Francois Le Loc'h | Institut de Recherche pour le Développement (IRD - France) (original) (raw)

Papers by Francois Le Loc'h

Environmental Pollution, Aug 1, 2023

Je tiens tout d'abord à exprimer ma profonde reconnaissance à mes deux directeurs de thèse qui m'... more Je tiens tout d'abord à exprimer ma profonde reconnaissance à mes deux directeurs de thèse qui m'ont accordé leur confiance, soutenu et guidé et dont la complémentarité a beaucoup enrichi ce travail : Messieurs Christian Hily et Gérard Thouzeau. Merci Christian, initiateur de ce sujet de thèse et encadrant au quotidien, d'avoir partagé tes connaissances en écologie benthique. Merci Gérard, travailleur infatigable, pour tes conseils et la rigueur que tu as apportée à ce travail. Je remercie sincèrement Messieurs Loïc Antoine et Pierre Chardy qui m'ont fait l'honneur d'être rapporteurs de cette thèse, pour la pertinence de leurs critiques. Je tiens à remercier chaleureusement Monsieur Jean Boucher qui partage la paternité de ce projet de recherche et qui a montré un vif intérêt pour ce travail de son commencement à sa soutenance. Je remercie également le Professeur Chris Frid d'avoir accepter de participer au jury de thèse et pour la justesse de ses commentaires. Je n'aurais pu réaliser l'analyse de l'évolution des peuplements benthiques du Nord Gascogne sans l'aide du pionnier, Monsieur le Professeur Michel Glémarec, auquel j'exprime ma profonde reconnaissance pour l'intérêt qu'il a porté à ce travail. Cette thèse doit également beaucoup à Jacques Grall. Merci à toi Jacques de m'avoir initié à la systématique des invertébrés benthiques, d'avoir été disponible pour les nombreuses déterminations sur lesquelles je séchais lamentablement et pour tes conseils avisés dans les analyses écologiques et statistiques. Merci aussi à Michel Le Duff pour sa précieuse aide dans la détermination des «coches». Je ne peux oublier mes collègues de bureau : Coralie Raffin, Joëlle Richard et Anne Lorrain, merci de m'avoir supporté au quotidien et de m'avoir accordé votre amitié. Merci Coralie pour ton aide efficace lors de la correction de la thèse et pour tes fameux gâteaux au chocolat, merci Joëlle pour nos discussions gastronomiques et pour tes chocolats suisses qui ont égayé les moments de rédaction et merci Anne pour nos échanges isotopiques et pour ta bouilloire qui m'a permis de faire mes (trop) nombreux cafés quotidiens. Je tiens à remercier très sincèrement mon ami Pascal Claquin pour son immense camaraderie, pour son soutien et pour nos mémorables pauses-cafés, et ma complice de l'Institut, Solène Connan pour son courage sur la Thalassa, les souvenirs de la mythique bagarre à Bayonne, les sorties terrains sur les estrans de la "pointe Bretagne", sa disponibilité et sa (trop) grande gentillesse. Merci à tous les deux pour tout ce que vous avez fait et pour les bons moments passés au boulot et dans la vraie vie.

Ices Journal of Marine Science, Feb 10, 2022

Tropical fisheries tend to be multispecies and require management approaches adapted to high dive... more Tropical fisheries tend to be multispecies and require management approaches adapted to high diversity but scarce and poorly informative data. Productivity and Susceptibility Analysis-PSA is particularly useful where catch or biological data are incomplete, aggregated across species or insufficient for quantitative stock assessment. We applied PSA to estimate vulnerability and potential risk to target and non-target species caught by the small-scale shrimp fishery in northeast Brazil, adapting the method to regional conditions and incorporating an assessment of uncertainties caused by its subjective choices. Our findings suggest that non-target species can be more vulnerable than target ones. Bagre marinus, Pseudobatos percellens, Micropogonias furnieri, Hypanus guttatus, Macrodon ancylodon, Polydactylus virginicus, Rhizoprionodon porosus, Cynoscion virescens, Larimus breviceps, and Menticirrhus americanus, were the top 10 species potentially at risk due to their low productivity (long lifespans, low spawning), high capture rates of juveniles and overlap of feeding and breeding grounds with fishing areas. Most species (76%) maintained the same risk category (low, moderate, or high) regardless of the score weighting or productivity and susceptibility attribute boundaries applied. Overall, the target species are not currently the main ones threatened, but bycatch such as elasmobranchs, catfishes and Scianidae should be prioritized for assessment and data collection.

