| EFFECTS OF DIFFERENT CONCENTRATIONS OF CRUDE OIL ON METAMORPHOSIS LARVAE OF HALIBUT (HIPPOGLOSSUS HIPPOGLOSSUS) AND NEWLY HATCHED TURBOT (SCOPHTHALMUS MAXIMUS) LAVAE. |
| INGVARSDOTTIR, A.1, IRIS Biomilj, Postboks 8046, 4068 Stavanger, Norway. ain@iris.no; Ravagnan, E1., Nilsen, M1., Arnberg, M1.,Lucas, C1., Beyer, J1., Sanni, S1,2.1, International Research Institute of Stavanger, IRIS Biomilj, Postboks 8046, 4068 Stavanger, Norway; 2University of Stavanger, Faculty of Science and Technology, N-4036, Stavanger, Norway |
| Studies have shown that exposure to Polycyclic Aromatic Hydrocarbons (PAHs) and other oil related components alter normal fish larvae development and can cause increased mortality in early life stages. Modelling of results from controlled laboratory exposure experiments will help relate typical oil exposure parameters (biomarkers) to field observations and are valuable tools for oil exposure monitoring and risk assessment. Metamorphosis larval stages of halibut were exposed to different concentrations of dispersed Arctic crude oil. The selected nominal concentrations were 0.015, 0.060, 0.250 and 0.750 mg l-1 and control seawater in flow through systems. The larvae were exposed for 28 days. The selected endpoints were mortality, body burden of PAHs in tissue and growth. Yolk sack larvae of turbot were exposed to nominal concentrations of 0.010, 0.04, 0.120, 0.360 and 0.720 mg L-1 raw dispersed oil and control seawater for 3 days and the selected endpoint was mortality. Daily mortality was recorded in all treatments in both experiments.
Similar mortality was seen in all treatments for halibut metamorphosis larvae, until day 15, when a general trend for higher mortality of halibut larvae in the oil exposure concentrations than in the control was recorded. After 28 days of exposure the mortality in the exposed groups of larvae was slightly higher for the 0.015, 0.06 and the 0.250 mg l-1 concentrations or 6-10 % higher than in the control. There was however only significant difference in mortality between the control and 0.750 mg/L oil exposed group after 28 days of exposure. Further there was a statistical difference between the lower oil concentrations and the 0.750 mg/L oil exposed group. The growth of halibut metamorphosis larvae did not seem to be affected by 4 weeks exposure to any of the exposure concentrations of the dispersed oil.
Analyses of tissue PAHs by means of GC-MS confirmed a dose-dependent accumulation of oil in exposed specimens. We conclude that for halibut larvae, 0.750 mg/L (5.53 g/L PAH) is the 28 day LOEC and 0.250 mg/L (2.43 g/L PAH) NOEC for the oil tested.
The results from the turbot experiment are being analysed and will be presented.
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