
The winged mapleleaf
mussel (Quadrula fragosa) was listed as a federally
endangered
species in 1991. It was once found in 13 states in river and stream
tributaries to the Mississippi River where it lived on gravel or sand
in riffles of clear, high quality water. Today it is only found in one
river, the St. Croix River in Minnesota and Wisconsin. Its decline and
restricted range is mainly due to changes in the ecology of the Mississippi
River - especially the spread of the zebra mussel, an aquatic nuisance
species. Zebra mussels become abundant and smother native mussels. Other
factors that could lead to the decline of the winged mapleleaf mussel
are contaminants and an increase in sediments.
In 2002, the
La Crosse Fishery Resources
Office, WI worked with the USGS-
Upper Midwest Environmental Sciences Center (UMESC) in laboratory
studies to identify the host fish necessary to complete the reproductive
cycle of the winged mapleleaf mussel. This process involved locating
gravid female winged mapleleaf mussels and working with a variety of
fish in an attempt to identify the host fish. Divers searched for gravid
female mussels and Genoa
National Fish Hatchery, WI and the UMESC provided fish for testing.
Very few gravid female mussels were found and it is hoped the project
will contine in 2003. The University
of Minnesota is also investigating host fish for the winged mapleleaf
mussel.
For more information on the
winged mapleleaf mussel view the Endangered
Species Fact Sheet or Species
Profile.
Field Offices Involved
With Winged Mapleleaf Mussel Recovery
Geona
National Fish Hatchery, WI | La
Crosse Fishery Resources Office, WI
Link
to More Information