Éditeur(s) : Kluwer
Résumé : We reviewed the literature concerning fish aggregation devices (FADs) to determine areas of relative research deficiency. Using specific searches of the Aquatic Sciences and Fisheries Abstracts ( ASFA) database from 1978 to December 2003 and a classical search of the pre-1978 literature, we collected 407 references on FADs. Publications before 1980 were predominantly peer-reviewed, although non-peer reviewed literature has dominated since 1980, due to the numerous technical reports produced as FADs became more widely used in artisinal and large-scale industrial. sheries in the 1980s. Most studies of the ecology of FAD-associated fish were descriptive, with few mensurative experimental studies and even fewer manipulative experimental studies that tested specific hypotheses, due to inherent difficulties in working in the open ocean on objects that are temporary in space and time. Research on the ecology of FAD-associated fish has focused on moored FADs, despite the major FAD-based. sheries being around drifting FADs. Publications presenting information on moored FADs outnumbered papers on drifting FADs by a ratio of 3.5: 1. We recommend that greater emphasis be placed by. sheries scientists and funding agencies on researching drifting FADs to provide better information for management of large-scale FAD-based industrial. sheries. Future research should focus on determining the patterns of use of drifting FADs by pelagic species, the underlying sensory processes of attraction and the ecological consequences for individual fish stocks and the wider pelagic ecosystem of the use of FADs as. sheries enhancement tools.
Reviews in Fish Biology and Fisheries (0960-3166) (Kluwer), 2004-03 , Vol. 14 , N. 1 , P. 21-42

Droits : 2004 Springer
http://archimer.ifremer.fr/doc/2004/publication-721.pdf
DOI:10.1007/s11160-004-3151-x
http://archimer.ifremer.fr/doc/00000/721/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Since the beginning of 1980, the Martinique fishermen have suffered a deep crisis. The traditional ways of fishing, based on benthic fish exploitation, have seen the decreasing of their profitability due to the over-fishing of the narrow continental shelf offering few resources. The pelagic fishery had become the professional main source of income. This fishery equally encounter difficulties: denied rights of access in the EEZ of Caribbean islands, expensive costs of exploitation. The disposal of FADs offers new ways to the Martinique fishermen. In 1999, it was decided the disposal of a onetworko of 30 permanent FADs around Martinique. The mooring of these FADs must be followed by legal and economic adapted measures to reach the desired aim: the development of local fishery economy through a sustainable fishing practice. Therefore, the French authorities have decided to make the regional fishermen committee responsible for the management of FADs.This committee is the only one to be entitled to moor and to deliver licences to FADs. This committee, gathering all the fishing industry representatives, has regarding the french law the right of mooring and delivering licences to the FADs access, collecting fishery statistics. These data should fund research to improve the management of the fishery, care and replace FADs. This programas realisation, as well as durability, need adequate financial planning. It has been included in the European commission financing program. This plans success will ensure the increase of the fishermen income, maintain and develop employment.Original Abstract: Apres une periode d'experimentation lancee localement au debut des annees quatre-vingt, les premiers resultats ont ete suffisamment probants pour conduire les professionnels a souhaiter l'implantation de dispositifs de concentration de poissons (dcp) en Martinique ou a les implanter eux-memes pour la capture des dorades coryphenes, des thons noirs, de l'albacore ou du listao. Le colloque international sur la peche thoniere et les dispositifs de concentration de poissons organise du 15 au 19 octobre 1999 en Martinique donne l'occasion de revenir sur le contexte, l'interet et les modalites de developpement de la technique des dcp en Martinique.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15305/12639.pdf
http://archimer.ifremer.fr/doc/00042/15305/

Éditeur(s) : EDP Sciences
Résumé : From April 2003 to April 2004 monthly sea surveys were conducted around 2 fish aggregating devices (FADs) moored at 2000 and 2500 m depth in Martinique (Lesser Antilles). The use of a dual frequency splitbeam echosounder combined with an underwater camera and fishing methods allowed assessment of average space and time distribution of pelagic fish aggregated beneath the FADs, as well as identification of their overall size and species composition. At daytime, 4 fish aggregations were identified at each FAD, representing 4 distinct types: i) an aggregation of small juvenile tuna (mean fork length, FL: 30 cm) observed very close to the surface in 25% of daytime periods; ii) a small surface aggregation dominated by carangids, Caranx crysos, present in 65% of daytime periods; iii) a large sub-surface aggregation observed during all daytime periods: this aggregation appeared to be primarily comprised of 58 cm FL blackfin tuna (Thunnus atlanticus), mixed with yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tunas of the same size; and iv) sub-surface scattered large predators (mainly blue marlin, Makaira nigricans) present in 10% of daytime periods. A smaller sub-surface aggregation comprised of medium tuna mixed with "extranatants" (fishes which remain within 10 to 50 m of a FAD) was observed in 75% of night-time periods, whereas unidentified scattered fishes were detected from 70 to 400 m depth. The low daytime vulnerability of medium sub-surface tunas to applied line techniques leads us to assume that their feeding motivation was low during daytime. These tunas could preferentially feed on mesopelagic organisms during night-time and transition periods around Martinican moored FADs. Local fishermen mainly targeted the large scattered predators using very small tunas as living bait. The sub-surface tuna aggregation hence appeared to be currently unexploited by local fisheries, though it represented the large majority of the pelagic biomass around the moored FADs.
