| Enregistrements |
| Auteur |
Jac, C.; Desroy, N.; Certain, G.; Foveau, A.; Labrune, C.; Vaz, S. |
| Titre |
Detecting adverse effect on seabed integrity. Part 1: Generic sensitivity indices to measure the effect of trawling on benthic mega-epifauna |
Type |
Article scientifique |
| Année |
2020 |
Publication |
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Revue Abrégée |
Ecol. Indic. |
| Volume |
117 |
Numéro |
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Pages |
106631 |
| Mots-Clés |
beam trawl; Benthic sensitivity; biological traits; biomass; community structure; disturbance; functional diversity; habitats; impacts; Indices; marine biotic index; msfd; Seabed integrity; southern north-sea; Trawling effect |
| Résumé |
The benthic fauna of European continental shelves is a severely impacted community, mostly due to intense bottom trawling activity. Trawling effect may be dependent on the spatial and temporal distribution of abrasion, the habitat type including natural perturbation intensity and the fishing gear used. Nonetheless, there is an urgent need to identify or develop indices likely to measure the effect of trawling. For this purpose benthic fauna by-catch monitored in scientific trawl surveys carried out in all European waters in the frame of the Common Fishery Policy Data Collection Multiannual Program may be used. Benthic invertebrates data used in this study were collected during scientific bottom trawl surveys covering the English Channel, the North Sea and the North-West Mediterranean. Swept area ratios derived from VMS data were used to quantify the intensity of fishery induced abrasion on the seabed. Fifteen indices were investigated: taxonomic diversity metrics, functional di-versity indices and functional indices, the two later based on sensitivity traits to physical abrasion. Their properties, such as their capacity to detect trawling effect, their statistical behavior or their ability to inform on community structure, were investigated. Among them, fours indices specific to fishery effect detection based on biological traits appeared to be the best performing benthic indices regarding these requirements: Trawling Disturbance Index (TDI), modified-Trawling Disturbance Index (mTDI), partial-Trawling Disturbance Index (pTDI), modified sensitivity index (mT). Maps of the distribution pattern of seabed sensitivity captured through each of these four indices were produced. This work has highlighted the need to use specific indices to monitor the effect of trawling on benthic communities but also that the use of different indices may be necessary to carry out this monitoring in all European waters. |
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English |
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| ISSN |
1470-160x |
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| Notes |
WOS:000555551000015 |
Approuvé |
pas de |
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MARBEC @ isabelle.vidal-ayouba @ |
collection  |
2846 |
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| Auteur |
Jac, C.; Desroy, N.; Certain, G.; Foveau, A.; Labrune, C.; Vaz, S. |
| Titre |
Detecting adverse effect on seabed integrity. Part 2: How much of seabed habitats are left in good environmental status by fisheries? |
Type |
Article scientifique |
| Année |
2020 |
Publication |
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Revue Abrégée |
Ecol. Indic. |
| Volume |
117 |
Numéro |
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Pages |
106617 |
| Mots-Clés |
assemblages; beam trawl; benthic communities; diversity; extraction; ges; impact; Indices; macrofauna; management; mfsd; term; Threshold values; trawling disturbance; Trawling impact |
| Résumé |
By relating observed changes to the pressures suffered, the Marine Strategy Framework Directive intends to better control the factors of environmental degradation and to manage their consequences in European waters. Several descriptors are defined within the framework of the MFSD and in particular descriptor 1 relating to the biological diversity of the seabed and descriptor 6 relating to the seabed integrity (i.e. the quality of their structures and functions). For each descriptor, indicators and threshold values must be defined and a novel conceptual approach to define and detect seabed integrity thresholds is proposed here. Bottom trawling being the main source of shelf continental disturbance, it is important to evaluate its impact on benthic habitat. The goal of this study is to propose a methodology to determine “Good Ecological Status” threshold values for each habitat type present in three contrasted MFSD sub-region (North Sea, English Channel and Mediterranean Sea). Trawling impacts are dependent of the spatial and temporal distribution