Browsing by Author "Lino, Pedro G."
Now showing 1 - 10 of 11
Results Per Page
Sort Options
- A comparison of monofilament gillnet and small hook longline selectivity in a multispecies artisanal fishery in the Algarve, Southern PortugalPublication . Erzini, Karim; Santos, M. N.; Monteiro, C. C.; Gonçalves, J. M. S.; Bentes, L.; Lino, Pedro G.As part of ongoing studies concerned with the small-scale fisheries of the South of Portugal, experimental fishing was carried out with monofilament gillnets and small hook longlines within the same area. Sixty-two species were caught, of which 20 were common to both gears. Pronounced differences in terms of the relative importance of different species in the catches were observed. Size selection patterns also differed, with highly overlapped hook catch distributions and few species showing evidence for size selectivity. In contrast, strong selectivity was characteristic of species which tend to be "wedged" in gillnets. Whereas smaller stretched mesh sizes (particularly 40 and 50 mm) caught significant numbers of illegal sized fish, this was minimal in the longlines. Some implications for management are discussed.
- Complementary sampling methods to improve the monitoring of Coastal LagoonsPublication . Adão, Ana Catarina; Bosch, Néstor E.; Bentes, Luis; Coelho, Rui; Lino, Pedro G.; Monteiro, Pedro; Gonçalves, Jorge Manuel Santos; Erzini, KarimMonitoring the ecological status of marine coastal lagoons requires the integration of multiple indices. However, the efficacy of monitoring programs is complicated by the diverse array of habitats that conform coastal lagoons. In this study, we compared four sampling methods (25-m and 50-m beach seines, beam trawl and Riley push net) in the Ria Formosa coastal lagoon (South Portugal) for assessing fish assemblage and diversity. We compared species richness and assemblage structure with species accumulation curves and multivariate analysis, and assessed diversity patterns using taxonomic, phylogenetic and functional diversity indices. Variation in fish assemblage structure was mostly explained by gear type, and almost all diversity metrics varied not only according to sampling method but also depending on habitat characteristics and season. Based on operational costs and diversity patterns captured by each gear, we conclude that the combined use of 25-m beach seine and beam trawl is the preferred approach. The proposed methodology will provide the data necessary for assessment of ecological status of coastal lagoons.
- Differentiation of spatial units of Genus Euthynnus from the Eastern Atlantic and the Mediterranean using Otolith Shape AnalysisPublication . Muñoz-Lechuga, Rubén; Sow, Fambaye Ngom; Constance, Diaha N’Guessan; Angueko, Davy; Macías, David; Massa-Gallucci, Alexia; da Silva, Guelson Batista; Gonçalves, Jorge Manuel Santos; Lino, Pedro G.The shape of sagitta otoliths was used to compare individuals of little tunny (Euthynnus alleteratus) harvested on board commercial fishing vessels from the coastal areas along the Eastern Atlantic, including the Mediterranean Sea. Fish sampling and selection was designed to cover possible seasonal changes and tuna size. The research encompassed both morphometric and shape analyses of left sagittal otoliths extracted of 504 fish specimens. Four shape indices (Circularity, Roundness, Rectangularity, and Form-Factor) were significantly different between two groups, showing a statistical differentiation between two clear spatial units. The degree of divergence was even more pronounced along the rostrum, postrostrum, and excisura of the generated otolith outlines between these two groups. One group corresponds to the samples from the coastal areas in the Northeast Temperate Atlantic and Mediterranean Sea (NETAM Area) and a second group from the coastal areas off the Eastern Tropical Atlantic coast of Africa (ETA Area). This study is the first to use otolith shape to differentiate tunas from separate spatial units. These results could be used to re-classify previously collected samples and to correct time series of data collected.
- 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.
