Browsing by Author "Hazin, Fábio"
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- Distribution patterns and population structure of the blue shark (Prionace glauca) in the Atlantic and Indian OceansPublication . Coelho, Rui; Mejuto, Jaime; Domingo, Andrés; Yokawa, Kotaro; Liu, Kwang-Ming; Cortés, Enric; Romanov, Evgeny V.; da Silva, Charlene; Hazin, Fábio; Arocha, Freddy; Mwilima, Aldrin Masawbi; Bach, Pascal; Ortiz de Zárate, Victoria; Roche, William; Lino, Pedro G.; García-Cortés, Blanca; Ramos-Cartelle, Ana M.; Forselledo, Rodrigo; Mas, Federico; Ohshimo, Seiji; Courtney, Dean; Sabarros, Philippe S.; Perez, Bernardo; Wogerbauer, Ciara; Tsai, Wen-Pei; Carvalho, Felipe; Santos, Miguel N.The blue shark (Prionace glauca) is the most frequently captured shark in pelagic oceanic fisheries, especially pelagic longlines targeting swordfish and/or tunas. As part of cooperative scientific efforts for fisheries and biological data collection, information from fishery observers, scientific projects and surveys, and from recreational fisheries from several nations in the Atlantic and Indian Oceans was compiled. Data sets included information on location, size and sex, in a total of 478,220 blue shark records collected between 1966 and 2014. Sizes ranged from 36 to 394 cm fork length. Considerable variability was observed in the size distribution by region and season in both oceans. Larger blue sharks tend to occur in equatorial and tropical regions, and smaller specimens in higher latitudes in temperate waters. Differences in sex ratios were also detected spatially and seasonally. Nursery areas in the Atlantic seem to occur in the temperate south‐east off South Africa and Namibia, in the south‐west off southern Brazil and Uruguay, and in the north‐east off the Iberian Peninsula and the Azores. Parturition may occur in the tropical north‐east off West Africa. In the Indian Ocean, nursery areas also seem to occur in temperate waters, especially in the south‐west Indian Ocean off South Africa, and in the south‐east off south‐western Australia. The distributional patterns presented in this study provide a better understanding of how blue sharks segregate by size and sex, spatially and temporally, and improve the scientific advice to help adopt more informed and efficient management and conservation measures for this cosmopolitan species.
- Movements, habitat use, and diving behavior of Shortfin Mako in the Atlantic OceanPublication . Casaca Santos, Catarina; Domingo, Andrés; Carlson, John; Natanson, Lisa J.; Travassos, Paulo; Macías, David; Cortés, Enric; Miller, Philip; Hazin, Fábio; Mas, Federico; Ortiz de Urbina, Josetxu; Lino, Pedro G.; Coelho, RuiThe shortfin mako is one of the most important shark species caught in Atlantic Ocean pelagic fisheries. Given increasing concerns for the stock status of the species, the present study was designed to fill gaps in the knowledge of habitat use and movement patterns of shortfin mako in the Atlantic Ocean. From 2015 to 2019, 53 shortfin makos were tagged with pop-up satellite archival tags within the North, Central, and Southwest Atlantic Ocean, with successful transmissions received from 34 tags. Generally, sharks tagged in the Northwest and Central Atlantic moved away from tagging sites showing low to no apparent residency patterns, whereas sharks tagged in the Northeast and Southwest Atlantic spent large periods of time near the Canary Archipelago and Northwest Africa, and over shelf and oceanic waters off southern Brazil and Uruguay, respectively. These areas showed evidence of site fidelity and were identified as possible key areas for shortfin mako. Sharks spent most of their time in temperate waters (18–22◦C) above 90 m; however, data indicated the depth range extended from the surface down to 979 m, in water temperatures ranging between 7.4 and 29.9◦C. Vertical behavior of sharks seemed to be influenced by oceanographic features, and ranged from marked diel vertical movements, characterized by shallower mean depths during the night, to yo-yo diving behavior with no clear diel pattern observed. These results may aid in the development of more informed and efficient management measures for this species.