Asian Seabass Part 1 Production and Biology скачать в хорошем качестве

Asian Seabass Part 1 Production and Biology

All references to copyrighted materials fall under the Fair Use doctrine for educational purposes. Music: Minimal by Alexey Anisimov - Licensed by JAMENDO S.A. ASIAN SEABASS, a.k.a. (also known as) Giant Perch, Giant Sea Perch, and as Barramundi in Australia and New Zealand, is cultured in most coastal states in Southeast Asia (Vietnam, Indonesia, Malaysia, Thailand, Myanmar, Philippines) as well as Taiwan. The Asian seabass is a euryhaline, catadromous species. Adults live in freshwater, but migrate to the sea to spawn, eggs drift and hatch in the sea, then juveniles nurse inshore to feed in littoral areas, then eventually migrate upstream into freshwater as they grow and become adults. Asian seabass are also hermaphroditic, with males spawning as males once or twice, then transforming to fertile spawning females. Singapore reports this occurs with 4-5 kg males, while French Polynesia reports males are larger at 6-7 kg. As adaptable as it is to a wide range of salinities from freshwater to brackish water to full strength seawater, it is easier to farm in ponds and cages than most other "marine" species, such as groupers. Wild Asian seabass are becoming harder to find, with Indonesia being the main supplier with reported fisheries of approximately 31,000 MT in 2023.. Data from the FAO reports total aquaculture production volume in 2022 was 155,000 MT, with a value of almost 600 million US dollars. Major Asian producers of farmed seabass are Malaysia (35% of total harvested), Thailand (25%), Taiwan (15%), Indonesia (10%), Saudi Arabia (5%), and Australia (5%). The Asian seabass has a typical carnivore digest tract, with esophageal and stomach pH of around 4-5, and intestinal pH of 7-8. Digestive proteases include pepsin, trypsin and chymotrypsin as well as various aminopeptidases. Several carbohydrases including amylase, maltase and trehalase have been identified in the intestine, and chitinases have been found in the stomach. The optimum environmental temperature for growth of Asian seabass is approximately 32-33 degrees Celsius. Asian seabass are opportunistic predators. They have a large mouth and can swallow other fish 70% of their size. Consequently, cannibalism is a significant problem for farmers. Methods of controlling cannibalism on the farm include proper feeds and feeding management, avoiding high stocking densities, grading out larger fish if necessary, and proving shelters for smaller fish. One useful function for their predatory behavior is to stock a small number of Asian seabass as "police fish" in polyculture ponds where they control the offspring of high fecund species like tilapia.