Des campagnes scientifiques mensuelles ont été menées autour de 2 dispositifs de concentration de poissons ancrés à 2000-2500 m de profondeur, en Martinique d'avril 2003 à avril 2004. L'utilisation combinée d'un échosondeur monofaisceau multifréquence, d'une caméra vidéo sous-marine et de techniques de pêche conventionnelles a permis de déterminer la distribution spatio-temporelle moyenne des poissons agrégés autour des DCP ancrés ainsi que la composition générale des agrégations. Les techniques de vidéo sous-marine ont joué un rôle majeur dans l'identification des espèces et l'observation de leur comportement. De jour; quatre types d'agrégations ont été définis : i) une agrégation de thonidés juvéniles (longueur à la fourche, LF, moyenne : 30 cm) observée très près de la surface durant 25 % des périodes diurnes échantillonnées ii) une petite agrégation composée essentiellement de Caranx crysos présente en surface lors de 65 % des phases diurnes iii) une grande agrégation de thons observée en sub-surface lors de toutes les phases diurnes; cette agrégation était constituée essentiellement de thons noirs (Thunnus atlanticus) de 58 cm LF, associés de façon saisonnière à des albacores (Thunnus albacares) et des listaos (Katsuwonus pelamis) de taille similaire iv) des grands prédateurs assez dispersés (essentiellement le marlin bleu, Makaira nigricans), observés lors de 10 % des phases diurnes. Une agrégation de sub-surface, aux dimensions plus réduites et composée de thons et "d'extranatants" (poissons restant à distance de 10 à 50 m du DCP) a été observée lors de 75 % des périodes nocturnes; ainsi que des organismes non-identifiés dispersés entre 70 et 400 m de profondeur. La faible vulnérabilité diurne des thons de sub-surface aux techniques de ligne utilisées indique qu'ils ne se nourrissent pas activement durant la journée. Ces poissons pourraient se nourrir préférentiellement d'organismes mésopélagiques durant les phases de transition et nocturnes autour des DCP ancrés. La pêcherie artisanale martiniquaise n'exploite qu'une faible part des ressources agrégées autour des DCP ancrés. Les principales espèces-cibles sont les grands prédateurs capturés de jour en utilisant des thonidés juvéniles comme appât vivant. L'agrégation de thons de sub-surface représente la grande majorité de la biomasse autour des DCP mais elle est quasiment inexploitée par les pêcheries locales.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2007-10 , Vol. 20 , N. 4 , P. 357-366

Droits : EDP Sciences, IFREMER, IRD 2007
http://archimer.ifremer.fr/doc/2007/publication-3634.pdf
DOI:10.1051/alr:2008004
http://archimer.ifremer.fr/doc/00000/3634/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Tuna world fisheries yield 3 million tons per year; the increase rate of whole production is constant and sustained since 30 years. This original figure for marine fisheries is due to enlargement of tuna fleets and fishing grounds over all the world ocean, the continuous increase of tuna fishing power by in board equipment and remote sensing equipment for searching and scouting (on board, aircraft, satellite, telecommunication_). During the last 20 years, the log-associated tuna fishing has contributed to the local individual and tuna fleets efficiency and fishing power either for large industrial tuna seiners by radio-equipped buoys on natural (debris) or artificial man-made logs. The same trend is noted for numerous artisanal tuna and large pelagic coastal fisheries on moored fishing aggregating devices and networks. The first part of the paper is a review of data and results to assess and rank the "Surfaces prospected by in board tuna seiners and associated aircraft and satellite technics" (visual, radar, sar-radar and satellite altimetry sensors). The final objective is the comparison with the surfaces and volumes associated to fads. Since 20 years, tuna ecology and behaviour data from ultrasonic tagging (short-term depth/distance/time migration around logs and fads) are used for fishing of tuna associated with floating objects, namely fads. The second part of this paper is an "Assessment of fad's aggregating associated surface and volume" linked with oceanographic data: large oceanic geostrophic current and observed drift speed of radio-equipped fads in the Indian Ocean. Using the available data on fads, tuna fishing technology linked with oceanographic and biological data results from ultrasonic tuna tracking experiments, the paper is an attempt to identify and place the fads technology in the scale of tuna fishing devices as a contribution to the increase of tuna fishing power