Situation en 2011 des ressources exploitées par les flottilles françaises Auteur(s) : Biseau, Alain Bellail, Robert Bertignac, Michel Biais, Gerard Bigot, Jean-louis Bouche, Ludovic Bourjea, Jerome Caro, Anthony Résumé : Ce document présente l'état des principaux stocks exploités par les flottes françaises en termes de mortalité par pêche et de biomasse de reproducteurs. La situation fin 2010 (début 2011) par rapport aux points de référence (de précaution et Fmsy) est indiqué lorsque les indicateurs sont estimés et que les références sont définies. Les grandes tendances en matière d'évolution des mortalités et biomasses sont également indiquées. Droits : 2011 Ifremer http://archimer.ifremer.fr/doc/00035/14656/11956.pdf http://archimer.ifremer.fr/doc/00035/14656/ | Partager |
Open environmental databases for open-sea fisheries biologists Auteur(s) : Fromentin, Jean-marc Royer, Francois Marsac, Francis Éditeur(s) : ICCAT Résumé : The present working document aims to list the main environmental databases (including in-situ observations, remote-sensing data and ocean models outputs), that are currently available on the Net and of interest in open-sea fisheries biology and ecology. Ce document a pour objet de lister les principales bases de données environnementales (concernant les données in-situ, satellitaires et les sorties de modèles océaniques), qui sont actuellement disponibles sur la toile et d’intérêt pour l’écologie halieutique se rapportant aux ressources thonières. El objetivo de este documento es presentar una relación de las principales bases de datos medioambientales (sobre datos in situ, vía satélite y valores de salida de los modelos oceánicos) que están disponibles actualmente en la red y que revisten interés para la ecología pesquera relacionada con los recursos atuneros. Collective Volume of Scientific Papers (1021-5212) (ICCAT), 2005 , Vol. 58 , N. 5 , P. 1756-1760 Droits : ICCAT http://archimer.ifremer.fr/doc/00194/30501/28911.pdf http://archimer.ifremer.fr/doc/00194/30501/ | Partager |
Biogeography of tuna and billfish communities Auteur(s) : Reygondeau, Gabriel Maury, Olivier Beaugrand, Gregory Fromentin, Jean-marc Fonteneau, Alain Cury, Philippe Éditeur(s) : Wiley-blackwell Résumé : Aim The aims of this study were: (1) to identify global communities of tuna and billfish species through quantitative statistical analyses of global fisheries data; (2) to describe the spatial distribution, main environmental drivers and species composition of each community detected; and (3) to determine whether the spatial distribution of each community could be linked to the environmental conditions that affect lower trophic levels by comparing the partitions identified in this study with Longhursts biogeochemical provinces. Location The global ocean from 60 degrees S to 65 degrees N. Methods We implemented a new numerical procedure based on a hierarchical clustering method and a nonparametric probabilistic test to divide the oceanic biosphere into biomes and ecoregions. This procedure was applied to a database that comprised standardized data on commercial longline catches for 15 different species of tuna and billfish over a period of more than 50 years (i.e. 1953-2007). For each ecoregion identified (i.e. characteristic tuna and billfish community), we analysed the relationships between species composition and environmental factors. Finally, we compared the biogeochemical provinces of Longhurst with the ecoregions that we identified. Results Tuna and billfish species form nine well-defined communities across the global ocean. Each community occurs in regions with specific environmental conditions and shows a distinctive species composition. High similarity (68.8% homogeneity) between the spatial distribution of the communities of tuna and billfish and the biogeochemical provinces suggests a strong relationship between these species and the physical and chemical characteristics of the global ocean. Main conclusions Despite their high tolerance for a wide range of environmental conditions, these highly migratory species are partitioned into clear geographical communities in the ocean at a global scale. The similarity between biogeochemical and biotic divisions in the ocean suggests that the global ocean is a mosaic of large biogeographical ecosystems, each characterized by specific environmental conditions that have a strong effect on the composition of the trophic web. Journal Of Biogeography (0305-0270) (Wiley-blackwell), 2012-01 , Vol. 39 , N. 1 , P. 114-129 Droits : 2011 Blackwell Publishing Ltd http://archimer.ifremer.fr/doc/00060/17141/14716.pdf DOI:10.1111/j.1365-2699.2011.02582.x http://archimer.ifremer.fr/doc/00060/17141/ | Partager Voir aussi Biogeochemical provinces global ocean Istiophorus Katsuwonus macroecology Makaira marine biogeography Tetrapturus Thunnus Xiphias Télécharger |
