Pathological findings and causes of death of Angelshark (Squatina squatina) in Canary Islands

Abstract

The Canary Islands are a very important cradle of marine biodiversity. The Angelshark (Squatina squatina) is a species of elasmobranch that uses the coasts of the Canary Islands as its habitat, since its population in other places has decreased significantly. The main objective is to know the epidemiology and pathologies related to the causes of death of Angelsharks stranded in the Canary Islands between 2021 and 2024. In order to carry out this final project, we used a database from “Red Vigía” of the Gobierno de Canarias” and Institute of Animal Heath and Food Safety of the University de Las Palmas de Gran Canaria, that collected the parameters and pathological results obtained from the necropsies performed on 47 individuals of Angelsharks between February 2021 and April 2024. Between February 2021 and April 2024, we received 47 carcasses of Angelsharks that appeared off the coast of the Canary Islands. A complete standardized necropsy was performed on each specimen to identify injuries and to make a final diagnosis of the cause of death. Of these, 5/47 (10.64%) Angelsharks had injuries related to anthropogenic activities, such as fishing interactions or boat trauma. Non-anthropogenic causes are referred to as "natural death" and were diagnosed in 8/47 (17.02%) Angelsharks and were associated with infectious processes, noninfectious pathologies and interspecific interactions. The causes of death could not be diagnosed in 34/47 (72.3%) of the animals subjected to necropsies. This work compiles for the first time all available information on Angelshark strandings in the Canary Islands from 2021 to April 2024 and try to provide future guidelines to understand the causes of the stranding of these elasmobranch species.