Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A central target in Earth sciences is the study of deformation at various depth levels within the Earth. Seismology has offered a remarkable tool for doing this via seismic anisotropy. It is however not always clear how to interpret those observations. A question of interest is to understand the relation between the deformation of the mantle and the crust, and in studying the relation between the two. Mantle deformation is expressed in seismic anisotropy. In this paper we seek an objective way of extracting information about crustal fabric as well, to be able to compare with seismic anisotropy. The magnetization of crustal rocks offers an attractive possibility for doing this. We thus explore the use of magnetic data, and we compare magnetic crustal fabric orientation with mantle fabric observations from seismic anisotropy. We apply our technique to the North American craton for which we have an excellent magnetic dataset, and we show that there is a clear relation between crustal and mantle fabric for the cratonic region. This has important implications for crustal formation, and for interpreting seismic anisotropy observations.
ISSN: 0012-821X

hal-00424536
https://hal.archives-ouvertes.fr/hal-00424536
DOI : 10.1016/j.epsl.2008.10.032

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : A development programme for the promotion of FADs in Sao Tome and Principe has implemented an original interactive approach by granting a predominant place to the initiative of the target group and its participation in decision making. The appropriation process of the innovative fads by the beneficiaries takes place in three stages described herewith. the technical research phase. This consists of formally describing an idea in reply to an expressed or potential need. The envisaged fad type is developed and tested by the project's agents in order to obtain a technically appropriate prototype.- the research and adjustment phase. The fad is given to a small number of people to be used in real-life conditions. Reaction surveys will enable its pertinence to be tested and its adaptation to normal conditions of use. This second phase results in the production of a technically and socio-economically appropriated fad. - the diffusion-perpetuation phase. This entails i) identification of the sequences of the various stages, ii) definition and grouping of contributions by the various parties, iii) production of educational auxiliaries, iv) initiating actions for user awareness and demonstration, v) staff training, vi) monitoring of the fad "socialisation", vii) solving funding problems.Original Abstract: Un projet visant, entre autres, la promotion de DCP pour la peche artisanale fonctionne a Sao Tome et Principe depuis 1993. Le processus d'appropriation daune telle innovation par les beneficiaires comprend trois etapes ici decrites. La phase de recherche technique. Il s'agit d'instrumentaliser une idee en reponse a un besoin exprime ou potentiel. L'innovation envisagee est mise au point et testee par les agents du projet en milieu controle de facon a obtenir un prototype techniquement approprie. La phase de recherche-developpement: l'outil est confie a un petit nombre de personnes pour une utilisation en conditions reelles. C'est une phase de mise au point interactive, seule susceptible de provoquer une reelle appropriation par les recipiendaires. Des enquetes de reaction permettront de tester sa pertinence et de l'adapter aux conditions normales d'utilisation. Cette seconde phase debouche sur la production d'un outil de reference approprie techniquement et socio-economiquement. La phase de diffusion-perennisation: il s'agira la : i) d'identifier les sequences d'intervention, ii) d'identifier et de regrouper les apports des differentes parties, iii) de definir et de produire les auxiliaires pedagogiques (manuels, affiches, radio), iv) d'entreprendre des actions de sensibilisation et de demonstration, v) de former les personnels, vi) de veiller a la socialisation de l'innovation, pour les outils collectifs, vii) de resoudre le probleme du financement.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15306/12641.pdf
