Breakthrough in tuna feed favours sustainable aquaculture
2017-04-19 16:29:03   copyfrom:    hits:

Marine cages for tuna aquaculture (Photo: Living Ocean Productions)UNITED STATESThursday, April 13, 2017,00:50 (GMT
 

Marine cages for tuna aquaculture. (Photo: Living Ocean Productions)

 

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Thursday, April 13, 2017, 00:50 (GMT + 9)

 

A new type of formulated tuna feed has been created, representing a breakthrough for sustainable tuna farming as it decreases the amount of fishmeal and fish oil in feed by tenfold.

The scientists of Ichthus Unlimited who carried out the research tested various soy-based diets for larval Atlantic bluefin tuna in Spain and for juvenile yellowfin tuna in land-based facilities in Panama.

Building on these experiences, a diet was successfully tested on ranched Pacific bluefin tuna in ocean net pens off the northwest coast of Mexico, which are normally fed wild-caught sardines, with a measured feed conversion ratio (FCR) of 28:1. The new formulated diet decreases the FCR to 4:1.

Another advantage of this new diet is the benefit it offers for the environment, as the floating feed can be better monitored and uneaten feed can be retrieved. It is nutritionally dense, requiring less volume, and is projected to be almost twice as economical as baitfish and made from sustainable, renewable ingredients.

The breakthrough, which was presented at the Offshore Mariculture Conference in Ensenada, Mexico last month by Dr. Alejandro Buentello of Ichthus Unlimited, LLC, offers potential impact on protecting endangered wild tuna stocks.

"The successful research results should help provide permanence to tuna aquaculture, and can become the platform upon which commercially manufactured tuna feeds can now be developed," pointed out Buentello.

"Closed cycle cultivation of tuna aquaculture, from hatch to harvest, combined with sustainable formulated grow out diets offer the best opportunity we have to prevent the depletion of wild tuna stocks while supplying the global market demand for these species," stressed Buentello.

In the past decade, much progress was made in developing hatchery technology to produce tuna from eggs for closed-cycle cultivation. Despite these efforts, most "farmed" tuna today are actually ranched – caught as juveniles in the wild, and fattened up in ocean pens to market size. A major impediment to sustainable tuna aquaculture is the large quantity of wild-caught baitfish required to feed tuna during the grow-out period.

For his part, Mark Albertson of the Illinois Soybean Association, which funded the feed research, said that Illinois farmers have long been supporters of sustainable aquaculture, and this project is a classic example of farmers helping farmers.

"This feed breakthrough is a significant step towards closed cycle cultivation of tuna species, which will ease pressure on threatened wild tuna populations," said Albertson.

"We are eager to see this work continue to both uncouple tuna ranching from the dependence on wild-caught baitfish, and open the door for truly sustainable hatch-to-harvest tuna farming," he concluded.

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