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From the Grand Forks Hearld….
Biologists explore catfish kill
By Brad Dokken, Herald Staff Writer
Published Wednesday, September 12, 2007
Fisheries crews from Minnesota and North Dakota are trying to find out why more than 1,600 channel catfish have died on the Red River south of Grand Forks.
The die-off appears to be limited to channel catfish, officials say, and the cats have ranged in size from about 5 inches to 30 inches.
According to Henry Drewes, regional fisheries supervisor for the Department of Natural Resources in Bemidji, a crew from the DNR’s area fisheries office in Detroit Lakes, Minn., was on the river Monday after a Grand Forks fisherman reported seeing dead catfish over the weekend.
Lynn Schlueter, fisheries biologist with North Dakota Game and Fish Department travels the Red River Wednesday to check on the number of dead catfish, hoping to find one partially alive to take as a specimen to check for a parasite. Herald photo by Jackie Lorentz.
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The crew observed the dead catfish all along the approximately nine-mile stretch of river they checked upstream from the landing in East Grand Forks, Drewes said. The fish were in various stages of decomposition, he said; some appeared to have died recently, while others had been dead for several days.
Some of the fish that had died more recently appeared blotchy and had lesions on their skin, Drewes said.
Fish will be tested
The DNR crew Monday was able to capture one catfish that was just about dead, and the fish was sent to the DNR’s pathology lab in St. Paul for testing, Drewes said. Results from the tests will be available sometime in the next several days.
Drewes said oxygen levels on the affected stretch of river were fine, and the water temperature was normal for this time of year. That tends to rule out “point source” pollution, such as the discharge of storm sewer water that killed fish of all species near Fargo after a heavy rainfall in the summer of 2006, Drewes said.
Instead, he said, disease or bacterial infection is the more likely culprit.
“The fact they’re distributed over a wide area and just channel catfish kind of points at some kind of disease, bacterial infection or something,” Drewes said. “I’m not an expert, but there are some diseases that affect catfish, and you see them on rising temperatures or dropping temperatures.
“But we’ll know a lot more when we get the analysis back from the lab.”
He said the DNR was collaborating with North Dakota Game and Fish Department and the North Dakota Department of Health to isolate the cause of die-offs and determine the extent of the fish kill.
N.D. explores
farther south
Lynn Schlueter, Red River fisheries biologist for the North Dakota Game and Fish Department in Devils Lake, picked up Tuesday afternoon where the DNR left off. He boated about 15 miles of river south of Grand Forks and encountered dead catfish the entire length.
The dead catfish were scattered, one here and one there, mostly along the banks, but some were floating. Schlueter said the nature of the die-off suggests a disease such as columnaris, a highly contagious bacterial infection that includes skin lesions, but that’s only speculation until test results are available.
He planned to visit sites even farther upriver Tuesday evening to better determine the extent of the die-off. So far, at least, Schlueter said he hadn’t heard reports of similar kills from other communities either upstream or downstream from Grand Forks.
“Was something just right here that allowed this to happen?” he asked.
Angler’s
perspective
Officials first got word of the die-off Saturday when Karry Kyllo, a local angler and fishing guide, contacted the DNR and Game and Fish after counting more than 300 dead fish upstream from Grand Forks.
Kyllo said he’s been seeing dead catfish along the river south of Grand Forks for the last few weeks. He also has spotted dead catfish along the river north of Grand Forks but said the fish could have died farther south and simply floated downstream.
According to Kyllo, who logs about 75 days on the river during the open water season, the die-off also appears to coincide with a pronounced decline in fishing success.
Normally, catfish anglers encounter some of the best fishing of the year in September, when the cats feed aggressively to bulk up for winter. That hasn’t happened this year, Kyllo said, adding he also has noticed other signs that something’s fishy, so to speak.
“I don’t know if it’s my imagination or not, but the fish I’ve been catching lately seem sluggish,” Kyllo said. “We pulled in a 24-pounder here a few weeks back, and a bigger fish like that usually heads to the bottom.
“This one didn’t even fight – it just laid on the surface.”
Despite the scope of the die-off, Drewes said disease – if that indeed turns out to be the cause – typically doesn’t have a long-ranging impact on fish populations.
On the downside, managers have fewer options than they would if discharge from a sewer or factory was killing the fish.
“With bacterial infection, your hands are kind of tied,” Drewes said. “But they tend to be short-term, and they don’t tend to infect the entire population. That’s the good news.”
Reach Dokken at (701) 780-1148, (800) 477-6572 ext. 148, or [email protected].
A large number of catfish in all sizes are washing up dead on the river banks of the Red River have been found in Grand Forks and south of Grand Forks according to the North Dakota Fish and Game Department. Herald photo by Jackie Lorentz.