- Influence of seagrass meadows on nursery and fish provisioning ecosystem services delivered by Ria Formosa, a coastal lagoon in PortugalPublication . Erzini, Karim; Parreira, Filipe; Sadat, Zineb; Castro, Margarida; Bentes, Luis; Coelho, Rui; Gonçalves, Jorge Manuel Santos; Lino, Pedro G.; Martínez-Crego, Begoña; Monteiro, Pedro; Oliveira, Frederico; Ribeiro, Joaquim; de los Santos, Carmen B.; Santos, RuiThis study is the first to evaluate the fish provisioning services of a whole transitional landscape (Ria Formosa lagoon, Portugal), in parallel with the enhancement of growth, survival and production of single cohorts of the most important commercial fish species by vegetated and unvegetated sub-tidal habitats. Based on monthly beach seine samples, total density and biomass of 96 species of fishes were 1.89 and 3.03 times greater in vegetated habitats than unvegetated habitats, respectively. Vegetated habitat enhanced survival in six of eight commercial species for which survival could be estimated in both habitats. The total production of all 12 commercially important species within vegetated habitat was approximately double that of unvegetated habitat, with production enhancement in 7 of 12 species ranging from 1.8 to 169-fold for the vegetated habitats. Within the lagoon, vegetated sub-tidal habitat covers an area 5-fold smaller than unvegetated habitat, yet it accounts for 27.1 % of fish production. Estimated total lifetime economic values of the single cohorts of the 12 commercial species were between 30 million and 59 million EUR. An exceptionally strong year class of the European seabass (Dicentrarchus labrax), a species with higher density and biomass in unvegetated habitat, accounts for the higher overall values per hectare for unvegetated habitat (Low natural mortality (M): EUR 32,844 ha-1; High M: EUR 16,751 ha-1) than for vegetated habitat (Low M: EUR 22,028 ha-1; High M: EUR 10,700 ha-1). These results highlight the enormous importance of temperate coastal lagoons as a nursery and source of recruits for coastal fisheries. Our evaluation of fish provisioning services based on data for individual cohorts of fish for a whole transitional landscape is a stronger and more valid approach for estimating future biomass and value than previous studies based on mean densities and biomasses of fish that did not distinguish between cohorts.
- Local indicators for global species: Pelagic sharks in the tropical northeast Atlantic, Cabo Verde islands regionPublication . Coelho, Rui; Macías, David; Ortiz de Urbina, Josetxu; Martins, Albertino; Monteiro, Carlos; Lino, Pedro G.; Rosa, Daniela; Casaca Santos, Catarina; Bach, Pascal; Murua, Hilario; Abaunza, Pablo; Santos, Miguel N.Pelagic sharks are an important bycatch in pelagic fisheries, especially for drifting longlines targeting swordfish. In the Cabo Verde Archipelago (tropical NE Atlantic), pelagic shark catches can reach a significant proportion of the total catches. Due to the increased concern on the status of pelagic shark species, this study was developed to enhance the current knowledge of those sharks in the Cabo Verde region in comparison to the adjacent areas, especially associated with European Union (EU) pelagic longline fishing activity. Stock status indicators for the two main species, blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus), were developed, based on fisheries data from logbooks and onboard scientific observers, including analysis of size frequency distributions and standardized catch-per-unit-of-effort (CPUE) indexes over time. The standardized CPUEs have been stable or increasing for both species in the past 10 years, indicating no signs of local depletion. In terms of sizes, the blue shark catch is composed mainly of adults, which can be a sign of a stable population. On the contrary, the catch of shortfin mako is composed mainly of juveniles, which in conjunction of a decrease of mean size might be a cause of concern, highlighting possible overfishing on the species in the region. Thirty satellite tags, 25 archival miniPATs and 5 SPOT GPS, were deployed in the Cabo Verde Exclusive Economic Zone (EEZ), showing that those species are highly mobile. The biomass and size distributions were modeled with spatial and seasonal models (GAMs) identifying locations where juveniles are predominantly concentrated and that should be prioritized for conservation. This work presents new information on the status of pelagic sharks in the Cabo Verde region in the context of those highly migratory species, and can now be used to promote more sustainable fisheries in the region.
- Movements of hatchery-reared dusky groupers released in a northeast atlantic coastal marine protected areaPublication . Silva, Ana Filipa; Horta E Costa, Barbara; Costa, José Lino; Pereira, Esmeralda; Marques, João Pedro; Castro, João J.; Lino, Pedro G.; Candeias-Mendes, Ana; Pousão-Ferreira, Pedro; Sousa, Inês; Bentes, Luis; Gonçalves, Jorge Manuel Santos; de Almeida, Pedro Raposo; Quintella, Bernardo RuivoNo-take areas are key instruments to promote the effectiveness of Marine Protected Areas (MPAs), particularly concerning the protection of endangered species such as the dusky grouper (Epinephelus marginatus). However, despite the establishment of no-take areas and the prohibition of catching this species in a southwestern Portuguese MPA (SACVMP—‘Sudoeste Alentejano’ and ‘Costa Vicentina’ Marine Park) since 2011, there is still no evidence of population recovery. By using acoustic biotelemetry, this work aimed to evaluate the feasibility of restocking hatchery-reared adult dusky groupers in two no-take areas within the SACVMP. In 2019 and 2021, thirty groupers were tagged with acoustic transmitters and the site attachment and movements of the groupers were assessed in the releasing sites (no-take areas). None of the tagged fish settled down in either of the areas, leaving the no-take areas mainly at dusk and night. Some individuals displayed extended movements of more than a hundred kilometers along the Portuguese coast which was rarely reported for this species. At least in some coastal stretches, those movements were performed close to the shore, which may evidence the importance of coastal MPAs to protect and promote the connectivity of species more associated with rocky reef habitats. Following studies should focus on the conditions that promote site attachment and fidelity by hatchery-reared dusky groupers so that future large-scale restocking programs can be successful in MPAs with appropriate habitats.
- 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.
- Spatial and temporal size distribution of swordfish in the Atlantic Ocean: implications for conservation and managementPublication . Rosa, Daniela; Schirripa, Michael; Gillespie, Kyle; Macías, David; Forselledo, Rodrigo; Mourato, Bruno; Kai, Mikihiko; Arocha, Freddy; Su, Nan-Jay; Kerwath, Sven; Bahou, Laurent; Pappalardo, Luigi; Diaz, Guillermo A.; Lino, Pedro G.; Salmeron, Francisca; Urbina, Josetxu Ortiz de; Cardoso, Luis Gustavo; Sant’Ana, Rodrigo; Travassos, Paulo; Santos, Miguel N.; Erzini, Karim; Domingo, Andrés; Báez, Jose Carlos; Hanke, Alex; Brown, Craig; Coelho, RuiSwordfish (Xiphias gladius) is a common target species of surface pelagic longline fisheries. In the Atlantic Ocean and Mediterranean Sea, swordfish is managed as three separate stocks, all having management measures in place to rebuild or conserve the stocks, including minimum landing sizes. The objective of this study was to review size data for swordfish in the Atlantic Ocean, model the sex-specific size distribution and determine areas where there is higher likelihood of capturing undersized fish. The size distribution differed between males and females and varied by quarter, indicating movements of large fish between temperate and tropical waters. Undersized fish seems to occur in association with coastal waters, with higher proportions in the Northwest Atlantic and tropical areas. This study provides a better understanding of the temporal and spatial size and sex distribution of swordfish and presents insights into the distribution of undersized swordfish that is subject to management measures.
- Spawning-related fish movement synchrony of white seabream diplodus sargus in a no-take zonePublication . Pedaccini, Marie; Sousa, Inês; Bentes, Luis; de Benito Abelló, Carmela; Lino, Pedro G.; Moland, Even; Gonçalves, Jorge Manuel Santos; Horta E Costa, BarbaraStudies assessing fish spatial behaviour are essential to better understand the performance of marine protected areas. However, few studies have focused on the fine-scale movements related to reproduction, a key feature in a population’s perpetuation. Knowledge of movements modulated by reproduction is particularly important since migrations towards spawning grounds may increase the vulnerability to threats if these occur outside protected areas. Further, reproductive behavioural polymorphism is widely understudied but may affect reproductive success. In this work, we used acoustic telemetry to study a harvested fish, Diplodus sargus, within a small no-take zone in Portugal.