Yjgtg" vq." vkigt" ujtkorA The dramatic fluctuation of tiger shrimp production and losses in the Asia-Pacific indicates an industry undergoing a boom and bust cycle. This issue presents the shrimp production trends in Asia-Pacific, along with notes about the diseases affecting the industry and interviews with shrimp farmers in the Philippines In the closed system, clean water is introduced into the rearing ponds and the reservoir only once during the highest tide, at the beginning of the culture cycle.
Water in the reservoir is gradually added to fill the growth pond until there is no water left. However, it is best to monitor ammonia and salinity levels in the growout ponds (not to exceed 0.1 ppm and 40 ppm respectively). Spherical occlusion viral bodies (pictured above) can be found in the hepatopancreas. The hepatopancreas appears yellowish white.
34;I think it is important to have a 'personal touch' and work hard to learn the ins and outs of shrimp farming.”. 34;I have had no technical background in shrimp farming,” says Freddie, “My only experience is breeding freshwater fish in aquariums as a hobby." Shrimp are very profitable and we hope that something will be done soon to solve the problems to tackle the area of diseases. shrimp alternatives (see pages 22-27).
The profit is small and we can't make anything from our land tax." His farm is zoned residential-industrial, not agricultural.
NEGROS SHRIMP VETERANS
34;I'm concerned about the lack of education of most fisherfolk on
Chance favors those organisms that happen to be in the right place at the right time to respond to a sudden increase in nutrients (eg from the breakdown of feed pellets falling around them).
Bioremediation and the use of probiotics are important management tools, but their efficacy depends on the correct number of bacterial strains, the persistence of the bacterial strains and the appropriate application procedures. 34;..that their ind i s r i m i n a use can cause mortality of cultured animals, morphological deformations and development of antibiotic-resistant bacterial strains," say fish health experts at AQD. In the Philippines alone, m o r e t h a c1 are used by farmers of fish for prophylaxis and treatment.
Erlinda Lacierda, a fish disease expert at A Q D who conducted a nationwide survey on chemical use in aquaculture. Although chemicals pose potential hazards to humans like other chemical residues in the food industry, aquaculture experts who gathered at AQD last summer for the 1Meeting on the Use of Chemicals in Aquaculture in Asia agreed that the risks are not excessive. Many chemicals are essentially harmless when applied properly, but indiscriminate use can cause major problems.
The meeting also highlighted the effects of chemical use on other farmed livestock on the farm, the immediate environment through discharge and effluent, surrounding areas (especially where other farms are operating), farm staff (such as toxicity, allergies), consumers (through residues in harvested shrimp and fish) and drug resistance of microorganisms. Representatives from the public sector (governments, R&D centers including AQD) and the private sector (farmers and suppliers-dealers of chemicals) who attended the meeting also identified solutions they could, and agreed. 1 The meeting on chemical use was organized by AQD and the FAO Fisheries Resources Division in collaboration with the Network of Aquaculture Centers in Asia and the Pacific, the Japan International Research Center for Agricultural Sciences, and the Taiwan Fisheries Research Institute.
The public sector will establish a research and information network and test alternatives to chemicals with potentially harmful effects on health, the environment and workers. Industry representatives agreed to self-regulation and cooperation with the private sector in the search for more environmentally friendly cultivation methods. These are solutions for the aquaculture sector not only in the Philippines, but also for countries represented at the meeting such as Bangladesh, Cambodia, China, India, Indonesia, Japan, Laos, Malaysia, Pakistan, Singapore, Taiwan, Thailand, and Vietnam.
A closer look at the bacterial world
IIntegrating effluent management
Grouper, mudcrab and company
Grouper culture
34; It is best to give fish litter during high tide so that the water can be changed easily," advised Elmer. Dissolved oxygen should be kept at no less than 3 p m ; the water should be relatively clean and free of pollutants. 34; Sufficient and regular supply of tilapia and waste fish can also minimize cannibalism," Elmer said.
Mudcrab culture (with milkfish)
You can put crushed ice in the transport bags to keep the temperature low. Mud crab can be harvested in some areas in Iloilo, Capiz, Aldan, Negros, Camarines Norte, Bicol, Bataan, Lanao, Zamboanga and Misamis. 34;Mud crab compartments should be 0.25 to 1 acre in size with independent inlets and outlets," Dan advised.
34;Provide earthen mounds that crabs can use as a breathing place in times of oxygen deficiency. To prevent the crabs from escaping, farmers can use a banata screen (bamboo slats woven with monofilament 1 cm apart). It also extends about 30cm from the waterline, topped by a bamboo overhang or plastic sheets (70cm wide).
34;The plankton or deep water method of growing natural food can ensure more harvests in mud crab-milkfish polyculture," Dan reported. 34;It also shortens the time for pond preparation and increases the carrying capacity due to greater water volume." Plankton can support 500-600 kg per ha of milkfish incremental weight gain for a 90-day culture. 34;It is essential to maintain good water quality that is favorable for both mud crab and milkfish,” noted Dan.
Mud crabs are fed twice daily every other day at 10% of initial body weight. Mud crabs and milkfish swim upstream and can be caught with a seine net as they congregate in a trapping device installed near the dam gate.
Sea bass farming
Milkfish farming*
A shrimp cooperative in action
Working together to save shrimp
Shrimp research at AQD
Epidemiology of viral and bacterial diseases Impact of chemical use in aquaculture. fate and effects of antibiotics in the environment.
Aquaculture clinic
But Biomanagement Systems Pty Ltd (ARDA-Tek Technical Bulletin, June 1996; email: djwm@ozemail.com.au or abody@ozemail.com.au) (see also page 12, this issue) says that the use of Sugar in ponds is not an ecologically sound procedure and will not work over a period of more than a few days. These "predators" also secrete ammonia, and the farmer will have a pond full of sugar, bacteria and protozoa. What will work in the long term, says Biomanagement, is the oxidation of ammonia to nitrate by the combined action of the ammonia-oxidizing autotrophs (Nitrobacter and Nitrosomonas). Nitrate can be reduced to nitrogen or nitrous oxide and released into the atmosphere).
However, Biomanagement noted that no bacterial product currently marketed actually contains active cells of Nitrobacter because it is very sensitive to stress, and active cultures must be shipped cold (5°C) and used within 2 weeks. Biomanagement worked with the University of Queensland, Australia, in this test.) Bacterial products that are dried, liquefied or stored at room temperature cannot contain active nitrifying bacteria. Although Nitrosomonas can survive longer, says Biomanagement, it takes many weeks to be resuscitated from a dormant phase. Instead, most bacterial products currently on the market contain heterotrophic bacteria that obtain their food from organic compounds such as excess shrimp feed (and sugar).
These bacteria also excrete nitrogen as ammonia, and this is not a useful solution for fish farmers who wanted to reduce ammonia concentration in their ponds.
AQD offers option to prawn
AQUACULTURE SYSTEMS SHOULD BE BIOTECHNICALLY FEASIBLE
ENVIRONMENTALLY SOUND, AND SOCIOECONOMICALLY VIABLE
Better life through aquaculture
