The floating upwelling system (FLUPSY) for breeding of Venerupis decussata (Linnaeus, 1758) juveniles in a coastal lagoon in Sardinia (Italy)

Abstract

1 - In recent years, interest in farming the grooved carpet shell Venerupis decussata (Linnaeus, 1758) in Sardinian lagoons has greatly increased due to a decrease in clam populations. Aquaculturists around the world have developed a variety of different clam farming systems, notably for the Manila clam, Venerupis philippinarum (Adams & Reeve, 1850). 2 - The aim was to test the aquaculture of V. decussata using the FLoating UPwelling SYstem (FLUPSY) to evaluate their growth rate over two seasons: spring 2011 (from 10 March, 2011, to 21 May, 2011), and autumn 2011 (from 18 October, 2011, to 28 December, 2011). The study was carried out in the Tortoli coastal lagoon, Eastern Sardinia (Italy; latitude 39°56’ N, longitude 9°41’ E). 3 - V. decussata juveniles with mean shell lengths of 10.88±0.91 mm in spring and 8.95 ± 0.75 mm in autumn, mean shell thicknesses of 5.21±0.54 mm in spring and 3.36 ± 0.27 mm in autumn, and mean total weight of 0.33±0.09 g in spring and 0.1 2± 0.03 g in autumn, were bred following FLUPSY. To compare this with the aquaculture of these V. decussata juveniles under natural conditions, a control group was transplanted to a separate area in the lagoon. The shell length, shell thickness and total weight were measured fortnightly and monthly from the FLUPSY and natural farming, respectively. Temperature, salinity, pH, dissolved oxygen and chlorophyll a were monitored monthly using a multiparameter probe. 4 - At the end of the seasons, V. decussata showed the mean spring parameters of shell length 19.60 ± 1.11 mm, shell thickness 9.99 ± 0.54 mm and total weight 1.87 ± 0.23 g, and the mean autumn parameters of shell length 15.87 ± 1.34 mm, shell thickness 6.70 ± 0.69 mm and total weight 0.79 ± 0.20 g. Comparisons with the natural control system showed significant improvements for FLUPSY. 5 - The use of the FLUPSY appears to be useful for the breeding of V. decussata juveniles, particularly during the spring season.