La Rochelle, France (7 jours/7)

Autopsy session at the Pelagis observatory

Thierry JAUNIAUX (University of Liège), Sophie LABRUT (LABOCEA) and Benjamin GUICHARD (French Office for Biodiversity), joined the PELAGIS Observatory team on 22, 23 and 24 February in order to carry out autopsies on 18 marine mammals, including 17 cetaceans (13 common dolphins, 2 blue and white dolphins, 1 bottlenose dolphin and 1 harbour porpoise) and 1 grey seal. These individuals underwent external and internal level 4 lesion examinations. Level 4 corresponds to autopsies and veterinary diagnoses with a sampling protocol of 3, i.e. protocol 2 + additional samples that are not yet standardised.

The objective of this workshop was to test the external and internal examination methodologies developed by the PELAGIS Observatory in order to determine the main causes of mortality. Thirteen of these animals were recovered from the field in early 2021, 4 were from 2020 and 1 was from 2019. Those from 2021 were part of a multiple stranding event in which almost all the individuals showed traces of external accidental capture. Since 1 January, hundreds of small cetaceans, mostly common dolphins, have stranded on the Atlantic coast. The largest numbers have been found in the Vendée. One of the objectives of these autopsies was to confirm the cause of death of these animals bearing traces of capture in fishing gear.

The discussions that took place before and during the workshop made it possible to improve the document compiling the internal examination sheets produced by Rebecca Laporte during her thesis in 2018. This document will be distributed after training to the correspondents authorised to carry out these internal examinations.

This autopsy session is the first in a series that is intended to be recurrent. The ultimate objective is to take advantage of the skills of the network’s veterinarians in order to carry out the most complete examination possible of around one hundred individuals per year. The level 4 examination thus carried out and standardised should make it possible to identify the main causes of mortality in marine mammal populations.