The impact of hangingcleaning husbandry practices on Mediterranean mussels, Mytilus galloprovincialis Lmk, cultivated in the Mar Piccolo (Taranto, Ionian Sea, Italy)

The impact of the stressful hanging-cleaning husbandry practices on the growth conditions of the cultured Mediterranean mussels, Mytilus galloprovincialis Lmk, cultivated in the Mar Piccolo (Ionian Sea) was investigated from November 2005 to June 2006. The experimental strings were randomly organized in four groups, with five replications, exposed to different time periods of hanging: Group A, none; Group B, once every 15 days; Group C, once every 30 days; Group D, once every 60 days. The study, carried out on a total of 2000 mussels, showed that the cleaning of the mussel strings using the hanging-cleaning practice exerted an adverse effect on mussel growth (SGR%=46.62 in Group A; 44.85 in Group D; 43.72 in Group C; 42.12 in Group B). In particular, the highest percentage of meat yield occurred in the mussels more frequently exposed to air (Group B, 4.2±0.43 g) in spite of their lower morphometric variable values. In order to evaluate mussel condition, three different indexes were calculated. The hanging practice in mussel cultivation, commonly used in the basin of Taranto and in many mussel farms all over the world, would provide an economic benefit to the mussel farmers allowing the greatest production and the highest specific growth rate (SGR%) of mussels, together with a more appreciable aesthetic for the consumer. Our findings suggest that the hanging practice every 60 days would provide an economic benefit allowing an increase of about 30% of total string weight compared to the 30-day hanging practice commonly in use.