La Rochelle, France
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Stranding monitoring

A collaborative science programme

The monitoring of marine mammal strandings is the main environmental observatory for monitoring marine mammals in France and is largely based on the concept of participatory science. This monitoring is mainly carried out by volunteer correspondents from the Réseau National Échouages (RNE).

Marine mammal strandings are the main source of biological sampling for these species. The samples collected by RNE are the source of much of the knowledge on the biology and ecology of marine mammals in France. The main parameters monitored provide information on population structure (genetics, age structure, reproductive status, etc.), feeding ecology (stomach contents, metallic and isotopic tracers, etc.) and health status (causes of mortality, contaminant content, exposure to pathogens, etc.).

Results

Based on these data, it is now possible to produce indicators of relative abundance, distribution, health status or to assess the areas and causes of mortality of marine mammals, which is often a real challenge for long-lived, mobile top predators living in habitats that are difficult to access.

The continuous collection of strandings for more than 40 years on the French coastline now makes it possible to obtain long time series that make it possible to monitor trends in stranding rates and to highlight unusual events.

The most striking examples of the last 20 years are the sudden increase in harbour porpoise strandings on the Channel and Atlantic coasts and the phenomenon of stranding peaks observed in common dolphins in the Atlantic.

Causes of strandingsPublicationsVisualize the data