Botulism Kills Lake Erie Birds

H A M B U R G, N.Y., Dec. 6, 2000 -- An estimated 8,000 water birds, includingas many as 1,000 common loons, have now fallen victim to a puzzlingoutbreak of botulism along Lake Erie, state environmental officialssaid.

Crews from the state Department of Environmental Conservationcombed sections of a roughly 60-mile stretch of lake shore fromDunkirk north to Buffalo this week retrieving thousands of deadgrebes, common and red-breasted mergansers, loons, diving ducks,ring-billed gulls and herring gulls.

Two truckloads of carcasses arrived at the state’s wildlifepathology lab near Albany on Tuesday.

Birds Died Quickly

With only 250 nesting pairs of loons in all of New York, many ofthe dead loons are believed to have been migrating from Canada,according to state Wildlife Pathologist Ward Stone. The popularbirds are prized for their beauty and yodel-like call.

“It’s possible this one kill killed as many loons as there arein New York state,” Stone said.

Scientists do not yet know where the Type E avian botulism(Clostridium Botulism) killing the birds came from or how it isbeing transmitted.

One thing is certain: it is striking quickly.

“They must have quite a bit of toxic material, they’re notthin,” Stone said of the birds. “They’re getting hit hard by itfairly swiftly ... It could be a number of hours to several days.”

“There are a lot of questions,” he said as the trucks of deadbirds pulled in.

Many of the birds are scavengers and could have eaten fishkilled by the bacteria — but aside from some dead carp found inDunkirk Harbor, there is no evidence of a corresponding fishdie-off.

Also puzzling is that other birds, including the loons andmergansers, feed only on live fish — raising questions aboutwhether live fish may carry the deadly toxin.

Related to Salamander Die-Off

Scientists also are looking at whether the outbreak is relatedto a fairly large die-off of mud puppies — a type of salamander — along the Canadian shoreline of Lake Erie over the summer, or torecent outbreaks of botulism among loons and gulls in Ontario andelsewhere.

Since August, birds have died of botulism — including the Type Estrain — in Great Lakes states like Michigan and Pennsylvania andin other places including Hawaii, California, Louisiana andVermont.

“They may be isolated incidents and we’re trying to put thepuzzle together now,” said Gerald Mikol, director of the stateDepartment of Environmental Conservation’s Buffalo region.

“Type E has been found in the Great Lakes for decades but allthe sudden there’s more of it,” Stone said. There are a number oftheories.

Stone said excessive rainfall and flooding this summer may havestressed sewage treatment plants, sending more nutrients into thelake that allowed the botulism organisms to thrive.

Scientists also are looking at whether zebra mussels, whicharrived in the Great Lakes in the 1980s, somehow hold the bacteriaor concentrate the toxin. Zebra mussels are eaten by goby fish,which in turn are eaten by mergansers and loons.

It’s possible a die-off of the small gobies would go unnoticed,Stone said.

“The gobies are pretty heavy and may not do a lot of floatingaround the way some fish do,” Stone said. “There are a lot ofquestions. The other question is, they may have some resistance tothe toxin.”

Carcasses Useful to Scientists

Although no humans have become sick from the outbreak, waterfowlhunters and anglers are being warned to thoroughly cook all fishand game before eating it. Pet owners also are advised to keeptheir animals from picking at the dead birds.

“There’s no reason to panic but we do need to figure out whythis is happening,” Stone said.

The glimmer of good news is the die-off appears to be ending —at least for this year — judging from an absence of dying birds.Scientists will keep watch for a similar outbreak in warmerweather, however.

A side benefit, Stone noted, is that the large number of deadloons being delivered to his lab will provide valuable data, beyondthe botulism outbreak.

The lab usually sees only three to five loons a year, he said.The numbers arriving now have the potential to shed light on thingslike parasitic infections, pesticide poisonings and mercury levels.