either individual tuna boat or tuna fleets.Original Abstract: La production mondiale des pecheries thonieres est actuellement de l'ordre de 3 millions de tonnes par an et conserve depuis pres de 50 ans un taux de croissance annuel soutenu. Cette croissance, exceptionnelle pour un secteur des peches maritimes, est due a plusieurs causes: accroissement des effectifs et des puissances de peche des grandes flottes thonieres industrielles oceaniques qui exploitent les ressources thonieres de l'ocean mondial et le developpement conjoint de nouvelles techniques de peche et de nouvelles technologies d'aide a la peche, telles que les dispositifs de concentration de poissons (DCP). L'accroissement de la puissance individuelle des navires est du au developpement de la construction navale (mecanisation, propulsion, hydraulique, conservation et traitement a borda) et a l'utilisation d'une gamme diversifiee d'aides a la peche : navigation, telecommunication, localisation des zones favorables, detection visuelle ou radiometrique assistee par equipement a bord, en helicoptere et avion, detection acoustique, detection par radar de bord, radar-avion ou, a terme, antenne SAR sur satellite. Plus recemment, soit depuis 20 ans, les caracteristiques du comportement, migration de court terme, agregation et concentration des poissons pelagiques, fixation et retention des bancs de thons, sont utilisees, par les dispositifs de concentration de poissons (DCP) ancres ou derivants. Cette contribution a pour objectif de situer et placer les DCP fixes ou derivants sur cet ensemble de techniques d'aide a la peche thoniere. Les donnees pour cet essai de classement sont d'ordres biologique, ethologique et comportementaux (amplitude de deplacement des thons et dimension de la sphere d'attraction d'un DCP) et d'ordres environnemental et oceanographique : masse d'eau concernee par un DCP dans une large veine de courant oceanique ou cotier. On tente de quantifier et d'ordonner les surfaces et les volumes prospectes par les thoniers et particulierement les volumes et masses d'eau exploites par les thoniers utilisant des DCP. Ce classement des DCP dans la serie des dispositifs d'aide a la peche thoniere facilitera l'appreciation de leur contribution a l'augmentation des puissances de peche des thoniers.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15297/12656.pdf
http://archimer.ifremer.fr/doc/00042/15297/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Hawaii was one of the first locations to adapt the Philippine payao concept for use in high energy, deep-water environments. Initial experimental fad deployments were made by the National Marine Fisheries Service in 1977. In 1980, the State of Hawaii started deploying FADs in a programme that has since expanded to its current status of 52 approved surface fad sites. Funding is primarily derived from federal US programmes and the FADs are primarily focused on the sport fishing community. fad sites were selected to expedite access by sport fishermen; specific sites were chosen after consultation with fishermen at public hearings. Since 1997, the FAD system has been managed on a collaborative basis between the State of Hawaii and the University of Hawaii. Hawaiian FADs evolved through two previous designs before the current system of single-sphere spar-buoy was adopted. Today's FADs have an "inverse catenary" mooring system comprised of sections of floating and sinking rope attached to a "tripod" concrete block anchor system. fad sites range between 3.2 km and 46 km from shore. Mooring depths range between 200 and 3,000 metres. Average on-site longevity is 31 months; there is no correlation between longevity and depth of mooring. Windward locations have significantly shorter lifespans than leeward locations. Ten to twenty fads are replaced each year. Each FAD costs approximately us$ 7,500 to build and deploy. Hawaiian fads are heavily used by private and commercial sport fishermen and by small-scale artisanal and commercial fishermen. Commercial pole-and-line boats occasionally use the FADs to capture skipjack tuna. Hawaiian FADs will continue to be used for various types of pelagic fisheries research.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15280/12666.pdf
