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| Registros recuperados: 64 | |
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| Akkus, Gizem; Jemaa, Sharif; Cemal Gucu, Ali; Marchal, Paul; Carbonara, Pierluigi; Bacha, Mahmoud; Amara, Rachid; Ernande, Bruno; Saraux, Claire; Mahe, Kelig. |
| European anchovy, Engraulis encrasicolus, is a small pelagic coastal marine fish largely spread from the North Sea to central Africa, including the entire Mediterranean and the Black and Azov Seas. The aim of the study is to understand the potential different population structure and their relationship between the Northeast Atlantic, Western, Eastern Mediterranean and the Black Sea anchovy population. The outlines of 2127 sagittal otoliths were collected from nineteen locations (English Channel, Atlantic, the Mediterranean and Black Sea), and added to existing information available from a previous study. Elliptical Fourier Analysis (EFA) was used to analyze the otolith shape variations among locations. Before examining the geographical differentiation by... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00436/54722/56157.pdf |
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| Amelot, Morgane; Bastleer, Jurgen; Foucher, Eric; Girardin, Raphael; Marchal, Paul; Poos, Jan Jaap; Sys, Klaas. |
| Rajidae stocks (Raja clavata, Raja brachyura, Raja montagui, Raja microocellata, Leucoraja naevus and Raja undulata) in the English Channel and North Sea (ICES divisions 3a, 4 and 7d) are actually managed as a complex (“skates and rays”) and subject to a single TAC. TAC advices from the ICES are based on scientific survey indices trends from each species. Rajidae catches are mainly bycatch from flatfish fisheries such are sole (Solea solea) and plaice (Pleuronectes platessa) fisheries. Furthermore, because of their top predator position as well as their life history, Rajidae are species sensitive to overfishing. These different factors have led to a revision in stock assessment methods. ICES classified Rajidae as category 3 data limited stocks. The lack of... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00620/73220/72433.pdf |
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| Amelot, Morgane; Batsleer, Jurgen; Foucher, Eric; Girardin, Raphael; Marchal, Paul; Poos, Jan Jaap; Sys, Klaas. |
| Six Rajidae stocks (Raja clavata, Raja brachyura, Raja montagui, Raja microocellata, Leucoraja naevus and Raja undulata) are currently exploited in the English Channel and North Sea area (ICES divisions 3a, 4 and 7d) and subject to a TAC regulation. This TAC is set based on monospecific approaches (abundance indices) when mangement is complex based. However, stock status disparities exist between these species. In this context a multispecific MSE (Management Strategy evaluation) framework has been developped based on DLMTool package from R. The main objective was to estimate the complex management impact at the different steps of stocks management (data collect, assessment, management measures implementation). The species species assessement and ... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76423/77495.pdf |
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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Cormon, Xochitl; Marchal, Paul. |
| The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles.... |
| Tipo: Text |
Palavras-chave: Commercial data; Eastern English Channel; Seasonality; Spatial distribution; Survey data. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49805/50385.pdf |
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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Marchal, Paul. |
| Managing mixed fisheries requires understanding fishers’ behaviour to allow predicting future fisheries distribution and impact on marine ecosystems. A new approach was developed to compare fine scale fishing effort distribution of Eastern English Channel (EEC) bottom trawlers, to the monthly- and spatially-resolved abundance distributions of commercial species. First, the added-value of using species-specific spatial overlap metric to quantify effective fishing effort and improve the relationship between fishing effort and fishing mortality was assessed. Second, based on the Ideal Free Distribution (IFD) theory, the species-specific weights given by fishers to different species were estimated by maximizing the overlap between target species assemblage and... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00446/55747/57402.pdf |
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| Cormon, Xochitl; Ernande, Bruno; Kempf, Alexander; Vermard, Youen; Marchal, Paul. |
| North Sea saithe Pollachius virens, a major top predator in the area, supports the fishery economy of several European countries. However, recent stock assessments suggested a decrease in spawning stock biomass along with a decline in saithe mean weight-at-ages. In this context, we investigated North Sea saithe growth characteristics at the population level. First, saithe annual weight increments and age-length relationships were studied. Modelling of saithe age-length relationships was carried out using (1) the traditional von Bertalanffy growth function model, (2) the Verhulst logistic model and (3) an empirical linear model. Second, the effects of environmental factors on saithe growth were investigated. Explanatory environmental factors included food... |
