What are the major causes of mortality in the Western Mediterranean cetaceans?
Most species of Mediterranean cetaceans are in population decline, being classified from “Vulnerable” to “Critically Endangered” according to the International Union for Conservation of Nature (IUCN). This study lists the main causes of cetaceans strandings and deaths in the Catalonia coasts (Western Mediterranean Sea), during the period of 2012 to 2019.
Stenella coeruleoalba cerebellum affected by necrotizing granulomatous encephalitis, as a result of morbilivirus infection.
Stenella coeruleoalba intestine (colon-rectum) opened longitudinally, showing prominent nodular scolexes of Strobilocephalus triangularis .
After necropsies, up to 89 cetacean individuals (72 of,whom were listed dolphins, Stenella coeruleoalba), it is concluded that the main causes are:
- Fisheries interactions.
- Collisions with ships (especially in large cetaceans such as the fin whale, Balaenoptera physalus).
- Maternal separation, with the consequent death by starvation (in neonates and calves).
- Serious infections (Cetacean morbilivirus, CeMV) and parasitic diseases (brucellosis, by Brucella ceti; sinusitis, by Crassicauda grampicola).
Reference: Cuvertoret-Sanz M, López-Figueroa C, O’Byrne A, Canturri A and others (2020) Causes of cetacean stranding and death on the Catalonian coast (western Mediterranean Sea), 2012-2019. Dis Aquat Org 142:239-253. https://doi.org/10.3354/dao03550