http://archimer.ifremer.fr/doc/00042/15306/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : El Caribe colombiano ha experimentado un acelerado proceso de urbanización y desarrollo turístico en los últimos 50 años. Solo en una ciudad como Cartagena de Indias (la ciudad turística por excelencia de Colombia), datos referidos al periodo noviembre 2009 – enero 2015, mostraron un incremento en la llegada de turistas cercano al 20%. Después de un gran número de encuestas realizadas alrededor del mundo, se encontró que los parámetros en que se basan los turistas a la hora de preferir una playa son: i) la seguridad, ii) el paisaje, iii) calidad del agua, iv) basuras, v) instalaciones. El paisaje es uno de los recursos costeros y por lo tanto su evaluación es una herramienta importante para los gestores y planificadores del litoral a la hora de la realización de planes de conservación, protección, desarrollo y manejo. Este trabajo se basa en la evaluación del valor paisajístico de las playas que constituyen la base de la economía de muchas ciudades costeras en el mundo y en especial de la zona central de litoral Caribe colombiano. Un problema importante en la evaluación del paisaje es la incapacidad de algunas metodologías de reflejar correctamente las percepciones de la gente, debido al alto peso que tienen algunos aspectos subjetivos (p. ej. altura de una geoforma).En este trabajo se presenta la evaluación del paisaje realizada para la zona central de Caribe colombiano (37 playas de los departamentos de Sucre, Bolívar y Atlántico) utilizando la lógica matemática y matrices ponderadas (fuzzy logic mathematics - parameter weighting matrices) las cuales permiten disminuir la subjetividad y cuantificar con exactitud la incertidumbre. Para la evaluación se utilizó una lista de chequeo que está conformada por 26 parámetros, 18 físicos (acantilados, playas, plataformas rocosas, dunas, características de los valles, forma del relieve, mareas, paisaje costero, color del agua y restos de vegetación), y 8 antropogénicos (ruido, basura, descarga de aguas residuales, grado de modificación y de construcción del medio, tipos de acceso, línea del horizonte y estructuras antrópicas). Los parámetros fueron calificados en una escala de 1 a 5 (presencia/ausencia o poca/alta calidad) y, con el fin de cuantificar la incertidumbre y excesos derivados de la subjetividad que pudo haber tenido la evaluación de los parámetros, se utilizó la lógica difusa (fuzzy logic). A la par, un sistema de matrices, se empleó para asignar valores de peso de acuerdo a las preferencias y prioridades de los usuarios. Como resultado de estos análisis lógico-estadísticos se obtuvo un valor (D) el cual resume la evaluación del paisaje en 5 clases que van desde la CLASE 1 (zona litoral sumamente atractiva) hasta la CLASE 5 (playas urbanas muy poco atractivas). De los 37 sectores estudiados, ninguno puede ser considerado como una zona litoral sumamente atractiva, mientras que 15 corresponden a zonas litorales urbanas poco atractivas, el resto de las playas (22) se ubicó entre las clases 2, 3 y 4. Los resultados obtenidos son útiles para los gestores costeros en la medida que, aunque no es posible mejorar los aspectos naturales de la clasificación, si es posible mejorar muchos de los parámetros antropogenicos y, de esta forma, hacer que una playa mejore su clasificación y sea paisajísticamente más atractiva.
In the past few years, the Colombian Caribbean coast has experienced rapid tourism development which has not been accompanied with a similar increase in urbanization facilities. For example, the city of Cartagena de Indias (the most famous tourist destination of Colombia), data related to November 2009 – January 2015 period, showed an increase of 20% in tourist arrivals. A large number of surveys developed in Europe found that the most critical parameters for tourists, when they choose a beach, are: i) security, ii) scenery, iii) water quality, iv) litter, v) facilities. Scenery is one of the most significant coastal resources. Therefore, its evaluation is a valuable tool for coastal managers when developing conservation and protection plans. This proposal provides coastal scenery assessment of 37 beaches along the North Colombian Caribbean littoral by analysing 26 physical and human factors. Results were weighted (not all parameters have equal weight) and subjected to fuzzy logic mathematics in order to reduce recorder judgment subjectivity. The sites were categorised into five classes; Class 1 locations had top grade scenery; Class 5 poor scenery. Of the 37 sectors studied, currently none can be considered as an extremely attractive coastal area (class1), while 15 were unattractive urban coastal areas (class 5), the rest of the beaches (22) placed in classes 2, 3 and 4. Classification of analysed sites depends on the geological setting and degree of human occupation. The technique opens new perspectives for analysis of the potential for coastal tourism development in natural areas and scenic quality improvement of current tourist developed areas. Concerning coastal management issues, emphasis should be given to the upgrading of human parameters eliminating litter and sewage evidence, vegetation debris and enhancing beach nourishment works. This proposal can help in moving some locations from their present status to a higher one.
