The challenge of domesticating bluefin tuna (Project SELFDOTT)

Folleto divulgativo del proyecto SELFDOTTSELFDOTT GA 212797 7FP E

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

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 ?

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)

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

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

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

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

Large scale RTD facility to take tuna farming forward

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

Efecto de diversos factores sobre el consumo de oxígeno de juveniles de seriola (Seriola dumerili Risso, 1810) en condiciones de cultivo

Se ha estudiado el efecto la temperatura, el peso de los individuos, la hipoxia, la alimentación, las manipulaciones y el tratamiento con formol, sobre el consumo de oxígeno de Seriola dumerili en condiciones de cultivo. Para la estimación del consumo de oxígeno se utilizaron dos métodos: el método de flujo cerrado, que consiste en medir el descenso de la concentración de oxígeno que se produce como consecuencia de la respiración de los peces una vez que se ha detenido la renovación de agua, y el método de flujo abierto, que consiste en estimar el metabolismo, con una medida simultánea en un tanque de idénticas características pero sin peces. Los resultados muestran que la temperatura aumenta de forma muy significativa el metabolismo, siendo este efecto más acusado tras la alimentación. Así mismo, los juveniles de esta especie parecen ser capaces de aclimatarse térmicamente, y se comportan como oxirreguladores frente a una hipoxia gradual. El consumo específico de oxígeno en rutina disminuye de forma muy marcada al aumentar el tamaño de los individuos. El consumo de oxígeno total diario de los juveniles de seriola mediterránea se muestra independiente del número de tomas de alimento, aunque es menor en los peces en ayunas. El pico de máximo consumo es superior en los peces alimentados con tres tomas al día que en los alimentados con dos. El retorno a los niveles de prealimentación se produce alrededor de las siete horas después del inicio de la alimentación, independientemente del número de tomas. No se ha observado ningún efecto de anticipación al alimento. En situación de ayuno se produce una variación significativa del patrón rutinario del ritmo diario de consumo de oxígeno en juveniles de seriola sugiriendo la existencia de un ritmo endógeno. Cuando la seriola es alimentada con una ración diaria no limitante, ésta puede ser distribuida con distintas frecuencias sin que se vean afectados ni el crecimiento ni el consumo de oxígeno, pero los perfiles diarios de consumo se ven significativamente suavizados, con una amplitud menor y una duración más prolongada del efecto de la alimentación. Ésta, realizada a saciedad con dietas con un nivel proteico no limitante y altos niveles de grasa, no afecta al crecimiento ni al consumo de oxígeno de esta especie, lo que sugiere que la energía excedentaria se acumula directamente en los tejidos corporales desplazando al agua. Frente a ciertas manipulaciones, esta especie muestra un aumento metabólico semejante al que se produce como consecuencia de la alimentación, con tiempos de recuperación inferiores a las 7 horas por lo que las manipulaciones propias de un cultivo pueden ser realizadas sin que afecten severamente a los rendimientos de esta especie. En el rango de temperaturas testado (19,7 - 25,8°C), el tratamiento con 300 ppm de formol no afecta ni al consumo de oxígeno, ni a la concentración de oxígeno del agua, por lo que puede realizarse sin un aporte suplementario de oxígeno

El sistema VICASS (Video Image Capturing and Sizing System) como medio para la medida de atunes de forma no invasiva

Pre-prin