Michigan Muskie Alliance

DNR looks for cause of fish kill

Anglers have found hundreds of dead muskellunge in the Detroit River in the past week and dead bass, bluegills, pike and other species in canals and bays. The reasons are unclear, but the deaths might have come from stress triggered by unusually high water temperatures this winter and spring.

"We're looking into it," said Gary Towns, a state Department of Natural Resources fisheries biologist. "I was out walleye fishing on Friday and saw about 30 dead muskies myself.

http://www.freep.com/apps/pbcs.dll/arti ... 6/SPORTS18

hello gents. im on the canadian side. theres still muskies dying as i type. reports are seeing fish still rolling over dying. if its the so called vhs i certainly hope its being monitered. hopefully with the erie walleye stocks the mnr, dnr will do their utmost. there was a large die off in the bay of quinte that killed thousands of sheepshead and gobies.. the end results are death from international shipping companies dumping ballasts. whats next in our future

Dead muskies turning up in Detroit River

http://www.mlive.com/outdoors/statewide ... xml&coll=1

Sunday, April 30, 2006 By Bob Gwizdz

Detroit River anglers have reported hundreds, perhaps thousands, of muskellunge floating in the river, and state fisheries officials are unsure about the reason.

The fish appear to be adult muskies -- at least 30 inches in length -- and are being reported along the entire length of the river.

Gary Towns, the Department of Natural Resources fisheries biologist for southeast Michigan, said he was on the river recently fishing for walleye and saw nine dead muskies. He sent the DNR research vessel to cruise the river and the crew counted 41 dead muskies one day.

The fish, discolored and often covered with fungus or silt, are thought to be long dead, Towns said. He theorizes that the fish died in late winter or early spring, sank, and then as the water temperature rose, they began to decompose, became bloated, and floated to the surface.

A bacterial disease known as musky pox (Piscirickettsia) was discovered in the fish in 2002 and there was a significantly smaller die-off of muskies in 2003. But the mortality did not occur in 2004 nor 2005, Towns said.

Although musky pox appeared to infect a significant portion of the population, only a small number of the fish succumbed to the disease. Towns said that if the current die-off is related to the same disease, he is optimistic it will not significantly impact the area's musky population, which is quite strong. Current ecological conditions on Lake St. Clair -- clear water and substantial aquatic vegetation -- favor muskies, Towns said.

Lake St. Clair and the Detroit River boast some of the best muskie fishing in North America.

"We have contacted Canadian fisheries biologists and have asked that they monitor their side of Lake St. Clair," Towns said. "Early reports are that they have found some dead muskies along the southern shore of Lake St. Clair."

Towns said that while spring die-offs of fish are not unusual, often because of stress, he had no information that muskies were especially susceptible, though a Canadian biologist told him he had seen the phenomenon before.

Because muskies are among the first species to spawn in the spring, it would make sense that they succumbed to post-spawn stress, especially as the water temperature rose unusually quickly this spring, Towns said.

Towns said he has also received reports of dead bass on both Lake St. Clair and the Detroit River, but cannot conclude that the die-offs are related.

Because of the physical deterioration of the dead muskies, Towns said it would be unlikely that necropsies would help determine the cause of the mortality.

There is no indication that the fish are currently dying, Towns said.

He also said there is no truth to rumors circulating on the Internet that the fish were dying because of a hatchery mishap several years ago when an anti-viral agent was accidentally introduced into the hatchery system and is causing the mortality.

The DNR will continue to monitor the situation, Towns said.

Note snippet:
Preliminary reports indicate the fish died of a viral infection, but more testing is needed to determine the strain.
"My worst fear, I suppose, is that the virus was transported by ballast discharge" from foreign ships, Tyson said. If so, fish native to the Great Lakes would not have a natural resistance to the disease. :(


Large fish kill hits western Lake Erie

Friday, May 05, 2006 Molly Kavanaugh Plain Dealer Reporter
mkavanaugh@plaind.com , 440-934-0506

An exceptionally large number of dead fish are littering Lake Erie beaches, disturbing lakefront residents and raising concern among state wildlife officials.

"It's much more extensive than we've seen," said Jeff Tyson, fisheries biologist supervisor with the state's Sandusky Fish Research Unit.

The dead fish are primarily freshwater drum, or sheephead, which is not a popular sport fish. The concentrated kills have been found in the western basin of Lake Erie, in Sandusky Bay and as far east as Vermilion.

Last week, Tyson sent samples to the U.S. Fish and Wildlife Service office in La Crosse, Wis. Preliminary reports indicate the fish died of a viral infection, but more testing is needed to determine the strain.

"My worst fear, I suppose, is that the virus was transported by ballast discharge" from foreign ships, Tyson said. If so, fish native to the Great Lakes would not have a natural resistance to the disease.

Scott Doty, manager of the Lake Erie Islands State Parks, said he has gotten several calls from lakefront property owners curious about all the dead fish. His staff has had to clean the beach at Catawba Island State Park.

At Cranberry Creek Marina, between Huron and Vermilion, the beach and surrounding shallow waters are not a pretty sight.

Is the smell bad? "It's going to be. I was out in a boat last night, and you can see freshwater drum with their tails up and heads down," said Chris Woods, vice president of sales at the marina.

Large numbers of dead fish also have been reported in Michigan's waters, including muskellunge in the Detroit River.

The last big fish kill in Ohio was about five years ago, when large numbers of carp washed ashore. Samples of those fish were sent for analysis, but the tests were inconclusive because the samples were too decomposed, Tyson said.

Hmm. I was having trouble accepting the temperature theory. Drum and shad tend to hang together in many situations and yet there has been no huge shad die-off even though shad are usually wimpy survivors by comparison. The selective virus might explain the drum mortality.

Larry Porter wrote:Hmm. I was having trouble accepting the temperature theory. Drum and shad tend to hang together in many situations and yet there has been no huge shad die-off even though shad are usually wimpy survivors by comparison. The selective virus might explain the drum mortality.

Two different situations in Erie and LSC.

There was a huge number of shad reported dead in LSC in February/March.

Stress may be factor in muskie deaths

http://www.freep.com/apps/pbcs.dll/arti ... 048/SPORTS

June 15, 2006 Eric Sharp

A large die off of muskellunge in Lake St. Clair and the Detroit River in May was attributed at first to above-average spawning mortality caused by unusually warm weather in April followed by unusually cold weather in May.

The Department of Natural Resources now says that the stress on the fish may have been exacerbated by a disease called viral hemorrhagic septicemia, which caused a huge die-off of freshwater drum and bluegills in Ohio waters of Lake Erie at about the same time.

"I know some people reported seeing 200 dead (muskies) in a day, but I think that was mostly because they all lay on the bottom until the water got warm, then they all filled with gas and floated to the surface at the same time," said Gary Towns, a DNR fisheries biologist.

"We did an aerial survey, and our best guess is that there were about 2,000 dead muskellunge. We know from other die-offs that only about half the fish usually float to the surface, so figure that total was maybe 4,000. That's still only about 1-to-3% of the muskies in the lake."

One muskellunge carcass has tested positive for the disease, and Gary Whelan, the DNR's fish production manager, said he hopes to get results on others in a few days and that the disease seems to have died off.