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MeetingMeeting documentMaldivian skipjack pole and line fishery catch rate standardization 2004-2010 2013
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MeetingMeeting documentMaldives Skipjack Pole and Line Fishery Catch Rate Standardization 2004-2010 2013
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MeetingMeeting documentMaldives skipjack pole and line fishery catch rate standardization 2004-2011: reconstructing historic CPUE till 1985 2013
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No results found.A qualitative description and GLM-based standardization of the Maldivian skipjack (Katsuwo pelamis, SKJ) pole and line fishery catch rate data are presented for the period 2004-2011. The raw data consists of around 124000 records of catch (numbers) and effort (fishing days) by month, atoll and vessel; vessel characteristics were added to the CPUE dataset based on information from the registry of vessels. A subset of 56,698 records were extracted from the dataset, identified as records of fishing activity targeting skipjack. In the process, the paper discusses several data quality issues with the CPUE dataset, notably records with zero skipjack catch with a directed PL fishery and which were eventually discounted from the fil alysis. FAD data was also incorporated into the alysis using the number of active FADS associated with the nearest atoll that the landing data is collected from. In order to do this, the distribution of FADs was split into three regions incorporating the North Atol ls, Middle Atoll and South Atolls. Vessel specific data including hull-type effects, length of the boat (as a vessel size class) and horse power was also used in the alysis. GLM based models using a log response on CPUE were examined. The fil model presented estimated log(CPUE) from independent variables Year, Month, Area (N, S, or M), number of FADs used in the area, and Length of vessel, and interaction effects between the last 3 categories. The data was alysed at a monthly resolution before b eing was collapsed into quarterly sigls for 2004-2011. Filly, using vessel length as a continuous covariate, the CPUE data was estimated for historic periods till 1985.
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Book (series)Technical studyAssessment and management of biotoxin risks in bivalve molluscs 2011
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No results found.Biotoxins produced by certain algal species can be accumulated by bivalve molluscs. This constitutes one of the major public health risks that need to be managed during shellfish production. With a view to aiding risk assessment, monitoring and surveillance programmes, this paper provides a range of information about the various biotoxins globally recorded in shellfish: levels detected, toxicological data, methods of analysis for detection and quantification of toxins, and the risk assessment ap proach for public health management. The complex chemical nature of the toxins, along with several analogues, hampers the development and validation of methods for their detection, for the evaluation of their toxicity and for the development of limits for shellfish safety management. This paper also illustrates the approach taken by the Codex Alimentarius Commission in developing guidelines for bivalve shellfish safety management and for establishing Codex standards for live and raw bivalve moll uscs. -
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Book (series)Technical studyA third assessment of global marine fisheries discards 2019
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No results found.This third update of FAO’s global discard estimate adopted the ‘fishery-by-fishery’ approach employed in the second discards assessment published in 2005. The update included publicly available discard data in the last 20 years to establish a baseline of a time series of global marine fisheries discards. This is essential for monitoring the status and trends of discard management, which is the first step of the ecosystem approach to fisheries management cycle. In addition, the study developed a new fisheries data table incorporating landings data from the FAO Global Capture Production dataset (FishStat J) from 2010 to 2014, which allocated the landings to over 2 000 fisheries worldwide. The current study estimated that the annual discards from global marine capture fisheries between 2010 and 2014 was 9.1 million tonnes (95% CI: 6.7 – 16.1 million tonnes). About 46 percent (4.2 million tonnes) of total annual discards were from bottom trawls that included otter trawls, shrimp trawls, pair bottom trawls, twin otter trawls and beam trawls. The study included a synthesis of estimates of bycatch and discards of endangered, threatened and protected (ETP) species. Substantial advances have been made in quantifying fisheries interactions with such species so as to make informed decisions on their protection. However, many challenges remain, especially for small-scale fisheries. The development of standardized data collection techniques, risk-based sampling and sharing of data across agencies and regions will help to identify management priorities and allow implementation and enforcement of mitigation measures. A review of previous research showed that discard practices were often related to a wide range of factors, so it is difficult to assess the effectiveness of fishery management actions on the amount and practice of discards. Many regulations are inconsistently enforced, and their implementation is often less strict than intended. Piecemeal approaches in many bycatch and discards management measures can result in unintended cross-taxa conflicts, where regulations designed to reduce bycatch and/or discards of one species or species group may increase bycatch and/or discards of another. Examination of approaches to accounting for and mitigating against pre-catch, post-capture and ghost fishing mortalities demonstrates that an understanding of the relative importance of factors affecting indirect fishing mortality is necessary for estimating total fishing-induced mortality and for designing and implementing mitigation measures.