The main objective is to study the sensitivity of the wolfish larvae/juveniles to crude oil and to compare the biological effect of mechanically dispersed versus chemically dispersed oil using sub lethal end points. In order to identify the toxicity of ch emically dispersed oil, we need to also evaluate the toxicity of mechanically dispersed oil (which represents the scenario of oil only and stormy weather), and the toxicity of water soluble fraction (scenario of oil and calm sea). Therefore a total of fou r treatments will be performed: 1) control (seawater) 2) water soluble fraction (oil on top of water with no agitation) 3) mechanically dispersed (oil only mixed thoroughly in the water) and 4) chemically dispersed (dispersant, oil and thorough agitation in the water). The set up that will be used to expose the fish has been designed and thoroughly used by the CEDRE institute (France). Exposure time of 48hr and oil doses of 20g for 300 L tank. 14 fish of same age (1 year) and size bought from an aquacultu re farm in Tromsø will be exposed for each treatment (total of 56 fish in total). Then 7 fish from each group will be sampled after 48hr and the remaining fish will be kept for one week in clean seawater to measure the recovery rate of the end points. The work will be performed at the Barents Ecotox laboratory owned by Akvaplan.niva and designed to carry out such experiment. All experiments will be carried out according to the Animal Protection Act of the Forsøksdyrutvalget regulations in Norway.