http://archimer.ifremer.fr/doc/00042/15280/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Installation and maintenance of FADs by the Government of Guam began in 1979, initially with funding from the Salstonstall-Kennedy Act through the Pacific Tuna Development Foundation. Current funding for the Guam FAD project is provided through the Dingell-Johnson/Wallop-Breaux Sport Fish Restoration programme, a Federal Aid Project funded by taxes collected on the purchase of fishing equipment and motorboat fuels nationwide. There are now sixteen operational FAD sites in Guam's waters. At a cost of approximately US$10,000 per system, concern for the rising costs of replacing and maintaining FAD systems has prompted the Department of Agriculture's Division of Aquatic and Wildlife Resources (DAWR) to investigate alternative FAD maintenance strategies and system design. Several cost-cutting measures being considered include the use of reliable solar-powered navigation lights to reduce the number of maintenance trips required, and switching to a newer generation of lighter, more durable buoys and mooring systems. Average time on station for a dawr fad system is nearing two years. Interestingly, in most cases where an errant system is recovered, the failure in the mooring system was observed to occur at a depth from 35 to 500 metres. These observations have led to speculation that additional protection of the mooring line down to 500 m may result in doubling the average time on station of most FAD systems.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15324/12650.pdf
http://archimer.ifremer.fr/doc/00042/15324/

Éditeur(s) : Ecole Nationale Supérieure Agronomique de Rennes (ENSAR)
Résumé : Artificial Fish Aggregating Devices (FADs) are known to concentrate tropical tunas. This aggregative behaviour drastically increases the vulnerability of these species to fishing. Alternatively, FADs can be used as oceanic observatories to study the aggregative behaviour of large pelagic fish. We conducted sea surveys in Martinique (Lesser Antilles) to i) establish a typology of the pelagic fish aggregations found around moored FADs ii) study their relations with their biotic and abiotic environment and the local fishery. The mean biomass of large pelagic fish aggregations was also estimated to provide scientific inputs to achieve a sustainable management of the moored FAD fishery. The first part presents the background of the study. We introduce the regional pelagic ecosystem, the aggregative behaviour of pelagic fish around FADs and the Martinican moored FAD fishery. The second part begins with a presentation of the conceptual framework of the study: the hierarchy theory. Observation scales and survey methodology are therefore described. Repeated echosounder surveys run in a star pattern were conducted around 2 moored FADs, in combination with underwater video observations, classical fishing experiments and CTD profiles. In the third part, the elements of the [moored FAD ¿ pelagic fish - environment - fishing] system and their interactions are numerically characterised in the vertical plane. The main type of pelagic fish aggregation was a large aggregation distributed in sub-surface (40-100 m) within a radius of 400 m of the FAD. This aggregation was mostly made of 60 cm FL blackfin tunas (Thunnus atlanticus). It appeared at sunrise and mostly spread away in the late afternoon. It was observed during all daytime surveys. The average density and the vertical structure of the micronektonic sound scattering layers (SSLs) were assessed locally around a FAD for 48h cycles. These SSLs descriptors showed positive correlation with the size and the abundance of the sub-surface tuna aggregation. Whereas this aggregation accounted for about 95% of the total biomass aggregated around a moored FAD, it was nearly unexploited by the local commercial fishermen. The fourth part focuses on the sub-surface tuna aggregation. A high variability of the spatial distribution of the aggregation was evidenced in the horizontal plane at daily, day to day and monthly temporal scales. These variations were related to fluctuations of the global abundance of the aggregation. The daytime average density of sub-surface tuna was modelled as a function of the distance to FAD, within an advection-diffusion framework. Based on these results, a universal kriging model was designed to assess the mean maximum daily biomass of the sub-surface tuna aggregation. This mean biomass estimate yielded 11 tons with an estimation error of 26%. To conclude, we present a hierarchical organization in space and time of a sub-surface tuna population distributed within a network of moored FADs, from micro to meso-scale. We suggest that the spatial distribution of tunas can be explained from fine to coarse-scales by behavioural processes (self-organization, feeding, aggregative behaviour) whereas their spatial distribution is mainly forced by environmental processes at broader scales.
