Meeting Abstract
Organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), are ubiquitous within aquatic habitats and bind to organic material that can accumulate through food webs. Ecological tracers, such as stable isotopes δ13C and δ15N, are useful to describe the resource use (foraging habitat and trophic position) of an organism within a given ecosystem. Although some previous studies have used stable isotopes to describe ecological sources of exposure to pollutants in fishes, this relationship remains unclear in sharks. Bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead (Sphyrna tiburo) sharks were selected for this analysis to compare sympatric species with different ecological niches from an industrialized basin (Galveston Bay, TX). Tissue-based burdens of 45 individual PAH and PCB congeners, as well as measures of δ13C and δ15N, were quantified in muscle tissue of each species. We hypothesized that PAH and PCB burdens would vary among species as a result of differing isotopic niches and that δ15N would be positively associated with increasing burdens of PCBs. A combination of univariate and multivariate analyses were conducted to discern the potential contributions of foraging habitat and relative trophic position to the accumulation of these pollutants. Patterns of pollutant burdens with isotopic niche were found within and among species.