Fisheries Research, Mar 1, 2021

Abstract Global shrimp catches are reported primarily in association with large industrial trawli... more Abstract Global shrimp catches are reported primarily in association with large industrial trawling, but they also occur through small-scale fishing, which plays a substantial role in traditional communities. We developed an Ecopath model in north-eastern Brazil, and applied a temporally dynamic model (Ecosim) to evaluate the potential effects of different fishing effort control policies and environmental changes on marine resources and ecosystem between 2015 to 2030 with a case study for small-scale shrimp fishing, novelty for tropical region. These scenarios included different management options related to fishing controls (changing effort and closed season) and environmental changes (primary production changes). Our findings indicate that it is possible to maintain the same level of landings with a controlled reduction of bottom trawlers activities, for example, close to 10 %, without compromising the ecosystem structure. This scenario provided better results than 3–4 months of closing the fishing season, which led to significant losses in catches of high market-value target species (white shrimp, Penaeus schmitti and pink shrimp, Penaeus subtilis). However, intense negative effects on biomass, catch and biodiversity indicators were reported in scenarios with decreasing primary production, from 2 %, reinforcing the need to simulate and project the possible impacts caused by environmental change. However, the control of bottom trawling activity may help to reduce, even at low levels, the highly adverse effects due to primary production reduction. The impacts of climate change in a near future on organisms and ecosystems is an imminent reality, and therefore the search for measures for mitigating and even minimizing these impacts is crucial.

Journal of Marine Systems, Dec 1, 2020

Size-based approaches are paramount tools for the study of marine food webs. Here, we investigate... more Size-based approaches are paramount tools for the study of marine food webs. Here, we investigated the relationship between zooplankton body size, stable isotope composition and trophic level (TL) along a large-scale onshore-offshore gradient in the western tropical Atlantic. Samples were obtained on the Brazilian continental shelf, slope and in oceanic waters (off Fernando de Noronha archipelago and Rocas Atoll) in September and October 2015. Zooplankton was sieved into five size fractions. Zooplankton was dominated by copepods, except for the largest (>2000 μm) size fraction, that showed a high biovolume of chaetognaths, decapods, and fish larvae. Maximum zooplankton abundance and biovolume was found at the continental slope. POM showed consistently lower δ13C than zooplankton, indicating a selective use of 13C-rich primary food sources by zooplankton. Particulate organic matter (POM) was more 13Cenriched in shelf areas (average: −22.8, −23.6 and − 24.3‰ at the shelf, slope and oceanic islands, respectively), probably due to the higher abundance of diatoms nearshore. POM had δ15N values between 2.5 and 6.9‰ (average: 4.0, 4.9 and 4.2‰ at the shelf, slope and oceanic islands, respectively). Zooplankton δ15N and TL increased with body size. The δ15N of the 200-500 μm size fraction was used as baseline for TL estimation. Oceanic areas (average baseline δ15N = 5.8‰ ± 0.52, n = 14) showed a higher baseline δ15N than the shelf (average = 3.9‰ ± 0.69, n = 9) and the slope areas (average = 3.1‰ ± 0.93, n = 9). In spite of differing baselines, the δ15N data produced a consistent pattern of log-linear increase in TL with increasing size, in all areas. The choice of input trophic enrichment factor (TEF) values only slightly changed the log10 (body size) vs TL slopes, but this choice had a considerable effect on the estimates of predator/prey size ratio (PPSR) and predator/prey mass ratio (PPMR). Using a TEF above 2.3 leads to unrealistic PPSR and PPMR estimates. Overall average slope was 0.59 ± 0.08 TL μm−1 with TEF = 2.3 and 0.42 ± 0.07 TL μm−1 with TEF = 3.2. Highlights ► Maximum zooplankton abundance and biovolume was found at the continental slope. ► POM showed lower δ 13 C than zooplankton, indicating selective feeding. ► Zooplankton δ 15 N and trophic level increased with body size. ► Using a δ 15 N trophic enrichment factor above 2.3 leads to unrealistic estimates.

Journal of Fish Biology, Apr 1, 2015

Potential trophic competition between two sympatric mullet species, Mugil cephalus and Mugil cure... more Potential trophic competition between two sympatric mullet species, Mugil cephalus and Mugil curema, was explored in the hypersaline estuary of the Saloum Delta (Senegal) using δ(13) C and δ(15) N composition of muscle tissues. Between species, δ(15) N compositions were similar, suggesting a similar trophic level, while the difference in δ(13) C compositions indicated that these species did not feed from exactly the same basal production sources or at least not in the same proportions. This result provides the first evidence of isotopic niche segregation between two limno-benthophageous species belonging to the geographically widespread, and often locally abundant, Mugilidae family.

