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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Conservation Ecology 1
Spatial and temporal dynamics in cercarial abundance of an exotic gill parasite in Comal Springs, Texas and co-occurrence and infection relationships with its exotic gastropod intermediate host and native fishes in springs of west Texas.
T.L. Arsuffi1, V. Cantu1, K. McDermott1, and T.M. Brandt2. 1Aquatic Station-Biology, Texas State University, San Marcos, TX, 78666, 2USFWS, National Fish Hatchery and Technology Center, San Marcos, TX 78666
Up to 46% of species federally listed as endangered are negatively impacted by invasive species. The Asian digenetic trematode, Centrosomus formosanus, is a recent U.S. invader and is a non-discriminating parasite of fishes as second intermediate hosts and may pose a threat to endangered fishes and sports fish. Here, we examine spatio-temporal variation in cercarial abundance patterns of C. formosanus in Comal Springs and distribution and co-occurrence with its exotic snail intermediate host (Melanoides tuberculata), and fish infection relationships in 9 spring systems throughout west Texas. Three springs had the exotic trematode and gastropod and all fish species collected from these springs were infected. Diamond Y Spring had M. tuberculata, but not C. formosanus. Fish infected were as high as 100% for 9 of 10 fish species. Cercaria collected quarterly from river water, and in caged and resident fountain darters from 8 different sites of the Comal River showed spatio-temporal variation associated with heterogeneity of current velocities, water volume, photoperiod, and recruitment processes initiated by definitive host concentrations. Cercariometry was a stronger predictor of infections in caged fish than in resident fish. Control and management considerations should focus on ecological relationships between the parasite and its definitive snail host.
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