Original scientific paper
https://doi.org/10.20302/NC.2017.26.23
New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea
Draško Holcer
; Blue World Institute of Marine Research and Conservation, Kaštel 24, HR-51551 Veli Lošinj, Croatia
Bojan Lazar
; Marine Sciences Program, Juraj Dobrila University of Pula, Zagrebačka 30, HR-52100 Pula, Croatia
Abstract
Two out of three critically endangered species of angelsharks (genus Squatina (Dumeril, 1806)) inhabiting the Mediterranean have been recorded in the Adriatic Sea, namely smoothback angelshark S. oculata Bonaparte, 1840 and common angelshark S. squatina (Linnaeus, 1758). While S. oculata has been extirpated from the Adriatic Sea due to overfishing, the presence of S. squatina remained questionable and some authors propose the species is regionally extinct since the 1980s. We present new data on the occurrence of S. squatina in the Croatian Adriatic Sea based upon inspection of collections from natural history museums and literature sources as well as three new records resulting from bycatch in commercial bottom trawls in 2016 and 2017. A low overall number of records and the complete absence of the species in scientific trawl surveys conducted since 1958, indicate its low abundance and question the effectiveness of scientific surveying in detecting rare species. Our analysis showed that this formerly abundant species is still present in the Adriatic Sea, emphasizing the importance of implementing novel approaches, such as citizen-science programmes, in studying its current distribution. Although the legal framework for angelshark conservation already exists, poor implementation and lack of any species-specific conservation measures will most probably result in further population declines and extinction of S. squatina from the Adriatic Sea.
Keywords
elasmobranchs; sharks; distribution; Adriatic Sea; Mediterranean Sea
Hrčak ID:
191545
URI
Publication date:
31.12.2017.
Visits: 2.393 *