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Auteur Melo, D.C.M.; Lira, S.M.A.; Moreira, A.P.B.; Freitas, L.; Lima, C.A.D.; Thompson, F.; Bertrand, A.; Silva, A.C.; Neumann-Leitao, S. doi  openurl
  Titre Genetic diversity and connectivity of Flaccisagitta enflata (Chaetognatha: Sagittidae) in the tropical Atlantic ocean (northeastern Brazil) Type Article scientifique
  Année (down) 2020 Publication Revue Abrégée PLoS One  
  Volume 15 Numéro 5 Pages e0231574  
  Mots-Clés acartia-tonsa; copepod; differentiation; global phylogeography; heterogeneity; marine; mesozooplankton; mitochondrial-dna; pelagic chaetognath; population-structure  
  Résumé The phylogeography of the holoplanktonic chaetognath Flaccisagitta enflata was investigated in the Tropical Western Atlantic (TWA). Considering the cosmopolitan range of this species and the fact that its entire life cycle is planktonic, the central hypothesis of this study is that F. enflata exhibits connectivity due to its high dispersal capacity, forming a panmictic population among the study sites. The evaluated areas included neritic (Port of Recife-PR, and Tamandare – TA) and oceanic (Fernando de Noronha Archipelago-FN, Rocas Atoll-RA, Guara seamount-GS and Saint Peter and Saint Paul's Archipelago-SPSPA) locations of the Brazilian Blue Amazon. We used COI gene sequences as molecular marker. Partial sequences (425 bp) were obtained for 116 specimens and employed to reconstruct the phylogeny, build an haplotype network, evaluate gene flow through a migration model, and estimate diversity indices, population structuring and demographic history. High levels of haplotype diversity (mean: 0.98) and moderate to high levels of nucleotide diversity (mean: 0.023) were observed. The phylogeny and the haplotype network topologies showed some geographic clustering, indicating local structuring in GS and PR. This finding was supported by the AMOVA high global phi st (0.033, significant) and some pairwise phi st comparisons (7 out of 15 were significantly > 0). Significant differences suggested lower levels of connectivity when GS population was compared to those of FN and SPSPA; as well as when TA was compared to FN. These results might be related to particularities of the oceanic dynamics which rules the TWA, sustaining such dissimilarities. Structuring was also observed between PR and all oceanic locations. We hypothesize that the topography of the port inlet, enclosured by a reef barrier, may constrain the water turnover ratio and thus migration rates of F. enflata in the TWA. Accordingly, Migrate-N yielded a four metapopulations model (PR (sic) TA (sic) SPSPA+FN (sic) GS+RA) as the best (highest probability; similar to 0.90) to represent the structuring of F. enflata in the TWA. Therefore, the null hypothesis of one randomly mating population cannot be accepted. The demographic evaluation demonstrated that the neutral hypothesis of stable populations may not be rejected for most of the locations. This work is the start point to broaden the knowledge on the phylogeography and population genetic structure of a numerically dominant species in the Western Atlantic, with key role in the marine trophic web.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2911  
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Auteur Cardiec, F.; Bertrand, S.; Witt, M.J.; Metcalfe, K.; Godley, B.J.; McClellan, C.; Vilela, R.; Parnell, R.J.; Loc’h, F. le url  doi
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  Titre “Too Big To Ignore”: A feasibility analysis of detecting fishing events in Gabonese small-scale fisheries Type Article scientifique
  Année (down) 2020 Publication Revue Abrégée Plos One  
  Volume 15 Numéro 6 Pages e0234091  
  Mots-Clés Animal behavior; Animal tagging; Boats; Engines; Fish; Fisheries; Gabon; Hidden Markov models  
  Résumé In many developing countries, small-scale fisheries provide employment and important food security for local populations. To support resource management, the description of the spatiotemporal extent of fisheries is necessary, but often poorly understood due to the diffuse nature of effort, operated from numerous small wooden vessels. Here, in Gabon, Central Africa, we applied Hidden Markov Models to detect fishing patterns in seven different fisheries (with different gears) from GPS data. Models were compared to information collected by on-board observers (7 trips) and, at a larger scale, to a visual interpretation method (99 trips). Models utilizing different sampling resolutions of GPS acquisition were also tested. Model prediction accuracy was high with GPS data sampling rates up to three minutes apart. The minor loss of accuracy linked to model classification is largely compensated by the savings in time required for analysis, especially in a context of nations or organizations with limited resources. This method could be applied to larger datasets at a national or international scale to identify and more adequately manage fishing effort.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2815  
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Auteur Trombetta, T.; Vidussi, F.; Mas, S.; Parin, D.; Simier, M.; Mostajir, B. url  doi
openurl 
  Titre Water temperature drives phytoplankton blooms in coastal waters Type Article scientifique
  Année (down) 2019 Publication Revue Abrégée Plos One  
  Volume 14 Numéro 4 Pages e0214933  
  Mots-Clés Artificial light; Biomass; Food web structure; Phytoplankton; Salinity; Spring; Surface water; Wind  
