Fiddler Crabs (Uca pugilator) as Bioindicators of Environmental Health in Coastal Estuarine Communities of Beaufort, South Carolina

Historically, coastal environmental health primarily has been analyzed through direct measurements of water, sediment, and contaminant residues in animal tissue. However, there is much evidence that certain species may serve as bioindicators, the ecological and morphological properties of which can predict the level of anthropogenic impact. The purpose of this study was to test the feasibility of utilizing the sand fiddler crab Uca pugilator as a bioindicator of anthropogenic impact. Three 30 m sq. sites (each divided into three subsites) were selected in Beaufort, South Carolina, as examples of different types and levels of human impact (a relatively unimpacted reference site, a municipal site receiving sewage effluent, and a golf course site receiving fertilizer and pesticides). Crabs (n = 1164) were assessed for carapace width, dominant to subordinate claw ratio (males only), and population density. Mating behavior was also observed. Carapace width was significantly reduced in the golf course crabs (p \u3c 0.001), and population densities were significantly greater at both affected sites compared to the reference site (p \u3c 0.001). Claw size ratios were significantly influenced by site, day, and the interaction of site and day (p = 0.005, 0.008, and 0.002 respectively), but there was no clear pattern in these influences. Reproductive behavior was increased in crabs at the golf course site. Due to limitations, this study suffers from pseudoreplication. However, this study demonstrates economical, noninvasive approaches to evaluate estuarine wellbeing