The effects of several environmental variables on reproduction and growth of the San Marcos salamander in laboratory culture
Date
1999-05
Authors
Wise, Martn R.
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Abstract
Three 84-d experiments were conducted at the San Marcos National Fish Hatchery and Technology Center on the San Marcos salamanders Eurycea nana in an attempt to isolate factors that may be necessary for reproduction. Because these salamanders often are found in association with spring openings with upwelling water, vegetation, and because they appear to have an unequal sex ratio in the wild, the factors tested were access to a tube with upwelling water, the presence of vegetation,, and different sex ratios. In the upwelling experiment, there was no significant increase in growth measured by length or weight either over time or between treatments. Also, there was no deposition of eggs in the upwelling experiment. In the vegetation experiment, the male salamanders in aquaria with vegetation demonstrated greater mean weight after the first month (P=0.00583), the second month (P=0.00950) and the third month (P=0.01621) and greater mean length after the second month (P=0.01738) and the third month (P=0.01545) than those without vegetation. One deposition of eggs occurred in an aquarium with vegetation. In the sex ratio experiment, the male salamanders in the majority male aquaria had significantly(P=0.00058) higher growth in mean weight over time.
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Keywords
reproduction, brook salamanders, salamanders, water chemistry, vegetation, sex ratio
Citation
Wise, M. R. (1999). The effects of several environmental variables on reproduction and growth of the San Marcos salamander in laboratory culture (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.