ACCORDING to the United Nations Food Agriculture Organisation, most of the world’s tuna stocks are over-exploited and on the verge of collapse.
Modern fishing methods used to catch tuna for canning increasingly catch juvenile yellow fin and big eye tuna before they have a chance to spawn, exacerbating the problem.
Poor and simply disregarded conservation management efforts and high levels of illegal, unregulated and pirate fishing have further decimated wild caught tuna populations.
Even the famed oceanographer, Sylvia Earl, no longer eats fish of any kind, stating that ‘We should think of fish primarily as wildlife, not food.’
Since 2006, Hawaii Oceanic Technology, Inc., has been on a mission to save tuna, or Ahi, as it is becoming known worldwide.
The company’s goal is to demonstrate that deep ocean mariculture can help meet the world’s voracious demand for tuna, in an environmentally responsible and sustainable manner.
After several years of compliance with an extensive array of regulatory requirements, the company is ready to fulfil its mission.
Bill Spencer, co-founder of the company, with the help of a handful of investors, is committed to finding a way to prevent the disappearance of tuna in our lifetime.
‘Farming rather than hunting for seafood is the solution’, Spencer believes. ‘Mankind can no longer ignore the need to domesticate seafood production, and the open ocean is the best place for this to happen.’
He is further committed to farming tuna in the most environmentally sustainable manner possible. Fish farming has evolved to the point where most of the problems have been addressed.
Recent evidence has shown that farming seafood in deep ocean settings results in lower food conversion ratios, faster growth, negligible environmental impact and no need for antibiotics because of reduced parasite loads and high water volumes.
Spencer is intent on proving these tenets of sustainable fish farming at his company’s 250 acre (11 million square foot) ocean lease site, the largest fully permitted mariculture site in the United States.
The depth at the site is almost 1,500 feet, assuring that no fish feed or other effluent from the farming activity will ever touch the ocean floor.
The massive volume of water within the ocean column combined with a gentle current assures that effluent will be quickly mineralised and serve as nutrient for organisms such as phytoplankton and zooplanktons that make up the lowest level of the ocean food chain.
The company is permitted to raise yellow fin and big eye tuna grown from eggs spawned in captivity and raised to fingerling size before being put in the company’s patented Oceansphere grow-out cages.
Research conducted by the company over the last five years has demonstrated that yellow fin tuna can readily be spawned in captivity and that a consistent supply of fingerlings is possible to achieve.
Eventually the company will grow its own tuna feed stock and formulate feed supplemented with omegas and protein from algae and other locally sourced nutrients.
Assuring sustainable feed for fish farming is the company’s highest priority. ‘The misinformation on the topic of food conversion in fish farming is so pervasive that the general public is seriously confused about how efficient egg-to-plate fish farming actually is,’ Spencer contends.
‘Farmers of Atlantic Salmon, the predominant ocean farmed species, have achieved a 1:1 food conversion ratio, that is one pound of feed for every pound of growth.
‘This is because fish raised in a hatchery from eggs are weaned on highly nutritious formulated feed and do not have to scavenge for their meals.’
The same principle will be applied to Spencer’s tuna, branded as King Ahi. The tuna will be weaned on and trained to consume a highly nutritious diet that will contain some fish from sustainable stocks, but a very low amount compared to what is fed to fattened Blue Fin tuna or even wild caught tuna.
‘In the wild, carnivorous species like tuna eat fish that have eaten fish all the way down the food chain, resulting in a massive food conversion ratio in terms of energy transfer’, Spencer explains.
‘This is also how mercury, PCBs and other toxins get concentrated into carnivorous species. The resulting food conversion ratio of a wild carnivorous fish can be as high as 100:1.
‘Even if one argues that it takes five pounds of baitfish for every one pound of farmed fish, it is still 20 times more efficient than in the wild.
‘To create a 10 lb mahi mahi in the wild it takes 1000 pounds of baitfish. To create a 10 lb. mahi mahi on a farm, it takes less than 50 lbs.
‘That comparison is still fairly conservative, as it does not include the by-catch involved in fishing or the higher efficiencies we see on modern fish farms.
The implications should be clear, Spencer continues: ‘farming leaves far more baitfish remaining in the ocean ecosystem. Simply stated, farming seafood is the most efficient way to produce seafood protein.
‘Our ambition is to achieve a 1:1 food conversion ratio, which is even better than any land based protein production including chickens, pigs and cattle.’
Between Hawaii Oceanic Technology’s use of its highly efficient, high-tech Oceanspheres and operation in its 250 acre, 1,500 foot ocean column, the company is ready to prove that domesticating tuna farming is possible, practical and an imperative that must be embraced by the seafood industry.