Japanese scientists are exploring ways to prevent the extinction of Pacific bluefin tuna, one of the most over-fished species in the world. CCTV’s Mike Firn reported this story from Tokyo.
Scientists search for ways to protect Pacific bluefin tunaJapanese scientists are exploring ways to prevent the extinction of Pacific bluefin tuna, one of the most over-fished species in the world. CCTV's Mike Firn reported this story from Tokyo.
Stocks of bluefin tuna have dropped by a third over the past 22 years, said the International Union For the Conservation of Nature, making the fish is at risk of extinction.
“The low spawning recruitment of tuna juveniles is also accountable for the population decline. In particular, the increased catch of large net fisheries. We call it purse sein fisheries,” Nobuyuki Yagi, the associate professor of Tokyo University Laboratory of Global Fisheries, said. “Also the increase of the catch of Mexico [is another reason] because bluefin tuna is migrating from Japanese coastal area to Mexico coast.”
At Tokyo restaurants diners can eat hon maguro without contributing to the problem of overfishing as the stock comes from fish farms such as the one run by Kinki University in Western Japan. Using pioneering bluefin aquaculture, the farm raise tuna from eggs and releases juveniles into the ocean. It also sells mature fish to restaurants and department stores.
Goro Yoshizaki, associate professor of Tokyo University of Marine Science and Technology, said fish farming is not enough to protect the bluefin. For the past 10 years, he’s been researching tuna surrogacy by injecting stem cells into mackerel, which has similar DNA.
“Bluefin tuna is a very big species. They mature when their body weight reaches 100 kilos (220.5 pounds). It’s a huge fish. It also needs five years to reach to maturation, but if we can make the surrogate mackerel that can produce tuna eggs and sperm, we can produce baby tuna in very small facilities and shorten the time required to obtain eggs and sperm,” Yoshizaki said.
Yoshizaki said it will probably take a few more years to finish his research. If he`s successful, the mackerel may be able to produce 60,000 bluefin eggs a day, he said.
“We really want to produce juvenile tuna using surrogate mackerel and release to the ocean. The ocean can take care of those baby tuna until they reach the market size,” Yoshizaki said.
The plan won`t work without the cooperation of the countries that fish in the Pacific, but most of the bluefin caught there are young tuna that haven’t had the chance to breed.
This month, members of the Western and Central Pacific Fisheries Commission took action to protect juvenile bluefin, agreeing to catch half as much as the average ten years ago.