La Rochelle, France (7 jours/7)

Causes of strandings

More and more anthropogenic causes

The causes of mortality of stranded animals are multiple. A distinction is made between those of natural and man-made origin.

Natural causes

Natural mortality

The stranded dolphins were old, very young or pregnant females.

Viral pathologies

Death is caused by a virus, bacteria or parasites.


The animal was attacked by a predator.

Inter or intra specific competition

The animals fought and their fight resulted in death.

Anthropogenic (man-made) causes


Incidental catches by fishing gear are the main causes of marine mammal mortality.

Less ressources

Overfishing is starving sea birds. Fishing discards are a less energetic food.

Ship Strikes

The intensification of maritime traffic is causing deadly collisions with large marine mammals.


Oil spills, micro-plastics, chronic chemicals, noise pollution, the degraded marine environment affects their survival.

Global changes

Global warming is changing ocean productivity and species ranges. Marine food chains are changing, affecting marine mammals. .

Variations in oceanographic conditions

El Nino, for example, in the Pacific, is a climatic phenomenon produced by oceanic and atmospheric deregulation, resulting in a rise in water surface temperature.