Related items
Showing items related by metadata.
-
Book (stand-alone)Introduction to tropical fish stock assessment - Part 1: Manual (French version not published) 1998
Also available in:
In Part 1, Manual, a selection of methods on fish stock assessment is described in detail, with examples of calculations. Special emphasis is placed on methods based on the analysis of length-frequencies. After a short introduction to statistics, it covers the estimation of growth parameters and mortality rates, virtual population methods, including age-based and length-based cohort analysis, gear selectivity, sampling, prediction models, including Beverton and Holt's yield per recruit model and Thompson and Bell's model, surplus production models, multispecies and multifleet problems, the assessment of migratory stocks, a discussion on stock/recruitment relationships and demersal trawl surveys, including the swept-area method. The manual is completed with a review of stock assessment, where an indication is given of methods to be applied at different levels of availability of input data, a review of relevant computer programs produced by or in cooperation with FAO, and a list of refer ences, including material for further reading. In Part 2, Exercises, a number of exercises is given with solutions. The exercises are directly related to the various chapters and sections of the manual. -
MeetingStock assessment of bigeye tuna (Thunnus obesus) in the Indian Ocean using ASAP 2013
Also available in:
No results found.Bigeye tu, Thunnus obesus (Lowe, 1839), is a large epi- and mesopelagic fish distributed in tropical and subtropical waters of Indian Ocean. The bigeye tu (BET) resource was initially harvested by longlines since the 1950s and now is one of the main economic tu recourses in the Indian Ocean. They are currently caught by longliners (deep-freezing and fresh-tu longliners), purse seiners (free-school and associated school), pole and line, and other small fleets as well. Stock assessments of BET in the Indian Ocean in recent years were conducted using forward-projecting based models such as Stock Synthesis (Shono et al., 2009; Kolody et al., 2010), Virtual population alysis (VPA) (Nishida and Takeuchi, 1999), and age-structured production model (ASMP)(Nishida and Rademeyer, 2011). These assessments suggested the Indian Ocean BET there was low probability that the stock has been overfished and overfishing is probably not occurring (Kolody et al., 2010; Nishida and Rademeyer, 2011). However, it should be cautious that the BET assessments were associated with many uncertainties according to explorations of extensive sensitivity alysis (Kolody et al., 2010). Following the uncertainty remaining in the assessments carried out for the previous Working Party on Tropical Tus (WPTT) meetings in 2010 and 2011, the WPTT recommended that bigeye tu would be the priority species for stock assessments in 2013 (IOTC–WPTT14, 2012). This working paper presented a stock assessment of Indian Ocean BE T using Age Structured Assessment Program (ASAP, Version 3; NOAA Fisheries Toolbox, 2011). ASAP is a formal stock assessment model and has been used for assessing many commercially exploited stocks, e.g. red grouper, yellowtail flounder, Pacific sardine, Greenland halibut, Gulf of Maine cod, Florida lobster (see NOAA Fisheries Toolbox, http://nft.nefsc.noaa.gov). The assessment included a base-case model and sensitivity alyses designed for the consideration of altertive key assumption regarding population dymics (i.e., the steepness parameter of the stock-recruitment relationship), and weighting scheme for the most important two abundance indices being used to tune the model. Stock status was evaluated based on fishing mortality and spawning stock biomass based reference points. Kobe plots will be presented to show historical trends in stock status, as recommended by the Scientific Committed (SC, 2012?). The current assessment was not considered to be fil and it would be revised and im proved based on the consensus in recommendations and comments reached on the WPTT15 meeting. -
ProjectReport of the training course on single-species length based stock assessment methods
Kavala, Greece, 21 - 25 February 2011
2011Also available in:
No results found.The training course on length-based stock assessment methods was held in Kavala, Greece between the 21 st to 25 th of February 2011. Twenty three scientists from Algeria, Cyprus, Egypt, Gaza Strip and West Bank, Greece, Lebanon and Turkey attended the course. The course was designed for fisheries biologists working in fisheries centres or other research institutions involved in fisheries monitoring, research and management in the Eastern Mediterranean. The course covered a five day period and provided instruction, demonstration, and exercises in estimating biological parameters and application of stock assessment models from length based methods. The last day was designed as an exercise session requiring the conduction of a complete stock assessment, starting from the estimation of biological parameters (growth, maturity, natural mortality), and including the calculation of total and fishing mortality using both the catch curve approach and th e LCA. The exercise was completed with the estimation of fishing reference points (F0.1) and the evaluation of the stock status. Formal procedures through which stock assessments are presented to the General Fisheries Commission for the Mediterranean (GFCM) were also described. Overall the participants were highly satisfied with the quality of the training, that scored a high mean evaluation (very good), from a feedback questionnaire that was distributed after the course. Followi ng the feedback received from the participants and the experience of the instructors recommendations have been proposed for a follow up of this training course
Users also downloaded
Showing related downloaded files
No results found.