Meeting Abstract

4.6  Jan. 4  Population- and family-level variability in toxicity of copper pyrithione to the barnacle, Balanus amphitrite ROMANO, J.*; HOLM, E.; MCCLELLAN-GREEN, P.; RITTSCHOF, D.; Duke University Marine Laboratory; Carderock Division, Naval Surface Warfare Center; North Carolina State University; Duke University Marine Laboratory jar21@duke.edu

Experiments were conducted to assess variation in mortality of the barnacle Balanus amphitrite exposed to the antifouling booster biocide copper pyrithione (CuPT), among and within populations. The first experiment compared the sensitivity of stage II nauplii to CuPT for barnacles from four different sites along the Newport River estuary, NC. Sites were chosen to provide a gradient in levels of industrial and residential pollutants. The lethal concentration to kill 50% of larvae (LC₅₀) was evaluated by exposing larvae to various concentrations of CuPT, dimethylsulfoxide (DMSO, solvent control), and filtered seawater (FSW, negative control). LC₅₀) varied significantly among the four sites, ranging from 4.0 to 6.1 &microg L^-1. In the second experiment, variation within a population of Balanus amphitrite with respect to CuPT sensitivity was examined. Stage II nauplii from fifteen barnacle families were exposed to 6.1 &microg L^-1 CuPT. Mortality varied significantly among the families ranging from 15.0% to 98.9%. This observed variability suggests there may be genetic diversity within and among barnacle populations with respect to tolerance of toxic stress. We discuss several possible mechanisms. The data suggest that extrapolating a general result (for example, a water quality standard) from tests on laboratory populations or particular field populations may result in conclusions that are too liberal or too conservative (as populations vary greatly in their susceptibility). A substantial number of individuals and populations must be sampled in the course of conducting toxicity tests in order to obtain results that are broadly applicable.