The Sphere of Action Research Developed with the support of Balfegó Group (2008-2011). Ana Gordoa Centro de Estudios Avanzados de Blanes (CEAB) CSIC gordoa@ceab.csic.es
Research Cooperation begun in 2008 Objective: to determine if tuna spawning took place in tuna transport cages. Method: an innovative sampling design was successfully implemented Results: The first time ever the spawning of Atlantic Bluefin was observed It could determine the time of day when spawning takes place. The consistency and regularity of spawning within tuna transport cages open a new line of research. Tuna transport cages become research platforms
Fundamental Research (FR) Reproduction of Atlantic bluefin tuna (ABFT): temporal pattern in Balearic waters Spawning temporal pattern Spawners (reproducers) temporal pattern Egg and early larvae development Genetic analysis between eastern and western Mediterranean ABFT spawners Growth rate in captivity Applied Research (AP) Implications of FR Results in the current policy - Adequacy of the current purse seine fishing season Implications in the estimations of annual catch rates (CPUE).
Spawning : temporal pattern Spawning Survey : Descriptors Component/research platform: transport cages Elements: 1. The first wild tuna caught in the fishing season 2. Captive tuna caught in 2008 (experimental group) Period : mid May mid July Frequency: daily Years: 2008-
Graphic description of the sampling methodology Transport cage
Night sampling Sampling nets
Filtered Samples Preserved Samples eggs
On board aquaculture experiments ABFT larvae
The Environment A new Research Line: Yellyfish spatio-temporal match and impact on ABF spawning Recently included in the European Master in Marine Biodiversity and Conservation (http://embc.marbef.org/index.asp).
Spawning Results 1000 Daily Spawning Pattern (2009 survey) 2:00-3:00 local time 3:00-4:00 local time 800 20.5ºc 600 400 200 0 23/05/09 25/05/09 27/05/09 29/05/09 31/05/09 02/06/09 04/06/09 06/06/09 08/06/09 10/06/09 12/06/09 14/06/09 16/06/09 18/06/09 20/06/09 22/06/09 24/06/09 26/06/09 28/06/09 30/06/09 02/07/09 04/07/09 06/07/09 08/07/09 10/07/09 12/07/09 14/07/09 16/07/09 18/07/09 20/07/09 Eggs volume (ml)
120 100 80 60 40 20 0 Daily cumulative spawning (based on 2009 and 2010 surveys) Impact on recruitment of the Present Fishing season Estimations based on 2010 Spanish cuota. Potential reduction above 500 000 recruits Closed fishing season 2010 Cuota filled 24-May 26-May 28-May 30-May 1-Jun 3-Jun 5-Jun 7-Jun 9-Jun 11-Jun 13-Jun 15-Jun 17-Jun 19-Jun 21-Jun 23-Jun 25-Jun 27-Jun 29-Jun 1-Jul 3-Jul 5-Jul 7-Jul 9-Jul 11-Jul 13-Jul 15-Jul 17-Jul 19-Jul 21-Jul Cumulative Spawning (%) 2010 2009
2,0 Spawners (reproducers) temporal pattern - through purse seine catch rates. 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 Mean coefficient of abundance 0,0 13-15 mayo 16-20 mayo 21-25 mayo 26-31 mayo 1-5 junio 6-10 junio 11-15 junio 16-20 junio 21-25 junio 26-30 junio 1-5 julio 6-10 julio 11-15 julio Higher temporal abundance Higher ecoeficiency (*)
Fundamental Research (FR) Reproduction of Atlantic bluefin tuna (ABFT): temporal pattern in Balearic waters Spawning earliest temporal pattern : Peak spawning 18-28 June Spawners (reproducers) temporal pattern : Peak abundance : 18-30 June Applied Research (AP) Implications of FR Results in the current policy (15 June fishing is closed) Spawning of the harvested cuota is inhibited impact on the population Higher effort to fill the cuota higher costs and CO2 emissions ecommendation : fishing season should be regionally adapted based on the pawning periods of the eastern, central and western Mediterranean. Implications in the estimations of annual catch rates (CPUE).
Balfego Catch rates (kg/day) : 2000-2010 16000 CPUE (kg/day) Baleares: Balfegó 2000-2010 CPUE until 8th June: Balfegó 2006-2010 20000 15000 CPUE (8th June)(L) CPUE Balfego(R) 20 june 18000 CPUE until 8th June (kg/day) 14000 13000 12000 11000 10000 11 july 30 june 13 june 8 june 16000 14000 12000 10000 CPUE total spawning period (Kg/day) 9000 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 8000 The positive trend in the most recent years has also been observed in: Moroco traps, Spanish traps, Japenese Long line fleet and juveniles from French aerial surveys.
Published studies with the direct support of Balfegó Group Gordoa, A, Olivar, MP, Arevalo, R., Viñas, J., Molí, B., Illas, X. 2009. Determination of Atlantic bluefin tuna (Thunnus thynnus) spawning time within a transport cage in the western Mediterranean. ICES Journal of Marine Science. 66, 2205-2210. Gordoa, A.2009. Temporal pattern of daily CPUE on the Atlantic bluefin tuna (Thunnus thynnus) in the western Mediterranean spawning area. ICCAT SCRS/2009/156. Gordoa, A. 2009. The Atlantic Bluefin Tuna: Study of the Temporal Pattern of Spawning in the Western Mediterranean Region and Reproductive Capacity in Captivity. ICCAT SCRS/2009/157. Gordoa, A. 2009. An indirect Approach to estimate the Fattening Factor of Atlantic Bluefin Tuna (Thunnus thynnus) on Tuna Farms: Ametlla de Mar Facility as a Case Study ICCAT SCRS/2009/158. Gordoa, A. 2010. Estudio del Patrón anual de la CPUE del Atún Rojo (Thunnus thynnus) en la región Balear y factores de distorsión: Flota Balfegó 2000-2010. SCRS/2010/097. Gordoa, A. 2010. Aproximación al Impacto sobre el Reclutamiento del Atún Roj (Thunnus thynnus) de las Capturas de Cerco en Baleares con el Actual Periodo de Veda. SCRS/2010/107. Viñas, J., Gordoa, A., Fernández-Cebrian, R., Pla, C., Ünal, V., Araguas, R.M. 2011 Facts and uncertainties about the genetic population structure of Atlantic bluefin tuna (Thunnus thynnus) in the Mediterranean. Implications for fishery management. Rev. Fish. Biol. Fisheries (in press).
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