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Tuna
In 1999, we published a report highlighting the depletion of the
bluefin tuna population in the Mediterranean Sea. The biomass of adult
bluefin tuna - the spawning stock - had decreased 80 percent over
the previous 20 years. Every year, far too many juvenile tuna were
being caught, and pirate fleets were depleting the stock. Clearly,
drastic measures were needed to restore the bluefin tuna population.
Sadly, since then, not only has the overfishing worsened, but a new industrial activity targeting tuna is posing an added threat to the survival of tuna in the Mediterranean. This is the capture, transport and fattening of tuna in cages all along the Mediterranean coast known as “tuna ranching”. Industrial purse seiners and tugboats sweep the whole region in search of tuna, assisted by a flotilla of aircraft and helicopters able to find schools of tuna, despite their dwindling numbers.
Tuna ranching is a highly profitable activity directed at the Japanese market. Instead of reducing fishing to help tuna recover in the Mediterranean, fast profits have brought more money into the fishery: this means new and bigger fishing boats, storage plants, and even new airports to export the tuna. Governments have greatly contributed to boost this expansion: European Union subsidies, as high as US$34 million since 1997, coupled with big investments from Japan and Australia, have encouraged even greater catches.
The practice has resulted in an increase in the catch of juvenile tuna, and exacerbated the management difficulties faced by ICCAT (conservation body for the Atlantic tuna stock). No one knows the actual amount of bluefin tuna caught in the Mediterranean Sea, but it is clearly higher than the total allowable catch .
The huge quantity of fish needed to feed farmed tuna is also a problem. Up to 20 kgs of bait, made from fish, is used to produce just one kilogram of tuna. An estimated 225,000 tonnes of bait are thrown every year to the Mediterranean Sea, most coming from West Africa, the North Atlantic and America. A recent report has highlighted the risk of introducing diseases to local fish species from the fish bait, as has previously occurred in tuna fattening operations in Australia. The spread of disease to important local fish stocks such as anchovy or sardine could be disastrous for local fishermen. From a precautionary point of view, this risk is unacceptable.
The demand for fish bait is also making fishermen harvest species that were not previously fished commercially. This is the case of round sardinella in the Alboran Sea, where increasing fishing for this species may put at risk one of the healthiest common dolphin populations in the Mediterranean.
Tuna ranching in the Mediterranean means that a previously common resource shared by fishing cultures all around the Mediterranean Sea is now controlled by a few investors. Not only is the bluefin tuna being privatised and over-exploited, but other fisheries of the region are also being placed in jeopardy.
Tuna ranching: a recipe for disaster
Sadly, since then, not only has the overfishing worsened, but a new industrial activity targeting tuna is posing an added threat to the survival of tuna in the Mediterranean. This is the capture, transport and fattening of tuna in cages all along the Mediterranean coast known as “tuna ranching”. Industrial purse seiners and tugboats sweep the whole region in search of tuna, assisted by a flotilla of aircraft and helicopters able to find schools of tuna, despite their dwindling numbers.
Tuna ranching is a highly profitable activity directed at the Japanese market. Instead of reducing fishing to help tuna recover in the Mediterranean, fast profits have brought more money into the fishery: this means new and bigger fishing boats, storage plants, and even new airports to export the tuna. Governments have greatly contributed to boost this expansion: European Union subsidies, as high as US$34 million since 1997, coupled with big investments from Japan and Australia, have encouraged even greater catches.
The practice has resulted in an increase in the catch of juvenile tuna, and exacerbated the management difficulties faced by ICCAT (conservation body for the Atlantic tuna stock). No one knows the actual amount of bluefin tuna caught in the Mediterranean Sea, but it is clearly higher than the total allowable catch .
Tuna farming
The huge quantity of fish needed to feed farmed tuna is also a problem. Up to 20 kgs of bait, made from fish, is used to produce just one kilogram of tuna. An estimated 225,000 tonnes of bait are thrown every year to the Mediterranean Sea, most coming from West Africa, the North Atlantic and America. A recent report has highlighted the risk of introducing diseases to local fish species from the fish bait, as has previously occurred in tuna fattening operations in Australia. The spread of disease to important local fish stocks such as anchovy or sardine could be disastrous for local fishermen. From a precautionary point of view, this risk is unacceptable.
Dolphin safe?
The demand for fish bait is also making fishermen harvest species that were not previously fished commercially. This is the case of round sardinella in the Alboran Sea, where increasing fishing for this species may put at risk one of the healthiest common dolphin populations in the Mediterranean.
Tuna ranching in the Mediterranean means that a previously common resource shared by fishing cultures all around the Mediterranean Sea is now controlled by a few investors. Not only is the bluefin tuna being privatised and over-exploited, but other fisheries of the region are also being placed in jeopardy.
