Sub-lethal effects of exposure of juvenile turbot to oil produced water

Exposure of similar to 50-day-old turbot (Scophthalmus maximus) to 0.001-1% produced mater (PW) from a North Sea oil platform for up to six weeks did not affect their survival, Overall, the results indicate that impacts of th is PW on young turbot are likely to be limited to an area close to its disc harge to surface waters. Sub-lethal physiological stress was evident (eleva ted whole body cortisol) only after six weeks in 0.1% or 1% PW, In these fi sh and those exposed to 1% PW for three weeks similar to 50% gill lamellae were fused at their tips and as a result respiratory and/or ionoregulatory processes were likely to be impaired. Decreased oxygen uptake or the narcot ic effects of aromatic hydrocarbons may account for the reduced swimming ac tivity of 1% PW-exposed fish. However, in 0.001% PW, fish increased swimmin g activity which may partially account for their depressed growth. Whole bo dy ethoxyresorufin O-deethylase (EROD) activity was elevated only after one or six week's exposure to 1% PW, not in all groups with hydrocarbon accumu lation. (C) 2000 Elsevier Science Ltd. AU rights reserved.