Nursery culture of wild and hatchery-produced juveniles of the West Indian top shell, Cittarium pica, fed microalgal and artificial biofilms

Abstract

Cittarium pica is an overexploited Caribbean top shell that is being produced at an experimental level by aquaculture for conservation purposes. To optimise nursery culture, the growth and survival of wild and hatchery-produced juveniles were assessed after feeding with different biofilm diets. The following three diets were tested over a 6-month period: (1) a microalgal biofilm of Nitzschia sp. and Tetraselmis chuii; (2) an artificial biofilm of dry seaweeds, Padina gymnospora and Laurencia obtusa, and the cyanobacterium Spirulina sp.; and (3) a mix of the microalgal and artificial biofilms. The biofilms were prepared and supplied on folded PVC plates, and treatments were administered in triplicated 10-L aquaria with down-welling systems at 25 ± 1 °C and a salinity of 36.5 ± 0.5 ppt. Higher growth rates were obtained in juveniles fed diets containing artificial biofilms, which had high protein and energy contents, whereas survival rates were higher in juveniles fed the mixed diet. The relatively high growth and survival values suggest that the nursery culture can be improved by feeding with the mix of microalgal and artificial biofilms and that the temporary translocation of wild juveniles to nursery conditions can be a tool for population enhancement.