A danger to our loons....

Dear Colleagues - I'll keep you posted on the situation described below, it could have an impact on Wisconsin's breeding loon population.

Kevin Kenow, USGS, found that nearly all Wisconsin loons fitted with satellite transmitters migrated through Lake Michigan during fall migration. The die-off described below has potential serious implications for Wisconsin's loon population as strong adult survival rates are critical to the long term stability of the population. It is likely many loons from the Michigan UP and Minnesota also stage in Lake Michigan during fall migration.

Several thousand loons have died from botulism toxicity during fall migration on Lake Erie the past several years, however we only know of one Wisconsin bird involved in that die-off as we believe most of WI birds do not migrate that far east before heading south. However, with botulism turning up in Lake Michigan, there may be a greater risk impact in Wisconsin. It appears the botulism outbreak is involved with the invasion of the Great Lakes by exotic invasive species, round goby and mussel in Lake Erie, where they anticipate the largest botulism kill yet in 2006.

For those of you that keep track of loon carcasses in Wisconsin, please keep your eye out for our color-banded loons if they turn up. We have color marked nearly 2000 individual loons from WI 1991-2006 and they may turn up in this die off.

I will let you know if I hear more over the fall. Mike

From: Kevin P Kenow [mailto:kkenow@usgs.gov]
Sent: Saturday, November 11, 2006 7:28 AM
To: Meyer, Michael W - DNR
Subject: Botulism outbreak in Lake Michigan

Mike,

Hope you made it back into the USA. Looks like it will be quite important for you to look at adult survival in your marked population this next year if this Lake Michigan botulism outbreak becomes big.

Kevin

*****

Botulism is killing migratory birds in Lake Michigan

The die-off of loons, grebes, cormorants and other migrating birds is linked to invasive species of mussels and fish in the Great Lakes.
Tom Meersman, Star Tribune
Last update: October 24, 2006 ? 9:34 PM


Hundreds of loons, grebes, mergansers, cormorants and other migrating birds have been killed in Lake Michigan recently, most likely from bacteria linked to non-native fish and mussels.
Biologists at Sleeping Bear Dunes National Lakeshore estimated this week that 2,600 dead birds have washed up on beaches during the past two months. It is the first large-scale bird die-off in Lake Michigan in decades.

"I've worked here for almost 30 years and I've never seen anything like it," said Steve Yancho, chief of natural resources at the park's office in Empire, Mich. He said the cause of the deaths seems to be Type E botulism, which occurs naturally in the sediment of the lake, but rarely enters the food chain.

Many wildlife biologists around the Great Lakes have noted similar mass bird deaths since 1999 in Lakes Erie, Ontario and Huron. Lake Superior seems to be the only Great Lake that has not been affected so far, said Doug Jensen, aquatic invasive species coordinator for the Minnesota Sea Grant at the University of Minnesota Duluth.

He said he doesn't know whether similar problems will occur in Lake Superior, because scientists are still trying to understand how water temperature and other factors may play a role in transforming the botulism bacterium into a potent neurotoxin.

What's clear from the evidence, said Jensen, is that the die-offs involve the interaction of two invasive species -- quagga mussels and a type of fish called round gobies -- which came originally from the Black and Caspian seas. They were carried into the Great Lakes in the ballast water of oceangoing ships and have been spreading since their arrival in the late 1980s.

Biologists believe that the birds die as the neurotoxin makes its way through the aquatic food chain.

First, invasive quagga mussels move into a lake-bottom area, filter the sediment and accumulate the botulism's bacteria, which produce the toxin. Then, the round gobies eat the mussels and become contaminated. Finally, migrating birds spot the dead or dying gobies, eat them and in turn get poisoned.

The toxin attacks the birds' nervous system and paralyzes their muscles, causing large numbers to drown when they can no longer flap their wings or hold up their necks.

Large bird die-offs have occurred in late summer when gulls eat poisoned fish, but especially in the late fall when migrating birds are searching for food.

New York biologists picked up more than 17,000 dead birds along the southern shore of Lake Erie in 2002. The toxin has also killed tens of thousands of other fish that consume gobies, and the gulls that feed on them.

Yancho said the botulism outbreak at Sleeping Bear Dunes occurred just after the piping plover, an endangered bird species, left the area.

"Had they been here when this was going full speed, it could have been disastrous," he said, adding that there are only 50 pairs of piping plovers left in the Great Lakes.

Helen Domske, senior extension specialist at the New York Sea Grant, is especially concerned about loons.

"They're wonderful birds that are such a critical part of the ecosystem," she said. "You start to wonder what kind of impact so many deaths is having on the entire [loon] population."


Tom Meersman ? 612 673-7388 ? meersman@startribune.com



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