Achotines: The Lab Behind An Aquaculture Revolution

With many global fish stocks worldwide in decline, aquaculture has been offered as a possible sustainable alternative to fishing. While there have been many successes in aquaculture through cultivating fish species such as salmon and carp, the tuna industry has long lagged behind in developing this potentially profitable sub sector.

Despite some success stories with larger tuna such as Pacific bluefin, many doubts have been cast over the feasibility of large scale production. Given the big consumption habits of bluefin, as well as the lengthened development of the species into maturity, production on a mass scale seems out of the question, at least for now.

However, a possible solution has been suggested by many; the yellowfin, a smaller, faster developing fish, maturing at two years, compared to bluefin which can take up to 12. Since 1996, IATTC’s Panama Achotines Lab Program has been at the forefront of research into the early life stages of this iconic species.

In 1992, collaborative work began by IATTC scientists to rear larval tunas alongside scientists from Japan. Receiving the majority of their funding from the Overseas Fishery Cooperation Foundation (OFCF), the researchers’ investigation focused on the culture and captive spawning of yellowfin tuna in land-based tanks to provide larvae and juveniles for research purposes. To date, the program is both the most successful and advanced of its kind, becoming the first and only facility to successfully rear yellowfin from insemination to recruitment size.

Dr. Dan Margulies, a leading researcher based at the facilities, spoke to Atuna about the basis and successes of his team’s work to date. The research team includes Vernon Scholey, Jeanne Wexler, and Maria Stein. Discussing why a land based tank was chosen for the rearing of the fish, Dr. Margulies said that the onshore tank provides his team with greater control over the process, when compared to offshore rearing. Onshore, laboratory studies are conducted to investigate the ageing, growth, nutrition and development in early-juvenile tunas.

Successfully spawning specimens since 1996, scientists can “routinely rear thousands of yellowfin up to two months of age for experimental purposes” according to Margulies. Last year, Achotines achieved another world first, successfully relocating 400 specimens to a sea cage located a kilometer off the coast for a period of a month.

Where Achotines has succeeded, many others have been unsuccessful; an attempt in Indonesia, which also received funding from the OFCF in 2000, failed after ongoing reproduction issues with its brood stock, resulting in the closure of the program.

While Achotines’ research is focused on the growth, nutrition and feeding stages, so far unstudied in the wild, its findings are applicable to the aquaculture business, reflected in the growing interest from tuna industry insiders. However, according to Margulies the technology and research hasn’t quite reached that stage yet, adding “you would be looking at a five to ten year time frame before a small [aquaculture] operation would be successful.”

High fatality rates continue to be an issue, with most adult mortalities occurring in early dawn as the fish struggle to switch from night to day vision and collide with the tank’s walls. Nonetheless, the burning issue continues to be striking a balance in the tunas’ feed, “the Holy Grail for everyone right now is the development of a nutritional feed for juveniles,” Margulies conceded.

For now, mature specimens are fed a 50:50 feed of fishmeal and soya extract. Squid has also been substituted for mackerel in fishmeal to reduce fat content of the yellowfin, an issue which bluefin ranchers have long been at odds with. While Margulies believes the rearing of yellowfin tuna from egg to maturity is at present too expensive, he estimates that the process of rearing the fish to maturity could be reduced in captivity to just 20 months.

Though still in its infancy, research conducted by scientists of the IATTC at the Achotines Laboratory, could herald considerable success to the birth of a profitable sub sector for the industry, through the controlled breeding of this iconic species in the near future.