Caraïbes
Colombie

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.9326
http://journals.openedition.org/etudescaribeennes/9326

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Yellowfin tuna (Thunnus albacares) is a main target for the fisheries at Fish Aggregating Devices (FADs) off the south of Okinawa island. Catch and weight composition of the tuna were monitored at a fisheries cooperative market from 1989 to 1998. Some distinct weight groups (considered to represent cohorts) appeared in the catch and the weight of these groups increased monthly - presumably as individual tuna grew. Although small, light weight fish were caught year-round, the 2 kg weight group that was recruited in May grew to about 15 kg by May of the next year. There was a significant seasonal cycle in the monthly catches. The catch of heavier weight groups decreased in winter indicating the tuna moved out of this FAD area. At one of huge FADs (Nirai), fifteen nautical miles southeast of Okinawa island (depth about 1.300 m), a current meter (Aanderaa RCM-7) recorded current and water temperature from June 1995 to March 1996. The current meter was attached to the FAD at 4 m depth. When typhoons attacked Okinawa, the water temperature drastically dropped. Typically, average current speed was 29 cm/s and eastward current was most frequent. Being affected by tide, the current was averaged over twenty-five hours. Current speed was correlated with the yellowfin catch in 120 daily sets at the FAD; the weaker the current speed, the greater the catch. Although not significant, the catch was greater with northeastward current than with southwestward current.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15300/12662.pdf
http://archimer.ifremer.fr/doc/00042/15300/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : Since the early 1990s, drifting Fish Aggregating Devices, or FADs, have rapidly become the dominant type of floating object used by the purse seine fishery in the Eastern Pacific Ocean to capture tunas. The development of this fishery for larger vessels is described using data collected by observers aboard vessels of more than 363 metric tons fish-carrying capacity. Bamboo rafts, equipped with radio-transmitters that allow for semi-continuous monitoring, are typically used as FADs. Old purse seine netting is often suspended below the bamboo raft to give the FAD an enhanced underwater profile. Similar to the fishery on flotsam between 1992-1998, most sets on FADs were made before 8 am, with skipjack and bigeye being the dominant tuna species caught, and yellowfin tuna captured in lesser amounts. Discard ratios of skipjack and bigeye were comparable for the two modes of fishing; however, the success rate on FADs for bigeye was more than twice that on non-FAD floating objects ("logs"). In addition, the fishery on logs was largely a coastal hshery, while the fishery on FADs extended west to 150 W, into areas that had not been significantly utilized by the purse seine fleet. The capture of tunas per set varied most with area, season and year. Nonetheless, capture per set for at least one of the three tuna species was also found to vary with the depth of the purse seine net and the amount of the netting hanging below the FAD. The effect of net depth and FAD depth on tuna capture varied by area, season and FAD color.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15282/12668.pdf
http://archimer.ifremer.fr/doc/00042/15282/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : A new programme concerning the experimentation of about thirty Fish Aggregating Devices (FADs) is to start in the Cape Verde Islands at the end of 1999. In this context, this communication is intended: - to evaluate the halieutic, economic and social conditions of the artisanal fishery in this archipelago, notably in terms of assets and constraints. Although these conditions are very heterogeneous depending on islands, the fads seem to be able to help the stabilization and the development of the fishing activities, disadvantaged by a low productivity, limited operating ranges of boats, and very irregular outings at sea. But the narrowness of the domestic market is likely to cause drops in the fish prices if the production increases, while the absence of institutional framework may be a handicap at the level of the management (of the programme itself, and/or of some possible conflicts of uses); - to carry out an assessment of the former experiments. It emphasized the insufficiency of the follow-up and the maintenance of the structures, of which the lifespan varied at the most between four and six months, as well as the positive effects of the concentration, and the interest of the fishermen already sensitized with these structures.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15317/12644.pdf
