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A comparison of changes in the exploration and exploitation of oceanic tuna resources in the Indian EEZ in 1970-2012









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    Report of the Fifteenth Session of the IOTC Working Party on Tropical Tunas 2013
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    The Fifteenth Session of the Indian Ocean Tu Commission‘s (IOTC) Working Party on Tropical Tus (WPTT) was held in San Sebastian, Spain, from 23 to 28 October 2013. The meeting was opened on 23 October 2013 by the Chair, Dr Hilario Murua (EU-Spain), who welcomed participants to San Sebastian, Spain. A total of 46 participants attended the Session (47 in 2012), including one invited expert, Dr. Andrew Cooper, from Simon Fraser University, Cada. The following are a subset of the complete recommenda tions from the WPTT15 to the Scientific Committee, which are provided at Appendix XII. Japan data collection and processing systems The WPTT THANKED Japan for addressing some of the concerns raised by the WPTT in 2012, and RECOMMENDED that Japan and the IOTC Secretariat continue joint work, in cooperation with other countries having longline fisheries, to address other issues identified by the WPTT, as the lack of specimens of small size from the samples and discrepancies in the average weights estimated using the available catch-and-effort and length frequency data. (para. 62) Taiwan,Chi data collection and processing systems NOTING that in recent years fishers from the Taiwan,Chi longline fleet have been collecting both length and weight measurements for the same specimens, the WPTT RECOMMENDED that the measured lengths and lengths derived from weight measurements are compared in order to validate the reliability of this dataset (para. 67) Length Frequency inter-sessiol meeting guide lines NOTING the size data issues (discrepancies in catch, effort and notably size data (low sampling rate, uneven distribution of sampling in regard to the spatial extent of the fishery) in the Japanese and Taiwan,Chi tropical tu data sets) identified by the WPTT in 2012 and 2013 and the Scientific Committee in 2012, the WPTT RECOMMENDED that an inter-sessiol meeting attached to the WPDCS and WPM on data collection and processing systems for size data from the main longline fleets in the Indian Ocean, be carried out in early 2014, under the guidelines contained in Appendix IV. (para. 74) The WPTT NOTED that the data collection and processing systems used for distant-water longline fisheries tend to apply to all oceans AGREEING that it is likely that the issues identified for the Indian Ocean also apply to other areas. In this regard, the WPTT RECOMMENDED that the IOTC Secretariat informs other tu-RFMO Secretariats about the issues identified and facilitates participation of their staf f to the WPDCS, where required. (para. 75) India fisheries NOTING the potential utility of the longline CPUEs derived from the research surveys conducted by the ?Fishery Survey of India?, the WPTT RECOMMENDED that as a high priority, India undertake a standardisation of the CPUE series, with the support of the IOTC Secretariat, and for this to be presented at the next WPTT meeting. (para. 92) Alysis of the Time-Area Closures (including Resolution 12/13) NOTING that the objective of Resolution 12 /13 is to decrease the overall pressure on the main targeted stocks in the Indian Ocean, in particular yellowfin tu and bigeye tu, and also to evaluate the impact of the current time/area closure and any altertive scerios on tropical tu population, the WPTT reiterated its previous RECOMMENDATION that the SC request that the Commission specify the level of reduction or the long term magement objectives to be achieved with the current or altertive time area closures, as these are not contained wit hin Resolution 12/13. (para. 245) Review of the draft, and adoption of the Report of the Fifteenth Session of the WPTT The WPTT RECOMMENDED that the Scientific Committee consider the consolidated set of recommendations arising from WPTT15, provided at Appendix XII, as well as the magement advice provided in the draft resource stock status summary for each of the tropical tu species under the IOTC mandate: (para. 271) o Bigeye tu (Thunnus obesus) – Appendix VII o Skipjack tu (Katsuwonus pelamis) – Appendix VIII o Yellowfin tu (Thunnus albacares) – Appendix IX A summary of the stock status for tropical tu species under the IOTC mandate is provided in Table 1.
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    National Report – Australia 2013
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    Pelagic longline and purse seine are the two main fishing methods used by Australian vessels to target tu and billfish in the Indian Ocean Tu Commission (IOTC) Area of Competence. In 2012, three Australian longliners from the Western Tu and Billfish Fishery and one longliner from the Eastern Tu and Billfish Fishery operated in the IOTC Area of Competence. They caught 13.1 t of albacore (Thunnus alalunga), 167.4 t of bigeye tu (Thunnus obesus), 23.0 t of yellowfin tu (Thunnus albacares), 209.3 t of swordfish (Xiphius gladius) and 2.5 t of striped marlin (Tetrapturus audax). These catches represent approximately 13 per cent of the peak catches taken by Australian vessels fishing in the IOTC Area of Competence in 2001, for these five species combined. In addition, Australian vessels using minor line methods took a small amount of catch. The number of active longliners and levels of fishing effort have declined substantially in recent years due to reduced profitability, primarily as a resu lt of lower fish prices and higher operating costs. The catch of southern bluefin tu (Thunnus maccoyii) in the purse seine fishery was 4503 t in 2012. A small amount of skipjack tu (Katsuwonus pelamis) was caught by purse seine fishing in 2012 (0.2 t). In 2012, less than 1 t of shark was landed by the Australian longline fleet operating in the IOTC Area of Competence and 11 371 sharks were discarded/released. In 2012, 17.8 per cent of all hooks set in WTBF longline operations were observed over three trips in the IOTC Area of Competence.
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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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