Filling the gap: study of the ecology of data-poor pelagic elasmobranchs in oceanic islands in the Atlantic

  • Estado
  • Nome
    Ana Filipa Lourenço Sobral
  • Entidade de acolhimento
    Centro Okeanos

Elasmobranchs (sharks and rays) are increasingly acknowledged as species with high-risk of extinction. However, our extremely limited knowledge of basic aspects of their ecology hampers the implementation of proper management and conservation actions. This situation is particularly worrying in the North East Atlantic (NEA) and especially in oceanic islands. The Azores (36°-40°N; 24°-32°W), the most isolated archipelago in the NEA, is one such region. Azorean habitats may represent Essential Fish Habitats (EFH) for elasmobranchs, such as nursery and mating areas, and it is urgent to identify and integrate them in future management plans. Thus, what is the importance of those EFH and their connectivity with other EFH in other oceanic islands for the sustainability of NA populations of these species? Are there critical areas where there is a high degree of overlapping between of EFH habitats and human activities and how may that affect these populations? This work will address these questions and, in order to provide the answers, the following specific objectives are proposed: Identify different EFH (mating, pupping and nursery grounds) in the region; Appraise the degree of genetic connectivity with other oceanic islands in the Atlantic; Clarify spatial and temporal segregation within oceanic islands populations as a purpose of life stage and sex; Understand the importance of particular islands (and respective EFH) for NA populations; Identify areas of critical overlap with human impacts (fishing, tourism and habitat degradation) in the region; and Evaluate the current status of Azorean populations of the target species. With the aim of achieving this objectives a multidisciplinary approach combining innovative, cost-effective and non or minimally invasive techniques, such as photographic identification (photo-ID), paired-laser photogrammetry, populations genetics, stable-isotope analyses, mark-recapture programs, acoustic and satellite telemetry, is proposed. These techniques will focus on three selected key species with distinct life histories: Smooth hammerhead shark (Sphyrna zygaena), Tope shark (Galeorhinus galeus) and Chilean devil ray (Mobula tarapacana). These species are currently listed under the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species, for the NEA region as ‘Vulnerable’, ‘Data Deficient’ and ‘Data Deficient’, respectively. The expected results of this work will have direct implications in the regional and global conservation of these species by providing science based support to the implementation of a regional spatial management plan, as well as, to international agencies (IUCN, ICES) for the assessment of the status of NA populations, but also by increasing awareness of the vulnerability and importance of elasmobranchs amongst stakeholders and the wider-public.