Complex interplays among population dynamics, environmental forcing, and exploitation in fisheries Auteur(s) : Rouyer, Tristan Fromentin, Jean-marc Menard, Felix Calzelles, B Briand, K Pianet, R Planque, Benjamin Stenseth, N Éditeur(s) : The National Academy of Sciences of the USA Résumé : The patterns of variations in fisheries time series are known to result from a complex combination of species and fisheries dynamics all coupled with environmental forcing (including climate, trophic interactions, etc.). Disentangling the relative effects of these factors has been a major goal of fisheries science for both conceptual and management reasons. By examining the variability of 169 tuna and billfish time series of catch and catch per unit effort (CPUE) throughout the Atlantic as well as their linkage to the North Atlantic Oscillation (NAO), we find that the importance of these factors differed according to the spatial scale. At the scale of the entire Atlantic the patterns of variations are primarily spatially structured, whereas at a more regional scale the patterns of variations were primarily related to the fishing gear. Furthermore, the NAO appeared to also structure the patterns of variations of tuna time series, especially over the North Atlantic. We conclude that the patterns of variations in fisheries time series of tuna and billfish only poorly reflect the underlying dynamics of these fish populations; they appear to be shaped by several successive embedded processes, each interacting with each other. Our results emphasize the necessity for scientific data when investigating the population dynamics of large pelagic fishes, because CPUE fluctuations are not directly attributable to change in species' abundance. Proceedings of the National Academy of Sciences of the United States of America (0027-8424) (The National Academy of Sciences of the USA), 2008-04 , Vol. 105 , N. 14 , P. 5420-5425 Droits : 2008 by The National Academy of Sciences of the USA http://archimer.ifremer.fr/doc/2008/publication-3984.pdf DOI:10.1073/pnas.0709034105 http://archimer.ifremer.fr/doc/00000/3984/ | Partager |
Environmental noise in spawning areas: the case of Atlantic bluefin tuna (Thunnus thynnus) Auteur(s) : Royer, Francois Fromentin, Jean-marc Éditeur(s) : Blackwell science Résumé : This paper provides an exploratory analysis aiming to seek whether the colour of environmental noise theory could help in understanding the intriguing reproductive strategy of Atlantic bluefin tuna (BFT). A frequency-based approach based on spectral exponents, f(beta) with beta < 0, is chosen and applied on 10 biogeographical provinces covering the North Atlantic. The major BFT spawning area, i.e. the Mediterranean Sea, was the only one to display a pink power spectrum, whereas open ocean regions displayed more reddened fluctuations, i.e. greater variance at low frequencies. Environmental noise in the Mediterranean could, thus, offer more favourable characteristics on the long-term than the open ocean. The implications of these findings are discussed in regards to medium and long (possibly evolutionary) time scales. Fisheries Oceanography (1054-6006) (Blackwell science), 2007-03 , Vol. 16 , N. 2 , P. 202-206 Droits : 2007 Blackwell science http://archimer.ifremer.fr/doc/2007/publication-2437.pdf DOI:10.1111/j.1365-2419.2006.00424.x http://archimer.ifremer.fr/doc/00000/2437/ | Partager |
Environmental noise affects the fluctuations of Atlantic large pelagics Auteur(s) : Rouyer, Tristan Fromentin, Jean-marc Stenseth, Nils Chr. Éditeur(s) : Pergamon-elsevier Science Ltd Résumé : Environmental variables affect many processes of fish biology and their fluctuations are thought to be one of the main factors in variability of fish stocks. Recent work has shown that the variability of the environment in the frequency domain (i.e., the environmental noise) can interact with endogenous processes (e.g., density dependence) and affect fluctuations of animal populations. In this study, we investigate whether fluctuations of large pelagics' time series are affected by environmental noise and whether life-history traits of species modulate this response. By analysing several environmental variables and a large dataset of tuna and billfish catch per unit effort (CPUE) time series from the Atlantic, we show that in environments dominated by long-term fluctuations (i.e., red noise) CPUE time series were less variable and displayed smoother fluctuations. Furthermore, larger, slower-growing and later-maturing species were found to be more sensitive to changes of environmental noise than species with a shorter turnover rate. Our results suggest that environmental noise interacts with fish biology; understanding how it is integrated into biological processes might provide important insights to understand the responses of fish stocks dynamics to exploitation and environmental changes. (C) 2010 Elsevier Ltd. All rights reserved. Progress In Oceanography (0079-6611) (Pergamon-elsevier Science Ltd), 2010-07 , Vol. 86 , N. 1-2 , P. 267-275 Droits : 2010 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00011/12230/9083.pdf DOI:10.1016/j.pocean.2010.04.025 http://archimer.ifremer.fr/doc/00011/12230/ | Partager |
