Percorrer por autor "Afonso, Pedro"
A mostrar 1 - 10 de 18
Resultados por página
Opções de ordenação
- An ecological framework for the development of a national MPA networkPublication . Abecasis, David; Afonso, Pedro; Erzini, KarimIsolated marine protected areas (MPAs) may not be enough to sustain viable populations of marine species, particularly the many small coastal MPAs which resulted due to social, economic and political constraints. Properly designed MPA networks can circumvent such limitations due to their potential synergistic positive effects, but this crucial step is frequently obstructed by lack of baseline ecological information. In this paper, we use systematic conservation planning on European Nature Information System coastal habitat information available for Portugal to demonstrate how an ecologically coherent nation-wide MPA network can be designed. We used the software Marxan to obtain near optimal solutions for each of three pre-determined conservation targets (10%, 30% and 50% protection) while maintaining the cost of including conservation units as low as possible. Marxan solutions were subsequently optimized with MinPatch by keeping each MPA above a minimum size that reflects the existing information on habitat use by some key marine fishes. Results show that 10% protection for all habitats would only require a relativelly small increase in the number (from 6 to 10) and area (from 479 km(2) to 509 km(2)) of already existing MPAs in mainland Portugal whereas substantial increases would be required to achieve the 50% target. This rather simple approach offers the added benefit of allowing design improvement as more relevant ecological information becomes available, including deeper habitat mapping across the whole continental shelf, allowing a coherent, adaptive and inclusive optimal MPA network to be designed.
- Depth and temperature preferences of meagre, argyrosomus regius, as revealed by satellite telemetryPublication . Winkler, Alexander; Astrid Bovim, Lily; Macena, Bruno C. L.; Gandra, Miguel; Erzini, Karim; Afonso, Pedro; Abecasis, DavidArgyrosomus regius (commonly referred to as meagre), is one of Europe's largest coastal bony fish species and supports important recreational and commercial fisheries in the Atlantic and Mediterranean coasts. Demand for this species, and more recently for their swim bladders, has led to regional population declines and growing importance as an aquaculture species. Despite intense research in captivity, little is known about the spatial ecology of A. regius's wild population, including basic information such as vertical migrations and depth/temperature preferences. Previous research based on indirect data suggests a seasonal habitat shift from shallow to deeper waters, but this has never been validated through direct high-resolution movement data. In this study, we tagged 13 adult A. regius with pop-up satellite archival tags in the South of Portugal, which successfully returned data from 11 individuals including high-resolution data from six recovered tags (mean, range: 167 days, 28-301 days). We found that adults of this population spend 95.2% of their time between 5 and 75 m depth (mean +/- SD, 30.9m +/- 18.3m) and do not venture beyond 125 m. Across seasons, A. regius move across water temperatures between 13.3 and 24.8 degrees C with a preferred thermal range between 14 and 18 degrees C where they spent 75.4% of their time. The inferential modelling using this electronic data validated previous hypotheses by showing significant differences between a shallower and warmer summer habitat vs. a deeper and cooler winter habitat. Visual investigation of the diel effects on depth preferences suggests subtle changes in depth use between day and night during the warmer months of the year. We speculate that these patterns are in response to the species' behavioural ecology and physiology, reflecting the seasonal changes in water stratification and presence of prey, as well as on the species reproduction, which results in summer spawning aggregations in shallower areas.
- DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)Publication . Neiva, J.; Bermejo, Ricardo; Medrano, Alba; Capdevila, Pol; Milla-Figueras, David; Afonso, Pedro; Ballesteros, Enric; Sabour, Brahim; Serio, Donatella; Nóbrega, Eduardo; Soares, João; Valdazo, José; Tuya, Fernando; Mulas, Martina; Israel, Álvaro; Sadogurska, Sofia S.; Guiry, Michael D.; Pearson, Gareth; Serrao, EsterCystoseira sensu lato (s.l.) - encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria - is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a similar to 1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. phylogenetic signal of coxl was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered.
