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- Movements of Sarpa salpa (Linnaeus, 1758) (Sparidae) in a coastal lagoon (Ria Formosa, Portugal)Publication . Abecasis, D.; Bentes, L.; Erzini, KarimThe salema, Sarpa salpa (Linnaeus, 1758), is a sparid with a distribution that includes the eastern Atlantic coast from the Bay of Biscay to South Africa, as well as the Azores, Madeira, Canary and Cape Verde archipelagos. It is also found in groups in the Mediterranean Sea and the Indian Ocean from South Africa to Mozambique, living on sandy and seagrass bottoms ranging from 0 to 70 m depth (Bauchot and Hureau, 1986). The species is a protandrous hermaphrodite where, according to Criscoli et al. (2006), sex change occurs between 24 and 31 cm total length (3–7 years old). While the economic value of S. salpa in fisheries is relatively limited, its ecological importance is well recognized, with several studies on its biology and interactions on seagrass meadows (e.g. Verlaque, 1990; Criscoli et al., 2006). As an herbivore Sarpa salpa has a strong impact with seagrass meadows, being responsible for much of the herbivory (Verlaque, 1990; Cebria´n et al., 1996; Prado et al., 2008), and representing a considerable part of the ichthyofauna in these habitats (Francour, 1997, 2000). Studies on S. salpa diel activity patterns, home range and habitat utilization in the Mediterranean Sea were undertaken by Jadot et al. (2002, 2006). These studies have revealed two behaviours, with some fish being highly sedentary while others use larger areas; great variation in mobility was found, with some fish showing both behaviours. The core areas (95%) range between 1600 and 279 000m2 , with some fish presenting diel movement patterns between day and night areas as well as homing abilities. The Ria Formosa, in the southern part of Portugal, is a shallow coastal lagoon with large meadows of seagrasses (Zostera noltii, Zostera marina and Cymodocea nodosa) where the influence of S. salpa on these communities is still unknown. Previous studies on the ichthyofauna of the Ria Formosa coastal lagoon focused largely on temporal and spatial changes in species composition (Monteiro et al., 1990; Ribeiro et al., 2006, 2008). Up to the present, the acoustic telemetry studies carried out in the Ria Formosa focused on the movements and home range of Sparus aurata (Abecasis and Erzini, 2008) and Diplodus spp. (Abecasis et al., 2009). A preceding tag-recapture study of juveniles of S. salpa (between 8.2 and 16.7 cm total length) provided limited information, with only a few recaptures (Abecasis, 2007). The present study was carried out to determine the movement patterns of S. salpa inside a coastal lagoon (Ria Formosa, south Portugal) in order to provide basic information on their home range and site fidelity.
- The impact of trammel nets as an MPA soft bottom monitoring methodPublication . Priester, C. Robert; Martínez-Ramírez, Lucas; Erzini, Karim; Abecasis, DavidWith the global increase of marine protected area (MPA) implementation, the need for monitoring and the evaluation of their effectiveness becomes ever more important. Currently there is a severe lack of information about the protection effects of soft-substrate ecosystems. While many different methods have been established for the monitoring of hard-substrate ecosystems, most of these minimally invasive methods prove ineffective for soft- bottom habitats. Information and quantification of the impact of monitoring methods is needed to provide decision makers with the necessary knowledge to choose appropriate and feasible monitoring methods. In this study we quantify the impact of experimental trammel net fishing as a monitoring method of the soft-substrate demersal fish community using the Arrábida MPA (Portugal) as a case study. Over the 14 biannual sampling campaigns (between 2010 and 2019) 21,873 individuals and 5.61 tonnes of fish were caught. The gear is highly effective with an average catch per unit effort higher than reported for commercial fisheries in adjacent areas. When excluding the pelagic species, mortality rates are 41.2% and 30.4% in numbers and biomass, respectively. Most of the dead individuals belong to small, non-protected species with relatively little commercial value while MPA conservation target groups such as Soleidae and Rajidae have high survival rates. Due to its low size- and species-selectivity and the high survival rate of protected valuable species, the trammel net experimental fishing proved to be an effective monitoring method for soft-substrate demersal fish communities. Given their relatively low impact on the local ecosystem experimental trammel nets are a good alternative for areas where nonextractive methods are not effective. Nevertheless, quantification of the impact of other monitoring methods is necessary to enable the determination of the methods with the lowest mortality and impact for future softsubstrate MPA monitoring.
- 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.
