E - Iccat

PANEL 2
There has not yet been enough time to detect with confidence the population response to the measures
implemented under the latest western bluefin rebuilding plan [Rec. 10-03]. Nevertheless, the available fishery
indicators as well as the current assessment suggest the SSB of western Atlantic bluefin tuna continue to
increase.
Despite the uncertainty regarding the long-term productivity of the stock under either recruitment scenario,
current catches (1,750 t) should allow the biomass to continue to increase. Larger catches in excess of 2,000 t
will prevent the possibility of the 2003 year-class elevating the productivity potential of the stock in the future.
Maintaining the catch at current levels is expected to allow the spawning biomass to increase, which may help
resolve the issue of low and high recruitment potential. For example, should the high recruitment hypothesis be
correct, allowing substantial increases in spawning biomass should lead to higher recruitment.
5.2.3 Other matters
The SCRS Chair elaborated on the creation and history of the ICCAT Atlantic-wide Research Programme for
Bluefin Tuna (GBYP). The ICCAT-GBYP started in March 2010 and its main research activities focused on
improving basic data collection, better understanding of key biological and ecological processes, improving
assessment models and provision of scientific advice, with special attention to the development of fishery
independent indicators.
The Chair then presented more details on specific GBYP projects. Phase 1 of the GBYP was the revision of the
tagging design and tagging manual. In Phase 2, 3600 tunas were tagged, and during Phase 3 (in progress) 4600
tunas were tagged providing direct estimates of fishing mortality, natural mortality, mixing and abundance. For
Phase 4 (2013) of the GBYP, there is a critical need to establish multi-year funding to avoid annual uncertainty
in cash flow. The current system of annual funding limits what can be achieved in the field and introduces
potential inefficiencies in the use of funds. It was stressed that the establishment of a Scientific Quota would be
extremely important for stability and the efficiency of the Programme and that all concerned CPCs need to
provide the financial support that will allow the GBYP to support the ICCAT Secretariat initiatives concerning
GBYP activities in their territorial waters and/or airspace.
Under the GBYP, the SCRS has been able to conduct aerial surveys of spawning aggregations of bluefin tuna in
order to provide indices of spawning stock abundance. These surveys must be conducted for several years to
have a minimum number of years to get reliable indices. The SCRS recommended the extension of the surveyed
area in 2012 and indicated that without a sufficient number of years of adequate financial support and the
guarantee of flight permits, these surveys would not provide reliable results.
Data recovery under the GBYP resulted in the acquisition of data on 23,000,000 tunas (740,000 t) from 118,000
fishing operations. This constitutes a considerable improvement in the data available for scientific use. The trap
database also now includes records from the XVI century.
Projects involving biological and genetic sampling and consequent analyses were awarded to a Consortium of 14
Institutes from 11 countries. The Consortium is collecting very valuable samples and some preliminary analysis
show very promising results. The priority for the next phase will be the analysis of the collected samples together
with the necessary continuation of sampling.
The Chair then addressed the SCRS responses to the following Commission’s requests:
− To advise the Commission on the creation of sanctuaries for bluefin tuna [Rec. 10-04, paragraph 26] (see
Item 18.1 of the 2012 SCRS Report).
In 2010, the SCRS gave advice to the Commission on the location and timing of bluefin spawning in the
Mediterranean. New information was available in 2012. The current knowledge indicates that bluefin tuna
spawning locations are probably wider than assumed in the past and could cover more than half of the
Mediterranean Sea surface (mostly in the southern part). Furthermore, the locations and timing of bluefin tuna
spawning is likely to vary substantially from year-to-year. Consequently, the implementation of sanctuary areas
aimed at protecting bluefin spawning should be large enough to be effective at the population level and would
necessitate an integrative approach to evaluate the optimal design in terms of size, location(s) and time/season.
− To advise the Commission on the identification of spawning areas for western Atlantic bluefin tuna [Rec. 10-
03, paragraph 20] (see 18.1 of the 2012 SCRS Report).
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