Furunculosis in Senegalese sole (Solea senegalensis) cultured in a recirculation system

IN recent years, the mariculture industry in Spain has focused on searching for new species to rear other than turbot ( Scophthalmus maximus ), gilthead sea bream ( Sparus aurata ) and sea bass ( Dicentrarchus labrax ), with the aim of increasing diversification. Senegalese sole ( Solea senegalensis ) is a flatfish belonging to the family Soleidae, which is of special interest for mariculture because of its high commercial value, its scarcity in the markets and its biological characteristics, which allow it to be ideally suited to aquaculture conditions. Although this fish species has been reared in extensive aquaculture in the marshes of the southern Atlantic coast of Spain and Portugal (Dinis and others 1999), at present some marine farms are introducing it in Galicia (north-west Spain), with promising results (Olmedo and others 2003). Until now, the most common bacterial diseases affecting cultured sole have been photobacteriosis, vibriosis and tenacibaculosis (Toranzo and others 2003). Aeromonas salmonicida subspecies salmonicida , the causal agent of so-called ‘typical’ furunculosis, was reported for the first time in 1894 in Germany, during a disease outbreak at a Bavarian brown trout ( Salmo trutta ) hatchery (Emmerich and Weibel 1894). Currently, this pathogen has a wide geographical distribution, including most European countries, and Canada and Japan, among others. In Spain, A salmonicida subspecies salmonicida was isolated for the first time in Galicia in 1987 from rainbow trout ( Oncorhynchus mykiss ) cultured in freshwater. In seawater culture, furunculosis was detected in 1989 in Atlantic salmon ( Salmo salar ) and trout; the disease most probably originated from the transport of infected yearling brown trout from central Spain (Toranzo and others 1990). The incidence of furunculosis in salmonids cultured in freshwater and seawater has increased steadily in Spain in subsequent years, constituting a significant threat to other cultured fish species. In 1992, an outbreak of furunculosis was diagnosed for …