Percorrer por autor "Cortés, Enric"
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- Beyond post-release mortality: inferences on recovery periods and natural mortality from electronic tagging data for discarded lamnid sharksPublication . Bowlby, Heather D.; Benoît, Hugues P.; Joyce, Warren; Sulikowski, James; Coelho, Rui; Domingo, Andrés; Cortés, Enric; Hazin, Fabio; Macias, David; Biais, Gérard; Casaca Santos, Catarina; Anderson, BrookeAccurately characterizing the biology of a pelagic shark species is critical when assessing its status and resilience to fishing pressure. Natural mortality (M) is well known to be a key parameter determining productivity and resilience, but also one for which estimates are most uncertain. While M can be inferred from life history, validated direct estimates are extremely rare for sharks. Porbeagle (Lamna nasus) and shortfin mako (Isurus oxyrinchus) are presently overfished in the North Atlantic, but there are no directed fisheries and successful live release of bycatch is believed to have increased. Understanding M, post-release mortality (PRM), and variables that affect mortality are necessary for management and effective bycatch mitigation. From 177 deployments of archival satellite tags, we inferred mortality events, characterized physiological recovery periods following release, and applied survival mixture models to assess M and PRM. We also evaluated covariate effects on the duration of any recovery period and PRM to inform mitigation. Although large sample sizes involving extended monitoring periods (>90 days) would be optimal to directly estimate M from survival data, it was possible to constrain estimates and infer probable values for both species. Furthermore, the consistency of M estimates with values derived from longevity information suggests that age determination is relatively accurate for these species. Regarding bycatch mitigation, our analyses suggest that juvenile porbeagle are more susceptible to harm during capture and handling, that keeping lamnid sharks in the water during release is optimal, and that circle hooks are associated with longer recovery periods for shortfin mako.
- Blue shark (Prionace glauca) movements, habitat use, and vertical overlap with longline fishing gears in the southwestern Atlantic OceanPublication . Mas, Federico; Cortés, Enric; Coelho, Rui; Defeo, Omar; Miller, Philip; Carlson, John; Gulak, Simon; Domingo, AndrésOver the last three decades, the advent and the continuous sophistication of telemetry devices have revolutionized our understanding of how pelagic sharks move and exploit their three-dimensional underwater habitat, with implications for management and conservation. In this study, conventional (4,648) and electronic (18) tags were used to assess the horizontal and vertical movements of blue sharks, Prionace glauca, and their vertical overlap with shallow and deep-set longline fishing gears in the southwestern Atlantic Ocean. Results revealed prolonged permanence in the area, large-scale displacements, including trans-equatorial, trans-Atlantic and Indian-Atlantic movements, and high daily displacement rates. Blue sharks showed an extensive use of the water column and considerable variability among and within individuals in vertical behavior, involving normal and reverse diel vertical migrations, surface-oriented behavior, extended use of mesopelagic waters, and occasional extreme dives into bathypelagic waters. Depth distribution appeared unrelated to size or sex but was influenced by the time of day and temperature, with deeper and colder temperatures consistently found during the day. The moon cycle affected the vertical distribution of some sharks but not others. Temperature-depth recorders deployed on hooks, combined with depth distribution from electronic tags, provided insightful information on the species' vertical overlap with shallow- and deep-set longline configurations. Encounterability values were higher during nighttime and lower during daytime for both longline configurations, but were largely affected by the individuals' vertical behavior, highlighting the importance of accounting for environmental conditions besides fishing gear configuration and metiers. This novel information on blue sharks' movements and fishery interactions in the South Atlantic Ocean can inform future management and conservation strategies.
- 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.
- Global habitat predictions to inform spatiotemporal fisheries management: initial steps within the frameworkPublication . Bowlby, Heather D.; Druon, Jean-Noël; Lopez, Jon; Juan-Jordá, Maria José; Carreón-Zapiain, María Teresa; Vandeperre, Frederic; Leone, Agostino; Finucci, Brittany; Sabarros, Philippe S.; Block, Barbara A.; Arrizabalaga, Haritz; Afonso, Pedro; Musyl, Michael K.; Cortés, Enric; Cardoso, Luis Gustavo; Mourato, Bruno; Queiroz, Nuno; Fontes, Jorge; Abascal, Francisco J.; Zanzi, Antonella; Hazin, Humberto Gomes; Bach, Pascal; Sims, David W.; Travassos, Paulo; Coelho, RuiTuna Regional Fishery Management Organizations (tRFMOs) are increasingly interested in spatiotemporal management as a tool to reduce interaction rates with vulnerable species. We use blue shark ( Prionace glauca ) as a case study to demonstrate the critical first steps in the implementation process, highlighting how predictions of global habitat for vulnerable life stages can be transformed into a publicly -accessible spatial bycatch mitigation tool. By providing examples of possible management goals and an associated threshold to identify essential habitats, we show how these key areas can represent a relatively low percentage of oceanic area on a monthly basis (16-24% between 50 degrees S and 60 degrees N), yet can have relatively high potential protection efficiency (similar to 42%) for vulnerable stages if fishing effort is redistributed elsewhere. While spatiotemporal management has demonstrable potential for blue sharks to effectively mitigate fishing mortality on sensitive life stages, we identify inherent challenges and sequential steps that require careful consideration by tRFMOs as work proceeds. We also discuss how our single-species framework could be easily extended to a multispecies approach by assigning relative conservation risk before layering habitat model predictions in an integrated analysis. Such broader application of our approach could address the goals of tRFMOs related to reducing the ecosystem effects of fishing and pave the way for efficient fisheries co-management using an ecosystem-based approach.
