Embryonic development, larval morphology and juvenile growth of the sea cucumber Athyonidium chilensis (Holothuroidea: Dendrochirotida)

Holothurians are a valuable resource for coastal communities in the Indo-Pacific region; however, the unsustainable exploitation of the species and the rising wholesale price of the processed product (bêche-de-mer) have resulted in the depletion of wild stocks worldwide. Athyonidium chilensis is the most economically important holothuroid in the Southeast Pacific coast; however, the early life-history of the species has not been previously described. A. chilensis developed through the lecithotrophic vitellaria and the pentactula larval stages in ~7 days at 13 ± 0.3°C. At settlement, individuals were capable of active feeding on micro-algae associated with the sediment. Thirty-five days post-fertilization, the buccal tentacles and the fourth pair of ambulacral podia were completely developed. After 4 months of cultivation, juvenile (~1.4 mm length) had a substantial number of podia on the body surface and some common adult behaviors were also displayed. An evident effect of the density during the culture of juveniles was observed, with higher growth rates and survival observed in the treatment with the lowest density (1 ind cm-2). This study provides the first descriptions of the early life-history stages of A. chilensis, but also shows this sea cucumber can be successfully reared in land-based nursery systems. Culture of this species is feasible and could be potentially developed as an alternative to maintain a sustainable harvest by contributing to the restoration of natural populations.