Home
Field Notes
 
U.S. Fish & Wildlife Service
Field Notes Entry   
A happy accident results in a great start for winged mapleaf recovery
Midwest Region, June 30, 2016
Print Friendly Version
Representatives from Genoa National Fish Hatchery, Wisconsin DNR, Minnesota DNR, The Nature Conservancy, Army Corps of Engineers and others form an assembly line to place shellfish tags on winged mapleleaf mussels near Hudson, Wisconsin.
Representatives from Genoa National Fish Hatchery, Wisconsin DNR, Minnesota DNR, The Nature Conservancy, Army Corps of Engineers and others form an assembly line to place shellfish tags on winged mapleleaf mussels near Hudson, Wisconsin. - Photo Credit: Tamara Smith
Newly tagged winged mapleleaf mussels
Newly tagged winged mapleleaf mussels - Photo Credit: Tamara Smith
Divers from Minbesota DNR and the Minnesota Zoo sort mussels collected near Hudson, Wisconsin.
Divers from Minbesota DNR and the Minnesota Zoo sort mussels collected near Hudson, Wisconsin. - Photo Credit: Tamara Smith
Dan Kelner, Army Corps of Engineers, and Megan Bradley, Genoa National Fish Hatchery) apply PIT tags to winged mapleleaf.
Dan Kelner, Army Corps of Engineers, and Megan Bradley, Genoa National Fish Hatchery) apply PIT tags to winged mapleleaf. - Photo Credit: Tamara Smith
National Park Service divers Allison Holdhusen and Byron Karns join University of Minnesota diver Mark Hove to reintroduce winged mapleleaf to the Mississippi River near St. Paul, Minnesota.
National Park Service divers Allison Holdhusen and Byron Karns join University of Minnesota diver Mark Hove to reintroduce winged mapleleaf to the Mississippi River near St. Paul, Minnesota. - Photo Credit: Tamara Smith
Winged mapleleaf tagged with PIT tags (left) and shellfish tags (right).
Winged mapleleaf tagged with PIT tags (left) and shellfish tags (right). - Photo Credit: Tamara Smith

Winged mapleleaf (Quadrula fragosa) was historically widespread in the central Unites States, with records from at least 41 rivers in 16 states. Today the species inhabits only five rivers; at least three of the five extant populations face significant threats or are of uncertain viability. The capability to propagate and reintroduce winged mapleleaf into habitats that it occupied historically would facilitate its recovery. In its 1997 recovery plan for the species, U.S. Fish and Wildlife Service stated that at least five viable populations would be necessary to recover the species, but that more than five may be necessary “to maintain the species” and to ensure its “optimal geographic distribution."

Winged mapleleaf are known to occur in the north (i.e., St. Croix and Mississippi rivers in Minnesota and Wisconsin) and the south (i.e., Bourbeuse River in Missouri, Saline and Ouachita rivers in Arkansas, and the Little River in Oklahoma). Two parallel efforts to propagate winged mapleleaf are ongoing – one in the northern part of the species’ range that uses mussels from the St. Croix River for propagation and one in the south that relies on the Saline River population in Arkansas for broodstock.

Since about 2003, the Service and our partners have been developing techniques to propagate winged mapleleaf, initially focusing on identifying a suitable reproductive host (discovered to be channel catfish, Ictalurus punctatus) and then refining techniques to facilitate efficient collection of brooding females, maximizing the likelihood of successful juvenile transformation, maintaining juveniles in situ (e.g., silos or cages in the river), and growing juveniles large enough for eventual release.

Using brooding females from one of the best populations of the species on the St. Croix River, the team began propagating winged mapleleaf at the Service’s Genoa National Fish Hatchery and placing them out in the St. Croix River near Hudson, Wisconsin, to grow in cages. In September 2006, these efforts paid off with 24 artificially propagated juvenile winged mapleleaf living in cages on the St. Croix River, upstream of Hudson; these juveniles were then placed in silos in other locations. The cages downstream of Hudson were checked for juveniles and because no juveniles were observed, the cage substrate was released into the river. Unfortunately, all of the cage sites near Hudson were abandoned in 2006 due to the heavy infestation of invasive zebra mussels.