HAL (Le Centre pour la Communication Scientifique Directe), Jan 10, 2023

African Journal of Marine Science, 2021

The lesser African threadfin Galeoides decadactylus (family Polynemidae) is one of the most captu... more The lesser African threadfin Galeoides decadactylus (family Polynemidae) is one of the most captured marine fish species in Central Africa. This study examines aspects of the reproductive biology of G. decadactylus in the Libreville area of Gabon. Fish caught with encircling gillnets and bottom gillnets were collected from May 2017 to May 2018 from artisanal fishermen. A total of 776 specimens were studied, comprising 401 females (14–36 cm total length [TL]), 347 males (13–28 cm TL), and 28 individuals of indeterminate sex (12–16 cm TL). Monthly monitoring of gonadosomatic ratio, condition factor and sexual maturity stages revealed that G. decadactylus reproduces continuously but has two slight peak periods: one in the long rainy season and the other in the short rainy season. The species is protandrous, with sizes at first sexual maturity of 17.7 cm TL for males and 18.7 cm for females. Mature individuals largely dominated the catches of small-scale fishers in Gabon. Mean absolute ...

Le régime alimentaire du chinchard d'europe, Trachurus trachurus (Linnaeus, 1758), a été étud... more Le régime alimentaire du chinchard d'europe, Trachurus trachurus (Linnaeus, 1758), a été étudié au sud de la côte atlantique marocaine, entre cap blanc et cap boujdour (21°00'N-26°30'N). L'échantillonnage a été réalisé durant les saisons chaude (juin-juillet-août) et froide (novembre-décembre) en 2007 et 2008. L'analyse du contenu stomacal de 456 individus a montré que le régime alimentaire de T. trachurus est diversifié, composé essentiellement de crustacés pélagiques qui représentent ses proies préférentielles. une analyse en composante principale normée, associée à un test de permutations, a mis en évidence une variation du régime alimentaire en fonction des périodes d'échantillonnage. une analyse de variance multiple (ManoVa) appliquée sur la période des campagnes, la position latitudinale des stations, la profondeur de chalutage et la taille des individus a permis de mettre en exergue les déterminants de cette variation. il en ressort que T. trachurus pr...

The Journal of Foraminiferal Research, 2005

ABSTRACT

Regional Studies in Marine Science

HAL (Le Centre pour la Communication Scientifique Directe), 2013

HAL (Le Centre pour la Communication Scientifique Directe), 2016

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL (Le Centre pour la Communication Scientifique Directe), 2016

Integrating ecophysiology and plankton dynamics into projected maximum fisheries catch potential ... more Integrating ecophysiology and plankton dynamics into projected maximum fisheries catch potential under climate change in the Northeast Atlantic.

Estuarine Coastal and Shelf Science, Oct 1, 2022

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial 4.0 International License

PLOS ONE, Feb 8, 2021

We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feed... more We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feeding relationships among species of the nektobenthic communities and the potential ecological effects of the bottom trawling of a coastal ecosystem in northeastern Brazil. Carbon (δ 13 C) and nitrogen (δ 15 N) compositions were determined for five basal sources and 28 consumers, from zooplankton to shrimp and fish species. Fishes and basal sources showed a broad range of δ 15 N (fishes: 6.49-14.94‰; sources: 2.58-6.79‰) and δ 13 C values (fishes:-23.86 to-13.71‰; sources:-24.32 to-13.53‰), while shrimps and crabs exhibited similar nitrogen and carbon ratios. Six trophic consumer groups were determined among zooplankton, crustaceans and fishes by SIA, with trophic pathways associated mostly with benthic sources. SCA results indicated a preference for benthic invertebrates, mainly worms, crabs and shrimps, as prey for the fish fauna, highlighting their importance in the food web. In overall, differences between SCA and the SIA approaches were observed, except for groups composed mainly for shrimps and some species of high δ 15 N values, mostly piscivorous and zoobenthivores. Given the absence of regulation for bottom trawling activities in the area, the cumulative effects of trawling on population parameters, species composition, potentially decreasing the abundance of benthic preys (e.g., shrimps, worms and crabs) may lead to changes in the trophic structure potentially affect the food web and the sustainability of the fishery.

