The Effects of Diel Water Quality Fluctuations on Reproduction and Growth in the San Marcos Salamander

Abstract

The effects of diel pH fluctuations and upwelling flow on growth and reproduction in the San Marcos Salamander (Eurycea nana) were examined in culture. Paired individuals were measured monthly for growth in length and weight during a 9-month experiment. Seven clutches of eggs resulted, with an average of 34.7 eggs deposited during each reproductive event. The average hatching success for each clutch was 22.9%. One breeding pair reproduced three times during a 5-month period, with a total of 132 eggs deposited and an average hatching success of 35.9%. Egg production in E. nana was not sufficient to determine if any of the pH or upwelling treatments affected reproduction. During the last month of the study, male salamanders with access to upwelling tubes were significantly greater in weight (P < 0.05) than those without access.