Diseases of Puntazzo puntazzo Cuvier in marine aquaculture systems in Greece

The culture and market potential of the marinespecies Puntazzo puntazzo Cuvier is considered tobe very promising in the Mediterranean area(Caggiano, Canese, Lupo & Cirillo 1993; Gatland1995; Georgiou & Stephanou 1995). However,despite the successful rearing of the early life stagesof this fish species, high mortality rates (up to 80%)have recently been experienced in on-growingfacilities, with devastating financial consequences.There is little published information regarding thepathology and nutritional requirements of this fish,either in the wild or in intensive culture systems(Ceccarelli, Fresi, Plastina & Scardi 1984; Ken-touri, Divanach & Paris 1984; Le Breton M Drury & Wall-ington 1980; Roberts 1989). Ten per cent of thefish were processed histologically, regardless of thenecropsy findings, as well as all fish with macro-scopic lesions.Samples were taken from the kidneys, spleen,liver and brain, and inoculated in different culturemedia (tryptose soy agar, TCBS, brain heartinfusion agar, McConkey, Ryan and blood agar).The identification of bacterial isolates was based onmorphological (Gram staining) and biochemicalcharacteristics (API 20E, 20NE, API Staph); insome cases, classical biochemical methods were alsoused (Ortigosa, Esteve & Pujalte 1989; Mercedes BBiosca, Esteve, Garay & Amaro 1993; Mercedes B Bakopoulos, Adams & Richards1995; Boira 1996).The pathological conditions found in thecultured fish and their overall prevalence in theeight farms studied are shown in Table 1. The mainconditions causing problems in fish in the earlystages of rearing (< 3 g) were caused by Photo-bacterium var. piscicida, Vibrio alginolyticus andAeromonas hydrophila. These bacteria were alwaysisolated from diseased fish as the sole infectiveagent.