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Auteur Ruiz, J.; Batty, A.; Chavance, P.; McElderry, H.; Restrepo, V.; Sharples, P.; Santos, J.; Urtizberea, A.
Titre Electronic monitoring trials on in the tropical tuna purse-seine fishery Type Article scientifique
Année 2015 Publication Revue Abrégée ICES J. Mar. Sci.
Volume 72 Numéro 4 Pages 1201-1213
Mots-Clés Bycatch; catch composition; data collection; electronic monitoring system; observers; Purse seining; Tropical tuna
Résumé The difficulty of ensuring adequate statistical coverage of whole fleets is a challenge for the implementation of observer programmes and may reduce the usefulness of the data they obtain for management purposes. This makes it necessary to find cost-effective alternatives. Electronic monitoring (EM) systems are being used in some fisheries as an alternative or a complement to human observers. The objective of this study was to test the use and reliability of EM on the tropical tuna purse-seine fishery. To achieve this objective, seven trips of tuna purse seiners operating in the three Oceans were closely monitored to compare the information provided by EM and on-board observers to determine if EM can reliably document fishing effort, set type, tuna catch, and bycatch. Total tuna catch per set was not significantly different between EM and observer datasets; however, regarding species composition, only main species matched between EM and observers. Success on set-type identification using EM varied between 98.3 and 56.3%, depending on the camera placement. Overall, bycatch species were underestimated by EM, but large bodied species, such as billfishes, were well documented. The analyses in this study showed that EM can be used to determine the fishing effort (number of sets) and total tuna catch as reliably as observers can. Set-type identification also had very promising results, but indicated that refinement of the methods is still needed. To be fully comparable with observer data, improvements for accurately estimating the bycatch will need to be developed in the application and use of the EM system. Operational aspects that need to be improved for an EM programme to be implemented include standardizing installation and on-board catch handling methodology as well as improvements in video technology deployment.
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ISSN 1054-3139, 1095-9289 ISBN Médium
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Numéro d'Appel (up) MARBEC @ isabelle.vidal-ayouba @ collection 1335
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Auteur Salvetat, J.; Lebourges-Dhaussy, A.; Travassos, P.; Gastauer, S.; Roudaut, G.; Vargas, G.; Bertrand, A.
Titre In situ target strength measurement of the black triggerfish Melichthys niger and the ocean triggerfish Canthidermis sufflamen Type Article scientifique
Année 2020 Publication Revue Abrégée Mar. Freshw. Res.
Volume 71 Numéro 9 Pages 1118-1127
Mots-Clés acoustics; aggregating devices fads; archipelago; atlantic; behavior; biomass estimation; frequency; north-east Brazil; shore fishes; small tuna; spinner dolphins; swimbladder; target strength-length relationships; tropical ecosystem; tropical tuna; underwater acoustics; underwater video
Résumé Triggerfish are widely distributed in tropical waters where they play an important ecological role. The black triggerfish Melichthys niger may be the dominant species around oceanic tropical islands, whereas pelagic triggerfish, such as the ocean triggerfish Canthidermis sufflamen, can assemble around fish aggregating devices (FADs) where they are a common bycatch of tuna fisheries. In this study we combined acoustic and optical recordings to provide the first in situ target strength (TS) measurement of black and ocean triggerfish. Data were collected in the Archipelago of Fernando de Noronha off north-east Brazil. The mean TS of a 27.8-cm-long black triggerfish at 70 and 200 kHz was -39.3 dB re 1 m(2) (CV = 14.0%) and -38.9 dB re 1 m(2) (CV = 14.4%) respectively. The mean TS values of ocean triggerfish (with a size range of 39-44 cm) at 70 and 200 kHz were -36.0 dB re 1 m(2) (CV = 15.7%) and -33.3 dB re 1 m(2) (CV = 14.0%) respectively. This work opens up the field for acoustic biomass estimates. In addition, we have shown that TS values for ocean triggerfish are within the same range as those of small tunas. Therefore, acoustic data transmitted from FADs equipped with echosounders can introduce a bias in tuna acoustic biomass estimation and lead to increased rates of bycatch.