By September 2011, of the 24 individuals, 11 remained alive and were divided between two cages (i.e., “silos” ) in the Mississippi River in St. Paul, Minnesota and a cage in the St. Croix River near Houlton, Wisconsin, to grow large enough for release. In 2012, nine of these mussels were 6 years old and released into the Mississippi River in St. Paul, Minnesota. Although nine individuals is a small number of winged mapleleaf, the significant knowledge gained in the process and the reintroduction of the species into the Mississippi River were considered a success.

Fast forward to 2014, when an adult winged mapleleaf was found during an Army Corp of Engineers sponsored mussel survey on the St. Croix River near Hudson. Subsequent timed searches resulted in the collection of approximately 380 adult winged mapleleaf, concentrated within a small area. Due to the large number of individuals that were all approximately the same size and in a small concentrated area, the Service and our partners theorized that these mussels were a “happy accident” – surviving winged mapleleaf from the abandoned cages that were thought to have failed several years earlier! It was estimated that there could be 500 individuals or more present at that location!

To investigate whether these sub-adult winged mapleleaf were indeed the progeny of two female winged mapleleaf collected from the St. Croix River near Interstate State Park in 2004, 50 randomly selected individuals at Hudson were swabbed for genetic analysis in 2015. Each of the sampled individuals was measured, tagged, photographed and released back on site. The estimation of relatedness between the sub-sample of mussels from Hudson confirmed the theory and indicated that the 50 individuals comprised 22 family groups of full siblings, and 26 of the 50 had the same mother. The theory was confirmed - the winged mapleleaf found in 2014 were from the cage substrate which was released at the downstream cages in 2006, but were too small to observe at the time.

Dr. Kevin Roe, the Iowa State University geneticist who conducted the analyses, suggested that it would be okay to found new populations with the Hudson mussels, but that subsequent genetic material (i.e., new individuals added to the populations in the future) should be as unrelated as possible. So, an inter-agency team developed site reintroduction plans in early 2016, with the intention of dividing the Hudson population for release into three reintroduction areas – the Mississippi River at Hidden Falls, the Chippewa River in Wisconsin, and the remaining will remain in the St. Croix River near Hudson, Wisconsin. The plan was to randomly allocate winged mapleleaf into defined grids parallel to the current where mussel and habitat data indicate a high likelihood of survival and where the mussels could be easily monitored.

On June 30 and July 1st 2016, the Service’s Twin Cities Field Office led biologists from several partnering agencies in an effort to capture, tag and release the Hudson winged mapleleaf. SCUBA divers from Minnesota Department of Natural Resources, National Park Service and the Minnesota Zoo retrieved 636 winged mapleleaf at the site! Before releasing the winged mapleleaf in their respective reintroduction area, each individual was marked with a unique identifier – a shellfish tag and a passively integrated transponder (PIT) tag. Every one of the 28 people on site pitched in to ensure that the effort was a success – those present included representatives from the Genoa National Fish Hatchery, Twin Cities Field Office, Minnesota DNR, Wisconsin DNR, National Park Service, Army Corps of Engineers, the Minnesota Zoo, The Nature Conservancy, St. Croix River Association, University of Minnesota and others. Double tagging 636 mussels was a huge effort!

On July 1st, approximately one-third of the newly tagged winged mapleleaf were released into the Mississippi River at Hidden Falls and one-third of them were re-distributed at the Hudson site. The remaining one-third, destined for the Chippewa River in Wisconsin, will be held in quarantine for at least 30 days at the MN DNR’s Lake City mussel propagation facility, to eliminate the risk of spreading zebra mussels. Monitoring of the survival of these mussels will begin in 2017 and each of these three populations will be supplemented with new individuals to help ensure the genetic and demographic health.

Sometimes a pleasant surprise occurs without being planned. This is one of those times. The Service and our partners are grateful for this happy accident that gave us a giant boost towards the recovery of the winged mapleleaf mussel!


Contact Info: Tamara Smith, 612-725-3548 (x2219), tamara_smith@fws.gov
Find a Field Notes Entry

Search by keyword

Search by State




Search by Region


US Fish and Wildlife Service footer