of the fishing effort, fishing gears, intensity of natural disturbances and habitat types. Benthic community structures present in these areas were studied using by-catch non-commercial benthic invertebrates data collected during French scientific bottom trawl surveys. Swept area ratios derived from VMS data were used to quantify the intensity of fishery induced abrasion on the seabed. A modeling approach was used to determine abrasion threshold values on each EUNIS level 4 habitat. The values, beyond which trawling has an adverse effect on benthic communities, have been determined for each habitat. This made it possible to assess and map the ecological status of each of the habitats and to determine the percentage of each habitat impacted by trawling. The method proposed here to evaluate the impact of trawling on benthic communities highlighted that the vast majority of the investigated sub-regions were adversely impacted or lost as a result of seabed impacting trawling. |
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English |
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1470-160x |
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| Notes |
WOS:000555554700002 |
Approuvé |
pas de |
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MARBEC @ isabelle.vidal-ayouba @ |
collection |
2845 |
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| Auteur |
Soares, A.; Lira, A.S.; Gonzalez, J.G.; Eduardo Nole, L.; Lucena-Fredou, F.; Le Loc'h, F.; Ferreira, B.P.; Fredou, T. |
| Titre |
Feeding habits and population aspects of the spotted goatfish, Pseudupeneus maculatus (Perciformes: Mullidae), on the continental shelf of northeast Brazil |
Type |
Article scientifique |
| Année |
2020 |
Publication |
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Revue Abrégée |
Sci. Mar. |
| Volume |
84 |
Numéro |
2 |
Pages |
119-131 |
| Mots-Clés |
biodiversity; biology; Brazil; coast; cross-shelf; diet composition; distribution patterns; dynamics; ecology; island; reef fishes; stable isotopes; stomach content analysis; strategy; teleostei |
| Résumé |
This study provides information about the feeding habits, population aspects and spatial distribution of the spotted goatfish, Pseudupeneus maculatus, along the coast of the tropical Brazilian continental shelf. Distribution patterns are described using length frequencies and catch rates. Stable isotope ratios of carbon (delta C-13) and nitrogen (delta N-15), along with stomach contents, were analysed to determine the diet of the spotted goatfish. Multivariate analysis and numerical indicators of the diet, such as numerical frequency. frequency of occurrence and weight percentage, were computed to evaluate the diet composition. The mean trophic position was defined using both stable isotope ratios and stomach content analysis. The length at first maturity for the species was determined as 13.7 cm. A slight pattern in size distribution was observed, with mean size increasing with depth along the shelf. The diet was mainly composed of crustaceans, teleosts and Polychaeta. No clear dietary difference was found between habitat types, water depth or latitude. Both trophic positions estimated by stable isotopes and stomach contents analysis ranged between levels 3 and 4. P. maculatus was found to be feeding on many rare and infrequent prey items, classifying it as a generalist zoobenthivorous predator, probably due to its efficient search strategy. |
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English |
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0214-8358 |
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| Notes |
WOS:000539067100006 |
Approuvé |
pas de |
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MARBEC @ isabelle.vidal-ayouba @ |
collection |
2825 |
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Leblad, B.R.; Amnhir, R.; Reqia, S.; Sitel, F.; Daoudi, M.; Marhraoui, M.; Abdellah, M.K.O.; Veron, B.; Er-Raioui, H.; Laabir, M. |
| Titre |
Seasonal variations of phytoplankton assemblages in relation to environmental factors in Mediterranean coastal waters of Morocco, a focus on HABs species |
Type |
Article scientifique |
| Année |
2020 |
Publication |
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Revue Abrégée |
Harmful Algae |
| Volume |
96 |
Numéro |
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Pages |
101819 |
| Mots-Clés |
bay; bizerte lagoon; climate-change; domoic acid; Environmental factors; gymnodinium-catenatum; HABs; harmful algal blooms; Phytoplankton diversity; pseudo-nitzschia; psp toxins; shellfish; SW Mediterranean; temperature; Toxins |
| Résumé |