- Habitat use and migrations of shortfin mako in the atlantic using satellite telemetryPublication . Santos, Catarina C.; Domingo, Andrés; Carlson, John; Natanson, Lisa J.; Cortés, Enric; Miller, Philip; Hazin, Fábio H. V.; Travassos, Paulo; Mas, Federico; Coelho, RuiThis paper provides an update of the study on habitat use for shortfin mako, developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Currently, all phase 1 (2015-2016) tags (23 tags: 9 miniPATs and 14 sPAT) and 11 tags from phase 2 (2016-2018) have been deployed by observers on Portuguese, Uruguayan, Brazilian and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 32 tags/specimens is available and a total of 1260 tracking days have been recorded. Results showed shortfin makos moved in multiple directions, travelling considerable distances. Shortfin mako sharks spent most of their time above the thermocline (0-90 m), between 18 and 22 °C. The main plan for the next phase of the project is to continue the tag deployment during 2018 in several regions of the Atlantic.
- 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.
- Pan-Atlantic distribution patterns and reproductive biology of the bigeye thresher, Alopias superciliosusPublication . Fernandez-Carvalho, Joana; Coelho, Rui; Mejuto, Jaime; Cortés, Enric; Domingo, Andrés; Yokawa, Kotaro; Liu, Kwang-Ming; García-Cortés, Blanca; Forselledo, Rodrigo; Ohshimo, Seiji; Ramos-Cartelle, Ana; Tsai, Wen-Pei; Santos, Miguel N.The bigeye thresher (Alopias supercilious) is occasionally caught as bycatch in pelagic longline fisheries targeting tunas and swordfish. Still, it is one of the least known and studied of all pelagic sharks, which hinders assessment of the status of its populations. As part of an ongoing cooperative program for fisheries and biological data collection, information collected by fishery observers and through scientific projects from several nations that undertake fishing activities in the Atlantic (Japan, Portugal, Spain, Taiwan, Uruguay and US) was compiled and analyzed. Datasets include information on location, size, sex and, in some cases, maturity stage. A total of 5590 bigeye thresher records collected between 1992 and 2013 were compiled, with sizes ranging from 70 to 305 cm fork length (FL). Considerable variability was observed in size, with tropical regions recording a smaller mean size compared to other regions. The distribution of juvenile and adult specimens also showed considerable variability, and the sex ratios varied between regions and size classes. Median sizes at maturity were estimated at 208.6 cm FL for females and 159.2 cm FL for males. Pregnant females were recorded in the tropical northeast and southwest Atlantic, with these regions possibly serving as nursery areas. The biological and distributional patterns presented in this study provide a better understanding of different aspects of this species in the Atlantic, which can help managers adopt more informed and efficient conservation measures.
- Post-release mortality of shortfin mako in the Atlantic using satellite telemetry: preliminary resultsPublication . Domingo, Andrés; Casaca Santos, Catarina; Carlson, John; Natanson, Lisa; Cortés, Enric; Mas, Federico; Miller, Philip; Hazin, Fábio H. V.; Travassos, Paulo; Coelho, RuiThis paper provides an update of the study on post-release mortality of the shortfin mako, Isurus oxyrinchus developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Up to date, 34 tags (14 sPATs and 20 miniPATs) have been deployed by observers on Brazilian, Portuguese, Uruguayan, and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 28 out of 34 tagged specimens could be used to obtain preliminary information regarding post-release mortality, resulting in a total of 7 mortality and 21 survival events.
- Satellite tagging of shortfin mako for habitat use and post-release survival: progress report for SRDCPPublication . Coelho, Rui; Domingo, Andrés; Carlson, John; Natanson, Lisa; Cortés, Enric; Miller, PhilipThis paper provides an update of two projects developed within the ICCAT Shark Research and Data Collection Program (SRDCP) using satellite telemetry, specifically a study on habitat use and another on post-release survival. Currently, all phase 1 (2015-2016) tags (23 tags: 9 miniPATs and 14 sPAT) have been deployed by observers on Portuguese, Uruguayan and US vessels in the temperate NE, temperate NW and SW Atlantic. A total of 668 tracking days have been recorded. In terms of post-release survivorship, data from 19 tags/specimens is available. From those, 6 specimens died (31.6%) while the remaining 13 (68.4%) survived the first 30 days after tagging. All planned project milestones and deliverables have been achieved and delivered in due time. For the 2nd phase of the project (2016-2017) 12 miniPATS were acquired and will be deployed during 2017 in various regions of the Atlantic, including temperate, tropical and equatorial waters.
- Shark Research and Data Collection Program: progress on the satellite tagging of shortfin mako for post-release survival and habitat use studiesPublication . Coelho, Rui; Domingo, Andrés; Carlson, John; Cortés, Enric; Rosa, Daniela; ller, Philip; Santos, Miguel N.This paper provides an update of two projects developed within the ICCAT Shark Research and Data Collection Program (SRDCP) using satellite telemetry, specifically a study on habitat use and other on post-release survival. At the time of this paper, 10 tags (6 miniPATs and 4 sPAT) had been deployed from observers on Portuguese fishing vessels in the temperate NE Atlantic. The remaining tags are being deployed by USA in the temperate NW and Uruguay in the SW. The preliminary analysis shows that specimens tagged in the temperate NE moved to southern areas, while specimens tagged in the tropical NE close to the Cabo Verde archipelago moved easterly to the African continent. Three tags were deployed in equatorial waters and one moved to the NE while the other moved SE. In terms of post-release survivorship, 2 specimens tagged with sPATs survived and 2 died. For the 2nd year of the project we will acquire additional miniPATs to be deployed preferably in equatorial waters, in the mixing zone for the stocks.