Reproduction and Diet of Pseudemys Concinna Inhabiting a Cold Water Reservoir in Southwest Missouri

Date of Graduation

Fall 1995


Master of Science in Biology



Committee Chair

Don Moll


River cooters, Pseudemys concinna, were colleced using fyke nets from two locations, one hypothermic cove (Rockaway Slough) and one normothermic cove (Bull Creek) at Lake Taneycomo, from April 1993 to August 1994. Quantitative and qualitative analyses of adult diets from both sites showed great similarity and primarily consisted of green algae (Spirogyra sp.). Mean annual reproductive potential (ARP) was 56.7 for the cooters inhabiting the hypothermic cove and 38.7 for those in the normothermic site. The mean egg mass index (EMI) was 0.39 for Rockaway cooters and was 0.47 for Bull Creek. The mean relative clutch mass (RCM) was 0.0879 for Rockaway cooters and was 0.09.25 for Bull Creek cooters. Significant differences were found for egg lengths between sites (P<0.001) and for egg mass (P<9.001). The estimated mean clutch sizes for Rockaway and Bull Creek were 21.3 and 18, respectively. Mean clutch frequency was 2.7 clutches per year in the hypothermic cove and 2.15 clutches per year in the normothermic cove. Significant differences were found in the slopes of lines generated by plastral length-ARP regression analysis (P<0.001) and also for the intercepts (P=0.003). Egg mass index, relative clutch mass, egg widths, clutch sizes, and clutch frequencies were not found to be significantly different (P>0.05). Evidence for extra uterine migration was found using counts of corpora lutea and oviductal eggs. Nesting in the hypothermic site appears to be prolonged and delayed when compared to the normothermic site. Sex ratio was 2.13 in Rockaway Slough and 3.11 in Bull Creek. These ratios were significantly different from a 1:1 ratio, but were not significantly different from each other.

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