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Book (series)Bycatch in longline fisheries for tuna and tuna-like species: a global review of status and mitigation measures 2014
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No results found.This publication is the third in a series on bycatch in global tuna fisheries. Dealing with longline fisheries, its scope is defined taxonomically to comprise only non-tuna and non-tuna-like species. The history of longline fishing illustrates the role of new technologies, the expansion of fishing grounds, and the operational characteristics of the fleets in shaping today’s fishery. More recently, management regulations, the price of oil, the cost of labour, and market demand have also exerted a n influence. No more than 23 percent of the tuna in each ocean is longline-caught. However, there may be up to 7 500 tuna longliners globally with almost 60 percent of them less than 24 m in length. Available data suggest that elasmobranch catches have fallen 14 percent since their peak in 2003. In longline fisheries, shark catch rates may be determined by bait type, soak time, hook shape, leader length and material, depth at which the hook is fished, and whether special gear is deployed to targ et sharks. Vulnerability to hooking, and resilience to haulback and handling, vary by species, size, area and fleet operational practices. Tuna regional fisheries management organizations (t-RFMOs) assess the status of shark populations but data limitations often hinder firm conclusions. There is little information on the implementation or effectiveness of finning bans and no-retention measures. Mitigation measures have been tested but results vary. Six of the seven species of sea turtles are th reatened with extinction, and while longline fisheries may have less impact than net-based fisheries, significant populationlevel impacts may be occurring in some regions. The greatest concern is associated with loggerhead–longline interactions in the Atlantic. Circle hooks and using finfish bait have proved effective mitigation techniques either by reducing hooking or hook swallowing. Other methods require further development. Interactions with pelagic longline fisheries kill 50 000–100 000 sea birds annually. Many of these species, particularly albatrosses, are threatened with extinction. Recent advances in tracking technologies have facilitated mapping of where interactions are most likely. The Western and Central Pacific contains more than 45 percent of the global total albatross and giant petrel breeding distributions. The most promising mitigation methods appear to be night setting, side-setting, line weighting and streamer lines, but further research is needed. All five t-RFMOs r equire use of one or more of these methods in areas that overlap albatross distributions. However, compliance data are limited and improved observer coverage is essential. Marine mammals’ interactions with longline fisheries are detrimental to the fishery but may be positive or negative for the mammals. Although it is often unclear which species are involved, pilot whale interactions in the western Atlantic and false killer whale interactions off Hawaii have triggered national mitigation plans. No t-RFMO has adopted management measures for marine mammal interactions. Research and testing of mitigation measures continue in order to ameliorate both marine mammal impacts and economic losses to industry from depredation. At least 650 species of other bony fishes may be caught in association with pelagic longline fisheries, e.g. dolphinfish, opah, oilfish, escolar and ocean sunfish. Some of these stocks are important as local food supplies. However, it is unclear whether these stocks or the ecosystem they help structure is at risk. More attention should focus on improving fishery statistics and initiating basic monitoring of these stocks’ status. The diversity of pelagic longline gear designs and fishing methods, the variety of habitats they are deployed in, the thousands of marine species they may interact with, v and the different mechanisms and behaviours that govern those interactions provide an array of topics to be addressed in any discussion of bycatch mitigation. Scientifi c and technical issues in mitigation including effects across taxa, effects of combinations of measures, economic and safety considerations, underlying biological mechanisms, handling and post-release mortality, and non-fishery impacts must all be addressed. In addition, it is also necessary to consider issues such as who takes the lead for ensuring mitigation is sufficient for the population as a whole, how to devise effective mitigation implementation strategies, and whether gear modification should be used in concert with more sweeping measures. -
ArticleA method to prioritize the surveillance of chemicals in food commodities to access international market and its application to four countries in Sub-Saharan Africa 2020
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No results found.The purpose of this study was to propose an approach to predict the distribution of chemicals in food in developing countries to assess consumer risk and access to the international market with a limited number of laboratory analyses. The first step consists of identifying the GEMS/Food Contaminants database and the chemical/food combination relevant for a particular country. The identification of critical chemical/food combination should be used to prioritize the analysis to be performed in a total diet study (TDS). The second step consists of modeling a distribution model based on the mean concentration generated from TDS associated with the variability observed in a larger dataset consisting of individual food contamination data from the GEMS food database. The simulated distributions may provide information regarding how to establish food safety standards and to assess the potential for accessing international market in the context of a value chain. This method is illustrated by case studies from the recent Regional TDS (RTDS) conducted in Sub Saharan Africa. We concluded that further work is needed to gain experience and to fully validate this approach. However, organized data sharing and developing harmonized methods for data analysis are key roles for international organizations, such as FAO, WHO, and WTO. Finally, it is important to remember that such a data-driven approach still requires significant investments in terms of human resources and analytical capacity. -
Book (series)DNA-based molecular diagnostic techniques: research needs for standardization and validation of the detection of aquatic animal pathogens and diseases.
Report and proceedings of the Expert Workshop on DNA-based Molecular Diagnostic Techniques: Research Needs for Standardization and Validation of the Detection of Aquatic Animal Pathogens and Diseases. Bangkok, Thailand, 7-9 February 1999.
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No results found.In efforts to limit trans-boundary movement of pathogens and reduce the economic and socioeconomic impact of disease in aquaculture, there is considerable scope for more effective use of DNA-based methods of pathogen detection. These technologies offer rapid results with potentially high sensitivity and specificity, at relatively low cost. Recognition of these advantages has led to rapid adoption of available DNA-based tests, particularly in shrimp culture for which histological procedures lack specificity and culture-based methods have not been possible. However, few if any of the available tests have been assessed appropriately against other diagnostic methods or standardized and validated for specified applications. In fish and shrimp, type or strain specificity of most tests for pathogens in the Asian region is poorly understood and, in molluscs, there is little information on the significant pathogens and few tests of any kind have been developed. Furthermore, tests presently avai lable are frequently conducted by technicians who may not be sufficiently aware of the need for stringent test protocols or the meaning and limitations of the data generated. Implementation of standardized practices that produce reliable, useful and comparable data will require a significant investment in research, training and infrastructure development. Effective implementation will also be assisted by enhanced communication between aquatic animal health practitioners in the region and scienti sts with expertise in molecular diagnostic technologies. This review recommends development by FAO/NACA of 2 programs of managed cooperative research to assist more effective use of DNA-based detection tests. Program A should focus on improving the knowledge base by identification of new and emerging pathogens, relating pathogens in the region to those described elsewhere, and defining the extent of genetic variation between related pathogens in the region. Program B should draw on information currently available or obtained from Program A to develop suitably specific DNA-based diagnostic methods and to evaluate and validate the methods for disease diagnosis and pathogen screening programs. To increase the availability of scientists and technicians with skills in pathology and molecular diagnostic technologies, the review also recommends development of FAO/NACA-sponsored training programs for staff from key laboratories in the region. Training priorities should be in: i) the use of standard histopathological methods for health screening of fish and molluscs; and ii) the use of standard DNA-based methods for pathogen detection including sample collection, application of test protocols and the analysis and interpretation of test results. Because of the urgency of disease problems and the availability of suitable tests, training in DNA-based methods should focus initially on detection of shrimp pathogens. The review also recommends the development of a laboratory accredita tion program in order to achieve standardization of sampling methods and test procedures. The establishment of reference laboratories will assist accreditation for each of the major pathogens. Laboratory accreditation and training programs should complement the activities of OIE in obtaining internationally agreed test standards for molecular diagnostic technologies.
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