The Lutz ReportBig on barramundi

Last month I noted a fish in the frozen foods section of my local store that I had never tried before, the barramundi. I brought some home, and it was very good. I had seen articles and research publications about barramundi (Lates calcarifer, also known as Asian sea bass) over the years but had never paid much attention. As the product has begun to show up in more places in the US, I decided to educate myself.

The biology of barramundi

L. calcarifer’s natural habitat includes coastal waters, estuaries and riverine environments with moderate temperatures – from the Arabian Gulf to China, and southward to northern Australia. Adults spend most of the year up river, descend to coastal waters to spawn, then return upstream. Eggs and larvae develop in brackish habitats adjacent to the spawning grounds and eventually move upriver themselves. As a result, there are many distinct genetic strains in different watersheds.

Interest in barramundi culture began with trials in Thailand in the 1970s, followed by investments in research and development in Australia and elsewhere. The commercial development of barramundi farming is helped by attributes such as rapid growth, acceptance of pelleted feeds, hardiness, tolerance of crowded conditions, high fecundity and, typically, good survival of larvae and fry. In fact, since 2018 aquaculture production has surpassed harvests from the wild fishery.

Fingerling production involves techniques that are widely used for similar marine and anadromous fishes. Spawning induction can be achieved utilising commercially available anaesthetics and hormones, but the fish will reach maturation outdoors under natural annual cycles or indoors in controlled environments. Larval rearing in tanks relies on microalgae, enriched rotifers and artemia. Cannibalistic behaviour begins as soon as the larvae are large enough to consume artemia.

Larval rearing can also be carried out in fertilised ponds that are managed to produce high densities of suitable zooplankton. After 20 to 25 days the juvenile fish are harvested, graded and stocked into nursery tanks or cages. Juveniles can tolerate brackish and fresh water conditions.

One complication for genetic improvement of barramundi involves their reproductive life history. Barramundi are protandrous sequential hermaphrodites: they initially develop as males and then change to females over the course of several years. Selective breeding designs become much more complicated when male and female broodstock are separated by two or more year classes.

Industry perspectives

Oceanpick is an established barramundi farm in Trinco, Sri Lanka. Founder Irfan Thassim had the goal of creating a sustainable business model, and this approach has earned the company a number of certifications and accreditations including BAP, ASC and SMETA. The farm uses marine cages for grow-out operations. And although the farm’s first batch of fingerlings came from Australia, the company subsequently developed its own hatchery, named after the French aquaculturist Alaine Michael, who helped to make the project a success. Oceanpick exports frozen and fresh barramundi products to Australia, Europe and the USA. Jacqueline Perera, Oceanpick’s senior sales and marketing manager, tells me the company has expansion plans for 2025, including entry into the retail space in the EU, the USA and regional markets.

Coral Coast Barramundi has been in operation for over 14 years in Bowen, North Queensland. In terms of the barramundi lifecycle, the company is fully integrated, with broodstock, hatchery, nursery and grow-out components. Coral Coast’s feed is produced in Australia and supplied by Skretting, and the company’s products have won gold, silver and bronze awards at the Sydney Royal Fine Food Show. Although Coral Coast relies on oceanic seawater, in order to minimise their footprint on the coastal ecosystem the company chose to develop their farming operation two kilometres from the coastline, despite the increased cost and complexity. Potential environmental impacts are further reduced by ongoing investments in technology to optimise water quality parameters for any discharge released from the farm’s operations.

Founded in 2001, Mainstream Aquaculture has grown to become a leading producer of barramundi in Australia and throughout the world. Mainstream operates the world’s largest barramundi hatchery, with an in-house genetics programme and they export fingerlings to producers in 31 countries around the world. They operate five farms in Australia and another in Arizona, with BAP accreditation and substantial accomplishments in sustainability. Dr Paul Harrison, chief scientist for Mainstream, co-founded the company with a vision to create an environmentally sustainable business based on best-practice technologies.

“For us, the major breakthroughs have been with genetics. In 2018 we invested heavily into SNP technology and shifted our entire programme to a genomics-driven breeding programme. We grow fish out ourselves and supply the same fish globally. We have been seeing and hearing about significantly improved growth rates, particularly over the past couple of years, so that has been a quantum shift. At market, we are seeing more and more people educating themselves on seafood and supply chains and this is helping uptake – barramundi is a strange sounding fish to many people who are not familiar with it. We started farming barramundi in Arizona in 2022 and are supplying the product in the US. It is great to see the positive feedback from people trying this fish for the first time,” he explains.

One of Mainstream’s farms is a 750 tonne capacity RAS in metropolitan Melbourne, which largely produces plate-sized fish of up to 1 kg.

“The larger market opportunities are for 3-5 kg fish and we are actively working on modifications to our design that support the production of large fish in RAS,” notes Harrison.

They also farm in open pond systems – both in Australia and the US.

“In Australia our farms use seawater and are located in a World Heritage environment area of the Great Barrier Reef catchment. To remediate water before returning to the environment we use natural settlement ponds, algal production ponds (to take up nutrient and subsequently harvest the algae) and constructed wetlands. One of the keys to ensuring proper remediation is to reduce water flow (hydraulic loading) on these systems so our R&D has focused on ways to do that,” Harrison explains.

“We have developed ponds with mixed bed bioreactors that ensure ammonia stays low despite elevated total nitrogen. This permits lower exchange levels. In addition we are experimenting with wood chip bioreactors to reduce nitrate (and phosphorous) and then re-circulating a portion of this water and releasing the rest. We continue to optimise this system but are seeing good results when we combine elements typical in our RAS operations to open ponds. Lower volumes are more easily remediated and by-products come from both algae and settled sludge,” he adds.

Meanwhile their US operations are slightly different again, with wastewater being used to grow grass, which can then be cut, dried and baled as forage for livestock.

“In Arizona, we have the benefit of using slightly brackish water that is suitable for growing Bermuda hay. By coupling pond and Bermuda hay operations, we are able to fully utilise all water from the farm and achieve zero discharge,” Harrison notes.

Harrison is also aware of the challenges facing the sector.

“Cost of living seems to be a global issue post-covid and this is resulting in less activity in restaurants. That is a challenge that we expect to remain in the coming years. For barramundi, we believe it is one of the best fish available because of its mild flavour and cooking versatility, the challenge for the barramundi industry is to make it more widely known and accepted,” he reflects.

“On the farming side of the business – feed developments have been rapid and have required a shift away from fishmeal. But this does appear to have some detriment to the fish and continuing to develop modern diets that fully support fish health and growth is an ongoing challenge. Energy is also a challenge globally and affects the cost of production in a major way. As an industry we need to find ways to continually improve our energy efficiencies, even though they are already good compared to a lot of industry,” he adds.

In summary, it seems barramundi is a fish we will be seeing more of in the coming years in various parts of the world. I, for one, am looking forward to it.