| Tipo: Text |
Palavras-chave: Bottom-up processes; Von Bertalanffy growth function; Logistic growth; Norway pout; Prey availability effects; Density-dependence; Predator-prey interactions; Resource limitation; Competition. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00314/42499/41875.pdf |
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| Cormon, Xochitl; Kempf, Alexander; Vermard, Youen; Vinther, Morten; Marchal, Paul. |
| During the last 15 years, northern European hake (Merluccius merluccius) has increased in abundance, and its spatial distribution has expanded in the North Sea region in correlation with temperature. In a context of global warming, this spatial shift could impact local trophic interactions: direct impacts may affect forage fish through modified predator–prey interactions, and indirect impacts may materialize through competition with other resident predators. For instance, North Sea saithe (Pollachius virens) spatial overlap with hake has increased while saithe spawning-stock biomass has decreased recently notwithstanding a sustainable exploitation. In this context, we investigated the range of potential impacts resulting from most recent hake emergence in... |
| Tipo: Text |
Palavras-chave: Hake; Interspecific competition; Maximum sustainable yield; Multispecies stock assessment; Norway pout; Predator-prey interactions; Saithe; Simple foodweb; SMS. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00327/43794/45917.pdf |
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| Cresson, Pierre; Timmerman, Charles-andre; Cordier, Remy; Couvreur, Clemence; Denamiel, Margaux; Engler, Alexandra; Lebon, Fabien; Lepretre, Marie-anais; Marchal, Paul. |
| This document summaries major information about the diet of mackerel Scomber scombrus in the English Channel, collected during the VARITROPH project. Mackerel consume quite exclusively copepods, with low effect of size on both diet and trophic level. |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00675/78716/80902.pdf |
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| Cresson, Pierre; Timmerman, Charles-andre; Couvreur, Clemence; Denamiel, Margaux; Lepretre, Marie-anais; Marchal, Paul. |
| This document summaries major results about the diet of sole Solea solea and plaice Pleuronectes platessa in the English Channel, collected in the framework of the VARITROPH project. Both species have a similar diet, based on crustaceans, but plaice exhibit a larger diversity of secundary species (bivalves, annelids and echinoderms) than sole (annelids only). Diversity of the preys for plaice is explained by differences between size classes. Diet of small individuals is less diverse than the diet of large individuals. Trophic similarity between sole and plaice is also exhibited when comparing ontogenic changes of trophic levels, that are pretty similar for both species, and consistent with a diet based on small invertebrates. |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00675/78718/80904.pdf |
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| Cresson, Pierre; Timmerman, Charles-andre; Denamiel, Margaux; Millet, Lucie; Marchal, Paul. |
| This document summaries the major findings about the diet of whiting Merlangius merlangus in the English Channel, in the framework of the VARITROPH project. Whiting diet is based on several main preys, with an ontogenic variation. Individuals lower than 30 cm mostly fed on crustaceans, while diet of larger individuals is based on cephalopods and fishes. As a result, trophic level show 2 phases, one increasing at the early life stages, and a constant trophic level for individuals larger than 30 cm. |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00675/78717/80903.pdf |
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| Delavenne, Juliette; Marchal, Paul; Vaz, Sandrine. |
| Classifying marine habitats is a growing research field and is of increasing interest to spatial planners and managers. Most studies have predominantly focused on the seabed to determine benthic habitat types, and only limited attention has been paid to the water column. Classification projects aim at identifying candidate management units for the application of various regional or national regulations such as the European Water Framework Directive. Here, we propose a seasonal classification of the water column in the eastern English Channel, which we validated with biological data. For the three tested compartments, phytoplankton, zooplankton and pelagic fishes, the validation results were satisfactory, with recall values (i.e. percentage of observations... |
| Tipo: Text |
Palavras-chave: Eastern English Channel; Pelagic typology; Clustering analysis; Seasonality. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00125/23655/22689.pdf |
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| Denis, Jeremy; Vallet, Carole; Vincent, Dorothée; Courcot, Lucie; Marchal, Paul; Loots, Christophe. |