How does fishing alter marine populations and ecosystems sensitivity to climate? Auteur(s) : Planque, Benjamin Fromentin, Jean-marc Cury, Philippe Drinkwater, Kenneth F. Jennings, Simon Perry, R. Ian Kifani, Souad Éditeur(s) : Elsevier Résumé : Evidence has accumulated that climate variability influences the state and functioning of marine ecosystems. At the same time increasing pressure from exploitation and other human activities has been shown to impact exploited and non-exploited species and potentially modify ecosystem structure. There has been a tendency among marine scientists to pose the question as a dichotomy, i.e., whether (1) "natural" climate variability or (2) fishery exploitation bears the primary responsibility for population declines in fish populations and the associated ecosystem changes. However, effects of both climate and exploitation are probably substantially involved in most cases. More importantly, climate and exploitation interact in their effects, such that climate may cause failure in a fishery management scheme but that fishery exploitation may also disrupt the ability of a resource population to withstand, or adjust to, climate changes. Here, we review how exploitation, by altering the structure of populations and ecosystems, can modify their ability to respond to climate. The demographic effects of fishing (removal of large-old individuals) can have substantial consequences on the capacity of populations to buffer climate variability through various pathways (direct demographic effects, effects on migration, parental effects). In a similar way, selection of population sub-units within metapopulations may also lead to a reduction in the capacity of populations to withstand climate variability and change. At the ecosystem level, reduced complexity by elimination of species, such as might occur by fishing, may be destabilizing and could lead to reduced resilience to perturbations. Differential exploitation of marine resources could also promote increased turnover rates in marine ecosystems, which would exacerbate the effects of environmental changes. Overall (and despite the specificities of local situations) reduction in marine diversity at the individual, population and ecosystem levels will likely lead to a reduction in the resilience and an increase in the response of populations and ecosystems to future climate variability and change. Future management schemes will have to consider the structure and functioning of populations and ecosystems in a wider sense in order to maximise the ability of marine fauna to adapt to future climates. (C) 2009 Elsevier B.V. All rights reserved. Journal of Marine Systems (0924-7963) (Elsevier), 2010-02 , Vol. 79 , N. 3-4 , P. 403-417 Droits : 2009 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/2010/publication-7384.pdf DOI:10.1016/j.jmarsys.2008.12.018 http://archimer.ifremer.fr/doc/00000/7384/ | Partager |
The True Challenge of Giant Marine Reserves Auteur(s) : Kaplan, David Bach, Pascal Bonhommeau, Sylvain Chassot, Emmanuel Chavance, Pierre Dagorn, Laurent Davies, Tim Dueri, Sibylle Éditeur(s) : Amer Assoc Advancement Science Science (0036-8075) (Amer Assoc Advancement Science), 2013-05 , Vol. 340 , N. 6134 , P. 810-811 Droits : 2013 American Association for the Advancement of Science. All Rights Reserved. http://archimer.ifremer.fr/doc/00139/25068/23186.pdf DOI:10.1126/science.340.6134.810-b http://archimer.ifremer.fr/doc/00139/25068/ | Partager |
Patterns of variations in large pelagic fish: A comparative approach between the Indian and the Atlantic Oceans Auteur(s) : Corbineau, A. Rouyer, Tristan Fromentin, Jean-marc Cazelles, B. Fonteneau, Alain Menard, Frederic Éditeur(s) : Pergamon-elsevier Science Ltd Résumé : Catch data of large pelagic fish such as tuna, swordfish and billfish are highly variable ranging from short to long term. Based on fisheries data, these time series are noisy and reflect mixed information on exploitation (targeting, strategy, fishing power), population dynamics (recruitment, growth, mortality, migration, etc.), and environmental forcing (local conditions or dominant climate patterns). In this work, we investigated patterns of variation of large pelagic fish (i.e. yellowfin tuna, bigeye tuna, swordfish and blue marlin) in Japanese longliners catch data from 1960 to 2004. We performed wavelet analyses on the yearly time series of each fish species in each biogeographic province of the tropical Indian and Atlantic Oceans. In addition, we carried out cross-wavelet analyses between these biological time series and a large-scale climatic index, i.e. the Southern Oscillation Index (Sol). Results showed that the biogeographic province was the most important factor structuring the patterns of variability of Japanese catch time series. Relationships between the SOI and the fish catches in the Indian and Atlantic Oceans also pointed out the role of climatic variability for structuring patterns of variation of catch time series. This work finally confirmed that Japanese longline CPUE data poorly reflect the underlying population dynamics of tunas. (C) 2010 Elsevier Ltd. All rights reserved. Progress In Oceanography (0079-6611) (Pergamon-elsevier Science Ltd), 2010-07 , Vol. 86 , N. 1-2 , P. 276-282 Droits : 2010 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00011/12231/9029.pdf DOI:10.1016/j.pocean.2010.04.019 http://archimer.ifremer.fr/doc/00011/12231/ | Partager |
Trends in the NE Atlantic and Mediterranean Bluefin Abundance Auteur(s) : Ravier, Christelle Fromentin, Jean-marc Éditeur(s) : JIMAR (Joint Institute for Marine and Atmospheric Research (JIMAR)) PFRP Quaterly Newsletter (Pelagic Fisheries Research Program) (JIMAR (Joint Institute for Marine and Atmospheric Research (JIMAR))), 2001 , Vol. 6 , N. 4 , P. 1;5-7 Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/00194/30569/29005.pdf http://archimer.ifremer.fr/doc/00194/30569/ | Partager |