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A large yellow fin tuna being cut up for sale. Yellow fin could be commercially extinct within five years if fishing is not controlled.
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Populations of top predators, a key indicator of ecosystem health, are
disappearing at a frightening rate. Large fish, such as
tuna, swordfish, marlin, cod, halibut, skate, and flounder are being
fished out of the oceans.
Most of the world’s major tuna stocks are fully exploited with some, such as Atlantic bluefin and Southern bluefin, being severely overexploited.
The depletion of these species can change entire ocean ecosystems where commercially valuable fish are replaced by smaller, plankton-feeding fish. This century may even see bumper crops of jellyfish replacing cod.
These changes endanger not only the structure and functioning of marine ecosystems, but also the future of people dependent on the oceans for their livelihoods.
More than half of the world’s tuna supply, over 2 million tonnes each year, comes from the Pacific region. Scientists warn that two key species of tuna, big eye and yellowfin, are in serious trouble if fishing is not controlled immediately. Within three to five years bigeye stocks could be overfished.
Bigeye tuna is relatively slow growing, with bigeye maturing at about three years. Assessment indicates that the stock is fished at unsustainable levels. The catches and fishing mortality of juveniles have increased greatly over the past decade, due mainly to increased catches in Indonesia, Philippines and the international purse seine fishery. A failure to reduce the bigeye catch and juvenile fishing mortality is likely to move the stock to an overfished state.
Yellowfin tuna are fast growing and mature at about two years of age. They can grow to 180 centimetres and weigh over 100 kilograms at six years of age. They are caught with a range of gear types, predominantly purse seines and longlines. There have been large increases in the catches of juvenile yellowfin tuna and assessment indicates that the stock is likely to be at full exploitation. Any increases in catch, particularly juveniles, is likely to move the yellowfin stock to an overfished state.
Scientists also warn that Albacore tuna stock show signs of depletion in some areas in the Pacific. Even though skipjack tuna is not in an overfished state, any increase in catches could lead to additional takes of vulnerable bigeye and yellowfin.
However, this expert advice is being ignored. In December 2007 meeting of the Western and Central Pacific Fisheries Commission, all proposals to reduce fishing effort were rejected.
Most of the world’s major tuna stocks are fully exploited with some, such as Atlantic bluefin and Southern bluefin, being severely overexploited.
The depletion of these species can change entire ocean ecosystems where commercially valuable fish are replaced by smaller, plankton-feeding fish. This century may even see bumper crops of jellyfish replacing cod.
These changes endanger not only the structure and functioning of marine ecosystems, but also the future of people dependent on the oceans for their livelihoods.
Tuna at risk
More than half of the world’s tuna supply, over 2 million tonnes each year, comes from the Pacific region. Scientists warn that two key species of tuna, big eye and yellowfin, are in serious trouble if fishing is not controlled immediately. Within three to five years bigeye stocks could be overfished.
Bigeye tuna is relatively slow growing, with bigeye maturing at about three years. Assessment indicates that the stock is fished at unsustainable levels. The catches and fishing mortality of juveniles have increased greatly over the past decade, due mainly to increased catches in Indonesia, Philippines and the international purse seine fishery. A failure to reduce the bigeye catch and juvenile fishing mortality is likely to move the stock to an overfished state.
Yellowfin tuna are fast growing and mature at about two years of age. They can grow to 180 centimetres and weigh over 100 kilograms at six years of age. They are caught with a range of gear types, predominantly purse seines and longlines. There have been large increases in the catches of juvenile yellowfin tuna and assessment indicates that the stock is likely to be at full exploitation. Any increases in catch, particularly juveniles, is likely to move the yellowfin stock to an overfished state.
Scientists also warn that Albacore tuna stock show signs of depletion in some areas in the Pacific. Even though skipjack tuna is not in an overfished state, any increase in catches could lead to additional takes of vulnerable bigeye and yellowfin.
However, this expert advice is being ignored. In December 2007 meeting of the Western and Central Pacific Fisheries Commission, all proposals to reduce fishing effort were rejected.