| The aim of this study was to characterize the feeding strategy of Downs herring larvae at "critical period" during winter in the English Channel and North Sea was defined to assess whether nutrition is responsible for low recruitment in stocks over the past years. Data collected during the French part of the International Bottom Trawl Survey from 2008 to 2014 were used to analyse fish larvae diet by direct observation using Scanning Electron Microscope (SEM). Gut content methods generally used for copepods was adapted to fish larvae to assess phytoplankton ingestion. The relative importance of small preys (0,5-375µm) observed in gut contents proved the essential role of SEM to better acknowledge Downs herring diet. We demonstrated that Downs herring larvae... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00255/36608/35174.pdf |
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| Di Pane, Julien; Gendrot, F.; Giraldo, Carolina; Marchal, Paul; Koubbi, Philippe; Loots, Christophe. |
| In the present study, the histological-based condition of common sole (Solea solea) larvae in the English Channel was evaluated to assess the relevance of experimentally-calibrated indices for wild collected specimens. Based on topographical observation of foregut, midgut, hindgut, liver and pancreas, each of the 202 larvae analysed was attributed one of the six grades of a condition index that was developed for sole in the nineties. In parallel, a synthetic table of 20 criteria historically used as condition indicators was created from an extensive review of the literature. These criteria were related to tissular integrity, cells height, nuclei, presence of prey and vacuolisation of the same five target organs. For each larva, each criterion was scored on... |
| Tipo: Text |
Palavras-chave: Condition index; Eastern English Channel; Fish larvae; Histology; Solea solea; Starvation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00601/71325/69754.pdf |
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| Di Pane, Julien; Joly, Lea; Koubbi, Philippe; Giraldo, Carolina; Monchy, Sébastien; Tavernier, Eric; Marchal, Paul; Loots, Christophe. |
| Condition indices aim to evaluate the physiological status of fish larvae by estimating both the level of starvation and potential of survival. Histological indices reveal direct effects of starvation whereas biochemical indices such as lipid classes or RNA:DNA ratios are used as proxies of condition, giving information on the amount of energy reserves and growth rate, respectively. We combined these three indices to evaluate ontogenetic variations of growth performance, lipid dynamics and nutritional condition of plaice larvae caught in the field during winter 2017 in the eastern English Channel and the Southern Bight of the North Sea. RNA:DNA ratios showed that larvae at the beginning of metamorphosis (stage 4) had a lower growth rate than younger... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00514/62610/66974.pdf |
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| Di Pane, Julien; Koubbi, Philippe; Giraldo, Carolina; Lefebvre, Valerie; Caboche, Josselin; Marchal, Paul; Loots, Christophe. |
| ish assemblages vary through time in both abundance and diversity, often due to changes in climate. The potential consequences of these changes on the larval phase need to be considered. In the Eastern English Channel, fish larvae of 30 taxa, from surveys conducted during spring in the nineties and in 2017 with bongo nets, were used to investigate seasonal and interannual changes in larval assemblages with different statistical tests and multivariate analyses (Outlying Mean Index, Principal Coordinate Analysis and variance partitioning). The major change observed was significant lower abundances in 2017 (in April and May) compared to the nineties. Most of the dominant taxa were two to three-fold less abundant in 2017 than the 1990s. We suggest that the... |
| Tipo: Text |
Palavras-chave: Fish larvae; Temporal variations; Atlantic Multidecadal Oscillation; Outlying Mean Index; Variance partitioning; English Channel. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00604/71631/70078.pdf |
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| Eigaard, Ole Ritzau; Marchal, Paul; Gislason, Henrik; Rijnsdorp, Adriaan D.. |
| Many marine fish stocks are overexploited and considerable overcapacity exists in fishing fleets worldwide. One of the reasons for the imbalance between resource availability and fishing capacity is technological development, which continuously increases the efficiency of the vessels—a mechanism referred to as “technological creep.” We review how the introduction of new and more efficient electronic equipment, gear design, engines, deck equipment, and catch-handling procedures influences the capture efficiency (catchability) of commercial fishing vessels. On average, we estimate that catchability increases by 3.2% per year due to technological developments, an increase often ignored in fisheries management. The documentation and quantification of... |
| Tipo: Text |
Palavras-chave: Catchability; Fishing mortality; Fishing power; Fisheries management; Fleet capacity; Technological development. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00222/33368/35784.pdf |
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| Registros recuperados: 64 | |
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