The U.S. Fish and Wildlife Service has released the draft revised recovery plan for the Higgins eye pearlymussel for public review and comment. The plan, when finalized, will guide state and federal agencies in their efforts to conserve this species. Higgins eye, listed as an endangered species in 1976, is a freshwater mussel native to the Upper Mississippi River and its major tributaries.
A team of state, federal and academic biologists completed the draft plan. When finalized, it will supersede the species original 1983 recovery plan. The revised plan applies significant new scientific information to the conservation of the Higgins eye and addresses factors that have become important to the conservation of Higgins eye since 1983. Most notably, the revised plan assesses the effects of the Mississippi River flood of 1993 and addresses the invasion of the Upper Mississippi River by zebra mussels.
Zebra mussels, which invaded the Upper Mississippi River in the early 1990s, are a profound threat to Higgins eye that the Service did not anticipate in its 1983 recovery plan. Zebra mussels, which are native to Eastern Europe, frequently exhibit rapid population growth and affix themselves to native mussels and other firm, stable substrates. Masses of live and dead zebra mussels frequently smother beds of native mussels that contain Higgins’ eye. Higgins’ eye and other native mussels covered by these masses are likely to die or become incapable of reproducing. Zebra mussels may also compete with Higgins eye for food -- both filter small food particles, such as plankton, from the water column. During the 1990s, zebra mussels devastated what may have been the largest population of Higgins eye, in the Mississippi River near Prairie du Chien, Wis.
Higgins eye pearlymussel prefers river bottoms that are relatively stable and primarily composed of sand or gravel. Between 1890 and 1920, it was one of many species heavily harvested for its shell to make mother-of-pearl buttons and pins. Higgins eye pearlymussels face several threats. In addition to the severe threat currently posed by zebra mussels, the Higgins eye faces degradation of its large river habitats caused by the operation and maintenance of the navigation system on the Upper Mississippi River.
Localized impacts of construction projects also threaten Higgins eye populations. Adverse impacts to water quality, environmental contaminants from both point and non-point sources, and commercial harvest of native mussels may also threaten the species.
The revised recovery plan outlines numerous measures to recover Higgins eye. They include assessing and limiting the impact of zebra mussels, limiting construction in essential habitat areas, developing plans to enhance the safety of shipping toxic or hazardous materials, reintroducing Higgins eye into historic habitats where zebra mussels are not an active or imminent threat, and identifying any contaminants that may affect the survival of Higgins eye populations.
The revised plan may be obtained from the Services website, in PDF format, at http://midwest.fws.gov/endangered/ For more information, or for assistance in obtaining a copy of the draft plan, contact Phil Delphey, U.S. Fish and Wildlife Service, Twin Cities Field Office, 4101 East 80th Street, Bloomington, Minn., 55425-1665; telephone 612-725-3548, extension 206 (email: phil_delphey@fws.gov). TTY users may contact Mr. Delphey through the Federal Relay Service at 1-800-877-8339. The Service will collect written public comments on the plan for the next 60 days. Comments should be submitted to Field Supervisor at the above address or by email to phil_delphey@fws.gov and must be received by October 14, 2003. The final recovery plan for the Higgins’ eye pearlymussel will be prepared once the Service has considered the comments received on the draft plan.
The U.S. Fish and Wildlife Service is the principal federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 95-million-acre National Wildlife Refuge System, which encompasses 540 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 69 national fish hatcheries, 64 fishery resource offices and 81 ecological services field stations. The agency enforces federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.