- Electronic tagging and tracking aquatic animals to understand a world increasingly shaped by a changing climate and extreme weather eventsPublication . Lennox, Robert J.; Afonso, Pedro; Birnie-Gauvin, Kim; Dahlmo, Lotte S.; Nilsen, Cecilie I.; Arlinghaus, Robert; Cooke, Steven J.; Souza, Allan T.; Jarić, Ivan; Prchalová, Marie; Říha, Milan; Westrelin, Samuel; Twardek, William; Aspillaga, Eneko; Kraft, Sebastian; Šmejkal, Marek; Baktoft, Henrik; Brodin, Tomas; Hellström, Gustav; Villegas-Ríos, David; Vollset, Knut Wiik; Adam, Timo; Sortland, Lene K.; Bertram, Michael G.; Crossa, Marcelo; Vogel, Emma F.; Gillies, Natasha; Reubens, JanDespite great promise for understanding the impacts and extent of climate change and extreme weather events on aquatic animals, their species, and ecological communities, it is surprising that electronic tagging and tracking tools, like biotelemetry and biologging, have not been extensively used to understand climate change or develop and evaluate potential interventions that may help adapt to its impacts. In this review, we provide an overview of methodologies and study designs that leverage available electronic tracking tools to investigate aspects of climate change and extreme weather events in aquatic ecosystems. Key interventions to protect aquatic life from the impacts of climate change, including habitat restoration, protected areas, conservation translocations, mitigations against interactive effects of climate change, and simulation of future scenarios, can all be greatly facilitated by using electronic tagging and tracking. We anticipate that adopting animal tracking to identify phenotypes, species, or ecosystems that are vulnerable or resilient to climate change will help in applying management interventions such as fisheries management, habitat restoration, invasive species control, or enhancement measures that prevent extinction and strengthen the resilience of communities against the most damaging effects of climate change. Given the scalability and increasing accessibility of animal tracking tools for researchers, tracking individual organisms will hopefully also facilitate research into effective solutions and interventions against the most extreme and acute impacts on species, populations, and ecosystems.
- Environmental representativity in marine protected area networks over large and partly unexplored seascapesPublication . Stratoudakis, Yorgos; Hilário, Ana; Ribeiro, Cláudia; Abecasis, David; Gonçalves, Emanuel J.; Andrade, Francisco; Carreira, Gilberto P.; Gonçalves, Jorge Manuel Santos; Freitas, Luis; Pinheiro, Luis Menezes; Batista, Marisa I.; Henriques, Miguel; Oliveira, Paulo B.; Oliveira, Paulo; Afonso, Pedro; Arriegas, Pedro Ivo; Henriques, SofiaConverting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14% of its area by 2020. An aggregate conservation value was estimated for each of the 27 habitats identified, from intertidal waters to the deep sea. This value was based on expert-judgment scoring for environmental properties and features relevant for conservation, chosen to reflect the strategic objectives of the network, thus providing an objective link between conservation commitments and habitat representativity in space. Additionally, habitats' vulnerability to existing anthropogenic pressures and sensitivity to climate change were also scored. The area coverage of each habitat in Portugal and within existing MPAs (regionally and nationally) was assigned to a scale of five orders of magnitude (from < 0.01% to >10%) to assess rarity and existing representation. Aggregate conservation value per habitat was negatively correlated with area coverage, positively correlated with vulnerability and was not correlated with sensitivity. The proposed framework offers a multi-dimensional support tool for MPA network development, in particular regarding the prioritization of new habitats to protect, when the goal is to achieve specific targets while ensuring representativity across large areas and complex habitat mosaics. It requires less information and computation effort in comparison to more quantitative approaches, while still providing an objective instrument to scrutinize progress on the implementation of politically set conservation targets.
