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.
The stranded dolphins were old, very young or pregnant females.
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
The intensification of maritime traffic is causing deadly collisions with large marine mammals.
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.