The Bali 2005 Conference (9-13 May 2005) organized by the World Aquaculture Society (WAS) included for the first time a full day session dedicated to tuna farming. The session was organized by Ms Francesca Ottolenghi, Conzorzio Mediterraneo (Italy), and Mr Alessandro Lovatelli, FAO Fisheries Department (Italy) and co-chaired with Mr Constantinos Mylonas of the Hellenic Center for Marine Research (Greece).
During this session, five main subject areas were covered, namely: (i) current status, (ii) farming; (iii) reproduction, (iv) environmental impact, and (v) marketing of tunas. Three to four invited experts from different parts of the world delivered, under each of the subject areas, interesting and high quality talks using dynamic and informative PowerPoint presentations.
The opening presentation provided an overview of tuna farming at the global level with particular focus on the situation in the Mediterranean Sea, Australia, Japan and northern America. The main driving force behind this growth has been and still is the high Japanese market demand albeit a number of important biological constraints. In the Mediterranean farming of the bluefin tuna (Thunnus thynnus) started almost a decade ago expanding from the western basin (Spain) to the east (e.g. Croatia, Cyprus, Italy and Turkey) and to the northern shores of the African Continent (Algeria, Tunisia) At present, tuna farming (all species included) occurs in all continents, in 18 countries and in 14 oceans and/or seas around the world. In the case of North America, the entire production comes just south of the U.S.A. border in Mexican waters. Mexican farming operations currently represent almost 10 percent of world production (35 000 tonnes).
A number of countries have channelled considerable research efforts in developing this relative new aquaculture industry, however, the successful and economical captive reproduction of most tuna species has yet to be fully achieved. In the current farming practice, particularly for bluefin tuna, seed material ranging from small to large fish specimen is exclusively collected from the wild. This type of aquaculture has been defined by FAO as capture-based aquaculture (Ottolenghi et al. 2004).
Some technical considerations on general engineering aspects of the bluefin tuna farming were presented also in relation to the effects of the harvesting/slaughtering stress on meat quality of the reared fish. Among the other topics covered during the session was a major discussion on the use of baitfish species (pilchards, sardines, mackerel, herrings, squid, etc.) of different origin as feed. The absence of formulated feed is of concern to the industry particularly as poor food conversion ratio is obtained using baitfish. Scientific evidence in fact indicates that fish weaned on a formulated diet that replicates normal nutritional intake will perform considerably better than those fed on baitfish. Furthermore, the availability of an artificial feed would partly eliminate or facilitate farm logistics in sourcing, purchasing, transporting and storing the feed as well as eliminate the quality and health risks associated with the use of raw fish.
Another issue that was discussed at certain length was the environmental impact of tuna farms. In the case of bluefin tuna, the majority of the commercial operators have selected farm sites with an adequate water depth and circulation effectively allowing the dispersion of wastes generated by the farms. These conditions do minimise sediment build-up, prevent site eutrophication and the risk of contaminating the farmed products. These precautions, however, have not prevented environmental and other pressure groups to target tuna farming and other mariculture activities as the general perception is that this industry has an adverse impact on the environment. This type of pressure has constructively induced relevant institutions and other stakeholders to increase research on environmental impact and monitoring. Studies conducted in different Mediterranean tuna farms as well as in other countries have demonstrated that the impacts to the benthic communities and sediment chemistry are generally limited and transitory. In fact a few months are sufficient for environmental recovery of the farmed site. Furthermore, the general farm practice of most Mediterranean tuna farms in confining the fish for a few months limits environmental impact in terms of space and time.
External pressures as the one described above as well as market requirements, particularly from Japan, are driving the tuna industry to continuously improve farming techniques and to adopt an integrated product safety and quality approach in the production process. All this has been paving the way in establishing good aquaculture practices aimed at preventing or mitigating possible adverse impacts to the environment and safeguarding the consumers. The session ended focusing on market issues indicating that the future of the tuna farming industry will remain closely linked to the Japanese market at least for the moment.
Farmed bluefin tuna (Thunnus thynnus thynnus) during harvesting
GFCM/ICCAT Working Group on Bluefin Tuna Farming in the Mediterranean
The Ad Hoc GFCM/ICCAT Working Group (WG) on Sustainable Bluefin Tuna Farming/Fattening Practices in the Mediterranean was set-up following a 2002 decision by the General Fisheries Commission for the Mediterranean (GFCM) which, in view of the expansion of bluefin tuna farming in the Mediterranean, decided that practical guidelines to ensure the sustainability of this activity were required. At its first meeting (Rome, Italy, 12-14 May 2003) the WG produced a survey form that would enable to prepare a summary of the current situation of bluefin tuna farming in the Mediterranean, identify problem areas with respect to the issues to be addressed, and propose solutions. During the second meeting (Izmir, Turkey, 15-17 December 2003) the WG finalized a first snapshot on the current situation of bluefin tuna farming based on the information made available in the survey forms and progressed with the drafting of the guidelines. The summary snapshot consisted of three documents covering capture fisheries, farming and marketing/trade of bluefin tuna in the Mediterranean. The WG held its third and final meeting in Rome, Italy, from 16 to 18 March 2005. The meeting was attended by 19 experts representing 10 Mediterranean countries, Japan and the European Commission and, representatives from the Secretariats of the GFCM and the International Commission for the Conservation of Atlantic Tunas (ICCAT). The WG completed its mandate and finalized and adopted the "Guidelines on Sustainable Bluefin Tuna Farming Practices in the Mediterranean". Furthermore updated summaries on capture fisheries, farming and marketing/trade of bluefin tuna in the Mediterranean were also prepared by selected participants of the WG.
Copies of the "Report of the Third Meeting of the Ad Hoc GFCM/ICCAT Working Group on Sustainable Bluefin Tuna Farming/Fattening Practices in the Mediterranean. Rome, 16-18 March 2005. FAO Fisheries Report. No. 779. Rome, FAO. 2005. 108p." can be obtained by contacting Alessandro Lovatelli (e-mail: Alessandro.Lovatelli@fao.org).
|  Alessandro Lovatelli
Inland Water Resources and Aquaculture Service
FAO Fisheries Department, Rome e - mail: Alessandro.Lovatelli@fao.org
 Francesca Ottolenghi
Consorzio Mediterraneo, Italy