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- Comparison of small remotely operated vehicles and diver-operated video of circalittoral benthosPublication . Boavida, Joana; Assis, J.; Reed, John; Serrão, Ester; Gonçalves, Jorge Manuel SantosUnderwater video transect methods using small remotely operated vehicles (ROVs) and diver-operated video (DOV) are commonly used in benthic biodiversity assessments. Constraints posed by deeper waters have made surveys of the circalittoral zone (> 30 m depth), a particularly challenging problem. Here we compare benthic diversity metrics and cluster analyses obtained with ROV and DOV between 45 and 65 m depth off southwest Iberia, across local (tens to hundreds of meters) and regional scales (tens of kilometers). Results showed no difference between methods in terms of the benthic species richness, taxonomic distinctness, and beta diversity, but only minor differences in the spatial structure depicted at the regional level. At the local scale, DOV performed better at discriminating patterns likely because of the divers visual acuity. We found that small ROV and DOV are reliable and comparable methods for the study of circalittoral benthic assemblages and can be used in a complimentary way to detect the greatest amount of variation in benthic ecosystems. Our study facilitates the understanding of capabilities and limitations of two underwater video methods and provides important insight into choice of the most appropriate technique.
- Genetic diversity increases with depth in red gorgonian populations of the Mediterranean Sea and the Atlantic OceanPublication . Pilczynska, Joanna; Cocito, Silvia; Boavida, Joana; Serrao, Ester; Assis, J.; Fragkopoulou, Eliza; Queiroga, HenriqueIn the ocean, the variability of environmental conditions found along depth gradients exposes populations to contrasting levels of perturbation, which can be reflected in the overall patterns of species genetic diversity. At shallow sites, resource availability may structure large, persistent and well-connected populations with higher levels of diversity. In contrast, the more extreme conditions, such as thermal stress during heat waves, can lead to population bottlenecks and genetic erosion, inverting the natural expectation. Here we examine how genetic diversity varies along depth for a long-lived, important ecosystem-structuring species, the red gorgonian, Paramuricea clavata.
- Performing fish counts with a wide-angle camera, a promising approach reducing divers' limitationsPublication . Assis, J.; Claro, B.; Ramos, Ana; Boavida, Joana; Serrão, EsterVisual standardised methods for census of reef fishes have long been used in fisheries management and biological surveys. However, these tools have inherent sources of bias and the SCUBA divers who perform them are highly constrained in terms of survey time,maximumdepth and frequency of sampling. Alternatives like underwater video are thus being recommended in a wide range of configurations. Yet, all these techniques are still limited in field of view, particularly when compared to the ability of a SCUBA diver performing censuses. In this scope, we evaluated the potential of an underwater wide-angle camera (UWC) to survey fish assemblages by testing it against instantaneous underwater visual census (UVC). Our results showed minimal yet significant differences between methods, mainly because of the camera's loss of resolution when under extreme visibility conditions. Both approaches had the same consistency and ability to detect changes in fish assemblages but, to estimate total species richness, the UWC needed less field effort. Moreover, a SCUBA diver performing census had an effect on fish assemblages which introduced differences of greater magnitude than those found between methods. The removal of the diver effect, the proven ability to detect changes in fish assemblages and the verified gain in field effort, pointed the wide-angle camera as a promising tool to perform census of reef fishes.
- Genetic diversity and local connectivity in the mediterranean red gorgonian coral after mass mortality eventsPublication . Pilczynska, Joanna; Cocito, Silvia; Boavida, Joana; Serrão, Ester; Queiroga, HenriqueEstimating the patterns of connectivity in marine taxa with planktonic dispersive stages is a challenging but crucial task because of its conservation implications. The red gorgonian Paramuricea clavata is a habitat forming species, characterized by short larval dispersal and high reproductive output, but low recruitment. In the recent past, the species was impacted by mass mortality events caused by increased water temperatures in summer. In the present study, we used 9 microsatellites to investigate the genetic structure and connectivity in the highly threatened populations from the Ligurian Sea (NW Mediterranean). No evidence for a recent bottleneck neither decreased genetic diversity in sites impacted by mass mortality events were found. Significant IBD pattern and high global F-ST confirmed low larval dispersal capability in the red gorgonian. The maximum dispersal distance was estimated at 20-60 km. Larval exchange between sites separated by hundreds of meters and between different depths was detected at each site, supporting the hypothesis that deeper subpopulations unaffected by surface warming peaks may provide larvae for shallower ones, enabling recovery after climatically induced mortality events.
