FAMILY: Centropomidae
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NAME: Lates calcarifer - Barramundi, Giant seaperch, ASIAN SEABASS |
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Data provided courtesy of Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff - (Dr. Peter Perschbacher) |
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DISTRIBUTION: L.calcarifer has a very extensive range in tropical and semi-tropical areas of the Indo-West Pacific. Its distribution extends from the eastern edge of the Arabian Gulf along to China, Taiwan and southern Japan, southward to southern Papua New Guinea and northern Australia. HABITS: Inhabits a wide variety of habitats: coastal waters, estuaries and lagoons; clear to turbid water; and fresh, brackish, or salt water. Found in depth of 10 - 40 m and tropical climat 15 - 28°C, 23°N - 26°S. Barramundi are euryhaline, and move between fresh and salt water during various stages of their life cycle. Mature barramundi live in estuaries and associated coastal areas or in the lower reaches of rivers. Larvae and young juveniles live in brackish temporary swamps associated with estuaries, and older juveniles inhabit the upper reaches of rivers. Barramundi are carnivorous and feed mainly on smaller fish as well as crustaceans. However, they have huge mouths and will eat anything that will fit in them. Juveniles take smaller fish fry, smaller crustaceans and aquatic insects. In barramundi culture, live foods are preferred, but will eat meat. In the wild, Barramundi appear to be mainly nocturnal feeders. however, in aquaria, they will readily feed in daylight and become very tame. SPAWNING: Barramundi are a catadromous species, that is it grows to maturity in the upper reaches of freshwater rivers and streams and adults move downstream, especially during flooding, to estuaries and coastal waters for spawning. Barramundi become sexually mature between two and three years of age. In the wild, most fish first mature as males and participate in one or more spawning seasons before undergoing a sexual change (protandry), becoming functional females by the next breeding season. As a general rule, fish less than 80cm length (8 - 10 lb) are usually males and those greater than 100cm are females. Broodstock held under captive conditions have been found to change sex to females at a smaller size than wild fish. This may be the result of the captive environment or hormone treatments used during the spawning season. In their natural environment, spawning takes place at night around the time of the slack tide and appears to be related to the lunar cycle. Nights following full and new moons are the periods of greatest spawning activity. Peak spawning periods are November-December and February-March. The female produce large numbers of small, non-adhesive, pelagic eggs. Eggs and larvae will only survive in brackish or salt water. Areas such as mangrove swamps provide ideal habitat for juvenile barramundi. All barramundi are born males.Distinct stocks of barramundi in various major river systems throughout Australia have been identified. Variation in maturation and spawning stimuli between these genetically discrete populations was found. This has caused problems in developing barramundi aquaculture because the same spawning technique can not be used on the different stocks. Eastern States barramundi spawn naturally in tanks following injection of luteinizing hormone-releasing hormone analogue (LHRH-a). Captive barramundi broodstock that are held in recirculating systems (20 to 80t) and conditioned to a constant environment of salinity 30 to 36ppt, temperature 28o to 29oC and summer photoperiod (13 hour day length) are able to be induced to spawn using hormones year round. Each female releases 3 to 6 million eggs and the males immediately 'pirouette' around the females' tail, releasing their sperm. Males do not require hormonal stimulation as they receive visual cues from the female to release sperm. GROWTH: Growth rate is variable, but generally rapid. Typical overall lengths in cm at the end of each year are as follows: 31-33 (year 1), 43-50 (year 2), 53-61 (year 3), 61-69 (year 4), 73-77 (year 5), 81+ (year 6), and reach a maximum size of 200 cm (60kg). USES: Barramundi is a highly commercial fisheries. Barramundi is also Australia's greatest sport fish. This fish is the major tourist attraction. This fish is renowned for its spectacular fighting, ferocity towards lures, large average size and superb eating qualities. Barramundi is sold fresh and frozen; consumed steamed, pan-fried, broiled and baked. CULTURE: In South-East Asia barramundi is a successful farming industry, particularly in Thailand, where it has been established for many years. Thailand was the first to mass produce barramundi seed and has a long history of hatchery production. Although many Asian countries with coastlines have the potential to grow this fish on a commercial scale in cages or in ponds, culture has not expanded in the last decade primarily due to lack of fish seed supply. There are large losses of juveniles in the nursery phase (up to 10 g), which are attributed to cannibalism. In Australia, the first commercial barramundi hatchery and farm was started in 1986. In 1995-96, the Australian production was estimated at 529 tonnes. Barramundi is now cultured in Thailand, Indonesia, Israel, and Australia. Farmed fish are usually sold at plate size (500 g) or around 3 kg (for filleting). Generally, a commercial barramundi hatchery holds between 25 and 70 brood fish, ranging in size from 3 to 20kg. There are three culture systems currently used in Australia for producing barramundi fingerlings: clear-water tank culture (considered intensive larval rearing); green-water tank culture (semi-intensive larval rearing); and pond culture (extensive larval rearing). The majority of barramundi farms in northern Australia use extensive larval rearing procedures. In South-East Asia, barramundi larvae are mainly reared intensively. The most common growout system is pond culture, in either brackish or fresh water. Fish are usually maintained in cages within the pond. Another growout method is cage culture in estuarine waters. Relatively few companies are using this technique, primarily because of the difficulties in obtaining government approval to establish fish farms in public waters. The third method of on-growing barramundi is intensive production in an indoor, controlled environment building, using underground water (i.e. pathogen free) and a high level of recirculation through biological filters. In Australia, farmed barramundi are reared on dry, pelleted diets, in contrast to South-East Asia where they are usually reared on 'trash' fish or in association with a foraging species such as Tilapia spp. In Australia, most product (about 90 per cent) are sold as 400 to 500g whole fish, with the remainder being larger fish for the premium fillet market. An increasing proportion is being sold at around 3kg. South-East Asian markets have a strong preference for live barramundi with product of this type taking 90 per cent of that market. The major markets identified are Malaysia, Singapore, Hong Kong, Taiwan, Thailand and southern provinces of mainland China. The ideal market size ranges between 600 to 700g per piece. REFERENCES:
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