Pacific Spirit Marine Institute
Friday, July 27, 2007
Breeding Bluefin Tuna Like Cattle!
In Australia a company called Clean Seas Tuna Limited is attempting to breed the highly sought-after Bluefin Tuna in captivity.
For the Tuna this may be a little like trying to get drunk on Sherry. It can be done, but it’s a lot of work, and probably not very satisfying. But, for the sushi and sashimi eater it could be very satisfying.
In 2003 researchers near Osaka Japan became the first in the world to successfully spawn southern Bluefin tuna in captivity. They were able to grow that generation of fish to the point where some actually produced their own eggs.
Remember how excited the world was when the first Panda Bears actually bred in captivity? This, for a lot of people is something like that.
In 2004 Marcus Stehr, Clean Seas Tuna Limited, was able to successfully move 6 Bluefin tuna from offshore nets into an onshore dam. At the time Clean Seas Tuna may have been the only company to even attempt such a thing, let alone succeed.
In April 2007 Clean Seas Tuna’s Bluefins started pairing up. Marcus Stehr be lived this to be one more milestone moving toward his quest. The Bluefins were very healthy and they were showing spawning tendencies. The captive tuna’s were also very healthy eaters.
Showing signs of wanting to breed, and having a healthy appetite sounds like the tuna aren’t too depressed with their situation. Maybe fish Viagra keeps their spirits high.
In the Clean Seas’ Arno Bay Breeding facility male Bluefins were given hormone therapy to stimulate their ‘need to breed’. Again, maybe like trying to get drunk on Sherry, as I recall the Panda’s were shown some X rated Panda films. What ever does the trick I suppose. Though the release of sperm by the Southern Bluefin Tuna was captured on film by an underwater video camera.
How are the females responding to all this courtship behaviour? Hagen Stehr Clean Seas Chairman says the broodstock will continue to be monitored and the therapy potentially repeated, with the expectation of completing their reproductive maturation and producing viable (fertilised) eggs.
If all of this turns out to be really successful the Bluefin in the wild may be given a chance to get a little R&R. While they rest up maybe their Bluefin Brethern in captivity can help shoulder the burden of supplying at least some of the world the protein it so desperately craves.
Oh please, someone pass me the Sherry!
Photo thanks (c) Wolcott Henry 2005/Marine Photobank
Labels: Bluefin Tuna, Longline Fishing, Ocean, aquaculture, bycatch
© 2009, Pacific Spirit Marine Institute.
Breeding Bluefin Tuna Like Cattle. Home, home on the Range.
Tuesday, July 10, 2007
Longline Fishing is said to be one of the most efficient methods of killing unintended sea life by commercial fisheries.
These lines can stretch for 50 miles. In some cases up to 3,500 hooks are baited per day. Longlines aren’t discriminating when it comes to what they catch either.
In the course of a year more than 4 million creatures are the unintentional bycatch of these longlines. This bycatch includes whales, dolphins, sea turtles and porpoises. Sea lions can also fall victim to the longlines.
Longline fishing has killed approximately 65,000 albatross and Southern Giant Petrels, in just the last 20 years, in the waters off of New Zealand. Longline fishing is a huge threat to these petrels.
Longline fishing is used to catch the bluefin tuna among other types of fish.
Diving birds, like the petrels, plunge into the ocean to grab a morsel of bait and are then hooked and pulled under the sea to their death.
There are method being employed by some to mitigate bycatch of some types of sea birds. Weights attached to lines can cause them to sink faster thereby taking the bait out of the petrels view. Streamers attached to the lines may also scare some of the birds away from the bait. Setting lines at night can also decrease the attraction to birds. But, these methods of mitigation don’t address other species in the bycatch such as sea turtles.
In what seems to be an unimaginable or at least surreal scene they bycatch is tossed back into the ocean either dead or dying.
On the other hand, the bluefin tuna once caught on the longlines are very carefully ‘KILLED with a SPIKE to the head’. The crew will gently lift the catch wearing gloves to protect the bluefin ‘gold’. Blankets and grass mats are used to protect the fish from bruising.
How can mankind be so cruel?
With the advent of bluefin aquaculture maybe flooding the market with more tuna will bring down the prices. If prices are lower maybe it will become economically unfeasible to continue longling fishing.
Photo thanks to Lucy Kemp / Marine Photobank
Labels: Bluefin Tuna, Longline Fishing, Petrels, aquaculture, bycatch
© 2009, Pacific Spirit Marine Institute.
Longline Bycatch is a Cruel Way to Die
Monday, July 9, 2007
Did you know that the Bluefin Tuna is the most valuable fish in the ocean?
Thirty years ago this fish sold for as little as five cents a pound.
Today one single bluefin tuna can sell for between $10,000.00 to $20,000.00. In fact the highest price on record for a single bluefin tuna was $80,000.00 and that record could be broken as demand for them goes up, and their numbers decline.
A mature bluefin can weigh as much as 1,300 pounds, but we won’t be seeing many of those as time goes by. Most bluefin tuna never reach this size before they are caught. The average bluefin catch today is less than 1,000 pounds; not given the chance to mature.
One might think that at $75.00 for a single serving the demand just might go down. But, in Japan where demand is the highest in spite of the astronomical prices it is only now being considered to be a luxury. The Japanese consume more seafood per capita than any other country in the world.
The bluefin tuna can reach speeds of up to 50 miles per hour. They are one of the fastest swimmers in the ocean, but they can’t out swim demand.
The more we study these tuna the more we learn about their intelligence. These fish, like the dolphins, have social behavior patterns. They have been observed actually playing and socializing with each other and they have learned to cooperate with dolphins when feeding. In fact this sounds more civilized than some peoples of the earth.
Only 1 in 40 million bluefin tuna survive. This is a horrific number!
As the late Carl Sagan said “…A new consciousness is developing that sees the earth as a single organism, and recognizes that a single organism that is at war with itself is doomed”
Tomorrow we will look at Longline Fishing, which is how bluefin tuna is caught. In the meantime, opt out of that tuna sushi and have the rice and vegetables instead!
Labels: Bluefin Tuna, Carl Sagan, Japan, Longline Fishing, Ocean
© 2009, Pacific Spirit Marine Institute.
Bluefin Tuna: The Oceans Gold Rush!
