Exposure to either of the aliphatic hydrocarbons used in this study did not significantly effect total oyster growth. Organic contaminants are known to adversely affect bivalve molluscs in a variety of ways including reduced feeding (Widdows et al. 1990),induction of stress proteins (Cruz-Rodriguez & Chu 2002), inhibition of oogenesis (Chu et al. 2000) and increased respiration(Widdows et al. 1990). However, most of these studies involve either haloginated hydrocarbons, such as polychlorinated biphenyls(PCB), or polycyclic aromatic hydrocarbons (PAH), with very little toxicological information regarding aliphatic hydrocarbons available. The results from this study indicate that dissolved concentrations of aliphatic hydrocarbons in the high ng L−1 range do not impact total growth of P. imbricata.