L'utilisation de Dispositifs de Concentration de Poissons permet de provoquer la formation de larges agrégations de thonidés autour de dispositifs artificiels, ce qui augmente considérablement la vulnérabilité de ces ressources vis-à-vis de l'exploitation halieutique. Les DCP peuvent également être utilisés en tant qu'observatoires océaniques, afin d'étudier le comportement agrégatif du macronecton pélagique. Nous avons ainsi réalisé des observations autour de DCP ancrés en Martinique, afin de définir une typologie des agrégations de macronecton et de étudier leurs relations avec leur environnement biotique, abiotique et l'exploitation halieutique locale. Nous avons ensuite estimé la biomasse moyenne de macronecton agrégé autour d'un DCP ancré, afin de fournir des éléments scientifiques nécessaires à une gestion durable de ces ressources. La première partie présente le contexte de l'étude i.e. l'écosystème pélagique régional, le phénomène d'agrégation du macronecton autour des DCP et la pêche associée aux DCP ancrés en Martinique. La deuxième partie introduit la théorie de la hiérarchie qui a fourni le cadre conceptuel de l'étude et présente les échelles et méthodes d'observation. Le principal outil d'observation est un échosondeur scientifique, mis en oeuvre le long de parcours en étoile autour du DCP. Les prospections acoustiques ont été combinées à des observations vidéo sous marines, des pêches expérimentales et un suivi in-situ de l'environnement abiotique. La troisième partie présente une typologie des éléments constituant le système [DCP ancré - macronecton - environnement - pêche] dans le plan vertical et précise leurs interactions. Le type d'agrégation de macronecton dominant est une grande agrégation composée d'une majorité de thons noirs (Thunnus atlanticus) de taille moyenne (60 cm) distribuée en sub-surface (40-100 m), dans un rayon de 300 m autour de la tête des DCP. Cette agrégation se forme au lever du soleil et se disperse presque totalement dans l'après midi. Elle a été observée de jour lors de toutes les campagnes. Une corrélation positive entre la densité et la structure moyenne des couches micronectoniques diurnes évaluée localement autour du DCP au cours de 48 h et les dimensions et l'énergie acoustique de l'agrégation de thons de subs-surface a été mise en évidence. Malgré le fait que cette agrégation représente en moyenne 95 % de l'énergie acoustique du macronecton autour des DCP, elle est presque inexploitée par les pêcheurs artisans locaux. La quatrième partie met en évidence les fortes variations conjointes de la distribution spatiale dans le plan horizontal de la densité de l'agrégation de thons de sub-surface et de son abondance globale. Ces variations ont été observées au cours du cycle nycthéméral et aux échelles inter-journalières et mensuelles. La distribution spatiale moyenne de la densité diurne de l'agrégation en fonction de la distance au centre de gravité de l'agrégation est cependant très stable et peut être modélisée au moyen d'une équation d'advection-diffusion. Un modèle de krigeage universel, utilisant les résultats du modèle d'advection-diffusion, a permis d'évaluer la biomasse maximale journalière moyenne de l'agrégation de thons de sub-surface à une dizaine de tonnes, avec un coefficient de variation d'estimation de 26%. Nous proposons une représentation hiérarchique synthétique de la distribution spatiale d'une sous-population de thons dans un réseau de DCP ancrés de la micro à la méso-échelle. Nous suggérons que la distribution spatiale des thons est déterminée principalement à l'échelle fine (100m-1km) et à l'échelle grossière (1-10 km) par des processus comportementaux (auto-organisation, agrégation, nutrition) et par des processus environnementaux à échelle plus large.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/these-1735.pdf
http://archimer.ifremer.fr/doc/2006/sup-1735.pdf
http://archimer.ifremer.fr/doc/00000/1735/

Éditeur(s) : NRC
Résumé : Universal kriging was used to model the spatio-temporal variability in the acoustic density of tuna aggregations recorded during star echosounding surveys around moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). The large-scale deterministic drift in the tuna spatial distribution was modeled using an advection-diffusion equation applied to animal grouping. Residuals from the drift were modeled as a random component with small-scale spatial correlation. An estimation variance formula was derived from this deterministic-statistical mixed model to assess the mean precision of density estimates of daytime tuna aggregation. The mean relative error obtained with our star design for daytime surveys was 24%. The methodology was applied to estimate daily maxima of tuna biomass around moored FADs during four monthly sea cruises. The daily peak of tuna biomass aggregated around moored FADs was 9 t on average (standard deviation = 4). Estimation variances for different survey designs were compared for optimizing sampling strategy.
La distribution spatiale d'agrégations de thons autour de dispositifs de concentration de poissons (DCP) ancrés a été étudiée en Martinique (Petites Antilles) au moyen de parcours acoustiques en étoile. Les densités acoustiques géoréférencées attribuées aux thons ont été analysées à l'aide d'un modèle de krigeage universel. Une tendance à large échelle a été identifiée dans la distribution spatiale des thons. Cette tendance a été modélisée de façon déterministe au moyen d'une équation d'advection–diffusion appliquée aux groupes d'animaux. Les résidus de la tendance ont été modélisés comme une composante aléatoire du modèle, spatialement corrélée à faible échelle. De ce modèle, qui contenant une composante déterministe et une composante statistique, a été déduite une formule permettant de calculer la variance d'estimation de la densité diurne moyenne de l'agrégation de thons autour des DCP. L'erreur relative moyenne commise sur l'estimation de la densité de thons lors d'un parcours en étoile diurne a été estimée à 24 %. Cette méthode a été appliquée afin d'estimer les maxima journaliers de biomasse de l'agrégation de thons observés lors de quatre campagnes en mer mensuelles successives autour des DCP ancrés. La biomasse maximale de thons agrégée autour des DCP ancrés durant une phase diurne était en moyenne de 9 t (écart type : 4). Les variances d'estimation obtenues avec différents parcours acoustiques ont été comparées afin d'optimiser la stratégie d'échantillonnage.
