Artisanal fisher ecological knowledge with morphometric measurements of Angel Sharks form Libya, Central Mediterranean.

Background: Angel sharks (Squatina spp.) in the Mediterranean Sea are critically endangered, and there is a significant knowledge gap regarding their populations in Libyan waters.

Aim: This study aimed to assess the status of Angel sharks in Libyan waters by integrating local ecological knowledge (LEK) from artisanal fishers with novel morphometric data.

Methods: Structured interviews were conducted with 53 artisanal fishers at the Tripoli fishing port (April-May 2022) to gather LEK on Angel shark distribution, abundance, and threats. Morphometric measurements were collected from seven Angel shark specimens that landed during the study period.

Results: Fishers encountered all three Mediterranean Angel shark species (Squatina squatina, Sesbania aculeata, and Squatina oculata) across several Libyan coastal areas (Tripoli, Misurata, Zuwara, Tajoura, and Qarabuli). Annual catch estimates of five or more Angel sharks per fisher were reported, primarily from depths of 10-300 m (mean: 124.02 m). Reported total lengths ranged from 15 to 200 cm, with the majority being between 15 and 100 cm. Trawling (43%), bottom gillnets (36%), and longlines (21%) were the main fishing methods associated with Angel shark captures. A significant positive correlation was found between distance from the coast and fishing depth (Spearman's r_s = 0.69, p < 0.001). Morphometric data included: S. squatina (n = 3; TL: 46-80 cm; weight: 884.0-6395.0 g), S. aculeata (n = 1; TL: 66 cm; weight: 1,884.0 g), and S. oculata (n = 3; TL: 44-52 cm; weight: 634.0-959.0 g). Fishers identified marine pollution, overfishing, illegal fishing practices, and inadequate enforcement as major threats to the Angel shark population.

Conclusion: This study provides critical baseline information on the abundance and distribution of angel sharks in Libyan waters, highlighting their continued presence and vulnerability. The findings underscore the urgent need for targeted conservation actions. This includes stock assessments, habitat protection, and fisheries management measures to ensure the long-term survival of these critically endangered species in the region.