- Aplicação de marcação convencional e telemetria no estudo dos movimentos de quatro espécies de esparídeos na ria FormosaPublication . Abecasis, David Maria Aguiar; Erzini, Karim
- Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciencesPublication . Christie, Alec P.; Abecasis, David; Adjeroud, Mehdi; Alonso, Juan C.; Amano, Tatsuya; Anton, Alvaro; Baldigo, Barry P.; Barrientos, Rafael; Bicknell, Jake E.; Buhl, Deborah A.; Cebrian, Just; Ceia, Ricardo S.; Cibils-Martina, Luciana; Clarke, Sarah; Claudet, Joachim; Craig, Michael D.; Davoult, Dominique; De Backer, Annelies; Donovan, Mary K.; Eddy, Tyler D.; França, Filipe M.; Gardner, Jonathan P. A.; Harris, Bradley P.; Huusko, Ari; Jones, Ian L.; Kelaher, Brendan P.; Kotiaho, Janne S.; López-Baucells, Adrià; Major, Heather L.; Mäki-Petäys, Aki; Martín, Beatriz; Martín, Carlos A.; Martin, Philip A.; Mateos-Molina, Daniel; McConnaughey, Robert A.; Meroni, Michele; Meyer, Christoph F. J.; Mills, Kade; Montefalcone, Monica; Noreika, Norbertas; Palacín, Carlos; Pande, Anjali; Pitcher, C. Roland; Ponce, Carlos; Rinella, Matt; Rocha, Ricardo; Ruiz-Delgado, María C.; Schmitter-Soto, Juan J.; Shaffer, Jill A.; Sharma, Shailesh; Sher, Anna A.; Stagnol, Doriane; Stanley, Thomas R.; Stokesbury, Kevin D. E.; Torres, Aurora; Tully, Oliver; Vehanen, Teppo; Watts, Corinne; Zhao, Qingyuan; Sutherland, William J.Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental datasets, that these types of designs usually give less biased estimates than simpler observational designs. We propose a model-based approach to combine study estimates that may suffer from different levels of study design bias, discuss the implications for evidence synthesis, and how to facilitate the use of more credible study designs.
- Multidisciplinary estimates of connectivity and population structure suggest the use of multiple units for the conservation and management of meagre, Argyrosomus regiusPublication . Abecasis, David; Ogden, R.; Winkler, Alexander; Gandra, Miguel; Khallahi, B.; Diallo, M.; Cabrera-Castro, R.; Weiller, Y.; Erzini, Karim; Afonso, P.; Assis, JorgeInformation on population structure and connectivity of targeted species is key for proper implementation of spatial conservation measures. We used a combination of genomics, biophysical modelling, and biotelemetry to infer the population structure and connectivity of Atlantic meagre, an important fisheries resource throughout its distribution. Genetic samples from previously identified Atlantic spawning locations (Gironde, Tejo, Guadalquivir, Banc d'Arguin) and two additional regions (Algarve and Senegal) were analysed using genome-wide SNP-genotyping and mitochondrial DNA analyses. Biophysical models were conducted to investigate larval dispersal and connectivity from the known Atlantic spawning locations. Additionally, thirteen fish were double-tagged with biotelemetry transmitters off the Algarve (Portugal) to assess movement patterns and connectivity of adult individuals. This multidisciplinary approach provided a robust overview of meagre population structure and connectivity in the Atlantic. Nuclear SNP-genotyping showed a clear differentiation between the European and African populations, with significant isolation of the few known Atlantic spawning sites. The limited level of connectivity between these subpopulations is potentially driven by adults, capable of wide-ranging movements and connecting sites 500 km apart, as evidenced by tagging studies, whilst larval dispersal inferred by modelling is much more limited (average of 52 km; 95% of connectivity events up to 174 km). Our results show sufficient evidence of population structure, particularly between Africa and Europe but also within Europe, for the meagre to be managed as separate stocks. Additionally, considering the low degree of larvae connectivity, the implementation of marine protected areas in key spawning sites could be crucial towards species sustainability.
