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Auteur (up) BRIND'AMOUR, A.; LAFFARGUE, P.; MORIN, J.; VAZ, S.; FOVEAU, A.; LE BRIS, H.
Titre Morphospecies and taxonomic sufficiency of benthic megafauna in scientific bottom trawl surveys Type Article scientifique
Année 2014 Publication Revue Abrégée Continental Shelf Research
Volume 72 Numéro Pages 1-9
Mots-Clés Bay of Biscay; Benthic descriptor; Bottom trawl surveys; English Channel; North sea; Taxonomic sufficiency
Résumé Scientific fisheries surveys routinely identify a large diversity of commercial and non-commercial benthic megainvertebrates that could provide useful information for Marine Strategy Framework Directive (MSFD) descriptors. Species is obviously the basic taxonomic level to which most ecological studies and theories refer. Identification at this level of organization is indeed always preferred over any other taxonomic level. Nevertheless, aggregation of species to higher taxonomic levels may be unavoidable sometimes, since errors of identification are known or suspected to occur in many surveys. Using analyses of taxonomic sufficiency (identification of organisms at various taxonomic resolutions) and groups of morphospecies (taxa identified easily by non-experts on the basis of evident morphological traits), this study aims to quantify the loss of ecological information incurred by partial identification of benthic megafauna in bottom trawl surveys in order to put such data to good use. The analyses were conducted on five scientific surveys representing a large range of geographical areas (from 150 km2 to 150 000 km2) and environmental conditions. Results show that genus, family and, particularly, morphospecies are good surrogates for species identification in community analyses. We suggest that bottom trawl surveys can provide reliable megafauna data that may usefully complete those obtained by grab surveys. The use of morphospecies could lead to new strategies, combining different datasets to provide indicators for MSFD descriptors (e.g. D6).
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0278-4343 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1141
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Auteur (up) CORMON, X.; LOOTS, C.; VAZ, S.; VERMARD, Y.; MARCHAL, P.
Titre Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) in the North Sea Type Article scientifique
Année 2014 Publication Revue Abrégée Ices Journal Of Marine Science
Volume 71 Numéro 6 Pages 1342-1355
Mots-Clés biotic interactions; competition; Generalized linear models; Hake; North sea; overlap; predator-prey relationship; saithe; species distribution modelling
Résumé Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) were investigated in the North Sea. Saithe is a well-established species in the North Sea, while occurrence of the less common hake has recently increased in the area. Spatial dynamics of these two species and their potential spatial interactions were explored using binomial generalized linear models (GLM) applied to the International Bottom Trawl Survey (IBTS) data from 1991 to 2012. Models included different types of variables: (i) abiotic variables including sediment types, temperature, and bathymetry; (ii) biotic variables including potential competitors and potential preys presence; and (iii) spatial variables. The models were reduced and used to predict and map probable habitats of saithe, hake but also, for the first time in the North Sea, the distribution of the spatial overlap between these two species. Changes in distribution patterns of these two species and of their overlap were also investigated by comparing species' presence and overlap probabilities predicted over an early (1991–1996) and a late period (2007–2012). The results show an increase in the probability over time of the overlap between saithe and hake along with an expansion towards the southwest and Scottish waters. These shifts follow trends observed in temperature data and might be indirectly induced by climate changes. Saithe, hake, and their overlap are positively influenced by potential preys and/or competitors, which confirms spatial co-occurrence of the species concerned and leads to the questions of predator–prey relationships and competition. Finally, the present study provides robust predictions concerning the spatial distribution of saithe, hake, and of their overlap in the North Sea, which may be of interest for fishery managers.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1054-3139 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1135
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Auteur (up) David, C.; Vaz, S.; Loots, C.; Antajan, E.; van der Molen, J.; Travers-Trolet, M.
Titre Understanding winter distribution and transport pathways of the invasive ctenophore Mnemiopsis leidyi in the North Sea: coupling habitat and dispersal modelling approaches Type Article scientifique
Année 2015 Publication Revue Abrégée Biol. Invasions
Volume 17 Numéro 9 Pages 2605-2619
Mots-Clés a. agassiz; anchoa-mitchilli; black-sea; caspian sea; fish; Habitat modelling; Jellyfish; Mnemiopsis leidyi; narragansett bay; North Sea; Overwinter refuges; Particle tracking; population connectivity; Predation; rhode-island
Résumé The invasive ctenophore Mnemiopsis leidyi has been reported in various coastal locations in the southern North Sea in the past years. Since 2009, International Bottom Trawl Surveys have recorded this species each winter in open waters. As this species, well-known for its dramatic disturbance of ecosystems, was expected not to be able to overwinter offshore it is crucial to understand its distribution dynamics. Two modelling methods, a quantile regression and a particle tracking model, were used (1) to identify habitats where the invasive ctenophore M. leidyi could survive the North Sea cold winters and (2) to investigate the dispersal of individuals between these different habitats, emphasizing favorable areas where sustainable populations could have been established. Temperature was found to be the crucial factor controlling the winter distribution of M. leidyi in the North Sea. High abundance predictions in winter were associated with low values of temperature, which characterise south-eastern coastal areas and estuaries influenced by riverine runoff. A retention-based M. leidyi population was indicated along the northern Dutch coast and German Bight and a transport-based population offshore from the western Danish coast. Individuals found in the open waters were transported from southern coasts of the North Sea, thus the open water population densities depend on the flux of offspring from these areas. This study provides the first estimates of the overwinter areas of this invasive species over the cold winters in the North Sea. Based on the agreement of habitat and dispersal model results, we conclude that M. leidyi has become established along south-eastern coasts of the North Sea where the environment conditions allows overwintering and it can be retained for later blooms.
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Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1387-3547 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1457
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Auteur (up) LELIEVRE, S.; VAZ, S.; Martin, C.S.; LOOTS, C.
Titre Delineating recurrent fish spawning habitats in the North Sea Type Article scientifique
Année 2014 Publication Revue Abrégée Journal Of Sea Research
Volume 91 Numéro Pages 1-14
Mots-Clés Egg Distribution; Glm; Habitat Modelling; North sea; Spawning Grounds; temporal variability
Résumé The functional value of spawning habitats makes them critically important for the completion of fish life cycles and spawning grounds are now considered to be “essential habitats”. Inter-annual fluctuations in spawning ground distributions of dab (Limanda Limanda), plaice (Pleuronectes platessa), cod (Gadus morhua) and whiting (Merlangius merlangus) were investigated in the southern North Sea and eastern English Channel, from 2006 to 2009. The preferential spawning habitats of these species were modelled using generalised linear models, with egg distribution being used as proxy of spawners’ location. Egg spatial and temporal distributions were explored based on six environmental variables: sea surface temperature and salinity, chlorophyll a concentration, depth, bedstress and seabed sediment types. In most cases, egg density was found to be strongly related to these environmental variables. Egg densities were positively correlated with shallow to intermediate depths having low temperature and relatively high salinity. Habitat models were used to map annual, i.e. 2006 to 2009, winter spatial distributions of eggs, for each species separately. Then, annual maps were combined to explore the spatial variability of each species' spawning grounds, and define recurrent, occasional, rare and unfavourable spawning areas. The recurrent spawning grounds of all four species were located in the south-eastern part of the study area, mainly along the Dutch and German coasts. This study contributes knowledge necessary to the spatial management of fisheries resources in the area, and may also be used to identify marine areas with particular habitat features that need to be preserved.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1385-1101 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 373
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