Environmental Pollution, Aug 1, 2023

Je tiens tout d'abord à exprimer ma profonde reconnaissance à mes deux directeurs de thèse qui m'... more Je tiens tout d'abord à exprimer ma profonde reconnaissance à mes deux directeurs de thèse qui m'ont accordé leur confiance, soutenu et guidé et dont la complémentarité a beaucoup enrichi ce travail : Messieurs Christian Hily et Gérard Thouzeau. Merci Christian, initiateur de ce sujet de thèse et encadrant au quotidien, d'avoir partagé tes connaissances en écologie benthique. Merci Gérard, travailleur infatigable, pour tes conseils et la rigueur que tu as apportée à ce travail. Je remercie sincèrement Messieurs Loïc Antoine et Pierre Chardy qui m'ont fait l'honneur d'être rapporteurs de cette thèse, pour la pertinence de leurs critiques. Je tiens à remercier chaleureusement Monsieur Jean Boucher qui partage la paternité de ce projet de recherche et qui a montré un vif intérêt pour ce travail de son commencement à sa soutenance. Je remercie également le Professeur Chris Frid d'avoir accepter de participer au jury de thèse et pour la justesse de ses commentaires. Je n'aurais pu réaliser l'analyse de l'évolution des peuplements benthiques du Nord Gascogne sans l'aide du pionnier, Monsieur le Professeur Michel Glémarec, auquel j'exprime ma profonde reconnaissance pour l'intérêt qu'il a porté à ce travail. Cette thèse doit également beaucoup à Jacques Grall. Merci à toi Jacques de m'avoir initié à la systématique des invertébrés benthiques, d'avoir été disponible pour les nombreuses déterminations sur lesquelles je séchais lamentablement et pour tes conseils avisés dans les analyses écologiques et statistiques. Merci aussi à Michel Le Duff pour sa précieuse aide dans la détermination des «coches». Je ne peux oublier mes collègues de bureau : Coralie Raffin, Joëlle Richard et Anne Lorrain, merci de m'avoir supporté au quotidien et de m'avoir accordé votre amitié. Merci Coralie pour ton aide efficace lors de la correction de la thèse et pour tes fameux gâteaux au chocolat, merci Joëlle pour nos discussions gastronomiques et pour tes chocolats suisses qui ont égayé les moments de rédaction et merci Anne pour nos échanges isotopiques et pour ta bouilloire qui m'a permis de faire mes (trop) nombreux cafés quotidiens. Je tiens à remercier très sincèrement mon ami Pascal Claquin pour son immense camaraderie, pour son soutien et pour nos mémorables pauses-cafés, et ma complice de l'Institut, Solène Connan pour son courage sur la Thalassa, les souvenirs de la mythique bagarre à Bayonne, les sorties terrains sur les estrans de la "pointe Bretagne", sa disponibilité et sa (trop) grande gentillesse. Merci à tous les deux pour tout ce que vous avez fait et pour les bons moments passés au boulot et dans la vraie vie.

Ices Journal of Marine Science, Feb 10, 2022

Tropical fisheries tend to be multispecies and require management approaches adapted to high dive... more Tropical fisheries tend to be multispecies and require management approaches adapted to high diversity but scarce and poorly informative data. Productivity and Susceptibility Analysis-PSA is particularly useful where catch or biological data are incomplete, aggregated across species or insufficient for quantitative stock assessment. We applied PSA to estimate vulnerability and potential risk to target and non-target species caught by the small-scale shrimp fishery in northeast Brazil, adapting the method to regional conditions and incorporating an assessment of uncertainties caused by its subjective choices. Our findings suggest that non-target species can be more vulnerable than target ones. Bagre marinus, Pseudobatos percellens, Micropogonias furnieri, Hypanus guttatus, Macrodon ancylodon, Polydactylus virginicus, Rhizoprionodon porosus, Cynoscion virescens, Larimus breviceps, and Menticirrhus americanus, were the top 10 species potentially at risk due to their low productivity (long lifespans, low spawning), high capture rates of juveniles and overlap of feeding and breeding grounds with fishing areas. Most species (76%) maintained the same risk category (low, moderate, or high) regardless of the score weighting or productivity and susceptibility attribute boundaries applied. Overall, the target species are not currently the main ones threatened, but bycatch such as elasmobranchs, catfishes and Scianidae should be prioritized for assessment and data collection.