Canadian journal of fisheries and aquatic sciences (0706-652X) (NRC), 2008-06 , Vol. 65 , N. 6 , P. 1193-1205

Droits : 2008 National Research Council Canada
http://archimer.ifremer.fr/doc/2008/publication-4559.pdf
DOI:10.1139/F08-050
http://archimer.ifremer.fr/doc/00000/4559/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : The Mediterranean small-scale fleet is highly adaptive, showing a dynamic fishing intensity and strategy, and exploiting seasonal abundant resources. In this area, the aggregatory behaviour under floats of juvenile fish has been used since ancient times to exploit oceanic migratory species such as dolphinfish (Coryphaena hippurus), using Fish Aggregating anchored Devices (fads). A total of 2 300 boats are engaged in this fishery from August to December, the main fishing areas being those around Malta, Tunisia, Sicily and Majorca. The fads ( arrow right m2) are made of different cheap floating materials, and are moored in fixed places, ranging from shore waters to areas 60 miles off the coast (1 500 m depth). Each boat deploys an average of 20 to 100 fads. The gears used are special surrounding nets without purse line, and traditional purse seine nets. The fishery exploits young-of-the-year dolphinfish (<6 months old), originated by a pre-spawning migration of adults from Atlantic waters. Their catches show high annual and monthly variability, depending on the recruitment and the accessibility of recruits to the fishery. Pilotfish (Naucrates ductor) and greater amberjack (Seriola dumerili) are also exploited in this fishery as by-catch. A total of about 1 000 metric tons of dolphinfish are yearly caught mainly in September-October. The fads are historically laid in August. Recently, the fads fishing period has increased in Sicily, and the fads are laid in July, so as to catch pilotfish and greater amberjak juveniles. In recent years, the interest for this fishing method and the study of these fisheries has increased in the Mediterranean. Though the market and its seasonality limit this exploitation, this fishery is economically profitable with good revenue.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15286/12672.pdf
http://archimer.ifremer.fr/doc/00042/15286/

Éditeur(s) : Edp Sciences S A
Résumé : Moored FADs (MFADs) have been a key area for development in Guadeloupe (Lesser Antilles) since the late 1980's. The main objectives underpinning the development of MFADs were to (i) reduce fishing pressure on coastal fishing resources; (ii) boost fishermen's incomes; and (iii) increase local consumption of locally generated fishery products as a proportion of overall consumption. This paper gives an overview of the current structure of Guadeloupe's fishing fleet and fisheries, with a specific focus on MFAD fleets in a relatively unstructured environment with regard to regulation, and so how these fleets operate in a context of unrestricted development of private MFADs. In addressing the following key issues, this paper aims to: assess the economic performance of fleets operating on MFADs, understand why the MFAD fishing activity has not developed more than it has, and suggest how better MFAD management could improve the situation. Socio-economic information on a trip and fleet level basis were collected and stored on a fisheries information system to analyse the relative attractiveness of MFAD fishing and assess the overall economic performance of MFAD fleets as compared to other non-MFAD fleets. Non-monetary variables were also tested to explain the degree of dependence on MFADs. In 2008, economic returns from FADs were relatively low, both in terms of wages for the crews and in terms of profit for vessel owners. Earnings were higher than coastal fishing activities, but seem to have been very sensitive to the indicators used in our analysis. MFADs are expected to become much more attractive as a result of MFAD regulation, especially through the establishment of collective MFADs.
Aquatic Living Resources (0990-7440) (Edp Sciences S A), 2013-01 , Vol. 26 , N. 1 , P. 97-105

Droits : EDP Sciences, IFREMER, IRD 2013
http://archimer.ifremer.fr/doc/00137/24836/22914.pdf
DOI:10.1051/alr/20013044
http://archimer.ifremer.fr/doc/00137/24836/

Éditeur(s) : Oxford university press
Résumé : Fish-aggregating devices (FADs) are increasingly used worldwide to enhance tuna catches. Meanwhile, ecosystem-based management of this fishery is constrained by a paucity of information regarding the interaction of FAD-associated tuna aggregations with their local environment. This paper reports the results of a nine-month study around a FAD moored near Martinique Island, aimed at assessing the effects of the local environment on the variability of monthly estimates of proximate tuna biomass. Dual-frequency, active acoustics provided highresolution quantitative data on the pelagic community around the FAD, from fish to micronekton forage. Geostatistics were used to compute biomass estimates of the tuna aggregation comprising most of the FADassociated fish biomass, with a sampling error of 27%. Environmental variability was summarized by a small set of principal components (PCs) derived from profiles of temperature, salinity and dissolved oxygen vs. depth; and maps of chlorophyll a derived from remotely sensed, sea-surface colour. A generalized linear model was used to relate tuna biomass to environmental PCs and revealed a positive correlation between tuna abundance and: i) a micronekton layer sensed at 38 kHz and potentially consisting of preferred prey at about 180 m depth; and ii) low subsurface salinity (60–80 m). These favourable environmental conditions may be related to thepresence of North Brazilian Current eddies that migrating tuna follow when not temporally associated with the FADs.