- Human mercury exposure levels and fish consumption at the French RivieraPublication . Petrova, Mariia, V; Ourgaud, Melanie; Boavida, Joana; Dufour, Aurelie; Onrubia, Javier A. Tesan; Lozingot, Aurelia; Heimburger-Boavida, Lars-EricHumans are exposed to methylmercury (MeHg), a bioaccumulative neurotoxin, mainly through the consumption of marine fish. Several studies showed that high MeHg exposure can lead to neurological damage. This is particularly relevant for pregnant women, because MeHg exposure negatively impacts foetal development. Populations living near the sea are generally at increased exposure risk due to higher consumption of fish and seafood. Here, we present the first study of MeHg exposure levels of the population living at the French Riviera, using mercury (Hg) concentrations in hair as a proxy for MeHg exposure. We found that older people that consume more fish presented the highest hair Hg concentrations. Compared to other Mediterranean bordering countries and other European countries, the southern France population is among those with high MeHg exposure (median for women of childbearing age is 0.56 mu g g(-1)). A global implementation of the Minamata Convention is necessary to lower MeHg exposure of the population. (C) 2020 Elsevier Ltd. All rights reserved.
- Open coast seagrass restoration. Can we do it? Large scale seagrass transplantsPublication . Paulo, Diogo; Cunha, Alexandra H.; Boavida, Joana; Serrao, Ester; Gonçalves, Emanuel J.; Fonseca, MarkSome of the major challenges in seagrass restoration on exposed open coasts are the choice of transplant design that is optimal for coastlines periodically exposed to high water motion, and understanding the survival and dynamics of the transplanted areas on a long time-scale over many years. To contribute to a better understanding of these challenges, we describe here part of a large-scale seagrass restoration program conducted in a Marine Park in Portugal. The goal of this study was to infer if it was possible to recover seagrass habitat in this region, in order to restore its ecosystem functions. To infer which methods would produce better long term persistence to recover seagrass habitat, three factors were assessed: donor seagrass species, transplant season, source location. Monitoring was done three times a year for 8 years, in which areas and densities of the planted units were measured, to assess survival and growth. The best results were obtained with the species Zostera marina transplanted during spring and summer as compared to Zostera noltii and Cymodocea nodosa. Long-term persistence of established (well rooted) transplants was mainly affected by extreme winter storms but there was evidence of fish grazing effects also. Our results indicate that persistence assessments should be done in the long term, as all transplants were successful (survived and grew initially) in the short term, but were not resistant in the long term after a winter with exceptionally strong storms. The interesting observation that only the largest (11 m(2)) transplanted plot of Z marina persisted over a long time, increasing to 103 m(2) in 8 years, overcoming storms and grazing, raised the hypothesis that for a successful shift to a vegetated state it might be necessary to overpass a minimum critical size or tipping point. This hypothesis was therefore tested with replicates from two donor populations and results showed effects of size and donor population, as only the larger planting units (PUs) from one donor population persisted and expanded. It is recommended that in future habitat restoration efforts large PUs are considered.
- High coral bycatch in bottom-set Gillnet Coastal fisheries reveals rich coral habitats in Southern PortugalPublication . Dias, Vítor; Oliveira, Frederico; Boavida, Joana; Serrao, Ester; Gonçalves, Jorge Manuel Santos; Coelho, MárcioBottom-contact fisheries are unquestionably one of the main threats to the ecological integrity and functioning of deep-sea and circalittoral ecosystems, notably cold-water corals (CWC) and coral gardens. Lessons from the destructive impact of bottom trawling highlight the urgent need to understand how fisheries affect these vulnerable marine ecosystems. At the same time, the impact of other fishing gear and small-scale fisheries remains sparsely known despite anecdotal evidence suggesting their impact may be significant. This study aims to provide baseline information on coral bycatch by bottom-set gillnets used by artisanal fisheries in Sagres (Algarve, southwestern Portugal), thereby contributing to understand the impact of the activity but also the diversity and abundance of corals in this region. Coral bycatch frequency and species composition were quantified over two fishing seasons (summer-autumn and spring) for 42 days. The relationship with fishing effort was characterized according to metiers (n = 6). The results showed that 85% of the gillnet deployments caught corals. The maximum number of coral specimens per net was observed in a deployment targeting Lophius budegassa (n = 144). In total, 4,326 coral fragments and colonies of 22 different species were captured (fishing depth range of 57-510 m, mean 139 +/- 8 m). The most affected species were Eunicella verrucosa (32%), Paramuricea grayi (29%), Dendrophyllia cornigera (12%), and Dendrophyllia ramea (6%). The variables found to significantly influence the amount of corals caught were the target species, net length, depth, and mesh size. The 22 species of corals caught as bycatch belong to Orders Alcyonacea (80%), Scleractinia (18%), Zoantharia (1%), and Antipatharia (1%), corresponding to around 13% of the coral species known for the Portuguese mainland coast. These results show that the impact of artisanal fisheries on circalittoral coral gardens and CWC is potentially greater than previously appreciated, which underscores the need for new conservation measures and alternative fishing practices. Measures such as closure of fishing areas, frequent monitoring onboard of fishing vessels, or the development of encounter protocols in national waters are a good course of action. This study highlights the rich coral gardens of Sagres and how artisanal fisheries can pose significant threat to corals habitats in certain areas.