Fisheries Research, Mar 1, 2021

Abstract Global shrimp catches are reported primarily in association with large industrial trawli... more Abstract Global shrimp catches are reported primarily in association with large industrial trawling, but they also occur through small-scale fishing, which plays a substantial role in traditional communities. We developed an Ecopath model in north-eastern Brazil, and applied a temporally dynamic model (Ecosim) to evaluate the potential effects of different fishing effort control policies and environmental changes on marine resources and ecosystem between 2015 to 2030 with a case study for small-scale shrimp fishing, novelty for tropical region. These scenarios included different management options related to fishing controls (changing effort and closed season) and environmental changes (primary production changes). Our findings indicate that it is possible to maintain the same level of landings with a controlled reduction of bottom trawlers activities, for example, close to 10 %, without compromising the ecosystem structure. This scenario provided better results than 3–4 months of closing the fishing season, which led to significant losses in catches of high market-value target species (white shrimp, Penaeus schmitti and pink shrimp, Penaeus subtilis). However, intense negative effects on biomass, catch and biodiversity indicators were reported in scenarios with decreasing primary production, from 2 %, reinforcing the need to simulate and project the possible impacts caused by environmental change. However, the control of bottom trawling activity may help to reduce, even at low levels, the highly adverse effects due to primary production reduction. The impacts of climate change in a near future on organisms and ecosystems is an imminent reality, and therefore the search for measures for mitigating and even minimizing these impacts is crucial.

Journal of Marine Systems, Dec 1, 2020

Size-based approaches are paramount tools for the study of marine food webs. Here, we investigate... more Size-based approaches are paramount tools for the study of marine food webs. Here, we investigated the relationship between zooplankton body size, stable isotope composition and trophic level (TL) along a large-scale onshore-offshore gradient in the western tropical Atlantic. Samples were obtained on the Brazilian continental shelf, slope and in oceanic waters (off Fernando de Noronha archipelago and Rocas Atoll) in September and October 2015. Zooplankton was sieved into five size fractions. Zooplankton was dominated by copepods, except for the largest (>2000 μm) size fraction, that showed a high biovolume of chaetognaths, decapods, and fish larvae. Maximum zooplankton abundance and biovolume was found at the continental slope. POM showed consistently lower δ13C than zooplankton, indicating a selective use of 13C-rich primary food sources by zooplankton. Particulate organic matter (POM) was more 13Cenriched in shelf areas (average: −22.8, −23.6 and − 24.3‰ at the shelf, slope and oceanic islands, respectively), probably due to the higher abundance of diatoms nearshore. POM had δ15N values between 2.5 and 6.9‰ (average: 4.0, 4.9 and 4.2‰ at the shelf, slope and oceanic islands, respectively). Zooplankton δ15N and TL increased with body size. The δ15N of the 200-500 μm size fraction was used as baseline for TL estimation. Oceanic areas (average baseline δ15N = 5.8‰ ± 0.52, n = 14) showed a higher baseline δ15N than the shelf (average = 3.9‰ ± 0.69, n = 9) and the slope areas (average = 3.1‰ ± 0.93, n = 9). In spite of differing baselines, the δ15N data produced a consistent pattern of log-linear increase in TL with increasing size, in all areas. The choice of input trophic enrichment factor (TEF) values only slightly changed the log10 (body size) vs TL slopes, but this choice had a considerable effect on the estimates of predator/prey size ratio (PPSR) and predator/prey mass ratio (PPMR). Using a TEF above 2.3 leads to unrealistic PPSR and PPMR estimates. Overall average slope was 0.59 ± 0.08 TL μm−1 with TEF = 2.3 and 0.42 ± 0.07 TL μm−1 with TEF = 3.2. Highlights ► Maximum zooplankton abundance and biovolume was found at the continental slope. ► POM showed lower δ 13 C than zooplankton, indicating selective feeding. ► Zooplankton δ 15 N and trophic level increased with body size. ► Using a δ 15 N trophic enrichment factor above 2.3 leads to unrealistic estimates.

Journal of Fish Biology, Apr 1, 2015

Potential trophic competition between two sympatric mullet species, Mugil cephalus and Mugil cure... more Potential trophic competition between two sympatric mullet species, Mugil cephalus and Mugil curema, was explored in the hypersaline estuary of the Saloum Delta (Senegal) using δ(13) C and δ(15) N composition of muscle tissues. Between species, δ(15) N compositions were similar, suggesting a similar trophic level, while the difference in δ(13) C compositions indicated that these species did not feed from exactly the same basal production sources or at least not in the same proportions. This result provides the first evidence of isotopic niche segregation between two limno-benthophageous species belonging to the geographically widespread, and often locally abundant, Mugilidae family.

