Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
4th Year of Field Work completed for the National Abnormal Amphibian Monitoring Project
Midwest Region, August 1, 2003
Print Friendly Version
National attention focused on malformed amphibians in 1995 when a group of school children in Minnesota discovered a large number of abnormal and misshapen frogs.

In 1997, based on this and an increasing number of reports of abnormal amphibians, Regions 3 and 5 of the FWS collaborated in developing a methodology for monitoring malformed frogs on national wildlife refuges and wetland management districts. The objectives of the monitoring were to determine whether this phenomenon was occurring on FWS lands, to develop a database that would include land use surrounding FWS amphibian monitoring sites and to contribute to the overall knowledge of the regional and national distribution of the phenomenon. That year, 41 field stations (34 national wildlife refuges and seven wetland management districts) in Region 3 conducted preliminary searches for abnormal frogs.

In 2000, the FWS's Environmental Contaminants Program (currently Environmental Quality Program) received funding as part of the Department of Interior's Amphibian Initiative. The assessments originally done in Regions 3 and 5 (1997) were refined and expanded into a nationwide assessment of more than 43 refuges in 31 states. As of December 2002, 85 refuges in 40 states have been monitored at least once through this project.

This year was the fourth year of field work for this nationwide project in Region 3. To date, Region 3 has sampled frogs at 13 refuges/wetland management districts. Sampling consists of collecting frogs from a minimum of two different sites per refuge and examining the frogs for abnormalities. Each refuge is sampled for at least two years, and most of them three years, depending on the incidence of abnormalities. In 2000, 2001 and 2002, abnormal frogs were sent to the USGS's National Wildlife Health Center in Madison, Wis., for radiograph analysis of the abnormalities. This year, a number of abnormal frogs from five different refuges were sent to the University of Wisconsin at LaCrosse for parasitology analysis. In addition, some frogs from the Fergus Falls WMD were sent to the University of New Hampshire for gonad and histology analysis.

Again this year, the Bloomington Field Office, with assistance from the East Lansing Field Office, coordinated the project for Region 3. Staff, volunteers and interns from each refuge also provided invaluable support. Through this collaborative effort, more than 1,700 amphibians from 10 refuges and wetland management districts were collected and examined this summer.

The refuges visited include: Muscatatuck NWR (IN), Clarence Cannon NWR (MO), Two Rivers NWR (IL), Crab Orchard NWR (IL), Upper Mississippi River NWR, McGregor District (IA), Shiawassee NWR (MI), Horicon NWR (WI), Litchfield WMD (MN), Fergus Falls WMD (MN) and Seney NWR (MI). Most abnormalities encountered were missing digits, feet and limbs. Several animals with atrophied, bent or misshapen limbs were found, and one individual with two extra toes was discovered at Horicon NWR. In addition, almost 50 percent of the green frogs collected from a single pond at Muscatatuck NWR were infested with metacercaria of a trematode called Clinostomum. There was also evidence (possibly the first record in Indiana) of the parasite Ribeiroia, which has been shown to cause developmental abnormalities.

A final report of this season's field work will be completed by the end of the calendar year. A fact sheet developed in March, 2003 by the Division of Environmental Quality in the Washington Office is also available and briefly describes the project and its objectives.

Contact Info: Larry Dean, 612-713-5312, Larry_Dean@fws.gov
Find a Field Notes Entry

Search by keyword

Search by State

Search by Region

US Fish and Wildlife Service footer