aquaculture

It might seem strange that Aquaoptima, a Norwegian company (www.aquaoptima.com) is assisting with the technology for farming the famous fugu – the deadly puffer fish of Japan. The attraction of farming fugu is obvious, according to a report on fugu by the Trade and Environment Database (TED).

Fugu is one of the most expensive foods in Japan. A single fish can bring $50 to $140. Cut up and served in a restaurant, it can bring $200. Yet fugu was increasingly popular. Each winter for 1982 and 1983, for example, has brought 40 million dollars in fugu sales at the small Haedomari Market in Shimonoseki, Japan’s “fugu city”.

It is becoming apparent that yellowtail kingfish Seriola lalandi have an exciting potential as an aquaculture species. They can grow to a maximum size of 2.5 metres (over 8 feet) or 70kg (approximately 140 pounds), but are more commonly found at 100 cm (approximately 3 feet) or 10-15 kg (approximately 20 – 30 pounds). In good conditions wild yellowtail kingfish may grow up to 3.0 kg (6 pounds) in 12 months. Yellowtail has a distinctive yellow tail fin with a body colour ranging from grey-green to blue-green, with a yellowish brown stripe along its sides. They are streamlined and can swim very quickly.

According to research published by the Government of South Australia Primary Industries and Resources Aquaculture, yellowtail kingfish are ideally grown out in high quality seawater with very low turbidity. In open systems using sea cages, the tidal or current flow needs to be sufficient to remove uneaten food, faeces and soluble waste products such as ammonia and maintain a dissolved oxygen concentration above 4mg/L. PIRSA have also published a FAQ on yellowtail kingfish.

Although still in the very early stages of development, tuna are being farmed in an increasing number of locations around the world. According to smartaqua, tuna are being farmed in South Australia (Thunnus maccoyii), Croatia (Thunnus thynnus), Japan (Thunnus thynnus), Spain and Portugal (Thunnus thynnus), Mexico (Thunnus thynnus, bigeye (Thunnus obesus), yellowfin (Thunnus albacares)), and Canada (Thunnus thynnus).

The Government of South Australia’s Department of Primary Industries and Resources have identified the farming of Southern bluefin tuna (Thunnus maccoyii) is currently the single most valuable sector of South Australia’s aquaculture industry. Southern bluefin tuna farming is unique to South Australia and its development in 1991 initially put South Australian aquaculture on the map.

Tuna farms are not always universally welcomed – the WWF reported:

On Sunday, 2 February 2003, a local referendum on the island of Vis, Croatia, stopped a new tuna-farming project from taking off. The community’s response is the first of its kind in Croatia. WWF applauds the community’s and local NGO Sunce’s firm stand against an activity which is damaging the environment and decimating the already over-fished wild tuna in the Mediterranean.

Croatia is the leading producer of farmed tuna in the Mediterranean, after Spain. In 2001, Croatian production reached 3,000 tons from its eight farms. A new tuna farming project was presented to the inhabitants of the island of Vis, in the Adriatic, as the only alternative for their economic future. When the community was invited to participate in a referendum on the issue, their vote was an emphatic “no” – 88% of the voters were against the project.

Other reports identify tuna breeding and farming in Croatia has been an economic success and thanks to the investments of Croatian expatriates, tuna farms have started cropping up along the coast. The fish are being bred in cages. The results after five years is that tuna farming seems to be one of the most successful investments in Croatia, and the domestically bred tuna has already become world-famous.

Several Kali fishermen from the island of Ugljan invested in a somewhat unknown field of fish-farming: tuna farmed in cages. The business was set up in 1995 with an initial capital of $2 million Australian dollars, with a further $5 million spent on the purchase of cages, fishing boats, and other infrastructure. It was the only farm of its kind in that part of the Mediterranean. Farmed tuna is becoming one of Croatia’s best-known export products.

According to an article published by Enaca, in 2005, the Rayong Coastal Fisheries Research and Development Center (Rayong CFRDC) made a breakthrough in mouse grouper Cromileptes altivelis larval rearing. The center uses the a simple recirculation system for their broodstock holding facilities. The broodstock tanks are rather small at 3×5×1.2 m. Although mouse grouper broodstock successfully spawn in these tanks, egg production is low, which limits fingerling production.

Rayong CFRDC also operates a large broodstock holding cage facility at nearby Koh Samet. This facility holds broodstock of several grouper species including P. maculatus, E. fuscoguttatus, E. lanceolatus, E. coioides, mangrove snapper Lutjanus argentimaculatus and cobia Rachycentron canadum. Like Trad, Rayong have not been able to spawn their P. maculatus broodstock, despite attempts at hormonal induction of spawning.

There is considerable interest amongst the private sector in Thailand in developing marine finfish hatcheries. There is already considerable production of seabass Lates calcarifer in Thai hatcheries, and many are keen to diversify their production to higher-value species such as groupers. A major constraint to diversification amongst private hatcheries is access to eggs and larvae. Many are now working with the government centers and stations so that when fertilized eggs are available in government facilities, they can obtain them for grouper larviculture trials. The government also provides training and technical support on grouper hatchery technology to the private sector.

Review of Grouper Hatchery Technology
Successful larviculture of groupers has been constrained by generally poor, and irregular, survival. The principal constraints to successful larviculture are: the small gape of the larvae and hence their requirement for small prey at first feed; and the occurrence of high mortality at various stages through the larval rearing phase. This document, prepared by Dr. Mike Rimmer of the Queensland Department of Primary Industry provides a nice review grouper larviculture technology, and summarises the current status of this technology.

Filipino Agriculture Secretary, Luis Lorenzo, announced recently that a Filipino aquaculturist had developed a technology which enables live fish to be transported, alive, for several hours, without water. This would allow fish traders to bring in more fish and earn more profit.

Lorenzo said the technique, officially introduced on June 8, extends a fish’s survival without water by virtually putting it into a deep sleep or in “suspended animation” using certain procedures and some liquid solutions, and later allowing it to recover from unconsciousness and get back to life.

Lorenzo, citing a report from Bureau of Fisheries and Aquatic Resources director Malcolm Sarmiento Jr., said the new technology is a better alternative to conventional practices of putting fish in containers with water, a cumbersome and costly method.

“Let in be known in the fishing world that the Philippines has now developed a technology for waterless transport of live fish, a method that will revolutionize the way we normally handle fish after harvest,” he said.

In recent test to determine if the technique works, groupers (lapu lapu) delivered to the BFAR central office laboratory in Quezon City from Iloilo using the “waterless technology”. The fish were observed to regain consciousness after eight hours of travel, with the temperature in the storage box at 25 degrees C, Sarmiento said.

Groupers, Epinephelus spp ~ source: SEAFDEC/AQD – Technotips

Popularly known as “lapu-lapu” in some Philippine dialects are important marine fishes belonging to the Family Serranidae. Thick-set or stout bodies, slightly elongate with brown spots or blotches, characterize them. They also have very large mouths and normally protruding lower jaw. It is, however, difficult to differentiate one species from another due to the fish’s ability to change colors.