Scaup mortality continues this fall on North Central Minnesota lakes
Wildlife managers from the Minnesota Department of Natural
Resources (DNR) are again finding dead lesser scaup on Lake
Winnibigoshish (Winnie) this fall.
Although not yet confirmed, the ducks are suspected to have died
from acute infestation of intestinal parasites called trematodes,
which are carried by Faucet snails, an invasive species that
inhabits lakes. Lesser scaup feed on the snails and become infected
with the trematodes.
“So far, about 100 to 200 dead scaup have been observed along the
northwestern shoreline of Winnie in the Third River Flowage area,”
said Area Wildlife Manager Perry Loegering, who along with office
staff conducts weekly searches of the west shore of Winnie,
Bowstring and Round lakes. A small number of sick and dead scaup
have been observed on Bowstring and Round lakes as well.
“Faucet snails have not been found in Bowstring or Round lakes, so
we think the birds are moving from lake to lake feeding on Winnie
but getting sick on the other lakes,” Loegering said.
The DNR Wetland Wildlife Research Group is studying Faucet snails
in infested waters to learn more about their habitat use, abundance
and parasite prevalence. These waters include Winnie, Upper and
Lower Twin lakes, Shell River, First and Second Crow Wing lakes,
and Crow Wing River.
Officials continue to sample Round and Bowstring lakes to
facilitate early detection of Faucet snails. They are also sampling
areas where scaup are feeding to learn where scaup are most likely
to encounter snails.
Die-offs of lesser scaup have occurred on Winnie in 2007 and 2008
when an estimated 8,000 and 2,000 scaup died, respectively. About
2,000 scaup were estimated to have died on Bowstring in 2010.
The DNR reminds hunters, anglers and other recreation boaters to
check their boats, trailers, anchors, decoys and lines, and other
submersed equipment when moving between waters. The best way to
reduce the spread of Faucet snails is to prevent their