1,376 research outputs found

    The challenge of domesticating bluefin tuna (Project SELFDOTT)

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    Folleto divulgativo del proyecto SELFDOTTSELFDOTT GA 212797 7FP E

    Domestication of Bluefin tuna, the last great challenge of marine aquaculture

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    The bluefin tuna Thunnus thynnus (L., 1758) is a teleost fish belonging to the Scombridae family and is an emblematic species that has fed the Mediterranean populations for millennia. From the 90´s starts the process called «bluefin tuna fattening» which involves capturing live specimens by purse seiners in spawning areas, transferring them to nearby farms to the coast, feeding them for several months with small pelagic fish rich in fat and sent to market later, especially Japan. This activity led to severe exploitation of natural populations, risking the future of the fishery. To mitigate this, the International Council for the Conservation of Atlantic Tunas (ICCAT) established from 2007 a recovery plan, with a drastic limitation of catches and several conservation measures, which have made the fishery of Atlantic bluefin tuna one of the most regulated. Clearly, despite the undoubted positive effects on the recovery of the stock, limited catches will continue in the near future. Therefore, to ensure the supply of this iconic species in the quantity and quality required by an increasingly important and selective market, the bluefin tuna production has to come inevitably by techniques of integrated aquaculture completely independent of natural populations, such as it happens today with species such as gilthead sea bream, sea bass or turbot. This activity also promotes the recovery of natural stocks by reducing the fisheries pressure. The Oceanographic Centre of Murcia, belonging to Spanish Institute of Oceanography (IEO, has been developing for more than 10 years, techniques for the captive breeding of bluefin tuna and production of juveniles who have been subsequently raised to market size in floating cages companies the sector, within the framework of research projects with the IEO

    Recruits from farmed ABFT in Murcia ?

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    It has been demonstrated at least in the Murcia area, that the captive ABFT (Thunnus thynnus) for fattening activities reproduce actively in the farming cages in the natural spawning season (early June – middle July). Tens of millions of fertilized eggs coming from these cages had been collected in the last years and cultured in the facilities of the Spanish Institute of Oceanography (IEO) in Mazarrón (Murcia, SE Spain) and grown up to juveniles, demonstrating as well their viability. Taking into account that an ABFT female could spawn roughly hundred thousands of eggs per kg during all the spawning season and thousands of tones of ABFT adults have been farmed in the Murcia coast during the last years, the total fertilized eggs could reach hundreds of billions every year. Obviously the conditions in the Murcia coast are different of the natural spawning areas not only regarding the feeding availability but also the massive presence of many egg and larvae predators. It would be recommendable to carry out prospecting surveys in the aim to shed some light on this possible effect of farmed ABFT on the recruitment at least in Murcia

    Eight years of research on bluefin tuna (Thunnus thynnus) culture at the Spanish Institute of Oceanography (IEO)

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    Since 2000 the Spanish Institute of Oceanography (IEO) is participating in several research projects on BFT culture with the aim of contributing of the Domestication of this species, for improving the productive process and reducing the pressure on the wild stock as it has already happened with other full cycle cultured species

    Spain's Atlantic Bluefin Tuna Aquaculture

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    In this chapter, we outline the advantes in Spain's ABT aquaculture between 2011 and 2015 and conclude with the details of the new land-based facility designed to take us into the future.Versión del edito

    La deformabilidad del suelo "in situ". Un método para la interpretación conjunta de los ensayos de laboratorio y de campo

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    Los ensayos de laboratorio y de campo que permiten evaluar la defonnabilidad del terreno conducen generalmente a resultados poco acordes entre sí. La interpretación conjunta de los resultados de ambos tipos de ensayos es un procedimiento habitual para el establecimiento de leyes constitutivas tensióndeformación del suelo "in situ", con validez para estados tensionales variables dentro de límites determinados. El ensayo "in situ" estudiado en este caso (placa de carga) se reproduce de forma numérica utilizando un modelo de cálculo capaz de admitir la ley constitutiva establecida en el laboratorio (modelo hiperbólico) y, posteriormente, se comparan sus resultados con los del ensayo real. Para simular el ensayo de carga se ha desarrollado un modelo simplificado que permite tener en cuenta la respuesta heterogénea del suelo debida a la existencia de presiones de confinamiento variables y la no linealidad entre tensiones y deformaciones para un confinamiento dado. El modelo simplificado se ha desarrollado en lenguaje FORTRAN ("PLACAR"), consiguiéndose un programa de utilización sencilla y coste reducido. Los resultados se han contrastado con un modelo de elementos finitos. Finalmente, se incluyen dos ejemplos de aplicación práctica. En el primero la interpretación conjunta resulta eficaz y se analiza la extrapolación de los resultados a las dimensiones de las cimentaciones reales. En cambio, en el segundo ejemplo la interpretación no tiene utilidad práctica.Peer Reviewe

    Large scale RTD facility to take tuna farming forward

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    The Atlantic Bluefin tuna is an emblematic species which is feeding the Mediterranean human populations for centuries. In the last two decades its wild stocks have been severely overfished having been established important capture limits with the consequent reduction of the production. For satisfying the high market, it is essential the increase the bluefin tuna production coming from the self-sustained aquaculture. The Spanish Institute of Oceanography (IEO) has recently built a land-based large scale facility (ICRA) for the control of the reproduction of this species, capable of hosting big size breeders. This facility is near the already existing IEO Aquaculture facility in Mazarrón, (Murcia, SE Spain), devoted to the research on Atlantic Bluefin tuna larval rearing and juveniles production. Both facilities are a model of how research centres of excellence can enhance cooperation to generate new knowledge on performance that can be transferred directly to operators and provide the technical basis needed to take the sector forward.Co-funded by European Regional Development Funds (FEDER) and Spanish Institute of Oceanography (IEO

    Closing the life cycle of the Atlantic bluefin tuna Thunnus thynnus in captivity

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    This is the first time that closing the life cycle of ABFT in captivity is reported. Egg size, larval size and hatching rate were similar to those observed in wild broodstock in last five years. This milestone will enable faster development of integrated aquaculture of this species, consolidating the leadership that the IEO and Murcia Region have in the domestication of bluefin tuna, at European and global scale
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