SCALE DROP DISEASE INFECTION ON MARINE CAGE CULTURE OF SEA BASS Lates calcarifer (BLOCH) IN INDONESIA

Aquaculture is promissing  aquatic  bussiness of both the world and Indonesian industry. Asian Seabaass in Australia known as  Barramundi, Lates calcarifer Bloch  is high valuable  fish and therefore a very active aquaculture industry in South Asian countries including Indonesia.. Movement of aquatic animals with a high market value such as Asian Seabass is necessary for development of aquaculture on both subsistence and commercial level.  However, the introduction of new species increases the probability of introducing new pathogens, which can have dirconsequences on aquaculture.   Since 2010,  mass mortality frequently occured in sea  cage culture of Asian Seabass. The gross sign of dead fish was  some scales of fish  are drop  and this pathogen infected to fish at  size of juvenile  up to adult  (3.0  to 2000 gr). Sample of cultured Asian Seabass were collected from  sea cages  located at Batam, Lampung and Bali coastal waters, and the only Batam sample have shown very weak, lost of apetite to eat and then moribund sign. PCR technique was use to analise the diseases of moribund fish from internal tissue organs of spleen, kidney, eyes and brain  and then preserved on 90% ethanol for further analyses. The PCR method was held by  using  two pairs of primers for Megalocityvirus, Red Sea Bream Iridovirus (RSIV) and Scale Drop  Disease  (SDD) primers. The result showed amplified by 643 bp DNA band visualized on 1.5% agarose moribund fish colected from  Batam  was confirmed  positively infected  by Scale Drop Disease Virus (SDD) and negative for Red Seabream Iridovirus (RSIV).