European Sea Bass (Dicentrarchus labrax L. 1758) As a Sentinel Species in Europe to Study the Effects of Contaminants

Aim: The current study was designed to evaluate whether European Sea Bass (Dicentrarchus labrax L. 1758) can be used as a sentinel species to test contaminants. For this aim the acute lethality (96 h) of anionic surfactant sodium dodecyl sulfate (SDS) on sea bass juveniles at two different water salinity percentages (20‰ and 5 ‰) were tested in order to assess how the water salinity may affect the sensitivity of the sea bass to SDS. A comparison with results from scientific literature especially freshwater species was also reported.

Study Design: Five different sized fish groups (from 0.068 g to 1.42 g) were assessed in 96-h semi-static tests according to OECD guideline n. 203 (1992). The average 96h-LC50 (plus 95% confidence interval) values were calculated using SDS nominal concentrations.

Results: At a percentage of salinity of 20‰, the 96h-LC50 values increased from 5.76 mg/l to 9.50 mg/l increasing the size of juveniles as well. SDS at a salinity of 5‰, was always found to be significantly less toxic (96h-LC50: from 13.50 mg/l to 14.87 mg/l) independently of fish size.

Conclusion: The results of this study show that the characteristics of D. labrax make this species useful to provide information of toxicity in both seawater and freshwater. Its ease of maintenance and testing under laboratory conditions, and its broad euryhalinity confirm the convenience of use it as a sentinel species for detecting environmental impact and as a rule in monitoring studies. A comparison with other Italian and international data on sea bass is reported.