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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 1323-1650 ISBN Médium
Région Expédition Conférence
Notes WOS:000562536400007 Approuvé pas de
Numéro d'Appel (up) MARBEC @ isabelle.vidal-ayouba @ collection 2872
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Auteur Dueri, S.; Guillotreau, P.; Jiménez-Toribio, R.; Oliveros-Ramos, R.; Bopp, L.; Maury, O.
Titre Food security or economic profitability? Projecting the effects of climate and socioeconomic changes on global skipjack tuna fisheries under three management strategies Type Article scientifique
Année 2016 Publication Revue Abrégée Global Environmental Change
Volume 41 Numéro Pages 1-12
Mots-Clés Bioeconomic model; climate change; fishery management; Mey; Msy; Skipjack tuna
Résumé We investigate the interactions between anthropogenic climate change, socioeconomic developments and tuna fishery management strategies. For this purpose, we use the APECOSM-E model to map the effects of climate change and commercial fishing on the distribution of skipjack tuna biomass in the three oceans, combined with a new bioeconomic module representing the rent or profit of skipjack fisheries. For forcing, we use Representative Concentration Pathway (RCP) 8.5, the highest emission scenario for greenhouse gas concentrations presented in the IPCC’s Fifth Assessment Report (AR5), and the IPCC Socioeconomic Shared Pathway (SSP) 3, which is characterized by low economic development and a strong increase in the world population. We first investigate the impact of climate change on regional skipjack abundance, catches and profits in three oceans (Atlantic, Indian and Pacific) in 2010, 2050 and 2095. We then study the effects of three management strategies (maximum sustainable yield or MSY, maximum economic yield or MEY, and zero rent or ZR) on the future distribution of fishing fleets between oceans and on global economic rent. Our model projections for 2050 and 2095 show an increase in global skipjack biomass compared to 2010 and major changes in its distribution, impacting local and regional fishing efforts. The Pacific Ocean will continue to dominate the skipjack market. In our modeling of management strategies, the currently predominant MSY strategy would have been unprofitable in 2010, due to a decreased catch per unit effort (CPUE). In the future, however, technological developments should increase fishing efficiency and make MSY profitable. In all the scenarios, a MEY strategy is more profitable than MSY but leads to the lowest catches and the highest prices. This raises ethical questions in a world where food security may become a top priority. In the scenarios where MSY generates an economic loss (e.g. 2010), a ZR strategy allows global stocks to be exploited at high but still profitable levels. Conversely, in the scenarios where MSY is profitable, (e.g. 2095) ZR leads to overfishing and smaller global catches. We conclude that the most appropriate management strategy at any time is likely to change as environmental and socioeconomic conditions evolve. The decision to follow one or other strategy is a complex one that must be regularly reviewed and updated.
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ISSN 0959-3780 ISBN Médium
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Numéro d'Appel (up) MARBEC @ isabelle.vidal-ayouba @ collection 1601
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Auteur Bodin, N.; Chassot, E.; Sardenne, F.; Zudaire, I.; Grande, M.; Dhurmeea, Z.; Murua, H.; Barde, J.