  Résumé Phytoplankton blooms are an important, widespread phenomenon in open oceans, coastal waters and freshwaters, supporting food webs and essential ecosystem services. Blooms are even more important in exploited coastal waters for maintaining high resource production. However, the environmental factors driving blooms in shallow productive coastal waters are still unclear, making it difficult to assess how environmental fluctuations influence bloom phenology and productivity. To gain insights into bloom phenology, Chl a fluorescence and meteorological and hydrological parameters were monitored at high-frequency (15 min) and nutrient concentrations and phytoplankton abundance and diversity, were monitored weekly in a typical Mediterranean shallow coastal system (Thau Lagoon). This study was carried out from winter to late spring in two successive years with different climatic conditions: 2014/2015 was typical, but the winter of 2015/2016 was the warmest on record. Rising water temperature was the main driver of phytoplankton blooms. However, blooms were sometimes correlated with winds and sometimes correlated with salinity, suggesting nutrients were supplied by water transport via winds, saltier seawater intake, rain and water flow events. This finding indicates the joint role of these factors in determining the success of phytoplankton blooms. Furthermore, interannual variability showed that winter water temperature was higher in 2016 than in 2015, resulting in lower phytoplankton biomass accumulation in the following spring. Moreover, the phytoplankton abundances and diversity also changed: cyanobacteria (< 1 μm), picoeukaryotes (< 1 μm) and nanoeukaryotes (3–6 μm) increased to the detriment of larger phytoplankton such as diatoms. Water temperature is a key factor affecting phytoplankton bloom dynamics in shallow productive coastal waters and could become crucial with future global warming by modifying bloom phenology and changing phytoplankton community structure, in turn affecting the entire food web and ecosystem services.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2565  
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Auteur Henckel, L.; Meynard, C.N.; Devictor, V.; Mouquet, N.; Bretagnolle, V. doi  openurl
  Titre On the relative importance of space and environment in farmland bird community assembly Type Article scientifique
  Année (down) 2019 Publication Revue Abrégée PLoS One  
  Volume 14 Numéro 3 Pages e0213360  
  Mots-Clés beta diversity; dispersal; ecology; habitat; landscape; metacommunity structure; model; patterns; scale; skylarks alauda arvensis  
  Résumé The relative contribution of ecological processes in shaping metacommunity dynamics in heavily managed landscapes is still unclear. Here we used two complementary approaches to disentangle the role of environment and spatial effect in farmland bird community assembly in an intensive agro-ecosystem. We hypothesized that the interaction between habitat patches and dispersal should play a major role in such unstable and unpredictable environments. First, we used a metacommunity patterns analysis to characterize species co-occurrences and identify the main drivers of community assembly; secondly, variation partitioning was used to disentangle environmental and geographical factors (such as dispersal limitation) on community structure and composition. We used high spatial resolution data on bird community structure and composition distributed among 260 plots in an agricultural landscape. Species were partitioned into functional classes, and point count stations were classified according to landscape characteristics before applying metacommunity and partitioning analyses within each. Overall we could explain around 20% of the variance in species composition in our system, revealing that stochasticity remains very important at this scale. However, this proportion varies depending on the scale of analysis, and reveals potentially important contributions of environmental filtering and dispersal. These conclusions are further reinforced when the analysis was deconstructed by bird functional classes or by landscape habitat classes, underlining trait-related filters, thus reinforcing the idea that wooded areas in these agroecosystems may represent important sources for a specific group of bird species. Our analysis shows that deconstructing the species assemblages into separate functional groups and types of landscapes, along with a combination of analysis strategies, can help in understanding the mechanisms driving community assembly.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2548  
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Auteur Heather, F.J.; Childs, D.Z.; Darnaude, A.M.; Blanchard, J.L. url  doi
openurl 
  Titre Using an integral projection model to assess the effect of temperature on the growth of gilthead seabream Sparus aurata Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Plos One  
  Volume 13 Numéro 5 Pages e0196092  
  Mots-Clés Age groups; Aquaculture; Fish; Fisheries; Lagoons; Linear regression analysis; Otolith; Oxygen  
  Résumé Accurate information on the growth rates of fish is crucial for fisheries stock assessment and management. Empirical life history parameters (von Bertalanffy growth) are widely fitted to cross-sectional size-at-age data sampled from fish populations. This method often assumes that environmental factors affecting growth remain constant over time. The current study utilized longitudinal life history information contained in otoliths from 412 juveniles and adults of gilthead seabream, Sparus aurata, a commercially important species fished and farmed throughout the Mediterranean. Historical annual growth rates over 11 consecutive years (2002–2012) in the Gulf of Lions (NW Mediterranean) were reconstructed to investigate the effect of temperature variations on the annual growth of this fish. S. aurata growth was modelled linearly as the relationship between otolith size at year t against otolith size at the previous year t-1. The effect of temperature on growth was modelled with linear mixed effects models and a simplified linear model to be implemented in a cohort Integral Projection Model (cIPM). The cIPM was used to project S. aurata growth, year to year, under different temperature scenarios. Our results determined current increasing summer temperatures to have a negative effect on S. aurata annual growth in the Gulf of Lions. They suggest that global warming already has and will further have a significant impact on S. aurata size-at-age, with important implications for age-structured stock assessments and reference points used in fisheries.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2348  
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