Assessment of the use of Oblada melanura (L. 1758) otolith fluctuating asymmetry as environmental disturbance indicator.

Human impact on the environment is of widespread concern. The majority of anthropogenic impacts are centred on coastal ecosystems, so surveying them is an important step in the protection of the marine environment. We have tested Oblada melanura (L. 1758) otoliths' fluctuating asymmetry as a bioindicator in a Mediterranean coastal zone. The French Riviera is characterised by a summer population increase leading in particular to more yachting, and seasonal climatic changes with reduced, more concentrated waterway flows and storm events causing soil erosion. The present three-year study compares nine sites, situated in three zones, and characterised by three types of chemical pollutant states (low; waterway mouth; recreational harbour). For O. melanura juveniles, we have not shown any significant difference in the otoliths' fluctuating symmetry between zones or types of sites. We hypothesize that high stress levels are needed to induce significant fluctuating asymmetry variation.