Juvenile Oblada melanura (L. 1758) otolith shape is impacted near recreational harbours or due to settlement position in nearby sites

Abstract

The coastal zone is a hotspot of biodiversity and anthropogenic activities. Its conservation is of major concern. To test whether different types of environmental disturbance have an impact on marine fishes, in this three-year study we have compared otolith shapes of Oblada melanura juveniles. One type of disturbance was the type of site: recreational harbours, waterway mouths, or preserved from identified sources of contamination. Another disturbance comes from the geographical zones mainly presenting different levels of population density. We have demonstrated that zones only separated by 20 km have an impact, and that, comparatively to preserved sites, waterway mouths do not impact fish otolith shape in contrast to mid-size recreational harbours. We highlighted that a minimum recreational harbour size may be needed to impact the marine environment. The present work opens up new perspectives for surveys of the impact on marine life of regulation policies and changes in human behaviour.