Vibriosis (vibrio spp.) in aquaculture farms

Marine aquaculture is an emerging industrial sector which requires continuous research with scientific and techni­cal developments, and innovations. The world aqua­culture production is constantly increasing. Greece is the leader in production amongst the Mediteranean countries, the main fish species cultured being sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). Bacterial diseases of fish are the main limiting factor for the viability of marine aquaculture. Vibrionaceae are responsible for the most important of these diseases , especially Vibrio (Listonella) anguillarum and Pasteurella piscicida ( synon. Photobacterium damselae subsp piscicida ). In the present study the natural microflora of the fish and the water of their ongrowing units were studied for a period of 20 months. The scope was to examine its natural variation and its relation with disease outbreaks, especially those that Vibrionaceae were held responsible for. In fact, the total bacterial count of the fish and the water ecosystems of their farms were studied, emphasising the characteristic microorganisms indicators of fecal contamination of waters (Total coliforms, fecal coliforms, streptococci) as well as the anaerobe microorganism indicator Clostridium perfringens and the pathogenic Vibrionaceae in cases of epizootic outbreaks. Finally in the current study we make an evaluation of collected epizootiological data during 17 years of practice in maricultures in Western Greece, as well as an evaluation of mortality rates and treatment effectiveness in disease outbreaks caused by Vibrionaceae . Increase of resistance of the isolated microorganisms in antibiotics is also discussed, in relation with results of researches from different regions of Greece and the Mediterranea