Minn. lake has die-off of bluebill ducks

[Niko]

Minn. lake has die-off of bluebill ducks

<!-- END HEADLINE --> <!-- BEGIN STORY BODY --> Tue Nov 6, 4:36 PM ET

As many as 3,000 bluebill ducks have died along the western shore of Lake Winnibigoshish in northern Minnesota, and wildlife biologists say they were likely poisoned by a parasite present in snails.

Officials with the Minnesota Department of Natural Resources collected the dead bluebills, also known as lesser scaup, on Friday and anticipated the die-off would continue.

"We're going to find a lot more dead," said Steve Cordts, a DNR waterfowl specialist in Bemidji.

DNR officials sent samples of the dead ducks to the National Wildlife Health Center in Madison, Wis., and are advising hunters against eating any duck that appears to be diseased.

The snails the ducks eat contain a trematode, which is a kind of parasitic fluke. It's likely new to the ducks' ecosystem, Cordts said.

"This is potentially pretty bad because of this snail," Cordts said. "It could be along the whole stretch of the Mississippi River and could get into other lakes and into other species."

Wildlife officials along the Mississippi River have reported more than 25,000 dead coots and scaup since 2002 between northern Iowa and Dresbach, Minn.

Dan Markham of Duluth was duck hunting on Lake Winnibigoshish near Deer River on Saturday when he and his hunting partner found dozens of dead bluebills.

"We were just heartbroken," Markham said. "It's depressing."
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Information from: Duluth News Tribune, http://www.duluthsuperior.com

http://news.yahoo.com/s/ap/20071106/ap_on_sc/dead_bluebills;_ylt=AvWpktYQzQgoMasLTeUujQ14hMgF

[Niko]

Re: Minn. lake has die-off of bluebill ducks

Parasite has killed thousands of scaup

The deadly organism has infected snails at Lake Winnibigoshish and has been picked up by the ducks, who dive below water to feed. The DNR is concerned the parasite might spread to other lakes.


By Doug Smith, Star Tribune
Last update: November 06, 2007 ? 8:58 PM


A parasite has killed thousands of ducks on Lake Winnibigoshish in northern Minnesota, and could kill many more before the fall migration is over."We picked up 1,000 dead scaup [also known as bluebills] on Saturday," said Steve Cordts, Minnesota Department of Natural Resources waterfowl specialist.

He saw many other scaup still alive but unable to fly, or to fly far. "You could boat right up to them," Cordts said. Perhaps 3,000 ducks, mostly scaup, and some coots have died in the past week.

"I'm sure there's more dead birds," Cordts said Tuesday.

The ducks apparently are dying from trematodes, a tiny 1-millimeter intestinal parasite or fluke that has infected snails in the lake. Scaup -- a duck that dives below water to feed -- eat the snails, then are infected.
"They essentially bleed to death," Cordts said.

The parasite was confirmed in scaup and coots sent to the National Wildlife Health Center in Madison, Wis.

Similar die-offs caused by trematodes have occurred spring and fall since 2002 on the Mississippi River near La Crosse, Wis., killing about 40,000 ducks and coots since then. Die-offs again are occurring there this fall.

Cordts said he's not sure how the trematodes made it to Winnie. They apparently have infected a snail called the banded mystery snail, which was first found on Winnie about eight years ago. They are infecting the faucet snail on the Mississippi.

Officials aren't sure how many ducks might eventually die on Winnie, or what impact, if any, it will have on the scaup population. But Cordts is concerned that the snails and parasites might spread to other Minnesota waters.

Other duck species also could eat the snails and become infected, he said.
There is concern because the continental scaup population has been declining since 1984 and hit an all-time low last year at about 3 million. Hunters annually kill about 300,000. Minnesota hunters killed about 20,000 last year.

Lake Winnibigoshish is a major scaup resting area during migration. "We could have 20,000 scaup show up on Winnie right now," Cordts said. "If that happens, they'd pretty much all be at risk."

Cordts plans to check the lake again today, but he won't collect any more dead ducks. Instead, carcasses will be left to decompose or be eaten by scavengers. The parasite apparently is not a threat to other species, including humans, but Cordts said hunters shouldn't eat sick waterfowl.

Doug Smith ? dsmith@startribune.com

http://www.startribune.com/outdoors/story/1533319.html

Information on trematodes snipped from here: http://www.emedicine.com/med/topic2301.htm

Background

Trematode infections occur worldwide. Trematodes, also called flukes, cause various clinical infections in humans. The parasites are so named because of their conspicuous suckers, the organs of attachment (trematos means "pierced with holes"). All the flukes that cause infections in humans belong to the group of digenetic trematodes. Important features exhibited by adult digenetic trematodes are summarized below (see Features of digenic trematodes).

Depending on the habitat in the infected host, flukes can be classified as blood flukes, liver flukes, lung flukes, and intestinal flukes (see Classification of trematodes according to their habitat). The flukes that cause most human infections are Schistosoma species (blood fluke), Paragonimus westermani (lung fluke), and Clonorchis sinensis (liver fluke). Other less important flukes include Fasciola hepatica and Opisthorchis viverrini, which are liver flukes, and Fasciolopsis buski, Heterophyes heterophyes, and Metagonimus yokogawai, which are intestinal flukes.

[Niko]

Re: Minn. lake has die-off of bluebill ducks

DNR Doubles Estimate Of Dead Bluebill Ducks

DEER RIVER, Minn. (AP) ― The Minnesota Department of Natural Resources has increased its estimate of the number of dead scaup, or bluebills, on Lake Winnibigoshish to as many as 6,000 with more dead birds expected before the fall migration is over.
Lake Winnibigoshish is a major scaup resting area during migration.
The DNR said about 3,000 ducks, mostly scaup, have died on the lake in the last week, along with some coots. The deaths are being blamed on a tiny trematode parasite that is infesting snails in the lake. The ducks eat the snails and die.
The parasite was confirmed in scaup and coots sent to the National Wildlife Health Center in Madison, Wis.
DNR waterfowl biologist Steve Cordts said a large raft of live scaup were on the lake Thursday and he feared they also might eat the snails and die.
"We could have 20,000 scaup show up on Winnie right now," Cordts said. "If that happens, they'd pretty much all be at risk."
But Cordts won't collect any more dead ducks. Instead, carcasses will be left to decompose or be eaten by scavengers. The parasite apparently is not a threat to other species, including humans, but Cordts said hunters shouldn't eat sick waterfowl.
Similar die-offs caused by trematodes have occurred spring and fall since 2002 on the Mississippi River near La Crosse, Wis., killing about 40,000 ducks and coots since then. More die-offs are occurring there this fall.

http://wcco.com/local/dnr.bluebill.ducks.2.564153.html