Studies on phytoplankton and in particular Harmful Algal Blooms (HABs) species in southern Mediterranean waters are scarce. We performed from April 2008 to June 2009 weekly investigations on microphytoplankton community structure and abundance in two contrasted marine ecosystems located in the western Moroccan Mediterranean coast, M'diq Bay and Oued Laou Estuary. Simultaneously, we measured the main physico-chemical parameters. Globally, the two studied areas showed comparable values of the assessed abiotic environmental factors. Temperature and salinity followed seasonal variation with values ranging from 13.5 degrees C to 21.4 degrees C and 31 to 36.8, respectively. Average nutrient values in surface water ranged from 0.7 to 45.76 mu M for dissolved inorganic nitrogen, 0.02-2.10 mu M for PO4 and 0.23-17.46 mu M for SiO4 in the study areas. A total of 92 taxa belonging to 8 taxonomic classes were found. The highest number of microphytoplankton abundance reached 1.2 x 10(6) cells L-1 with diatoms being the most abundant taxa. Factorial Discriminant Analysis (FDA) and Spearman correlation test showed a significant seasonal discrimination of dominant microphytoplankton species. These micro-organisms were associated with different environmental variables, in particular temperature and salinity. Numerous HABs species were encountered regularly along the year. Although Dinophysis species and Prorocentrum lima were present in both sites, no Lipophilic Shellfish Poisoning was detected for the analyzed bivalve mollusks. Domoic acid (DA), produced by toxic species of Pseudo-nitzschia was found with concentrations up to 18 mu g DA g(-1) in the smooth clam Callista chione. Data showed that the observed persistent and dramatic Paralytic Shellfish Poisoning (PSP) intoxication of mollusks resulted probably of Gymnodinium catenatum proliferations in both studied areas. Contrary to C. chione, the cockle Achanthocardia tuberculatum showed a permanent and extremely high toxicity level during the 15 months survey with up to 7545 mu g Equivalent Saxitoxin kg(-1) flesh (ten times higher than the sanitary threshold of 800 tg eqSTX Kg(-1) flesh). The present work highlights for the first time the dynamic of microphytoplankton including HABs species and their associated toxin accumulation in the commercially exploited shellfish in the southern western Mediterranean waters of Morocco. Furthermore, the acquired data will help us to improve the monitoring of HABs species and related toxins in these coastal marine systems. |
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English |
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1568-9883 |
ISBN |
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| Notes |
WOS:000541912700003 |
Approuvé |
pas de |
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MARBEC @ isabelle.vidal-ayouba @ |
collection |
2820 |
| Lien permanent pour cet enregistrement |
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| Auteur |
Forget, F.; Dagorn, L.; Mérigot, B.; Gaertner, J.C.; Robinson, J.; Cowley, P.D.; Adam, M.S.; Rilwan, Y.; Koonjul, M.; Mangar, V.; Taquet, M.; Ménard, F. |
| Titre |
Beta diversity of pelagic assemblages at fish aggregating devices in the open ocean |
Type |
Article scientifique |
| Année |
2020 |
Publication |
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Revue Abrégée |
African Journal of Marine Science |
| Volume |
42 |
Numéro |
2 |
Pages |
247-254 |
| Mots-Clés |
FADs; Indian Ocean; Maldives; Mauritius; pelagic fish diversity; Seychelles; species composition; underwater visual census |
| Résumé |
Owing to difficulties in accessing the vast open ocean, the beta (β) diversity of pelagic fish assemblages remains poorly studied. We investigated the relationship between assemblage similarity and geographical distance between anchored fish aggregating devices (FADs), sampled by standardised underwater visual censuses in three anchored FAD arrays in the Indian Ocean—at the Maldives, the Seychelles and Mauritius. The use of two complementary indices of β-diversity, based on presence/absence data (Jaccard similarity coefficient) and abundance data (Bray–Curtis index), revealed that geographical distance between sampling sites (from 4 to 257 km) appeared to have no effect on the similarity of fish assemblages associated with FADs within each array. The results of this preliminary study question the generalisation of the paradigm of an increase in β-diversity with geographic distance to the open-ocean fish community. Large-scale studies using a variety of datasets should be conducted to further investigate patterns of β-diversity in the open ocean. |
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1814-232x |
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| Notes |
WOS:000558450600011 |
Approuvé |
pas de |
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MARBEC @ isabelle.vidal-ayouba @ |
collection |
2813 |
| Lien permanent pour cet enregistrement |