http://archimer.ifremer.fr/doc/00042/15317/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Over the last 16 years, the Secretariat of the Pacific Community (SPC - formerly the South Pacific Commission) has been developing and providing information on mid-water fishing techniques targeting the larger, deeper-swimming tunas that aggregate around FADs. SPC masterfishermen have conducted in-country fishing trials to test methods, such as vertical longlines, and train local fishermen in their construction and use. Vertical longline catch rates have varied considerably due to a range of reasons with no catches reported in some locations, or just sharks, to highs of over 6.5 kg /10 hooks/hour being recorded in other locations. Other methods like drop-stone, palu-ahi, and single-hook drifting lines have been developed within the region, with SPC adopting and transferring this technology to other locations. To further disseminate this information, SPC has recently published a technical manual outlining a range of mid-water fishing gears and techniques that can be used in association with FADs. An outline of the main gears and techniques with catch data where available is presented, with factors influencing catches discussed based on the findings of SPC masterfishermen over the years.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15295/12653.pdf
http://archimer.ifremer.fr/doc/00042/15295/

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 : For most fisheries, increasing the local production of pelagic fish is the main objective of Fish Aggregating Devices (fads). This does not rule out the existence of a larger-scale impact, especially on the migratory behaviour of fish. The analysis of data collected during 25 experimental fishing surveys around Martinique between 1995 and 1997 has led to the hypothesis that fads influence the migratory behaviour of young dolphinfish. Unlike recent studies of dolphinfish migration in the Caribbean, which tend to show an annual migration pattern with a seasonal passage through the French West Indies, the experimental fishing surveys done over more than a year on a monthly basis on a single cohort, show that the migratory pattern of part of the regional stock could be disrupted. This analysis has made it possible to estimate an average growth rate for this species during the first year of life.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15321/12635.pdf
http://archimer.ifremer.fr/doc/00042/15321/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : Payao is a traditional concept, which has been successfully commercialized to increase the landings of several species valuable to the country's export and local industries. It has become one of the most important developments in pelagic fishing that significantly contributed to increased tuna production and expansion of purse seine and other fishing gears. The introduction of the payao in tuna fishing in 1975 triggered the rapid development of the tuna and small pelagic fishery. With limited management schemes and strategies, however, unstable tuna and tuna-like species production was experienced in the 1980s and 1990s. In this paper, the evolution and development of the payao with emphasis on the technological aspect are reviewed. The present practices and techniques of payao in various parts of the country, including its structure, ownership, distribution, and fishing operations are discussed. Monitoring results of purse seine/ringnet operations including handline using payao in Celebes Sea and Western Luzon are presented to compare fishing styles and techniques, payao designs and species caught. The fishing gears in various regions of the country for harvesting payao are enumerated and discussed. The inshore and offshore payaos in terms of sea depth, location, designs, fishing methods and catch composition are also compared. Fishing companies and fisherfolk associations involved in payao operation are presented to determine extent of utilization and involvement in the municipal and commercial sectors of the fishing industry. The issues and problems concerning the use of payao, and its biological, economic impact as well as management aspect are presented. Recommendations are given for future research and actions.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15284/12670.pdf
http://archimer.ifremer.fr/doc/00042/15284/

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) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : The original baitboat fishing technique using a permanent association between the fishing boat and the tuna school has been developed by the baitboat fleet of Dakar, Senegal and is also in use in the Canary Islands. This new fishing technique, the result of 20 years of improvements still on, has induced a dramatic increase of the catch yields which, in turn, has sustained the survival and even a recent development of the fleet. This technique is based on the aggregating behaviour of tropical tunas. However, it contains a dynamic component which is not found in tuna fishing on drifting or anchored fads. The specifications of the method, its refinement over the years and its main consequences for the fishery are described together with the school exchanges between baitboats over months even from one year to the next. Based on the analysis of 1228 recoveries from 5500 tagged fish, tuna movements among associated schools, between associated schools and free schools fished by purse seiners and movements in and out of the baitboat fishing grounds help to better understand the dynamics of tunas and schools of this peculiar tuna association. These data show a very high recovery rate, a remarkable tuna fidelity to the original school for all species, a small number of recoveries within the purse seine catch as well as the rare tuna movements outside the baitboat area. The study highlights the complexity and the numerous consequences of tuna and school behaviour.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15304/12637.pdf
