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Report on the regional training course on fish stock assessment







Report on the Regional Training Course on Fish Stock Assessment, 21 January-15 1991 February 1991, Kariba, Zimbabwe. Denmark funds-in-trust FI: GCP/INT/392/DEN-Act. Rep. No 29 and UNDP/FAO Regional Project for Inland Fisheries Planning (IFIP), RAF/87/099-TD/24/91 (En): 29p.


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    Book (stand-alone)
    Introduction to tropical fish stock assessment - Part 1: Manual (French version not published) 1998
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    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.
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    Traditional small scale fishing for yellowfin tuna Thunnus albacares in Andhra Pradesh along east coast of India 2013
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    The yellowfin tus form one of the major components of oceanic tu catch along the Indian coast. They are fished both along the mainland as well as the Island systems with the total annual catch from the mainland varying from 10,307 t to 19,163 t during 2010-2012. Commercial fishing is mainly by small mechanized wooden crafts and non-mechanized traditiol crafts. Mechanized crafts operated pole and line, long line and gillnets and non- mechanized crafts operated hand lines and troll lines. Highly s killed fishermen of Andhra Pradesh State situated along the east coast of India use traditiol catamarans fitted with sails to catch yellowfin tus from deep waters by operating either the hand lines or the troll lines. Around 1500 such units operated along the coast with an average annual landings of 4,300 t during 2010-2012. Fishing is carried out for a day as the crafts do not have any storage facility. Peak landings are during October–January followed by May-July. The annual catch per unit at Visakhapatm was 58 kg and during the peak fishing season it increased to 71 kg per unit. The fork length of the yellowfin ranged from 20 to 185 cm with the mean at 130 cm. Fishes above 80 cm were found to be mature and the size at first maturity was estimated to be between 85 and 90 cm. Males were domint with a male: female ratio of 1: 0.53. The length- weight relationship is W= 0.017077L 2.976. Feeding habit of yellowfin tu indicated the fish to be a nonselective generalist feeder, foraging on micronektonic pelagic or benthic organisms available in the epipelagic waters. Teleost fish, crabs, squids and shrimps were the major food items. Age and growth were estimated using length based methods. The von Bertalanffy growth parameters estimated were L∞ = 197.42 cm, annual K= 0.30 and t0= -0.1157. Mortality estimates were M= 0.48 and Z= 0.71 and F= 0.23 with the exploitation ratio E= 0.32. Growth was rapid during the initial years when the annual growth increments was as high as 36.6 cm du ring the first year then declined to as low as 3.3 cm in the tenth year. The fish attained a fork length of 56.2 cm at the end of one year. Size at maturity (87.5 cm) corresponded to an age of 1.7 years and the oldest individual in the sample was 9+ years (186 cm). The annual mean lengths varied from 80.6 cm to 115.3 cm with an average mean length of 101.9 cm. The fishery comprised of mostly adults with 64% comprising of fishes larger than size at first maturity.
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    Project
    Growth And Mortality Of The Malaysian Cockle (Anadara Granosa L.) Under Commercial Culture: Analysis Through Length-Frequency Data - BOBP/WP/47 1986
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    This paper analyses length frequency data, by several methods, of the Malaysian cockle (Anadara granosa L). The data were collected monthly from five different plots under commercial culture during a period of 12-17 months. Parameters of the von Bertalanffy growth formula (VBGF) were derived for each of the five plots, along with estimates of related parameters (mortality, mean length of first capture, etc.). “Yield per recruit” analyses suggest that the present legal size for the five culture p lots is well above the maximum yield per recruit. The paper discusses the limitations of the methodology and data used. Suggestions for further studies are also made. The cockle samples were collected and measured by staff of the cockle team, headed by the author, of the Glugor Fisheries Research Station (GFRI), Penang, Malaysia. The analyses were made by the author on a fellowship visit to the International Center for Living Aquatic Resources Management (ICLARM), Manila, in October 1985. The author wishes to thank the GFRI’s Director of Research, Mr. Mohd Shaari bin Sam Abdul Latiff, and Mr. Ong Kah Sin, Head of the Aquaculture Section, for their encouragement and suggestions on the project; Dr. Daniel Pauly (ICLARM), for his help with the analyses; Dr. J. Saeger and Mr. Gayanilo (GTZ) for allowing him to use their revised version of the ELEFAN programs and their computer facilities; Ms. Faazaz bte Latiff, Mr. Kamal Zaman bin Mohamad and Ms. Devaki Nair for collecting and co mpiling the length frequency data at Penang and Set an gor. The work described in this paper is one component of a programme for the Development and Management of Cockle Culture in Malaysia, supported by the smallscale fisheries project of the Bay of Bengal Programme (BOBP). The programme’s first phase, undertaken during 1985, consisted primarily of biological studies.

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