HAL (Le Centre pour la Communication Scientifique Directe), Jan 10, 2023

African Journal of Marine Science, 2021

The lesser African threadfin Galeoides decadactylus (family Polynemidae) is one of the most captu... more The lesser African threadfin Galeoides decadactylus (family Polynemidae) is one of the most captured marine fish species in Central Africa. This study examines aspects of the reproductive biology of G. decadactylus in the Libreville area of Gabon. Fish caught with encircling gillnets and bottom gillnets were collected from May 2017 to May 2018 from artisanal fishermen. A total of 776 specimens were studied, comprising 401 females (14–36 cm total length [TL]), 347 males (13–28 cm TL), and 28 individuals of indeterminate sex (12–16 cm TL). Monthly monitoring of gonadosomatic ratio, condition factor and sexual maturity stages revealed that G. decadactylus reproduces continuously but has two slight peak periods: one in the long rainy season and the other in the short rainy season. The species is protandrous, with sizes at first sexual maturity of 17.7 cm TL for males and 18.7 cm for females. Mature individuals largely dominated the catches of small-scale fishers in Gabon. Mean absolute ...

Le régime alimentaire du chinchard d'europe, Trachurus trachurus (Linnaeus, 1758), a été étud... more Le régime alimentaire du chinchard d'europe, Trachurus trachurus (Linnaeus, 1758), a été étudié au sud de la côte atlantique marocaine, entre cap blanc et cap boujdour (21°00'N-26°30'N). L'échantillonnage a été réalisé durant les saisons chaude (juin-juillet-août) et froide (novembre-décembre) en 2007 et 2008. L'analyse du contenu stomacal de 456 individus a montré que le régime alimentaire de T. trachurus est diversifié, composé essentiellement de crustacés pélagiques qui représentent ses proies préférentielles. une analyse en composante principale normée, associée à un test de permutations, a mis en évidence une variation du régime alimentaire en fonction des périodes d'échantillonnage. une analyse de variance multiple (ManoVa) appliquée sur la période des campagnes, la position latitudinale des stations, la profondeur de chalutage et la taille des individus a permis de mettre en exergue les déterminants de cette variation. il en ressort que T. trachurus pr...

The Journal of Foraminiferal Research, 2005

ABSTRACT

Regional Studies in Marine Science

HAL (Le Centre pour la Communication Scientifique Directe), 2013

HAL (Le Centre pour la Communication Scientifique Directe), 2016

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL (Le Centre pour la Communication Scientifique Directe), 2016

Integrating ecophysiology and plankton dynamics into projected maximum fisheries catch potential ... more Integrating ecophysiology and plankton dynamics into projected maximum fisheries catch potential under climate change in the Northeast Atlantic.

Estuarine Coastal and Shelf Science, Oct 1, 2022

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial 4.0 International License

PLOS ONE, Feb 8, 2021

We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feed... more We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feeding relationships among species of the nektobenthic communities and the potential ecological effects of the bottom trawling of a coastal ecosystem in northeastern Brazil. Carbon (δ 13 C) and nitrogen (δ 15 N) compositions were determined for five basal sources and 28 consumers, from zooplankton to shrimp and fish species. Fishes and basal sources showed a broad range of δ 15 N (fishes: 6.49-14.94‰; sources: 2.58-6.79‰) and δ 13 C values (fishes:-23.86 to-13.71‰; sources:-24.32 to-13.53‰), while shrimps and crabs exhibited similar nitrogen and carbon ratios. Six trophic consumer groups were determined among zooplankton, crustaceans and fishes by SIA, with trophic pathways associated mostly with benthic sources. SCA results indicated a preference for benthic invertebrates, mainly worms, crabs and shrimps, as prey for the fish fauna, highlighting their importance in the food web. In overall, differences between SCA and the SIA approaches were observed, except for groups composed mainly for shrimps and some species of high δ 15 N values, mostly piscivorous and zoobenthivores. Given the absence of regulation for bottom trawling activities in the area, the cumulative effects of trawling on population parameters, species composition, potentially decreasing the abundance of benthic preys (e.g., shrimps, worms and crabs) may lead to changes in the trophic structure potentially affect the food web and the sustainability of the fishery.