Reproductive Seasons and Life Histories of Three Texas Percina (actinopterygii)
Date
2010-05
Authors
Folb, Clara E.
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Abstract
Reproductive seasons of fishes in temperate regions are influenced by water temperature and, to a lesser extent, photoperiod, corresponding in theory to adaptive benefits of producing young during periods of adults and juvenile food availability, times of minimal predation of eggs and young, and availability of breeding sites. Often, phylogenetic constraints or inertia of reproductive timing obscure contemporary environmental influences on reproductive seasonality. In this study, reproductive seasons of three closely-related percinid fishes of central Texas were determined by gonadosomatic indices (GSI), ovarian stages, and oocyte diameters to test the effects of water temperature, photoperiod, river discharge, and food availability on seasonal and aseasonal reproduction. The three percinid species inhabit different stream environments, ranging from highly stable spring systems to variable run-off dominated systems. Additional life history parameters, such as age of sexual maturity, population structure, and age-group growth rates, were quantified to provide basic information for conservation efforts. Reproductive seasons ranged from five months in the river darter Percina shumardi, which inhabits abiotically variable, run-off dominated reaches of the lower Guadalupe River, to nine months in the endemic Guadalupe darter Percina apristis, which generally inhabits the abiotically stable reaches of the San Marcos River. Regionally endemic Texas logperch Percina carbonaria, which inhabits moderately variable systems within Central Texas, had a reproductive season of six months. Pooled GSis among all three species were inversely related to water temperature (P = <0.001) and photoperiod (P = 0.013). Relationships were not detected between GSis and river discharge or adult food availability. Though reproductive seasons and habitats differed among the three percinids, reproduction, as measured by presences of mature ovaries, ceased at water temperatures near 23°C. The start of reproductive quiescence at or near 23°C is reported for Percina throughout their North American distribution, suggesting that ancestral condition influences contemporary reproductive seasons versus an alternative hypothesis that predicts aseasonal reproduction in abiotically stable systems is a derived trait (i.e., spring-adapted).
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Keywords
Percidae, fishes reproduction, Fish development, life cycles, freshwater fishes
Citation
Folb, C. E. (2010). Reproductive seasons and life histories of three Texas Percina (actinopterygii) (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.