- Overlooked habitat of a vulnerable gorgonian revealed in the Mediterranean and Eastern Atlantic by ecological niche modellingPublication . Boavida, Joana; Assis, J.; Silva, Inga; Serrão, EsterFactors shaping the distribution of mesophotic octocorals (30-200 m depth) remain poorly understood, potentially leaving overlooked coral areas, particularly near their bathymetric and geographic distributional limits. Yet, detailed knowledge about habitat requirements is crucial for conservation of sensitive gorgonians. Here we use Ecological Niche Modelling (ENM) relating thirteen environmental predictors and a highly comprehensive presence dataset, enhanced by SCUBA diving surveys, to investigate the suitable habitat of an important structuring species, Paramuricea clavata, throughout its distribution (Mediterranean and adjacent Atlantic). Models showed that temperature (11.5-25.5 degrees C) and slope are the most important predictors carving the niche of P. clavata. Prediction throughout the full distribution (TSS 0.9) included known locations of P. clavata alongside with previously unknown or unreported sites along the coast of Portugal and Africa, including seamounts. These predictions increase the understanding of the potential distribution for the northern Mediterranean and indicate suitable hard bottom areas down to > 150 m depth. Poorly sampled habitats with predicted presence along Algeria, Alboran Sea and adjacent Atlantic coasts encourage further investigation. We propose that surveys of target areas from the predicted distribution map, together with local expert knowledge, may lead to discoveries of new P. clavata sites and identify priority conservation areas.
- Population model of the recent subtidal invasion of Sargassum muticum in southern PortugalPublication . Boavida, Joana Ruela; Santos, Rui; Engelen, A. H.As espécies invasoras constituem uma ameaça à biodiversidade global. Actualmente, a tendência no estudo das espécies introduzidas é tentar elucidar os padrões e os processos que podem estar envolvidos no estabelecimento e capacidade invasora das espécies exóticas. A alga castanha Sargassum muticum é originária da Ásia oriental, onde existem muitas espécies de Sargassum. Na Europa foi introduzida no início dos anos 1970 e actualmente encontra-se distribuída ao longo da costa Atlântica Europeia, desde a Noruega até Portugal, assim como em algumas zonas do Mediterrâneo. Na costa Oeste portuguesa foi inicialmente observada na zona intermareal da Figueira da Foz em 1989. Desde então já se estendeu para Sul. Na costa Oeste a espécie desenvolve-se maioritariamente em poças intermareais, mas na costa Sul foi recentemente observada na zona subtidal, no porto de pesca de Albufeira assim como no Parque Natural da Ria Formosa. Combinando informação obtida através de um modelo de matriz baseado nas diferentes fases do ciclo de vida com observações sobre a estratégia de vida de S. muticum, este estudo pretendeu (1) estimar o tamanho total da população estabelecida na Ria Formosa e no porto de pesca da Albufeira, (2) descrever o seu ciclo de vida sazonal, (3) reconhecer a importância relativa da reprodução, sobrevivência dos micro recrutas (incluindo o efeito de herbívoros), regeneração dos órgãos de fixação e persistência das fases adultas para a manutenção e crescimento da população, (4) e finalmente a identificação de fases críticas do ciclo de vida que possam ser alvos adequados a acções de gestão com vista a proteger áreas invadidas. O resultado esperado é que a reprodução e a sobrevivência dos micro recrutas sejam críticas para o crescimento da população, já que têm sido mencionados frequentemente na literatura como importantes características para o sucesso invasor desta alga. Um modelo periódico de matriz foi construído, com base nas sete fases do ciclo de vida. Uma fase microscópica: micro recrutas, e seis fases macroscópicas: juvenis (J), que se identificam como pequenos talos com folhas mas sem um órgão de fixação desenvolvido ou ramificações, adultos não reprodutivos sem vesículas gasosas (A), adultos não reprodutivos com vesículas gasosas (G), adultos reprodutivos sem vesículas gasosas (F), adultos reprodutivos com vesículas gasosas (FG), e indivíduos que consistem apenas num órgão de fixação basal (H). Numa experiência no campo o assentamento dos micro recrutas foi monitorizado, utilizando substratos artificiais. Numa outra experiência o efeito dos mesoherbívoros nos micro recrutas foi estimado através de substratos iv artificiais “semeados” em laboratório, posteriormente incubados no campo. Estes substratos foram divididos por diferentes tratamentos, um em que os recrutas não são afectados pelos herbívoros, um outro em que se deixa acesso livre