Records of the critically endangered Squatina aculeata and Squatina oculata (Elasmobranchii: Squatiniformes: Squatinidae) from the Mediterranean Sea

Abstract

All three species of angelsharks that inhabit the Mediterranean Sea, Squatina aculeata Cuvier, 1829; Squatina oculata Bonaparte, 1840; and Squatina squatina (Linnaeus, 1758), are classified as Critically Endangered on the IUCN Red List of Threatened Species, since their populations have suffered severe decline and range reduction, mainly due to fishing pressure. The presently reported study aims to further update records of S. aculeata and S. oculata in the basin in order to achieve a clearer picture of their current status and geographical distribution. In this way, we were able to add a contribution to our knowledge about their biological characteristics. Records on the incidental capture and observation of specimens of S. aculeata and S. oculata between 2005 and 2022 were collected through the input of alerted professional fishermen, fisher amateurs, and specialist observers on fishery landings or on board in the context of specific surveying programs as well as of citizens’ science initiatives. Biological characters such as total length, total weight, sex, and maturity were determined whenever possible. A total of 18 S. aculeata and 34 S. oculata specimens were recorded. Data corroborate the current occurrence, which is almost rare, of these two Critically Endangered elasmobranchs from the central to the east part of the basin, revealing furthermore the presence of S. aculeata in Sardinian waters, in the western part of the basin. Data document the important habitats for both species existing in the Strait of Sicily, especially in the area around Malta, and confirm the occurrence of S. aculeata in the southern Aegean Sea. The current presence of both species is also established in Mediterranean Egyptian waters. Our study suggests the urgent need for a wider application and/or reinforcement of existing protection measures for these angelshark species and their habitat, including populations of the southern Mediterranean waters.