- Changes in movements of white seabream (Diplodus sargus) during the reproductive seasonPublication . Abecasis, D.; Afonso, P.; Erzini, KarimIt has been hypothesized, based on anecdotal information and reports, that adult white seabream migrate and aggregate during spawning. Because most of the past telemetric studies on this ecologically and commercially important species were short in duration and did not cover the reproductive season, we set out to use longer-term passive acoustic telemetry to test this hypothesis. We found that white seabream expands its home range and increases the frequency of forays during the reproductive season, but found no obvious signs of spawning aggregations. Our results thus provide evidence for short-range behavioral shifts in fish space use related to reproductive activity, and support the notion that small MPAs may be effective in managing reef fish populations by effectively protecting their spawning biomass. (c) 2015 Elsevier Ltd. All rights reserved.
- Toward adaptive management of coastal MPAs: The influence of different conservation targets and costs on the design of no-take areasPublication . Abecasis, D.; Afonso, P.; Erzini, KarimThere is still much discussion on the most appropriate location, size and shape of marine protected areas (MPAs). These three factors were analyzed for a small coastal MPA, the Luiz Saldanha Marine Park (LSMP), for which a very limited amount of local ecological information was available when implemented in 1998. Marxan was used to provide a number of near-optimal solutions considering different levels of protection for the various conservation features and different costs. These solutions were compared with the existing no-take area of the LSMP. Information on 11 habitat types and distribution models for 3 of the most important species for the local artisanal fisheries was considered. The human activities with the highest economic and ecological impact in the study area (commercial and recreational fishing and scuba diving) were used as costs. The results show that the existing no-take area is actually located in the best area. However, the no-take area offers limited protection to vagile fish and covers a very small proportion of some of the available habitats. An increase in the conservation targets led to an increase in the number of no-take areas. The comparative framework used in this study can be applied elsewhere, providing relevant information to local stakeholders and managers in order to proceed with adaptive management. (C) 2015 Elsevier B.V. All rights reserved.
- Reserve effect of a small North-East Atlantic marine protected area (Arrabida, Portugal) on soft-sediment fish speciesPublication . Martínez Ramírez, Lucas; Priester, Carl Robert; Sousa, Inês; Erzini, Karim; Abecasis, DavidThe implementation of marine protected areas (MPAs) has been widely used as a tool to manage and conserve marine resources and services. Yet, to date, the reserve effect is still weakly evaluated, particularly for soft-sediment habitats. The Arrabida MPA, considered as a biodiversity hotspot, was fully established in 2009 on the west coast of Portugal and is characterized by large expanses of soft-sediment habitats. This MPA was established to protect biodiversity and to ensure the livelihood of the local small-scale fisheries community. Beyond before-after-control-impact (BACI) analyses were carried out on catch data (abundance and biomass) of 351 trammel net sets from experimental fishing campaigns (2007-2019) to study the reserve effect on demersal fish populations. The results show a declining trend in abundance inside and outside the protected area, with significant positive effects only found for undersize commercial species and Solea senegalensis, and a general increase in fish species total length. Despite the lack of any obvious reserve effect, the increase in fish length can be considered as a first sign. Anthropogenic pressures are generalized around the area, and transgressions of the restrictions are frequently observed inside the no-take zone. These can, among other aspects, delay or prevent the expected reserve effects. Therefore, enforcement and/or modification of the spatial plan must be incentivized to achieve the goals of the MPA.
- Small MPAs do not protect cuttlefish (Sepia officinalis)Publication . Abecasis, D.; Afonso, P.; O'Dor, R. K.; Erzini, KarimMarine reserves have been widely implemented as tools for biodiversity conservation and fisheries management, amongst other goals. A large number of empirical studies have focused on their effects on reef fish populations. Yet, few studies have looked at their effectiveness on semelparous species such as cephalopods, in spite of their commercial importance in many coastal regions across the globe. In this study we combine behavioural (biotelemetry) and demographic (experimental fishing) data to understand the effects of the Luiz Saldanha Marine Park (LSMP) on local populations of cuttlefish, Sepia officinalis. We used a beyond-BACI design to analyze the possible effect of the implementation of a no-take area on the abundance and biomass of this species and acoustic telemetry data to assess its site fidelity and movements within the study area. Results indicate that there was no detectable effect of the implementation of the no-take area on the abundance or biomass of cuttlefish. We found evidence that acoustically tagged adult cuttlefish leave the reserve a few days or weeks after tagging. The fact that cuttlefish have low site fidelity inside the reserve and large movements across and beyond the study area explains why there is no increase in the population inside the MPA. These results suggest that small coastal marine reserves such as the LSMP are not effective in providing long term protection to cuttlefish populations and, probably, those of other short-lived, highly mobile cephalopods. (C) 2013 Elsevier B.V. All rights reserved.