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Standardized CPUE series for blue and shortfin mako sharks caught by the Portuguese pelagic longline fishery in the Indian Ocean, between 1999 and 2012









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    Brief presentation of the Portuguese research plan for the improvement of knowledge on pelagic sharks caught in the swordfish fishery in the Indian Ocean 2013
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    Portuguese longliners targeting swordfish and operating in the Indian Ocean regularly capture elasmobranch fishes as bycatch. Of those, the blue shark (Prioce glauca) and the shortfin mako (Isurus oxyrinchus) constitute the two main shark species captured, even though several other species are also occasiolly captured. IPMA, the Portuguese Sea and Atmospheric Institute, is responsible for the Natiol Data Collection Program, which maintains fishery observers on those vessels to collect data and s amples. Therefore, IPMA has currently the means and opportunity to collect a wide variety of biological samples that are of ultimate importance to the work of the IOCT scientific commission. In this report we present the current Portuguese program research on sharks in the Indian Ocean, and propose the research plans for the near future (over the next 5 years), following IOTC Resolution 13/06.
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    Report of the Ninth Session of the IOTC Working Party on Ecosystems and Bycatch 2013
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    The Ninth Session of the Indian Ocean Tu Commission‘s (IOTC) Working Party on Ecosystems and Bycatch (WPEB) was held in La Reunion, France, from 12 to 16 September 2013. A total of 32 participants (48 in 2012) attended the Session. The meeting was opened by Mr Ludovic Courtois, Secrétaire général du Comité régiol des pêches maritimes et des élevages marins (CRPMEM) de La Réunion, who welcomed participants to La Reunion and formally opened the Ninth Session of the IOTC Working Party on Ecosystems and Bycatch. The Chair, Dr. Charles Anderson also subsequently welcomed participants to La Reunion, including the Invited Expert, Dr. Ronel Nel, from the Nelson Mandela Metropolitan University, Port Elizabeth, South Africa. Employment of a Fisheries Officer NOTING the rapidly increasing scientific workload at the IOTC Secretariat, including a wide range of additiol duties on ecosystems and bycatch assigned to it by the SC and the Commission, and that the new Fishery Officer (Science) supporting the IOTC scientific activities has not been given a mandate by the Commission to work on ecosystems and bycatch matters, the WPEB strongly RECOMMENDED that the Commission approve the hiring of a Fishery Officer (Bycatch) to work on bycatch matters in support of the scientific process. (para.12) Regiol observer scheme The WPEB RECOMMENDED that the Compliance Committee and Commission consider how to address the lack of implementation of regiol observer schemes by CPCs for their fleets and reporti ng to the IOTC Secretariat as per the provision of Resolution 11/04 on a Regiol Observer Scheme, noting the update provided in Appendix VI. (para.35) The WPEB RECOMMENDED that as a priority, the IOTC Secretariat should immediately commence work with CPCs that are yet to develop and implement a Regiol Observer Scheme that would meet the requirements contained in Resolution 11/04, and provide an update at the next session of the WPEB. (para.37) Training for CPCs having gillnet fleets on species id entification, bycatch mitigation and data collection methods and also to identify other potential sources of assistance – Development of plans of action The WPEB RECOMMENDED that the Commission allocate funds in its 2014 and 2015 budgets for the IOTC Secretariat to carry out training for CPCs having gillnet fleets on bycatch mitigation methods, species identification, and data collection methods (budget estimate: Table 4). (para.64) Ecological Risk Assessment: review of current knowledge and pot ential magement implications The WPEB RECOMMENDED that the Commission note the list of the 10 most vulnerable shark species to longline gear (Table 7) and purse seine gear (Table 8) in the Indian Ocean, as determined by a productivity susceptibility alysis, compared to the list of shark species/groups required to be recorded for each gear, contained in Resolution 13/03 on the recording of catch and effort by fishing vessels in the IOTC area of competence. At the next revision to Resolution 13/03 , the Commission may wish to add the missing species/groups of sharks and rays. (para.123) Review of data needs and way forward for the evaluation of shark stocks NOTING that Resolution 10/02 mandatory statistical requirements for IOTC Members and Cooperating Non- Contracting Parties (CPC's), makes provision for data to be reported to the IOTC on ?the most commonly caught shark species and, where possible, to the less common shark species?, without giving any list defining the most common and le ss common species, and