Titre Ecological data for western Indian Ocean tuna Type Article scientifique
Année 2018 Publication Revue Abrégée Ecology
Volume 99 Numéro 5 Pages 1245-1245
Mots-Clés energetics; fatty acids; lipids; morphometrics; multi-tissues; proteins; stable isotopes; trophic ecology; tropical marine ecosystems; tuna fisheries
Résumé Tuna are marine apex predators that inhabit the tropical and sub-tropical waters of the Indian Ocean where they support socially and economically important fisheries. Key component of pelagic communities, tuna are bioindicator species of anthropogenic and climate-induced changes through modifications of the structure and related energy-flow of food webs and ecosystems. The IndianEcoTuna dataset provides a panel of ecological tracers measured in four soft tissues (white muscle, red muscle, liver, gonads) from 1,364 individuals of four species, i.e., the albacore (ALB, Thunnus alalunga), the bigeye (BET, T. obesus), the skipjack (SKJ, Katsuwomus pelamis), and the yellowfin (YFT, T. albacares), collected throughout the western Indian Ocean from 2009 to 2015. Sampling was carried out during routine monitoring programs, at sea by observers onboard professional vessels or at landing. For each record, the type of fishing gear, the conservation mode, as well as the fishing date and catch location are provided. Individuals were sampled to span a wide range of body sizes: 565 ALB with fork length from 58 to 118 cm, 155 BET from 29.5 to 173 cm, 304 SKJ from 30 to 74 cm, and 340 YFT from 29 to 171.5 cm. The IndianEcoTuna dataset combines: (1) 9,512 records of carbon and nitrogen stable isotopes (percent element weights, δ13C and δ15N values) in 1,185 fish, (2) 887 concentrations of total proteins in 242 fish, (3) 8,356 concentrations of total lipids and three lipid classes (triacylglycerols TAG; phospholipids PL; sterols ST) in 695 fish, and (4) 1,150 and 1,033 profiles of neutral and polar fatty acids in 397 and 342 fish, respectively. Information on sex and weights of the whole fish, gonads, liver and stomach is provided. Because of the essential trophic role and wide-ranging of tuna in marine systems, and the large panel of tropho-energetic tracers and derived-key quantitative parameters provided (e.g., niche width, trophic position, condition indices), the IndianEcoTuna dataset should be of high interest for global and regional research on marine trophic ecology and food web analysis, as well as on the impacts of anthropogenic changes on Indian Ocean marine ecosystems. There are no copyright restrictions for research and/or teaching purposes. Usage of the dataset must include citation of this Data Paper.
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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1939-9170 ISBN Médium
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Numéro d'Appel (up) MARBEC @ isabelle.vidal-ayouba @ collection 2373
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Auteur Dortel, E.; Pecquerie, L.; Chassot, E.
Titre A Dynamic Energy Budget simulation approach to investigate the eco-physiological factors behind the two-stanza growth of yellowfin tuna (Thunnus albacares) Type Article scientifique
Année 2020 Publication Revue Abrégée Ecol. Model.
Volume 437 Numéro Pages 109297
Mots-Clés Behavioral changes; bioenergetics; bluefin tuna; Body-size scaling; DEB theory; fisheries; indian-ocean; management; Ontogeny; populations; rates; stable-isotopes; temperature; tropical tuna
Résumé The growth of yellowfin tuna has been the subject of considerable research efforts since the early 1960s. Most studies support a complex two-stanza growth pattern with a sharp acceleration departing from the von Bertalanffy growth curve used for most fish populations. This growth pattern has been assumed to result from a combination of physiological, ecological and behavioral factors but the role and contribution of each of them have not been addressed yet. We developed a bioenergetic model for yellowfin tuna in the context of Dynamic Energy Budget theory to mechanistically represent the processes governing yellowfin tuna growth. Most parameters of the model were inferred from Pacific bluefin tuna using body-size scaling relationships while some essential parameters were estimated from biological data sets collected in the Indian Ocean. The model proved particularly suitable for reproducing the data collected during the Pacific yellowfin tuna farming experience conducted by the Inter-American Tropical Tuna Commission at the Achotines Laboratory in Panama. In addition, model predictions appeared in agreement with knowledge of the biology and ecology of wild yellowfin tuna. We used our model to explore through simulations two major assumptions that might explain the existence of growth stanzas observed in wild yellowfin tuna: (i) a lower food supply during juvenile stage in relation with high infra- and inter-species competition and (ii) ontogenetic changes in food diet. Our results show that both assumptions are plausible although none of them is self-sufficient to explain the intensity of growth acceleration observed in wild Indian Ocean yellowfin tuna, suggesting that the two factors may act in concert. Our study shows that the yellowfin growth pattern is likely due to behavioral changes triggered by the acquisition of physiological abilities and anatomical traits through ontogeny that result in a major change in intensity of schooling and in a shift in the biotic habitat and trophic ecology of this commercially important tuna species.
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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 0304-3800 ISBN Médium
Région Expédition Conférence
Notes WOS:000579484600005 Approuvé pas de
Numéro d'Appel (up) MARBEC @ isabelle.vidal-ayouba @ collection 2891
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