Atlantic Bluefin Tuna (Thunnus Thynnus) Farming and Fattening in the Mediterranean Sea

Abstract

The Atlantic bluefin tuna (Thunnus thynnus) is one of the tunas with the highest commercial value and it is supporting the capture-based tuna aquaculture industry in the Mediterranean Sea. This is a seasonal activity and it involves the capture of fish from the wild and their rearing in sea cages for periods ranging between 3 months to 2 years. Short-term rearing is done mainly to: (a) achieve a greater body fat percentage and (b) obtain a better price by not flooding the market in the brief fishing period. Due to the increasing fear of a collapse of the fishery, the International Commission for the Conservation ofAtlantic Tunas currently reduced the total allowable catches for 2010 to 13,500 mtn from 32,000 mtn previously. Therefore, there is great interest in establishing a proper and sustainable tuna aquaculture industry. This necessitates the development of specific technologies for tuna aquaculture that will not rely on captured individuals from the wild, as it is practiced today. This article reviews the methods used for the farming and fattening of the species in the Mediterranean Sea, and the current status of the efforts at controlling reproduction in captivity.

Aggregations of wild Atlantic Bluefin Tuna (Thunnus thynnus L.) at Mediterranean offshore fish farm sites: Environmental and management considerations

“…For farming purposes, wild-caught ABT are transferred to towed cages, and transported to the farm site by tugboats, after which they are moved again into on-growing cages to which they adapt very quickly (Ottolenghi, 2008;Mylonas et al, 2010). However, it is known that, occasionally, densities of ABT in the fattening cages exceed the quota established by the ICCAT, and therefore some individuals must be intentionally released to the marine environment to comply with the regulations.…”

“…Furthermore, there is great interest in establishing a sustainable tuna farming industry. This necessitates the development of specific technologies for tuna aquaculture that will not only rely on captured individuals from the wild, as practiced today (Mylonas et al, 2010), but on juveniles hatched in captivity. A 'true' tuna aquaculture industry that is independent of capture fisheries, controlling all the stages of the life cycle and with cages placed in off-shores locations, would greatly improve the current situation, but concerns regarding fishing pressure on small pelagic fish to feed the farmed tuna will remain (Relini, 2003).…”

Ecosystem effects of bluefin tuna Thunnus thynnus thynnus aquaculture in the NW Mediterranean Sea

“…The fattening method is conducted on a much shorter time scale, 3 to 7 mo, and uses larger tuna (> 30 kg). The fattening method, on which the present paper focuses, creates a greater muscle fat content, making this fish highly valued in the Japanese sushi and sashimi market (Mylonas et al 2010). Two-thirds of the tuna exported to Japan from the Mediterranean Sea come from these capture-based aquaculture operations (Ottolenghi 2004).…”

“…As most of the tuna used for the farms are caught in the Medi terranean Sea, the International Commission for the Conservation of Atlantic Tunas (ICCAT), the regional fisheries management organization responsible for the conservation of tunas and tuna-like species in the Atlantic Ocean and its adjacent seas, assumes that all Mediterranean farmed tuna belong to the eastern stock of Atlantic bluefin tuna. However, obtaining accurate estimates of these removals from the current stock is complicated by the fact that there is no exact method of determining the amount of the fish stocked in the grow-out cages (Aguado-Gimenez & Garcia-Garcia 2005, Mylonas et al 2010.…”

“…Our results suggest, in the case of the Western Mediterranean Sea, increasing bluefin tuna farming activities will likely contribute towards further degradation of an already highly exploited ecosystem. Turkey, with plans for further expansion (Miyake et al 2003, Mylonas et al 2010. As most of the tuna used for the farms are caught in the Medi terranean Sea, the International Commission for the Conservation of Atlantic Tunas (ICCAT), the regional fisheries management organization responsible for the conservation of tunas and tuna-like species in the Atlantic Ocean and its adjacent seas, assumes that all Mediterranean farmed tuna belong to the eastern stock of Atlantic bluefin tuna.…”