http://archimer.ifremer.fr/doc/00042/15304/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : The volcanic island of Mayotte (374 km super(2)) is part of the Comoros Archipelago, which is situated on the North of Mozambic's Canal (Indian Ocean). Mayotte is composed of two islands and some thirty small islands distributed in a lagoon of more than 1,000 km super(2). Being one of the French Republic's Territorial Collectivity, this island is characterized by a very fast demographic evolution (growth rate : 5.8 %), which constitutes the foundation of the development problematic. Most of local halieutic production comes from the reef (nearly 2,000 t in 1999), the technic of "palangrotte" (deep line) is still dominating. The fishing fleet is composed of monoxyl pirogues and polyester fishing boats for the 1,200 fishermen. The first FADs (Fish Aggregating Devices) were installed in 1989. Now, 5 FADs are situated in the lagoon whereas 10 others have been installed out of it. If it is very hard to evaluate economic impact of FAD in Mayotte, their success seems to be limited because of several local constraints : fear to fish out of the lagoon, little interest in tuna, lack of formation. Nevertheless, faced to the demographic evolution and the decrease of the reef ressources, a program of fishing development on FAD has been initiated in 1998, with those following themes : realization of a new prototype of FAD, experimental fishing program with vertical drift "long line", teaching programs for the local fishermen. Today, it is too early to analyze the informations already collected, but the results are very promising, and validate the technical improvement of the new prototype.Original Abstract: L'ile volcanique de Mayotte (374 km super(2)) fait partie de l'archipel des Comores situe au Nord du canal du Mozambique (ocean Indien). Mayotte comprend deux iles et une trentaine d'ilots repartis dans un lagon de plus de 1 000 km super(2). Collectivite territoriale de la Republique francaise, l'ile se caracterise par une evolution demographique tres rapide (taux de croissance: 5,8 %), qui constitue le socle de toutes les problematiques de developpement. L'essentiel de la production halieutique provient du milieu recifal (environ 2 000 t en 1999), la peche a la ligne de fond reste la technique dominante. La flottille de peche est constituee de pirogues monoxyles et de barques polyester pour une population de 1 200 pecheurs. Les premiers DCP mahorais furent installes en 1989. A ce jour, on denombre cinq DCP dans le lagon et dix hors lagon. Il semble que leur succes soit reste limite en raison de plusieurs contraintes locales : peur de la peche hors lagon, peu d'interet pour les poissons pelagiques, manque de formation. Neanmoins, face a l'explosion demographique et a l'appauvrissement des ressources lagonaires, un nouveau programme de developpement de la peche sur DCP a ete initie en 1998. Ce programme comporte trois axes : realisation d'un nouveau prototype de DCP, lancement d'un programme de peches experimentales a la palangre verticale derivante et formation des pecheurs. A ce jour, les informations obtenues sont trop parcellaires pour etre analysees mais les donnees et observations realisees sur les nouveaux dispositifs permettent de valider leur conception technique.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15290/12647.pdf
http://archimer.ifremer.fr/doc/00042/15290/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : In recent years, the use of fads in Martinique has evolved from an experimental stage to a productive one. This transformation results in the pitching up of operational device park by the regional fishery committee. Nevertheless, this technical change in fishing practices is not implemented in a homogeneous way all around the island; some differences exist especially between the Atlantic and the Caribbean coasts. From surveys carried out during an annual cycle on two main landing sites, this study describes the pelagic fishing activity around fads and in the open sea. A comparison of fishing strategies adopted in different places as well as an analysis of the results obtained by the fishing units in terms of species (size of catches and daily yields) allow to describe the progress made in the implementation adoption of this new fishing practice. For several fishermen, fishing around fads has become an exclusive job, practised all year round. For others, fads is used in addition to traditional fishing activity on flotsam, "Miquelon" fishing and keeps a seasonal character.Original Abstract: Au cours des recentes annees, l'utilisation des DCP en Martinique est passee du stade experimental au stade operationnel. Cette mutation se traduit par la prise en charge du parc de dispositifs operationnels par le comite regional des