Monday, June 4, 2007 - 2:00 PM
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Life History and Secondary Production of Goniobasis proxima (Prosobranchia: Pleuroceridae) from Four Appalachian Headwater Streams in Western North Carolina

Nicholas Jeremiah, MS, Student, Biological Sciences, Virginia Polytechnic and State University, 250 Sheliah Court, Blacksburg, VA 24060

The objective of this study was to investigate the life history and secondary production of Goniobasis proxima, an Appalachian stream dwelling snail. We measured snail density and size, algal biomass and physical and chemical stream variables monthly for one year. An instantaneous growth rate was measured in a lab colony and applied to field data to estimate production. Results indicate these snail populations have no appreciable grazing effect on the algal community, display seasonal variation in abundance we suspect to be temperature driven, and prefer rock and allochthonous material as a substrate over depositional. Secondary production was low compared to some aquatic insect species, ranging from 39 mg m-2 y-1 to 540 mg m-2 y-1 with turnover rates of 0.025 y-1. These low turnover rates indicate long development times which coincides with our data suggesting these snails can live close to 10 years. Production may be limited due to physical barriers preventing snail migration upstream, low quality and quantity of food sources, and low calcium concentrations.