| Abstract: | Pacific herring (Clupea harengus pallasi) larvae were exposed either directly to the water-soluble fraction (WSF) of crude oil or indirectly via oil-contaminated prey (OCP) (Artemia salina) for <- 28 days, to determine the relative effects of diet and water as routes of contamination. Larvae were affected rapidly by 0·9 ppm WSF, which caused high larval mortality, reduced swimming ability and rapid reductions in feeding rates. Larval length was significantly reduced by 0·7 ppm WSF in 7 days and by 0·3 ppm WSF within 14 days. The WSF exposure also caused similar reductions in larval weights. Highly contaminated prey (6 ppm prey exposure) caused significant mortality, but surviving larvae appeared robust. The OCP did not affect swimming, feeding, or growth. Exposure of larvae was not significantly extended by OCP, which rapidly depurated WSF in clean water (98% in 1 day). Therefore, OCP is probably not an important source of low molecular weight petroleum contamination to larval fish in the marine environment. |