peches. Toutefois, l'adoption de cette nouvelle technique d'exploitation ne s'effectue pas de facon homogene dans toutes les communes de l'ile, des differences existent notamment entre les cotes Atlantique et Caraibe. A partir d'enquetes effectuees pendant un cycle annuel, sur deux principaux points de debarquement, cette etude decrit l'activite de peche des poissons pelagiques avec ou sans DCP. Une comparaison des strategies de peche developpees dans les differents sites ainsi qu'une analyse des resultats obtenus par les unites de peche en termes d'especes, de taille des captures, de rendement journalier permettent de decrire la progression differenciee de l'adoption de cette nouvelle activite halieutique. Pour certains pecheurs, la peche sous DCP est devenue un metier exclusif, pratique tout au long de l'annee. Pour d'autres, le DCP est utilise en complement de l'activite traditionnelle de peche sous bois derivants, " peche a Miquelon ", et conserve un caractere saisonnier.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15298/12657.pdf
http://archimer.ifremer.fr/doc/00042/15298/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : In 1998, the French and Spanish tuna-boat owners associations have volentarily reconducted the Atlantic tuna protection plan (also called moratorium) initiated the previous year. This plan which has become an iccat recommendation for 1999, consists mainly in preventing fishing on floating objects (logs) and in having observers on board tuna purse seiners. Data collected by these observers and landing statistics allow to draw preliminary conclusions on some effects of the protection plan, on the fleets and on the Atlantic tuna stocks. Largely respected, the moratorium has led to a spatial redistribution of the fishing effort, an important reduction of the proportion of sets on logs and a decrease of the landings by one third compared to those realised the years before during the same months, particularily for the skipjack and the bigeye tunas. Moreover, data collected allow to calculate catch rates for a number of by-catch species in the purse seine fishery.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15313/12660.pdf
http://archimer.ifremer.fr/doc/00042/15313/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : Since 1983, the research on the optimal conception of FADs in Martinique was particularly focused on the improvement of their resistance to different maritime or human aggressions. Following several experimentations made with different types of fads, the choice was brought on light devices anchored in 1 500 to 2 000 m depths and an experimental approach was conducted to identify the causes of loss of fads and to attempt to modelize their hydrodynamic behaviour with relation to the sea conditions. Three mathematical models are used to simulate the fad behaviour under current action and swell, and to estimate the forces exerted on each part of the device. The results of this study are presented. The fad design used nowadays for the development of pelagic fishing in Martinique, recommendations for maintenance and preservation of the fads are also proposed.Original Abstract: De 1983 a 1994, les recherches sur une conception optimale des DCP de la Martinique ont ete plus particulierement orientees sur l'amelioration de leur resistance aux diverses agressions marines ou humaines. Suite aux multiples experimentations menees avec differents types de DCP, le choix de systemes legers ancres par fonds de 1 500 a 2 000 m a conduit a une demarche scientifique comprenant a la fois une analyse des causes de perte des DCP et la modelisation de leur comportement hydrodynamique en fonction des conditions de mer. Les resultats de ce programme ainsi que le plan du DCP retenu pour le developpement de la peche des poissons pelagiques en Martinique sont presentes. Des recommandations pour la maintenance et la preservation des dispositifs sont egalement proposees.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15287/12673.pdf
http://archimer.ifremer.fr/doc/00042/15287/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : In early 1980s, fad fisheries were introduced from the Philippines to Japan, mainly to Okinawa. The fisheries have well developed becoming one of the main fisheries in Okinawa where 210 fads are approved to deploy in 1999. The annual catch by roughly 1 000 boats (most of them are small) is 2500-4000 mt; average catch from one fad is about 20 mt; average catch by one boat on one day is 73 kilogrammes. fads are also important for easing the fishing pressures on bottom fish stocks. Most of the fads were deployed and managed by local fishermen's groups that have improved the structures of the system to withstand typhoons. The catches are strongly depending on the sites, usually the farther offshore, the better the catches. A variety of fishing methods are devised targeting each species and the size of the fish. Being most abundant and having relatively higher prices, yellowfin tuna is the most important and consists 68% of the total production. There have been conflicts among fishermen on the use of fads since the early stage of the fisheries development. Now, the number of fads is regulated by a management committee. Conflicts between fishermen and sport fishermen have become problems; on the other hand, the sport fishing could lead to further development of the fisheries. Degraded fish meat caused by high meat temperature and occasional oversupply have been major marketing problems since prices are strongly related to the meat quality and the fish supply.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15281/12667.pdf
