Population characteristics and habitat of muskrats on Pool Nine of the Upper Mississippi River / Robert T. Clay.
Material type:
TextSeries: Thesis ; (M.S.)Publication details: Ames, Iowa : Iowa State University, 1983.Description: vi, 73 leaves ; 28 cmOnline resources: Abstract: Backwater and openwater habitats in Pool Nine of the Upper Mississippi River were studied to determine muskrat (Ondatra zibethicus) population density, natality, survival and exploitation rates. Density in backwater habitats ranged from 0.3 to 3.7 +- 0.7 adults/ha which was lower than openwater densities which ranged from 1.0 +- 0.1 to 9.3 +- 1.3 adults/ha. Litter sizes (7.0 +- 0.2 young/litter) and number of litters (1.5 to 2.0 litters/female/year) were similar in each habitat. Monthly adult breeding-season rates (from March to October) in openwater habitats were 0.86 +- 0.6 in 1981 and 0.82 in 1982. Monthly survival rates (from May to October) for juveniles throughout Pool Nine were 0.80 in 1981 and 0.87 in 1982. The monthly overwinter survival rate (from October to March) in both habitats were 0.81 +- 0.04. Harvest rate was 0.79 during the 1981-1982 trapping season; however, rates of 0.92 were observed in openwater habitats compared with rates of 0.47 in backwaters. Lower backwater
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Thesis(M.S.)--Iowa State University, 1983.
Includes bibliographical references.
Backwater and openwater habitats in Pool Nine of the Upper Mississippi River were studied to determine muskrat (Ondatra zibethicus) population density, natality, survival and exploitation rates. Density in backwater habitats ranged from 0.3 to 3.7 +- 0.7 adults/ha which was lower than openwater densities which ranged from 1.0 +- 0.1 to 9.3 +- 1.3 adults/ha. Litter sizes (7.0 +- 0.2 young/litter) and number of litters (1.5 to 2.0 litters/female/year) were similar in each habitat. Monthly adult breeding-season rates (from March to October) in openwater habitats were 0.86 +- 0.6 in 1981 and 0.82 in 1982. Monthly survival rates (from May to October) for juveniles throughout Pool Nine were 0.80 in 1981 and 0.87 in 1982. The monthly overwinter survival rate (from October to March) in both habitats were 0.81 +- 0.04. Harvest rate was 0.79 during the 1981-1982 trapping season; however, rates of 0.92 were observed in openwater habitats compared with rates of 0.47 in backwaters. Lower backwater