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DocumentOther documentDeep-Sea Fish Aggregating Devices (FAD’s) in The Philippines 1990
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DocumentOther documentGlobal spatio-temporal patterns in tropical tuna purse seine fisheries on drifting fish aggregating devices (DFADs): Taking a historical perspective to inform current challenges 2013
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No results found.This study provides a historical overview of the use of drifting fish aggregating devices (DFADs) in purse seine fisheries since the early 1990s, using global tu fisheries datasets from the four tu Regiol Fisheries Magement Organizations (RFMOs). Tropical tu purse seine fisheries typically target large yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tus on free-swimming schools and skipjack (Katsuwonus pelamis) and juveniles of yellowfin and bigeye associated with drifting objects. DFA Ds have ebled global skipjack catches to markedly increase, and have also introduced major scientific issues for all tu-RFMOs. In particular, they have strongly modified the fishing strategies of purse seiners that fish on a combition of free-swimming and DFAD-associated schools. Consequently, the cumulated search time traditiolly used to quantify nomil fishing effort to assess the status of tu stocks is inconsistent and cannot be used to derive time series of abundance indices from catch-per-un it of-effort (CPUE). In addition, the lack of information available on the construction, deployment, and use of DFADs has prevented effective monitoring of the fishing pressure over the last two decades exerted by purse seine fleets using this fishing mode. Juveniles of tropical tus represent a substantial proportion of purse seine catch on DFADs in the three oceans, which has raised particular concern for some bigeye stocks that have been subject to overfishing in the past. Catches of juvenile tus by DFAD fishing may also result in a decrease in recruitment for fisheries that target adult tus such as longliners. In addition, some demographic parameters of tus and other species associated with DFADs may be affected by the resultant habitat modification arising from the widespread deployment of DFADs. Evidence in the literature and provided by the ratio-estimator method suggest that fishing DFAD-associated schools may result in about 100 000 t of bycatch and discards annually. In additi on, there is further potential for ghost fishing related mortality of sensitive species such as marine turtles and pelagic sharks. In this context and following a precautiory approach, we filly discuss the increasing need for all tu-RFMOs to reduce, or at least monitor and control, the use of DFADs to mitigate their adverse effects not only on yellowfin and bigeye stocks but also on open-ocean ecosystems. -
DocumentOther documentMovement behaviour of skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares) tuna at anchored fish aggregating devices (FADs) in the Maldives investigated using acoustic telemetry 2013
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No results found.The pole and line tu fishery in the Maldives relies heavily on an array of 45 anchored fish aggregat- ing devices (FADs), making it one of the largest anchored FAD-based tu fisheries in the world. We examined the behaviour of skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares) tu around anchored FADs (1 000 to 2 000 m deep) in the Maldives using passive acoustic telemetry. Eight neighbouring FADs (distance range: 30 to 95 km, average: 50 km) were equipped with automated acoustic rece ivers in January 2009, for a period of 13 months. A total of 40 skipjack (37−54 cm FL) and 21 yellowfin (35−53 cm FL) tu were tagged with Vemco V13 transmitters in January (start of the northeast monsoon, dry season) and November (end of the southwest monsoon, wet season) 2009 and released at the two central FADs within this instrumented array. No movement between FADs was observed for any acoustically-tagged tu in the instrumented FAD array. These results suggest that FADs in the Maldives may a ct inde- pendently. The maximum time a tagged skipjack remained associated with a FAD was 12.8 days in January but only one day in November. In addition, residence times at FADs were found to differ with time (month) and space (FAD location) for skipjack tu, suggesting that exterl biotic factors (e.g., prey, conspecifics or predators) might influence the time this species spends at FADs. In November, the residence times of yellowfin tu (maximum observed time: 2.8 days) were three times greater t han those of skipjack tu at the same FADs. This specific difference could be explained either by the two species responding to different factors or by the species’ responses being dependent on the same factor but with different thresholds. No particular preference for time of departure from the FADs was observed. Some monospe- cific and multispecific pairs of acoustically-tagged individuals were observed leaving the FADs simultaneously. Thus, this study indicates a high degree of complexity in t he behavioural processes driving FAD associations.
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Book (stand-alone)General interest bookВопросы лесного хозяйства и агролесоводства в национальных планах адаптации
Вспомогательные руководящие принципы
2023Данная публикация «Вопросы лесного хозяйства и агролесоводства в национальных планах адаптации: вспомогательные руководящие принципы» представляет собой техническое руководство по интеграции лесов, агролесоводства и деревьев в процесс разработки и реализации НПА. Его цель – информировать разработчиков политики и государственных служащих, ответственных за планирование и процессы в рамках НПА, а также субъектов деятельности в области лесного хозяйства и других заинтересованных сторон о потребностях лесного хозяйства и агролесоводства для адаптации и их потенциале для поддержки адаптации других отраслей, подотраслей и видов деятельности. -
Book (series)Technical studyPacific oyster farming
A practical manual
2024Also available in:
No results found.The purpose of this manual is to give the reader a foundation of practical knowledge regarding all aspects of Pacific oyster cultivation. It is targeted at new entrants to the market wishing to establish a farm, and existing operators who wish to develop their farms and explore new cultivation techniques. The methodologies described can be applied both to low-tech, low budget, small-scale farming operations and to high-tech, big budget, industrial-scale aquaculture production enterprises. This guide focuses on the functional expertise and technical equipment required to construct and manage an operational farm in the diverse environmental and physical locations in which they can be situated, from the initial stages of finding and selecting a suitable site, to the conclusion of the first production cycle and harvesting the crop. The manual contains a brief introduction which describes the relevance of the species with regards to global aquaculture production figures and how it can form an important part of future food production strategies. Chapter 2 describes the anatomy and biology of Crassostrea gigas and gives an indication as to the environmental conditions in which the species thrives as well as the pathologies and predators that can result in poor health leading to potential mortalities. Chapter 3 deals with all aspects of undertaking a survey of potential oyster farming sites and what data should be collected and examined to assess a site’s suitability, but also which areas are best suited to different cultivation techniques. After this, Chapter 4 introduces the main farming techniques that will be described in detail in the following chapters, which includes off-bottom cultivation, on-bottom cultivation, and suspended cultivation, and gives details of some of the most common cultivation equipment necessary to undertake these operations. The techniques and strategies necessary to procure seed oysters and how to develop them through the nursery stage are also introduced. This includes the basic principles of upwelling, which then leads into Chapter 5, which provides a detailed description of how to build and operate one particular example of a Floating Upwelling System (Flupsy) which is suitable for use in remote but sheltered conditions. Chapters 6, 7 and 8 constitute the main body of the manual and provide an in-depth look into the three major cultivation techniques that this guide concentrates on: “Farming with trestles and bags in the intertidal zone”, “On-bottom cultivation in the intertidal or subtidal zone” and “Offshore longline cultivation”. -
Book (series)High-profilePerspectives agricoles del’OCDE et de la FAO 2023-2032 2023Les Perspectives agricoles 2023-2032 sont le fruit de la collaboration entre l’Organisation de coopération et de développement économiques (OCDE) et l’Organisation des Nations Unies pour l’alimentation et l’agriculture (FAO). Les deux organisations mettent en commun leurs connaissances spécialisées sur les produits, les politiques et les pays, ainsi que les informations fournies par leurs pays membres, afin de produire chaque année une analyse des perspectives des marchés nationaux, régionaux et mondiaux des produits agricoles de base pour la décennie à venir.La présente édition des Perspectives agricoles a été préparée conjointement par les Secrétariats de l’OCDE et de la FAO.