aos herbívoros e um terceiro como controlo. Esta experiência foi realizado em dois locais, na ria Formosa e no porto de pesca de Albufeira. As probabilidades de transição dos micro recrutas foram estimadas através da experiência de assentamento e incluídas no modelo. Para determinar as transições das fases macroscópicas, indivíduos de cada fase foram marcados na Ria Formosa e seguidos ao longo de vários meses. O comprimento de cada indivíduo foi registado para análise da distribuição de classes de comprimentos. A análise do modelo foi realizada com MatLab 7.0. A informação sobre transições e taxas vitais da população da Ria Formosa foi utilizada para a elaboração do modelo. Os valores reprodutivos foram calculados através das matrizes populacionais. Estes valores permitem reconhecer as fases do ciclo de vida que mais contribuem para as futuras gerações. A análise de elasticidade é um conjunto de técnicas que permite perceber como o modelo responde a variações nos seus parâmetros, desta forma permitindo determinar quais são as fases mais importantes e vulneráveis do ciclo de vida da espécie. Foram simuladas três estratégias de gestão, remoção com draga, apanha manual e corte. S. muticum no Sul de Portugal demonstrou um ciclo de vida no qual a reprodução ocorre durante um curto período de tempo de três meses (Março a Maio ou Abril a Junho), durante a Primavera. Também ocorre reprodução assexuada a partir dos órgãos de fixação da alga. No início do Verão, uma curta época de quebra das frondes tem lugar. Durante o Verão os micro recrutas desenvolvem-se e os órgãos de fixação basais entram na época de regeneração, desenvolvendo lentamente novas folhas e ramificações. Antes da reprodução tem início uma época de crescimento rápido. A sobrevivência dos micro recrutas revelou-se independente do tratamento a que foram sujeitos. No geral, o assentamento e a sobrevivência dos micro recrutas foram baixos, e na Ria Formosa a sobrevivência foi superior do que no porto de pesca de Albufeira, o que poderá estar relacionado com diferentes condições abióticas e composição faunística dos locais. A população total na Ria Formosa já alcançou mais de 450000 indivíduos, estendendo-se por mais de 4 km2. No porto de pesca de Albufeira a área invadida é menor, 2,5 km2 e a população alcança quase 450000 indivíduos. O ciclo de vida sazonal da espécie mostra que o padrão é semelhante em toda a Europa. Nos países do norte da Europa também foi observada uma alternância entre uma época de crescimento lento prolongado após o curto período de quebra, com uma época de v crescimento rápido. A taxa de crescimento da população revelou que a população da Ria Formosa está a decrescer (Q = 0,6 ± 0,1). A análise de elasticidade demonstrou que a persistência dos indivíduos adultos foi a transição mais importante para a taxa de crescimento da população, especialmente durante a Primavera e o início do Verão, e permitiu reconhecer que, surpreendentemente, a reprodução e a sobrevivência dos micro recrutas (incluindo o efeito de mesoherbívoros) não têm importância para a manutenção e crescimento da população. Além disso, permitiu concluir que a regeneração a partir dos órgãos de fixação e persistência de fases adultas durante o ano contribuem de forma notável para a população, sendo os melhores alvos num contexto de gestão. Esta situação poderá ser uma resposta desta população a condições desfavoráveis que se verificaram no ano anterior a este estudo, tais como uma campanha de remoção e condições abióticas não estudadas neste trabalho. Finalmente, foi possível identificar que a melhor estratégia de gestão consistirá na dragagem da área invadida.
- High genetic differentiation of red gorgonian populations from the Atlantic Ocean and the Mediterranean SeaPublication . Pilczynska, Joanna; Cocito, Silvia; boavida, joana; A, Serrão; Queiroga, HenriquePatterns of genetic variation within a species may be used to infer past events in the evolutionary history of marine species. In the present study we aimed to compare the genetic diversity of the red gorgonian Paramuricea clavata in the Atlantic Ocean and the Mediterranean Sea. For genetic markers we used microsatellites and a mitochondrial gene fragment. Our results revealed a distinct genetic composition and diversity between the Mediterranean and the Atlantic. The Mediterranean samples had higher microsatellite heterozygosity, allelic richness and private allelic richness. The hypotheses that can explain these patterns are the isolation of Atlantic populations and/or a founder effect. Additionally, a clear difference was obtained from the mitochondrial locus, since sequences from Atlantic and Mediterranean samples diverged by 1%, which is high for soft corals.