Multiple biomarker approach in the fiddler crab to assess anthropogenic pollution in tropical coastal environments

Context: Fiddler crabs are important to the ecology of estuarine systems around the world, however, few studies have incorporated them as bioindicators. Urias estuary represents one of the most urbanized lagoons in the Gulf of California region and received discharges from different sources: shrimp farm, thermoelectric plant, fish processing plants, and untreated domestic and sewage wastes.

Objective: Assess the effects on anthropogenic contamination on female fiddler crabs reproduction, survival and genetic stability.

Methods: Exposition of wild crabs from a less impacted (reference) site to naturally contaminated sediments on under controlled laboratory conditions. Reproductive parameters, levels of DNA damage and mortality rates were measured, together with chemical analyses of sediments.

Results: The most contaminated sediments corresponded to the site where fish processing plants were located and the integrated biomarker response analysis revealed that the most adverse effects were produced by exposure to sediments from this site; these crabs showed higher mortality (67%) and poorer ovarian development than those crabs exposed to sediments from other sites.

Conclusions: Female crabs under pollution stress are able to trade-off reproduction for survival, and surviving animals were able to restore genetic stability possibly by activating DNA repair mechanisms. Multiple biomarker approach discriminates different coastal contamination scenarios.