1. Effects of Prestige fuel oil ingestion on growth of juvenile turbot (Scophtalmus maximus) Rosario Domínguez Petit Instituto de Investigaciones Marinas, Vigo Rosario Domínguez Petit Instituto de Investigaciones Marinas, Vigo

2. INTRODUCTION Prestige heavy fuel oil was poor in volatile and soluble components  low degradation rates (Albaigés & Bayona, 2003). Models prediction (Gin et al, 2001) surface water time Sea bed sediments Contamination of prey resources Contamination of gills and skin Degradation of natural environments

3. MATERIAL & METHODS 202 juvenile turbot (Scophtalmus maximus) from commercial hatchery One week before starting the experiment Weight(0.01 g) Total length (1mm; 90 mm aprox.) Tagged (codified soft VI alfa tags) Condition Factor (K = 100*W/L 3 )

4. MATERIAL & METHODS TANKS Capacity of 250 l 2 l/h filtered seawater 18º C 12L:12D photoperiod FOOD 15.01 ± 0.02 g/day 3 times/day Excess food was removed daily 0 mg/g n = 33 2.4 mg/g n = 32 5.6 mg/g n = 34 16 mg/g n = 33 29.5 mg/g n = 35 48.2 mg/g n = 35 CONTROL

5. MATERIAL & METHODS Fuel Dissolved fuel Mixed Dried Pellets + Fuel (4ºC) dichloromethane pellets Rotary evaporator 1 h 50º C dichloromethane Food preparation

6. RESULTS ANOVA: Difference between mean length within treatment at the beginning and at the end of the experiment.

7. RESULTS ANOVA: Difference between mean weight within treatment at the beginning and at the end of the experiment.

8. RESULTS Relationship between weight increment and initial weight in each specimen for each treatment.

9. Relationship between length increment and initial length in each specimen for each treatment. RESULTS

10. Length-weight relationships (main panel) and mean K (upper panel) for each treatment at the end of the experiment. Error bars = Mean ± 2*SE Relationship between mean growth rate and oil concentration. Error bars = Mean ± 2*SE

11. BACKGROUNDS - Crude oil components inhibit growth of several fish species, specially at earlier life stages as a result of ingestion of oil contaminated food (Schwartz 1985; Mortensen & Carls 1994; Carls et al. 1996). - Reduction of feeding rate with increasing of oil concentration has been observed in other species (Schwartz 1985; Omeregie & Ufodike 2000) - Reduction of energy assimilation can be derived from alteration in fish metabolism after assimilation of some oil components (Moles & Norcross 1997) - Effects provoked by oil ingestion may remain well after the oil is no longer present, including any effect on feeding behaviour (Schwartz 1985; Heintz et al. 2000) - Juvenile flatfishes do not avoid areas polluted with oil at low concentrations (Moles at al. 1994) - Reduced growth may impact on the recruitment strength and the population dynamics, including maturation process (Heintz et al. 2000)

12. CONCLUSIONS - Significant differences in somatic growth have been detected after 40 days providing fish with contaminated food within a range of oil concentration. - At the end of the experiment, differences in growth performance could be explained because of the considerably mean fish body size differences between treatements (small fish fed at low rate). - The growth reductions are probably the result of the reduction in feeding activity combined with a major reduction in the ability for food energy conversion. - Care should be used in extrapolating these results to the field. While some of the concentrations used in this study are likely to be found after oil spill, others may be considered too high, although, there are a general lack of data about some oil components accumulation trough the food web.

13. Thank you very much