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RESEARCH ARTICLE

Abundance, distribution and reproduction of the Data-Deficient species (Squalus blainville) around Sardinia Island (central western Mediterranean Sea) as a contribution to its conservation

Martina Francesca Marongiu https://orcid.org/0000-0002-0582-8865 A B D , Cristina Porcu https://orcid.org/0000-0003-2649-6502 A B , Andrea Bellodi https://orcid.org/0000-0002-9017-1692 A B , Rita Cannas https://orcid.org/0000-0001-6627-4053 A B , Pierluigi Carbonara https://orcid.org/0000-0002-2529-2535 C , Alessandro Cau https://orcid.org/0000-0003-4082-7531 A B , Elisabetta Coluccia https://orcid.org/0000-0003-4412-8033 A , Davide Moccia https://orcid.org/0000-0001-7306-8573 A B , Antonello Mulas https://orcid.org/0000-0003-1635-691X A B , Paola Pesci https://orcid.org/0000-0002-9066-8076 A B and Maria Cristina Follesa https://orcid.org/0000-0001-8320-9974 A B
+ Author Affiliations
- Author Affiliations

A Dipartimento di Scienze della Vita e dell’Ambiente, Università degli Studi di Cagliari, Via Tommaso Fiorelli 1, I-09126 Cagliari, Italy.

B Consorzio Nazionale Interuniversitario per le Scienze Mare (CoNISMa), Piazzale Flaminio 9, I-00196 Roma, Italy.

C COISPA Tecnologia & Ricerca – Stazione Sperimentale per lo Studio delle Risorse del Mare, Via dei Trulli 18/20, I-70126 Bari, Italy.

D Corresponding author. Email: mfmarongiu@unica.it

Marine and Freshwater Research 72(1) 118-130 https://doi.org/10.1071/MF19372
Submitted: 28 November 2019  Accepted: 19 March 2020   Published: 13 May 2020

Abstract

Data-Deficient (DD) species are currently under threat because of the paucity of information regarding their abundance, distribution and biological traits. In this study we analysed temporal trends and bioecological features of the DD shark, Squalus blainville. Biological and fishery data were collected through two different scientific surveys spanning 1994–2018 and commercial hauls around Sardinia Island (central western Mediterranean) from 2008 to 2018. The analysis of temporal trends based on abundance data revealed a significant population decline over time. The late attainment of maturity and low fecundity of S. blainville are suspected to have contributed to making it highly vulnerable to overfishing. No bathymetric segregation by sex and size was found. However, the almost exclusive presence of pregnant females south-west of Sardinia could be due to sexual spatial segregation. This is also supported by histological findings showing long-term sperm storage to ensure the persistence of the species when females and males are separated. The documented decline of this species, its low reproductive potential and similarities in the depth distribution of immature and mature individuals indicate the need for urgent protection plans for S. blainville in Sardinian waters.

Additional keywords: histology, longnose spurdog, sexual spatial segregation, sperm storage.


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