- Evaluating seabed habitat representativeness across a diverse set of marine protected areas on the Mid-Atlantic RidgePublication . Milla-Figueras, David; Schmiing, Mara; Amorim, Patricia; e Costa, Horta; Afonso, Pedro; Tempera, FernandoMarine ecosystem-based management requires good spatial information on the distribution of marine species and habitats. Often, such information is limited to a few sampled locations, but modelling techniques can be applied to produce predictive distribution maps. A harmonized broad-scale seabed habitat map was recently produced for the archipelagos of Macaronesia under the EMODnet Seabed Habitats Programme. We use this new information to produce an extent-based evaluation of the representativeness and level of protection conferred by the current set of marine protected areas (MPAs) in the Azores to the variety of benthic marine habitats found in this oceanic region. A more objective assessment of the protection effectively provided to the habitats is obtained by applying a scoring system to the MPAs based on the number of allowed extractive and non-extractive human activities and their potential impact on marine biodiversity and habitats. Results show that Azorean habitats within the MPAs are nearly entirely classified as highly protected. In total, 26 habitats (7 of which are endangered and 2 are rare) have at least 10% of their extent in the Azores EEZ protected by MPAs, but another 29 fail to meet this target (4 on-shelf habitats and 25 deep-sea habitats), highlighting the need to extend current protection of bathyal and abyssal habitats and applying adequate ecological coherence criteria. This approach sets a standard that can be used wherever similar information is available, be it in other European regions or beyond.
- 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.
- 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.
- Intra- and interspecific associations in two predatory reef fishes at a shallow seamountPublication . Gandra, Miguel; Afonso, Pedro; Fontes, Jorgethe spatial dynamics of marine populations are shaped by habitat availability, environmental variability and individual interactions, particularly when multiple species share limited habitat such as patchy offshore reefs. the yellowmouth barracuda Sphyraena viridensis and the almaco jack Seriola rivoliana are the 2 most abundant bentho-pelagic reef predators in the Azores archipelago (central North Atlantic). They aggregate at shallow offshore seamounts, and largely share diet preferences, but very little is known about how habitat and resources are shared by these predators intra- and inter-specifically. Here we use long-term (over 3 yr) passive acoustic telemetry to investigate the patterns of activity, space use and associative behaviour at an isolated, small shallow seamount. By quantifying fine-scale spatiotemporal overlaps and performing null model randomization tests, we found evidence of non-random associations, mostly between conspecifics of both species, as well as shifts in diel and seasonal patterns of space occupancy. Both species were detected more often during spring, and appear to be more active during daytime, suggesting the absence of fine-scale temporal habitat partitioning. Additionally, we found evidence of size-dependent spatial behaviour in almaco jack, with similarly sized individuals co-occurring more often and larger specimens being more infrequently detected. This study quantitatively assesses individual associations using solely presence-absence data collected through passive acoustic telemetry, showing the potential of this approach in a broader application to a significant number of past and ongoing studies, even if many were not originally designed to study this important aspect of fish ecology.
- Long-term multitracking reveals contrasting yet highly resident movement ecologies of two sympatric and endangered deep-sea sharksPublication . Gandra, Miguel; Fontes, Jorge; Macena, Bruno C.L.; Meyer, Carl G.; Afonso, PedroStudying shark movement ecology is vital for understanding their ecological roles and supporting sustainable management and conservation strategies. However, such information remains scarce for deep-sea sharks. We used biotelemetry to investigate the spatial behaviour and movements of two endangered deep-sea predators, the kitefin (Dalatias licha) and bluntnose sixgill (Hexanchus griseus) sharks, in the Azores, northern Mid-Atlantic Ridge. We tagged a total of 21 kitefin sharks with acoustic transmitters (some including depth sensors) and seven sixgill sharks with different tag configurations: three were fitted exclusively with acoustic transmitters, two were double-tagged with both acoustic transmitters and pop-up satellite archival tags (PSATs), and two were tagged exclusively with PSATs deployed via a speargun-equipped submersible. Both species exhibited diel vertical migrations and unexpected high site fidelity (up to 4 years), using habitats that inter-connect seamounts, slopes, and island shelves. Sixgill sharks exhibited more extensive and diverse individual home ranges and vertical diel activity patterns than kitefin sharks. Sexual segregation was evident in kitefin sharks, with males and females displaying distinct differences in depth distribution and habitat use, supporting earlier hypotheses based on fisheries data. These behavioural patterns suggest that sixgill sharks function as wide-ranging, deep-sea opportunistic foragers and predators, traversing interconnected habitats in search of prey – including kitefin sharks, which occupy a more slope-associated mesopredator niche. Our novel findings support ecological theory suggesting that deep-sea sharks exhibit far more contrasting spatial ecologies than previously thought, driven by their life histories. These differences may have implications for their high vulnerability to fisheries and climate change-induced habitat degradation.