ICES Journal of Marine Science (1054-3139) (Oxford university press), 2009-07 , Vol. 66 , N. 6 , P. 1410-1416

Droits : 2009 Oxford university press
http://archimer.ifremer.fr/doc/2008/publication-6162.pdf
DOI:10.1093/icesjms/fsp039
http://archimer.ifremer.fr/doc/00000/6162/

Éditeur(s) : Elsevier
Résumé : Sea cruises were conducted for 57 days over 16 months to characterise pelagic fish aggregations around 2 moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). Echosounder surveys run in a star pattern were used in conjunction with obliquely beamed sonar observations. An echo-integration-by-shoal algorithm was implemented to isolate pelagic fish shoals from sound scattering layers and to compute mean morphometric, positional and density parameters. Tree regressions were used to select and classify pelagic fish Target Strengths (TS), with reference to their spatial and temporal characteristics. The main type of pelagic fish aggregation was a large sub-surface aggregation. It was observed during all daytime periods within a radius of 400 m of the FAD. A smaller type of aggregation was observed closer to the surface and to the FAD in 65% of daytime periods. Large scattered fish were observed in 16% of daytime periods. At night, a medium-sized aggregation was detected in the sub-surface in 75% of night-time periods. The sizes of the fish inside the aggregations (determined from TS values) were lower in the small near-surface aggregation than in the large sub-surface aggregation. Mean packing densities of sub-surface medium fish and near-surface small fish aggregations (determined from TS and shoal acoustic density) were respectively 0.2 fish per m3 and 1.3 fish per m3. The acoustic methodology and results are discussed with reference to the characteristics and performance of the echosounder and to the spatial structure of pelagic fish aggregations around moored FADs in Martinique.
Fisheries Research (0165-7836) (Elsevier), 2006-06 , Vol. 82 , N. 1-3 , P. 162-175

Droits : Elsevier 2006
http://archimer.ifremer.fr/doc/2006/publication-1734.pdf
DOI:10.1016/j.fishres.2006.06.025
http://archimer.ifremer.fr/doc/00000/1734/

Éditeur(s) : EDP Sciences
Résumé : Daily growth increments measured in the otolith of Thunnus atlanticus were used to estimate the age and growth of individuals. which were sampled from an artisanal fishery operating around fish aggregating devices (FADs) moored off Martinique Island. In this study, 76 otoliths were analysed for fish ranging from 20 to 68 cm fork lengths (FL). The fish were caught using trolling lines at depths ranging from 0 to 10 m. Counts were made, under a light microscope, on the external part of the transverse section of the sagittae, from the primordium to the ventral edge. The mean coefficient of variation of the age reading was 2.4%. To validate readings, the number of increments for 11 individuals was counted using both optic and scanning electron microscopes. The calculated relationship between readings of both methods was found to be linear, with a slope of 1.03 and R-2 = 0.99. Frequency of growth increment formation could not be validated. Growth rates derived from otolith readings were, however, compared to those obtained using a modal progression analysis, which was performed on the length-frequency distributions of the landings over a period of two months. The corroboration between the growth rates was good. One increment was assumed to represent one day. The parameters of the von Bertalanffy growth curve for both sexes were L-infinity = 71.4 cm FL, k = 0.002 day(-1) and tau(0) = -80 days. According to our results, there is no evidence that Martinican moored FADs act as ecological traps for blackfin tuna. Instead, young blackfin tuna probably leave the vicinity of Martinican moored FADs to undergo a trophic migration at 7 to 8 month-old, and then come back about 8 months later to breed in the Lesser Antilles area.
