Stavanger, Norway-based aquafeed producer Skretting has introduced a new soft-extruded pellet feed developed specifically for Japan’s bluefin tuna farming sector.
The product, MaGro, is the result of more than 20 years of research and development on producing a a viable alternative to baitfish feeding protocols, the company said in a press release.
“During that time, Skretting evaluated several feed types – everything from wet mashes to a wide variety sausage formats – and these appraisals led to the finding that a soft extruded diet was by far the best option for tuna farming moving forward,” it said. "The resulting, groundbreaking diet takes the specific nutritional needs of bluefin into consideration and delivers it in a form that the fish want to consume.”
MaGro is now available for purchase in Japan, and the company said it expected to see solid sales given the rapid advances made recently in bluefin tuna farming techniques in Japan. Japan’s Kinki University mastered the process of raising bluefin tuna bred from artificially-hatched eggs in 2002 and began sales in 2004, and several Japanese companies now run their own commercial egg-to-table aquaculture processes for bluefin tuna, including Kyokuyo, Maruha Nichiro, and Nippon Suisan Kaisha.
Prior to this development, farmed tuna was produced by capturing juvenile fish and growing them out in pens, a process that is still in wide use today. However, the practice has been criticized as threatening conservation of the species, as it involves capturing tuna before they have a chance to breed.
MaGro was developed by the Skretting Aquaculture Research Centre, which led a number of experimental trials spanning the different growth stages of bluefin tuna. The trials were conducted in Australia, Japan, United States, and Mediterranean Europe, and found that the tuna fed with MaGro consistently demonstrated equal or improved growth compared with those on baitfish diets, meaning tuna farmers no longer need to follow baitfish feeding protocols, thereby reducing biosecurity risks, Skretting said.
“[It’s significant] because bluefin tuna are particularly fussy eaters; previous attempts by the industry to replace this feed component have failed, usually with the tuna rejecting the pellets for being too hard and unpalatable,” the company said.
While MaGro’s texture is softer than the pellets tailored for other fish farming sectors, it has a lower water content than baitfish, therefore offering a much better feed conversion ratio, Skretting Global Product Group Manager Marine Species Chris van Bussel said.
“MaGro is a sophisticated diet that offers many clear advantages over baitfish. On average, farmers only need to use one-third of the volume to achieve the same or better growth performance,” van Bussel said. “At the same time, being a soft extruded pellet, it is not only digestible for the fish, it’s also much easier and cleaner to handle, and a lot more cost-effective to transport.”
MaGro’s texture allows it to be used with semi-automatic “cannon” feeding systems, which results in feed and manpower savings while also diminishing water pollution, van Bussel added.
Additionally, in the company’s research, it found that farmed bluefin fed MaGro continued to maintain their feeding regime during the colder months of the year, “overcoming the so-called ‘winter dip’ that has historically slowed the growth of farmed tuna,” Skretting said.
“With this new diet, we have cleared some of the major obstacles that have stood between tuna farming and a safer, more sustainable future. It’s important that farmers recognize this opportunity to change up to formulated diets, because it can provide the stable platform from which the whole sector can progress,” van Bussel said.
Skretting Japan General Manager Yoshihito Ito said the market for MaGro in Japan looks promising.
“Japan is the world’s largest consumer for bluefin tuna and its per capita consumption of this species continues to steadily increase. There is also fast-rising demand from emerging markets like China and Hong Kong. The prospect of supplying an expanding marketplace is a key driver for Japanese tuna farming. At the same time, most tuna producers are capital intensive companies and understand the importance of fish sustainability and traceability. As such, many of them have long-term plans to provide overseas markets with sustainably-certified products, if and when such a standard is created. This new diet will help them achieve that aim,” Ito said. “We have also learned from our customers that there is considerable further potential for formulated feed development in the tuna sector, with opportunities including increased pellet sizes for larger fish, and the ability to enhance meat quality, color, and marbled fat through these diets.”
Photo courtesy of Skretting
