Browsing by Author "Damalas, Dimitrios"
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- Fishers’ perceptions of the European Union discards ban: perspective from south European fisheriesPublication . Maynou, Francesc; Gil, Maria del Mar; Vitale, Sergio; Giusto, Giovan Battista; Foutsi, Antigoni; Oliveira, M.R.; Rainha, Rita; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Bentes, Luis; Viva, Claudio; Sartor, Paolo; Carlo, Francesco De; Rossetti, Ilaria; Christou, Maria; Stergiou, Konstantinos; Maravelias, Christos D.; Damalas, DimitriosThe estimated impact of the EU Landing Obligation was investigated, which bans discards of regulated species, in South European fisheries through stakeholders' perceptions with the intention to identify implementation shortcomings and practicalities that might lead to obstacles to enforcement. Structured interviews were conducted with 173 fishers in 4 countries practicing 4 generic fisheries (as typified by the dominant fishing gear) asking a total of 26 questions. Results show that fishers estimate that the full implementation of the discards ban will result in longer sorting times. Added to the limited space on board, especially in the more productive trawl and purse seine vessels, this may lead to practical difficulties in relation to compliance. Most of the respondents estimate that there are no realistic possibilities of utilizing the formerly discarded fish in the short term, because of the lack of adequate infrastructure on land Furthermore, the possible utilization types foreseen in the regulation will not help offset the costs of bringing former discards to land. The outcomes of this study have confirmed the implementation difficulties of the landing obligation, especially when the fishing industry cannot expect any medium to long-term benefits.
- 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.