Les microstructures présentes dans les otolithes de Thunnus atlanticus ont été utilisées pour estimer l'âge et la croissance des thons capturés par la pêcherie artisanale exploitant les dispositifs de concentrations de poissons (DCP) mouillés autour de la Martinique. Des thons de 20 à 68 cm de longueur à la fourche (LF) ont été capturés à la ligne de traîne de surface entre 0 et 10 m de profondeur. Les stries d'accroissement ont été comptées sur 76 otolithes en microscopie optique sur la partie externe des coupes transversales de la sagitta, du nucléus jusqu'à l'extrémité verticale de la coupe (coefficient de variations 2,4 %). Afin de vérifier qu'il n'y avait pas de sous-estimation du nombre de stries, nous avons effectué un comptage, en microscopie électronique à balayage, pour 11 individus. La relation établie entre ces deux méthodes de comptage est linéaire avec un pente égale à 1,03 et R2 = 0,99. La vitesse de croissance issue de l'analyse des otolithes a été comparée à celle estimée à partir de l'analyse en progression modale des distributions en fréquence de taille des débarquements sur une période de 2 mois. La corroboration entre les deux méthodes était bonne. Nous avons supposé que la formation des stries de croissance suivait un rythme journalier. Les paramètres de l'équation de croissance de von Bertalanffy pour les 2 sexes confondus sont: L-infinity = 71.4 cm FL, k = 0.002 day(-1) and tau(0) = -80 days. Les résultats de cette étude n'indiquent pas que les DCP ancrés martiniquais puissent agir comme des pièges écologiques pour les thons noirs. Les jeunes thons noirs semblent au contraire quitter la proximité des DCP et entreprendre une migration trophique lorsqu'ils atteignent 7 à 8 mois. Ils ne reviendraient ensuite dans la zone des Petites Antilles qu'environ 8 mois plus tard, manifestement pour se reproduire.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2004 , Vol. 17 , N. 1 , P. 13-18

Droits : EDP Sciences, IFREMER, IRD 2004
http://archimer.ifremer.fr/doc/2004/publication-396.pdf
DOI:10.1051/alr:2004009
http://archimer.ifremer.fr/doc/00000/396/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Since the early 1980's, the Secretariat of the Pacific Community (SPC, formerly the South Pacific Commission) has contributed to the development of FAD programmes for the artisanal fisheries sector in the Pacific region. In particular, it has put considerable efforts into developing technology that would assure a two-year average FAD lifespan, while maintaining costs under US$ 4,000 per FAD unit. From 1996 to 1998, this work led to the publication of three volumes of the SPC FAD Manual. Volume 2 of this manual, "Rigging Deep-Water FAD Moorings", describes in great detail two FAD models that were developed from the original 1983 SPC-recommended model, and gives precise instructions on the way to construct them. Despite SPC's work, the objectives set, in particular the two-year average lifespan for FADs, have not been consistently met, resulting in many FAD programmes in the region being suspended. An analysis of the reasons why this has occurred is presented, along with a short description of the practical research that could be pursued, using different objectives, to introduce new FAD programmes in the region.Original Abstract: Depuis le debut des annees quatre-vingt, le secretariat general de la communaute du Pacifique (SPC, anciennement commission du Pacifique Sud) a soutenu et accompagne le developpement de programmes DCP destines au secteur de la peche artisanale, dans la region Pacifique. Il s'est en particulier efforce de mettre au point des modeles de DCP repondant principalement aux deux criteres suivants: duree de vie superieure a deux ans et cout unitaire moyen inferieur a 4 000 dollars US. Entre 1996 et 1998, ces travaux ont abouti a la publication en trois volumes du manuel de la SPC sur les DCP. Le volume 2 de ce manuel, " La fabrication de DCP pour grandes profondeurs ", presente deux evolutions d'un modele concu en 1983 et en detaille tres precisement les methodes de fabrication. Le present document analyse les raisons pour lesquelles, malgre les efforts deployes, les objectifs fixes, et en particulier la duree de vie minimum de deux ans pour les DCP, n'ont pas ete pleinement atteints et la plupart des programmes DCP de la region ont ete interrompus. Il donne egalement une breve description des axes de recherche appliquee qui pourraient etre suivis, en se fixant d'autres objectifs, pour relancer des programmes DCP dans la region.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15291/12648.pdf
http://archimer.ifremer.fr/doc/00042/15291/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : The first fad's in the islands of the South West Indian Ocean were moored in the fifties. The area under study forms part of the Indian Ocean Commission which include Comoros, Madagascar, Mauritius, Seychelles, Reunion and the island of Mayotte. After a few isolated trials that turned to be inconclusive, especially for lack of reliability of the devices moored, trials were pursued under the auspices of International Organizations. A new type of fad was successfully designed and implemented in Mauritius. This model was then applied in the Comoros in 1987, in la Reunion and Madagascar in 1988 and in Mayotte in 1989. The various programmes have had various results. In some cases such as la Reunion and Mauritius, they have played a key role in the development of the inshore fishery. In other cases they have been less significant. Finally in other cases although a significant impact on artisanal fishery, the experience was halted due to financial constraints. Beyond the history of the various programmes and the results obtained, the authors have attempted to underline the social and economic factors that have characterized the various trials in the different regional countries.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15285/12671.pdf
http://archimer.ifremer.fr/doc/00042/15285/