress and when water temperatures are in the upper part of their preferred temperature range. The disease commonly occurs in channel catfish when water temperatures are in the range of 25 to 32 C (77 to 90 F) in the spring, summer and fall.
Columnaris, 1st described by Herbert Spencer Davis in 1922, is one of the oldest known diseases of warm water fish. References to the disease can be confusing. The causative bacterium has been referred to by different names including _Bacillus columnaris_, _Flexibacter columnaris_, _Cytophaga columnaris_, and most recently _Flavobacterium columnare_.
Temperatures have been hot for prolonged period across much of the United States. Many lakes, streams and bays are reported to be above normal temperatures and swimmers indicate it is like being in a warm bathtub. When water temperatures are high, fish are stressed, and bacteria thrive.
Portions of this comment were extracted from:
<http://www.ustfa.org/Trout%20production/Columnaris%20Disease%20-%20A%20Bacterial%20Infection%20Caused%20by%20Flavobacterium%20columnare%20%20%20srac%201998.pdf>
- Mod.TG
The interactive HealthMap/ProMED map for Alabama is available at:
<http://healthmap.org/r/00cn> - CopyEd.EJP]
[see also:
Undiagnosed die-off, fish - USA (02): (GA) columnaris 20110528.1641 2010
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Undiagnosed fish die-off - USA (04): (WV, OH, PA) columnaris
20100610.1946
2008
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Columnaris disease, fish - USA 20091111.3908
1999
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Columnaris, white bass - USA (Kansas) 19990713.1178] .................................................sb/tg/ejp/dk/ll
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