*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
TOKYO — The next time you dine at a Japanese restaurant, try to steer clear of the tuna sashimi. If you're unable to resist the temptation — and, let's face it how many of us can? — make sure you savor every last slice. In just a few years, it may have disappeared from the menu for good. Our appetite for the undisputed “king of sushi,” whose succulent flesh is prized by diners at high-class restaurants from Tokyo to London and New York, is far from being sated. Only last week the conservation group WWF warned that Mediterranean bluefin tuna stocks were on the verge of collapse, and the breeding population just three years from extinction, as a result of overfishing and a failure to curb our desire for melt-in-the mouth otoro. Demand in Japan, and increasingly the U.S., Europe and China, is decimating stocks among the world’s four bluefin populations. The number of Mediterranean bluefin, for example, has more than halved since the 1950s. Attempts at imposing ambitious quotas have had little impact. Although fisheries from several countries agreed on new bluefin quotas late last year, they were still some 47 percent higher than the levels recommended by their own scientists — a political fudge that environmental groups condemned as a “disgrace.” While Japan is often cast as the villain of the piece for its voracious consumption of bluefin, it may also offer the key to the species’ survival, thanks to a team of researchers working out of a laboratory in Tokyo. The team’s leader, Goro Yoshizaki, a professor at Tokyo University of Marine Science and Technology, has perfected a method of assisted reproduction in which sperm and ovaries from donor trout are implanted in salmon recipients. When the salmon reach maturity and mate, they produce a large number of hybrids, but also a smaller number of pure trout. Last year his work reached a critical point when he identified the presence of sperm of a nibe croaker in the testes of a mackerel, saltwater fish that have physiological similarities to tuna. Now Yoshizaki is in a race against time to save the imperiled bluefin.
He believes he is only a few years away from adapting the technology to enable him to transplant sperm and ovary stem cells from bluefin tuna to mackerel, and for the recipient mackerel, when mature, to produce a precious bounty of bluefin sperm and eggs. The biggest obstacle is obtaining enough stem cells from bluefin testes to produce both eggs and sperm. Preliminary experiments have proved unsuccessful, but the professor is certain he is close to a breakthrough. Success, he says, depends on his ability to exploit the sexual bipotency of enriched stem cells from bluefin to produce both sperm and ovaries in mackerel. “The hypothesis is that the bluefin tuna has some stem cells in its testes, but that the concentration is very low,” he tells GlobalPost. “If that’s the case, and we can find a way to enrich them, then we should be able to repeat the success we had with the salmon and trout.” Replicated on a big enough scale, the process could produce masses of tuna fry with enough genetic variation to survive and multiply in open sea after being raised in marine ranches, thereby helping replenish stocks of wild fish. The approach has several advantages over the bluefin farming pioneered by Kinki University in western Japan, in which the sperm and eggs from farm-raised tuna are used to create test-tube fish, which in turn are reared for about four years in offshore pens until they are big enough to be sold. The process is time-consuming and costly, and, aficionados insist, produces sashimi of an inferior quality. The Japanese government, aware of mounting international criticism of its failure to rein in fishermen, have given Yoshizaki’s team a 300 million yen ($3 million) grant for the five-year project. They have three years left to produce results. “In that time I want to produce at least one tuna bred using surrogate mackerel,” Yoshizaki says. “And if I’m being optimistic, we should have all of the techniques we need to mass produce tuna through surrogate mackerel in less than 10 years. If we can make it work in conjunction with marine ranching, then we can ensure there will be a healthy population of bluefin tuna forever.” The professor is almost evangelical in his enthusiasm for his work, but he also feels a heavy moral responsibility to succeed. “Japanese people consume a lot of tuna so it is up to us to do something to save this precious ocean resource.” In the meantime, the bluefin tuna’s hopes of staving off extinction partly rest with consumers. Several sushi and supermarket chains have stopped selling it, while diners can refer to a selection of new ethical eating guides telling them exactly what and what not to order over the sushi counter. Needless to say, bluefin is a definite no-no.
Article from: The Australian AFTER years of research and millions of dollars, tuna baron Hagen Stehr has finally hit the jackpot -- the world's first southern bluefin tuna bred in tanks. Now he confidently declares the revolutionary impact this could have on the booming seafood market: sidestepping tough fishing quotas and even replenishing wild supplies. "It could have monstrous paybacks for Australia and the world," said Mr Stehr, chairman of Clean Seas Tuna, based at Port Lincoln in South Australia. The tuna are still tiny, with the oldest only a month out of the egg. They range from the size of an apostrophe to about 2.5cm. Swimming in large tanks at Clean Seas' Arno Bay hatchery, an hour north of Port Lincoln, the fish are closely guarded by staff who are in uncharted scientific territory. But Mr Stehr says it is "purely a numbers game" from now on, a question of how much money to pour in for commercial production. It's welcome news for investors, with the share price hovering between 70c and 80c, double what it opened at this year but a long way short of the $2.10 highs struck in 2007. While Clean Seas' fingerlings are still years away from maturity, they are already showing strong signs of development, such as cannibalism. "It's a very, very good sign but it pisses you off," said Mr Stehr, one of South Australia's more colourful characters since he emigrated from Germany in the 1960s. "Every fish now is worth $4000-$5000." Clean Seas aims to produce 10,000 tonnes of the tuna annually by 2015 with a $10-per-kilogram before tax farmgate margin. Market size for the fish, known as the "Porsche of the sea" because of its 70km/h top speed, is about 20-30kg. Interesting developments over the project's past three years include 35 days of continuous spawning this March and April, viewed as a world first by Mr Stehr. That result came after the breeding team finally conquered the biggest hurdle: coaxing the female tuna to spawn. In the end, it came down to getting the ladies relaxed and comfortable, naturally. "If you are stressed, you can't make love at all," Mr Stehr said. "Tuna are exactly the same. Stressed fish can't make love." Tank conditions can be manipulated to replicate the natural migratory routes the tuna would take on the outside, using simulated tide and weather patterns to even recreate a moonlit night off the West Australian coast. Once the tuna mated, there was enough larvae to meet Australia's current tuna production for 33 years, or 15 years of world production. The resulting fingerlings testify to progress made since March last year, when the company announced the world-first hatching of live and active larvae, only to have the larvae die five days later. Clean Seas' success follows a few years on the heels of the Japanese, who have now bred northern bluefin tuna, a project that Mr Stehr said took more than 35 years. Meeting with some Japanese visitors -- "our friends from the north" -- last week, Mr Stehr was startled to learn they had grown the northern bluefin up to 70kg in three winters, and he proceeded to consult every fishery worker he came across on the news. "That's bloody outrageous," he said. "It's unbelievable." If the fingerlings grow to maturity and the process can be reproduced, Clean Seas will be able to get around tough quotas imposed on Australian, Japanese and New Zealand wild tuna catches, and cash in on the insatiable demand. "The quota pressure is coming on around the world, not just in Australia," Mr Stehr said. "This is the Holy Grail, that's what everybody thinks we have done."
Don't know how I feel about messing with stem cells of bluefin so mackeral can make tuna? That just doesn't sound right.
Breeding in captivity on the other hand just seems like the end all be all cure!!! The wild breeding population "should" come back string with no commercial pressure. Honestly I don't understand why this method isn't used for more species of fish. If you can "pen" raise the fish why not do that and leave the wild fish alone?
This idea is making me think of Jurassic Park. Not good in my opinion. Leave nature alone. Catch and release. Or slot fish with low daily limits and strictly enforced low quotas.
Hope for the Bluefin Tuna??
Why Rob.......everyone knows oil rigs do nothing bur polute the environment and are of no value to anything!
