BLUE CATFISH AND CHANNEL CATFISH ARE SUITABLE HOSTS FOR THE ENDANGERED WINGED 
MAPLELEAF MUSSEL

Mark C. Hove1, Mark T. Steingraeber2, Michelle R. Bartsch3, Daniel J. Hornbach4, 
Marissa McGill1, Teresa J. Newton3, John A. Kalas2, Carrie L. Nelson1, and Erick 
A. Simonsen1
1University of Minnesota, Department of Fisheries, Wildlife, and Conservation 
Biology, St. Paul, MN 55108, 2U.S. Fish and Wildlife Service, Fishery Resources 
Office, Onalaska, WI 54650, 3U.S. Geological Survey, Upper Midwest Environmental 
Sciences Center, La Crosse, WI  54603, 4Macalester College, Biology Department, 
Saint Paul, MN 55105

The winged mapleleaf mussel is a federally listed species that has received 
considerable management attention in recent years. Once found throughout many 
Midwestern rivers, only two known populations exist, one of which is in a 10-
mile stretch of the St. Croix National Scenic Riverway that borders Minnesota 
and Wisconsin. This population is at risk from zebra mussel infestation, effects 
of variable water releases from an upstream hydropower dam, and an incomplete 
knowledge of its life history. One of the factors limiting the recovery of this 
species, as listed in its recovery plan, is the lack of data on which fish 
species serve as hosts for its glochidial larvae (mussel larvae require a fish 
host to complete their life cycle). In 1997, a team of biologists from 
universities and government, began working together to identify potential fish 
hosts for this endangered mussel. Prior to 2003, we had evaluated over 60 fish 
species (comprising 14 taxonomic families) but had achieved very limited 
success, and only with certain catfish species (Family Ictaluridae). Much of 
these early efforts were limited by finding sufficient numbers of gravid 
females. In the fall of 2003, winged mapleleaf had a strong reproductive year 
and we were able to expose glochidia to four Ictalurid species (blue catfish, 
channel catfish, flathead catfish, and slender madtom). About 8 to 12 weeks 
after the fish were exposed (19-22ºC), we recovered about 11,000 living 
juveniles from blue catfish and about 9,000 juveniles from channel catfish. Most 
of the juveniles produced by the blue catfish were placed into the St. Croix 
River near existing mussel beds and their survival rate will be checked 
periodically. The remaining juveniles are being used experimentally to test 
over-winter survival rate at two laboratory temperatures. These data show that 
blue and channel catfish are suitable hosts for this federally listed species. 
Thus, these data can be used in subsequent years to artificially propagate 
juveniles to augment existing populations of the winged mapleleaf within its 
historic range of the Upper Mississippi River System.

Key words: glochidia host, Quadrula fragosa, endangered species