Browsing by Author "Romanov, Evgeny V."
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- Corrigendum: The significance of cephalopod beaks as a research tool: An updatePublication . Xavier, José C.; Golikov, Alexey V.; Queirós, José P.; Perales-Raya, Catalina; Rosas-Luis, Rigoberto; Abreu, José; Bello, Giambattista; Bustamante, Paco; Capaz, Juan Carlos; Dimkovikj, Valerie H.; González, Ángel F.; Guímaro, Hugo; Guerra-Marrero, Airam; Gomes-Pereira, José N.; Hernández-Urcera, Jorge; Kubodera, Tsunemi; Laptikhovsky, Vladimir; Lefkaditou, Evgenia; Lishchenko, Fedor; Luna, Amanda; Liu, Bilin; Pierce, Graham J.; Pissarra, Vasco; Reveillac, Elodie; Romanov, Evgeny V.; Rosa, Rui; Roscian, Marjorie; Rose-Mann, Lisa; Rouget, Isabelle; Sánchez, Pilar; Sánchez-Márquez, Antoni; Seixas, Sónia; Souquet, Louise; Varela, Jaquelino; Vidal, Erica A. G.; Cherel, YvesIn the published article, there was an error in the author list, and author Jorge Hernández-Urcera was erroneously excluded. The corrected author list appears below.
- 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-scale environmental niche and habitat of blue shark (Prionace glauca) by size and sex: a pivotal step to improving stock managementPublication . Druon, Jean-Noël; Campana, Steven; Vandeperre, Frederic; Hazin, Fábio H. V.; Bowlby, Heather; Coelho, Rui; Queiroz, Nuno; Serena, Fabrizio; Abascal, Francisco; Damalas, Dimitrios; Musyl, Michael; Lopez, Jon; Block, Barbara; Afonso, Pedro; Dewar, Heidi; Sabarros, Philippe S.; Finucci, Brittany; Zanzi, Antonella; Bach, Pascal; Senina, Inna; Garibaldi, Fulvio; Sims, David W.; Navarro, Joan; Cermeño, Pablo; Leone, Agostino; Diez, Guzmán; Zapiain, María Teresa Carreón; Deflorio, Michele; Romanov, Evgeny V.; Jung, Armelle; Lapinski, Matthieu; Francis, Malcolm P.; Hazin, Humberto; Travassos, PauloBlue shark (Prionace glauca) is amongst the most abundant shark species in international trade, however this highly migratory species has little effective management and the need for spatio-temporal strategies increases, possibly involving the most vulnerable stage or sex classes. We combined 265,595 blue shark observations (capture or satellite tag) with environmental data to present the first global-scale analysis of species' habitat preferences for five size and sex classes (small juveniles, large juvenile males and females, adult males and females). We leveraged the understanding of blue shark biotic environmental associations to develop two indicators of foraging location: productivity fronts in mesotrophic areas and mesopelagic micronekton in oligotrophic environments. Temperature (at surface and mixed layer depth plus 100 m) and sea surface height anomaly were used to exclude unsuitable abiotic environments. To capture the horizontal and vertical extent of thermal habitat for the blue shark, we defined the temperature niche relative to both sea surface temperature (SST) and the temperature 100 m below the mixed layer depth (Tmld+100). We show that the lifetime foraging niche incorporates highly diverse biotic and abiotic conditions: the blue shark tends to shift from mesotrophic and temperate surface waters during juvenile stages to more oligotrophic and warm surface waters for adults. However, low productivity limits all classes of blue shark habitat in the tropical western North Atlantic, and both low productivity and warm temperatures limit habitat in most of the equatorial Indian Ocean (except for the adult males) and tropical eastern Pacific. Large females tend to have greater habitat overlap with small juveniles than large males, more defined by temperature than productivity preferences. In particular, large juvenile females tend to extend their range into higher latitudes than large males, likely due to greater tolerance to relatively cold waters. Large juvenile and adult females also seem to avoid areas with intermediate SST (similar to 21.7-24.0 degrees C), resulting in separation from large males mostly in the tropical and temperate latitudes in the cold and warm seasons, respectively. The habitat requirements of sensitive size- and sex-specific stages to blue shark population dynamics are essential in management to improve conservation of this near-threatened species.
- High connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: highlights for conservationPublication . da Silva Ferrette, Bruno Lopes; Mendonca, Fernando Fernandes; Coelho, Rui; Vasconcelos de Oliveira, Paulo Guilherme; Vieira Hazin, Fabio Hissa; Romanov, Evgeny V.; Oliveira, Claudio; Santos, Miguel Neves; Foresti, FaustoAmong the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity pi = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index phi(ST) = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.
- The significance of cephalopod beaks as a research tool: An updatePublication . Xavier, José C.; Golikov, Alexey V.; Queirós, José P.; Perales-Raya, Catalina; Rosas-Luis, Rigoberto; Abreu, José; Bello, Giambattista; Bustamante, Paco; Capaz, Juan Carlos; Dimkovikj, Valerie H.; González, Angel F.; Guímaro, Hugo; Guerra-Marrero, Airam; Gomes-Pereira, José N.; Hernández-Urcera, Jorge; Kubodera, Tsunemi; Laptikhovsky, Vladimir; Lefkaditou, Evgenia; Lishchenko, Fedor; Luna, Amanda; Liu, Bilin; Pierce, Graham J.; Pissarra, Vasco; Reveillac, Elodie; Romanov, Evgeny V.; Rosa, Rui; Roscian, Marjorie; Rose-Mann, Lisa; Rouget, Isabelle; Sánchez, Pilar; Sánchez-Márquez, Antoni; Seixas, Sónia; Souquet, Louise; Varela, Jaquelino; Vidal, Erica A. G.; Cherel, YvesThe use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960's, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed.