Browsing by Author "Monteiro, Pedro"
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- Age and growth, mortality and reproduction of the striped sea bream, Lithognathus mormyrusLinnaeus 1758, from the south coast of Portugal (Algarve)Publication . Monteiro, Pedro; Bentes, L.; Coelho, Rui; Correia, Carla; Erzini, Karim; Lino, Pedro; Ribeiro, Joaquim; Gonçalves, J. M. S.The striped sea bream, Lithognathus mormyrus, used for this population dynamics study were obtained from longline catches and market sampling in the Algarve (south Portugal). The macroscopic analysis of the gonads and the gonad somatic index showed that the south Portuguese population of L. mormyrus spawns mainly between late spring and summer (June to August). The length at first maturity was similar for males and females and the value for both sexes combined was estimated to be 16.08 cm, corresponding to an age between 1 and 2 years. Fish age classes (0 to 13) were determined by reading growth rings on whole otoliths. Age determination was validated by marginal increment analysis. The estimated parameters of the von Bertalanffy growth equation were L∞=35.30 cm, K=0.264 and t 0= − 0.809. Mortality rates were calculated for fish captured with longlines, and the estimated parameters were M=0.356, Z=0.622 and F=0.266. From an Algarve fishery management perspective, these results suggest the need for an increase in the minimum landing size (from 15 to 17 cm), which should be beneficial for the sustainability and conservation of this species. The results also showed that fishing with longlines off the Algarve coast may allow for a sustainable use of the resource.
- Age, growth and reproduction of the Axilary Seabream, "Pagellus acarne" (Risso, 1827), from the South coast of PortugalPublication . Coelho, Rui; Bentes, L.; Correia, C.; Gonçalves, J. M. S.; Lino, P. G.; Monteiro, Pedro; Ribeiro, J.; Erzini, KarimAxillary seabream, Pagellus acarne, caught by longlines in the Algarve (Southern Portugal), were sampled between August 1995 and August 1996. Age was studied by counting growth increments on otoliths and the estimated von Bertalanffy parameters were Linf = 28.82 cm, K = 0.29 year-1 and t0 = -1.47 year for males and Linf = 32.30 cm, K = 0.18 year-1 and t0 = -2.56 year for females. Evidence of the annual periodicity of the deposition of increments was found by marginal increment analyses. Macroscopic analysis of the gonads and the gonad somatic index showed that reproduction occurred over an extensive period of time, from May to November. Lengths at first maturity were 18.10 and 17.60 cm for males and females, respectively. This species was characterized as being a protandric hermaphrodite.
- An approach to map and quantify the fishing effort of polyvalent passive gear fishing fleets using geospatial dataPublication . Sales Henriques, Nuno; Russo, Tommaso; Bentes, Luis; Monteiro, Pedro; Parisi, Antonio; Magno, Ramiro; Oliveira, Frederico; Erzini, Karim; Gonçalves, Jorge Manuel SantosThe use of tracking devices, such as vessel monitoring systems or automatic identification system, enabled us to expand our knowledge on the distribution and quantification of fishing activities. However, methods and models based on vessel tracking data are mostly devised to be applied to towed gears, whereas applications to multi-gear and passive fisheries have been underrepresented. Here, we propose a methodology to deal with geospatial data to map and quantify the fishing effort, as soak time, of passive fishing gears used by a multi-gear fishing fleet. This approach can be adapted to other passive multi-or single-gear fisheries, since it requires only three variables that can be extracted from a pre-classified dataset, to identify the beginning (gear deployment) and the end (hauling) of passive fishing events. As far as we are aware, this is the first time a methodology that allows quantifying the soak time of static passive fishing events, within a polyvalent fishery context, is presented. We argue that the information that can be extracted from such approaches could contribute to improved management of multi-gear and static-gear fisheries and the ecosystem-based approach.
- An overview of the submerged sea caves of Sagres (South of Portugal-Algarve)Publication . Monteiro, PedroThe submerged sea caves of Sagres are located within the “Parque Natural do Sudoeste Alentejano e Costa Vicentina (PNSACV)” Marine Protected Area (MPA). This MPA integrates the national network of protected areas, addressed by the National Institute for Nature Conservation and Forest (ICNF) and was declared Site of Community Importance (SCI) under the Habitats Directive. Under the Annex I from the Habitat Directive these habitat caves are included in “8330 Submerged or partially submerged sea caves”. This conservation status should provide sufficient concern to have detailed information on biodiversity. However, among marine researcher, little is still known about these submerged sea caves and tunnels habitats. The only well-known study dealing with the Sagres sea caves was conducted in the late 80s and was only published in 2001. For effective management of such specific habitats a clear understanding of their localization and extension, the assessment of the biological communities, its conservation importance, its monitoring options and their sensitivity to natural change and human disturbance need to be a relatively clear. This report, produced under the MeshAtlantic Project, provides an overview of the available published and unpublished information relevant for the conservation management of the subtidal caves of Sagres. It mainly aims to be a base contribution for future studies.
- Biodiversidade marinha da costa sul de Sagres. Identificação e caracterização de biótoposPublication . Monteiro, PedroA necessidade de obter informação georreferenciada de habitats marinhos da costa portuguesa foi o principal motivador para a realização deste estudo. Sagres é reconhecido como sítio de importância comunitária, o que lhe confere redobrado interesse do ponto de vista da conservação da biodiversidade. Este estudo pretende colmatar parte do desconhecimento da biodiversidade e da distribuição dos habitats da zona subtidal de Sagres. A área de estudo situa-se na extremidade Sul entre a ponta de Sagres e a praia da Ingrina, entre a zona costeira e a batimétrica dos 86 metros. Os objectivos propostos foram alcançados pela realização de censos visuais através de mergulho subaquático com escafandro autónomo nos recifes rochosos costeiros, arrastos de vara na caracterização da epifauna e através da utilização de draga Van Veen na caracterização da infauna do substrato móvel. A área foi genericamente caracterizada por apresentar reduzida cobertura recifal e de baixa complexidade estrutural. O recife encontra-se sobretudo numa área entre a costa e a batimétrica dos 25 metros e outra para além da batimétrica dos 60 metros e por isso de difícil avaliação por métodos convencionais. No recife rochoso costeiro foi possível identificar três habitats de características particulares, nomeadamente áreas junto às falésias, constituídas por blocos de grandes dimensões, áreas de recife com pouco relevo no meio de áreas com alguma gravilha ou pedras roladas, e ainda, grutas e cavernas de grandes dimensões. O substrato móvel existente foi, por sua vez, caracterizado pela sua composição homogénea em toda a sua extensão.
- Broad-scale mapping of seafloor habitats in the north-east Atlantic using existing environmental dataPublication . Vasquez, Mickaël; Mata Chacón, D.; Tempera, Fernando; O'Keeffe, Eimear; Galparsoro, Ibon; Sanz Alonso, J. L.; Gonçalves, J. M. S.; Bentes, L.; Amorim, Patrícia; Henriques, Victor; McGrath, Fergal; Monteiro, Pedro; Mendes, Beatriz; Freitas, Rosa; Martins, Roberto; Populus, JacquesIf marine management policies and actions are to achieve long-term sustainable use and management of the marine environment and its resources, they need to be informed by data giving the spatial distribution of seafloor habitats over large areas. Broad-scale seafloor habitat mapping is an approachwhich has the benefit of producing maps covering large extents at a reasonable cost. This approach was first investigated by Roff et al. (2003), who, acknowledging that benthic communities are strongly influenced by the physical characteristics of the seafloor, proposed overlaying mapped physical variables using a geographic information system (GIS) to produce an integrated map of the physical characteristics of the seafloor. In Europe the method was adapted to the marine section of the EUNIS (European Nature Information System) classification of habitat types under the MESH project, andwas applied at an operational level in 2011 under the EUSeaMap project. The present study compiled GIS layers for fundamental physical parameters in the northeast Atlantic, including (i) bathymetry, (ii) substrate type, (iii) light penetration depth and (iv) exposure to near-seafloor currents andwave action. Based on analyses of biological occurrences, significant thresholds were fine-tuned for each of the abiotic layers and later used in multi-criteria raster algebra for the integration of the layers into a seafloor habitat map. The final result was a harmonised broad-scale seafloor habitat map with a 250 m pixel size covering four extensive areas, i.e. Ireland, the Bay of Biscay, the Iberian Peninsula and the Azores. The map provided the first comprehensive perception of habitat spatial distribution for the Iberian Peninsula and the Azores, and fed into the initiative for a pan- European map initiated by the EUSeaMap project for Baltic, North, Celtic and Mediterranean seas.
- Co-design of a marine protected area zoning and the lessons learned from itPublication . e Costa, Horta; Guimarães, M. Helena; Rangel, Mafalda; Ressurreição, Adriana; Monteiro, Pedro; Oliveira, Frederico; Bentes, Luis; Sales Henriques, Nuno; Sousa, Inês; Alexandre, Sofia; Pontes, João; Afonso, Carlos; Belackova, Adela; Marçalo, Ana; Cardoso-Andrade, Mariana; Correia, António José; Lobo, Vanda; Gonçalves, Emanuel J.; Pitta e Cunha, Tiago; Gonçalves, Jorge Manuel SantosMarine Protected Areas (MPAs) are a tool to safeguard marine natural systems, yet their effectiveness depends on how well they are integrated into the existing socioeconomic context. Stakeholder engagement in MPA design can contribute to increasing integration. This study focuses on the co-design of an MPA between researchers, public administration, the private sector, and non-governmental organizations. The proposed MPA is in Portugal and includes an area that is a hotspot for biodiversity and economic activities. This is the first MPA proposal in mainland Portugal co-designed using a participatory approach. This study highlights the steps of the zoning process and synthesizes the eight main lessons learned, useful for other cases, particularly for relatively small coastal MPAs with multiple socioeconomic activities. Three zoning proposals were developed and discussed within the participatory process. The proposals considered the best scientific and local knowledge available and were defined using ecological, socioeconomic, and shape-area guiding principles. In an iterative manner and following a participatory approach, compromises with stakeholders were achieved, and a final proposal, scientifically sound and socially accepted by most stakeholders, was delivered to the government. The final zoning plan will achieve ambitious conservation goals, including the largest fully protected area to be declared in mainland Portugal, while minimizing the impacts on the existing economic activities and promoting its sustainability. This process resulted in valuable lessons that may be applied elsewhere and guide future MPA implementation or rezoning of existing ones. These transdisciplinary and participatory processes can be time and resource-consuming but are vital for ensuring MPA effectiveness.
- 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.
- Do fisher associations really represent their members’ needs and opinions? The case study of the octopus fishery in the Algarve (south Portugal)Publication . Rangel, Mafalda; Pita, Cristina; de Oliveira, Manuela Maria; Guimarães, Maria Helena; Rainha, Rita; Sonderblohm, Carlos; Monteiro, Pedro; Oliveira, Frederico; Ballesteros, Marta; Gonçalves, Jorge Manuel Santos; Pierce, Graham J.; Erzini, KarimFishers’ participation in the fishery management decision-making process is generally low, particularly in small-scale fisheries (SSF). Within the overarching goal of improving fisheries governance, fishers’ participation is crucial. Yet, how can fishers participate in the decision-making processes which affect their actions, and to what extent do fisher associations represent their interests? These questions were tackled by means of an empirical case study in the “Tertúlia do Polvo” project, focusing on the octopus SSF in the Algarve region (south Portugal), where the octopus fishery is managed top-down with sporadic participation of fishers. During the study (2014 and 2015), seven participatory workshops (tertúlias) were held, involving fisher associations, management authorities and researchers, to propose and discuss management measures for the fishery. Also, a face-to-face questionnaire survey (121 valid replies) was undertaken with local fishers to gauge their opinions about the management measures proposed during the workshops. Results show a strong agreement between the outcomes achieved during the workshops and the main concerns and possible solutions identified by fishers. Taking into consideration the difficulty in structuring and assuring a transparent and effective participation of fishers in the management of their activity, the results obtained are promising. In this study, the use of a participatory process (restricted to a small group of stakeholders) combined with consultation (targeting a sample of the fisher population) allowed the validation of the overall results obtained. Such a methodological approach can be tried in other fishing communities to implement efficient and effective collaborative management, contributing to improved fisheries governance.
- Effects of different slipping methods on the mortality of sardine, Sardina pilchardus, after purse-seine capture off the Portuguese Southern coast (Algarve)Publication . Marçalo, Ana; Guerreiro, Pedro; Bentes, Luis; Rangel, Mafalda; Monteiro, Pedro; Oliveira, Frederico; Afonso, Carlos; Pousao-Ferreira, Pedro; Benoit, Hugues P.; Breen, Mike; Erzini, Karim; Gonçalves, Jorge Manuel SantosThe effects of two different slipping methods on the survival, physical and physiological response of sardines, Sardina pilchardus, captured in a purse-seine fishery were investigated in southern Portugal. Sardines were collected and transferred into holding tanks onboard a commercial fishing vessel after being captured, crowded and deliberately released using two slipping procedures: standard and modified. The standard slipping procedure aggregated fish at high densities and made them "roll over" the floatline, while the modified procedure aggregated the fish at moderate densities and enabled them to escape through an opening created by adding weights to the floatline. Both slipping methods were compared with minimally harmed non-slipped sardines (sardines collected from the loose pocket of the purse seine). Survival rates were monitored in captivity over 28 days using three replicates for each treatment. The estimated survival of sardines was 43.6% for the non-slipped fish, 44.7% for the modified slipping and 11.7% for the standard slipping treatments. Scale loss indicated the level of physical impact experienced, with dead fish from the non-slipped and modified slipping technique showing significantly lower scale loss than those fish from the standard slipping treatment within the same period. Of the physiological indicators of stress measured, cortisol, glucose, lactate and osmolality attained peak values during slipping and up to the first hours after introduction to captivity. This work indicates that although delayed mortality after release may be substantial, appropriately modified slipping techniques significantly enhance survival of slipped sardines.