http://archimer.ifremer.fr/doc/00042/15281/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : In the area served by the Secretariat of the Pacific Community (SPC), which includes 22 Pacific Island countries and territories, anchored FADs have been used since the late 1970s. First introduced from the Philippines, via Hawaii, they were quickly adopted by both industrial and artisanal fisheries sectors : in 1984 more than 600 anchored FADs had been deployed in the region. Since these early days, the development of the technique by the industrial and the artisanal sectors have followed parallel paths with little interaction. In the industrial private sector, companies are funding, deploying and monitoring their own FADs. For some fishing companies, using purse seiners and pole-and-line vessels, from the Solomon Islands or Papua-New-Guinea, these FADs have become a necessity. FAD programmes for small-scale fisheries have been almost exclusively run by the public sector, with technical support from regional and international development agencies and financial assistance from overseas funding agencies. These programmes have had mixed successes : becoming an on-going and essential tool in some places like French Polynesia or Guam; or being momentarily suspended, like in Vanuatu or Tonga, because of the lack of funds, partly due to the scarcity of proven economic return to the fishing communities. This document is an attempt to synthesise the current information on these very diverse situations, including technical, economical and social considerations.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15283/12669.pdf
http://archimer.ifremer.fr/doc/00042/15283/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : This paper develops a comparative overview of the development of Fish Aggregating Devices (or fads) by the tropical purse seine fisheries in various ocean areas (Atlantic, Indian, Western and Eastern Pacific Oceans). First, a comparative review of fishery statistics is developed. Recent catches on fads by purse seiners can be estimated at a level of one million tons yearly. This comparison allows to describe the fishing zones and catch trends over time, the species composition and size taken in the various fad fisheries. Skipjack tuna is the dominant species in most fad fisheries, but significant amounts of yellowfin and bigeye are also frequently taken under fads. The paper also presents an overview of various observer data concerning the by-catches of the various fisheries using fads. This comparison allows to estimate the total worldwide yearly by-catches at about 100,000 t, and their species composition in each ocean. The fad technology used in the various oceans by purse seiners is described. The recent use of fads by purse seiners has introduced major uncertainties in most stock assessments, because analyses are hampered by changes in the fishing effort in a fad fishery, by changes in fishing zones and in sizes caught. As a last point, the management of fads presently done or in view by the various tuna bodies are introduced. It appears that the present massive use of fads worldwide is perhaps an unsafe fishing mode, which could produce serious overfishing of many stocks. There is then a consensus that the use of fads needs to be controlled and limited to sustainable biological levels.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15278/12664.pdf
http://archimer.ifremer.fr/doc/00042/15278/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : More than ten years after its launching, an evaluation of the results of the FADs programme carried on in Reunion Island has been made. Its implementation and its impact on artisanal fishery in Reunion Island have been analysed. This analysis demonstrates that, following a continuously ascending phase, the production of fish caught on fads has reached a plateau. Parallel to the FAD-associated fishery, the longline fishery has developed since 1991. This type of fishery includes production units whose operating zone is bordering the FAD installation area. Analysing the evolution of the small longliner sector is based on general activity indicators (number of ships, production, fish selling prices). Besides, a synthesis of the interactions between those two types of fisheries, whether in terms of exploited resources, space conflicts, fishing population or market, has been effected. Judging from the complementary and antagonistic natures of the two fisheries identified above and given their evolution, the future of the FADs programme is pending. Have the fads just been a step in the evolution of the Reunion fishing system or have they modified it on a long-term basis?

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15319/12640.pdf
http://archimer.ifremer.fr/doc/00042/15319/