recognising the general lack of shark data being recorded and reported to the IOTC Secretariat, the WPEB RECOMMENDED that Resolution 10/02 is revised in order to include the list of most commonly caught elasmobranch species (Table 10) for which nomil catch data shall be reported as part of the statistical requirement for IOTC CPCs. (para.138) Review of Resolution 12/04 on the conservation of marine turtles The WPEB RECOMMENDED that at the next revision of IOTC Resolution 1 2/04 on the conservation of marine turtles, the measure is strengthened to ensure that where possible, CPCs report annually on the total estimated level of incidental catches of marine turtles, by species, as provided at Table 12. (para.168) Resolution 10/02 Mandatory statistical [reporting] requirements for IOTC Members and Cooperating Non- Contracting Parties (CPCs) NOTING that Resolution 10/02 does not make provisions for data to be reported to the IOTC on marine turtles, the WPEB RECOMMENDED that Resolution 10/02 is revised in order to make the reporting requirements coherent with those stated in Resolution 12/04 on the conservation of marine turtles and Resolution 13/03 on On the recording of catch and effort by fishing vessels in the IOTC area of competence. (para.169) Format of future WPEB Sessions The WPEB RECOMMENDED that the SC note the following: (para.253) ? The WPEB DISCUSSED the future format in order to focus the efforts of scientists working on different groups of bycat ch species to address more efficiently, the mandate of the group. ? The WPEB CONSIDERED a range of options which the SC is asked to consider: o Option 1: The current WPEB be split into two; A dedicated Working Party on Sharks (WPS) and a Working Party on Ecosystems and Bycatch (WPEB). o Option 2: Retaining the WPEB in its current form, with alterting focus of sharks in one year, followed by other ecosystem and bycatch issues in the next year. o Option 3: Maintaining the WPEB with clear guideline s to deal with sharks every year, as well as other issues and bycatch groups in alterte years or as required. ? The WPEB AGREED that shark issues were important to address on a yearly basis. Election of a Chairperson and Vice-Chairperson for the next biennium The WPEB RECOMMENDED that the SC note the new Chairperson, Dr. Rui Coelho (EU,Portugal) and Vice- Chairperson, Dr. Evgeny Romanov (La Réunion), of the WPEB for the next biennium. (para.263) Report of the Ninth Session of the Working Party o n Ecosystems and Bycatch The WPEB RECOMMENDED that the Scientific Committee consider the consolidated set of recommendations arising from WPEB09, provided at Appendix XXI, as well as the magement advice provided in the draft resource stock status summary for each of the seven shark species, as well of those for marine turtles and seabirds: (para.265) Sharks o Blue sharks (Prioce glauca) – Appendix X o Oceanic whitetip sharks (Carcharhinus longimanus) – Appendix XI o Scalloped hammerhead sharks ( Sphyr lewini) – Appendix XII o Shortfin mako sharks (Isurus oxyrinchus) – Appendix XIII o Silky sharks (Carcharhinus falciformis) – Appendix XIV o Bigeye thresher sharks (Alopias superciliosus) – Appendix XV o Pelagic thresher sharks (Alopias pelagicus) – Appendix XVI Other species/groups o Marine turtles – Appendix XVII o Seabirds – Appendix XVIII A summary of the stock status for some of the most commonly caught shark species caught in association with IOTC fisheries for tu and tu-like species is provided in Table 1.
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    An updated overview of the swordfish catches by the Portuguese pelagic longline fishery in the Indian Ocean between 1998-2012: catch, effort, CPUE and catch-at-size 2013
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    The Portuguese longline fishery targeting swordfish in the Indian Ocean started in the late 1990’s, targeting mainly swordfish. A recent effort by Portuguese Marine and Atmosphere Institute (IPMA) has been made aiming the collection of historical catch data on this fishery since the late 1990’s to the present date. This working document reports an updated overview of the Portuguese swordfish fishery, including alyses on the catches, effort, catch-at-size and CPUE trends for the period 1998-2012. The trends in the swordfish catch-at-size were alyzed annually, and compared between months and regions of operation of the fishery. Nomil annual CPUEs were calculated as kg/1000 hooks, and were standardized with Generalized Linear Models (GLMs) using year, quarter, location and swordfish/blue shark ratio as explatory variables. Three different modeling approaches were used and compared, including tweedie, gamma and lognormal models, and model validation was carried out with a residual alysis. A sensitivity alysis to the influence of the ratio factor in the models was carried out. The results presented in this paper update a previous alysis on the trends of swordfish catches available from the Portuguese longline fishery operating in the Indian Ocean.

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