I was taking a superficial look at tuna farming oceans… understanding of course that the very concept of tuna farming is fraught with issues… and I came across the video [below]…
This video is copyright Hawaii Oceanic Technology, Inc. Honolulu, HI 2007-2011
The Oceansphere™ was designed by Hawaii Oceanic Technology as a way to domesticate seafood production in the open ocean, which uses the latest technology and robotics. It is claimed that it is environmentally friendly and economically viable. Hawaii Oceanic Technology warrant that one Oceansphere can produce up to 2,000 tons of seafood depending on species. This depiction is of of twelve planned Oceanspheres that are to be deployed off the Big Island of Hawaii. The plan is to deploy all twelve Oceanspheres within a one square kilometre ocean column. With respect to there state of the art fish rearing sphere, Hawaii Oceanic Technology claims:
Our patented design includes innovations that pertain to robotics, geostatic positioning, inertial navigation telemetry and environmentally responsible fish rearing. By leveraging such breadth of expertise and intellectual property, the Oceansphere™ is able to support a self-sustaining deep water environment nearly twice as large as any contemporary tethered cage. The massive scale and deep water operation of this technology affords many benefits, all of which combine to provide an economically viable and environmentally sustainable method to meet society’s ever-growing demand for seafood.
Pretty Impressive in my view… by their numbers, I estimate this that all twelve sphere could produce a total yield of 24,000 tons. But my question is a yield of what? Sea Bream? Tuna? Bluefin tuna perhaps? I would wager that sustainable tuna is what the market requires.
It seems that the Oceansphere™ has all the technical aspects sorted. Is it this easy?
According to the Euronews article Breakthrough in Bluefin Tuna farming it is not easy at all. According to Robert Vassallo-Agius, a biologist at the Malta Aquaculture Research centre, Bluefin tuna are very difficult to raise for a number of reasons:
“Bluefin Tuna use light and temperature to know when to reproduce. They are also very sensitive to water-quality. But that’s not all. Bluefin Tuna poses another problem; it is a very big and delicate fish. So because of its size we can’t handle it, we can’t check it, we can’t see what maturation stage it is at, like we do with sea bream, for example. And for this reason it causes another problem which is logistics; how to collect the eggs.”
“We ensure that the fish have perfect living conditions. Also we ensure that every care is taken to avoid any kind of problem during the eggs-laying period.”
Harvesting even small quantities of farmed eggs is extremely difficult because Bluefin Tuna need special care all year round.
[…] “We have achieved the reproduction of Bluefin Tuna in captivity. So now that we have shown that is possible, the next hurdle is breeding Bluefin Tuna larvae [and ensuring their survival], and that will require a special effort.”
Last year scientists managed to keep some of them alive for more than 70 days. Now they are hoping that some of them will grow to at least a kilo, which is a challenge given that there are problems like stress and cannibalism to overcome. According to Aurelio Ortega, another biologist, from the Instituto Español de Oceanografía: “
“Bluefin Tuna grows very fast. This is why tuna have very high nutritional requirements. It needs a lot of energy, much more than other species that we are farming. So we have to give them very high-energy food compared with the food that we give to sea bream or seabass, for example. But this is also a fish that lays eggs in salt water rather than fresh, so it needs very high quality water with high concentrations of oxygen.”
I have a feeling that the Oceansphere™ has the larval problem sorted. But what about the high nutritional and high energy requirements? Afterall the sphere also claims that it promotes “environmentally responsible fish rearing”.
My next question is How? I think I still have to give this one some thought… I am not sure where I sit on this yet.
- Tuna collapse fears fail to curb Japan’s appetite (sfgate.com)
- Japanese Chefs Remain Calm Over Dwindling Tuna Supply (huffingtonpost.com)
- Canned Tuna: Are the Health Benefits Worth the Risk? (weightloss.answers.com)
- Pacific Bluefin Tuna in Trouble, Scientists Say (livescience.com)