Growth and foraging behavior of hatchery propagated long-spined sea urchins, Diadema antillarum: Implications for aquaculture and restocking

Abstract

Stocking hatchery propagated long-spined sea urchins Diadema antillarum is a priority option for recovery of this keystone herbivore on Caribbean reefs. However, information on captive culture of D. antillarum is very limited due to historical lack of successful juvenile production from gametes in the hatchery. In this study, hatchery propagated D. antillarum juveniles were cultured using two diets, commercially available herbivore pellets and dried nori, with the presence/absence of stony coral Acropora cervicornis skeleton to understand how diet and habitat complexity affect growth and behavior of juveniles. Juvenile urchin growth, and the diel pattern of feeding and foraging behavior were significantly affected by diet type. Juveniles fed dried nori gained significantly higher live weight and test diameter than those fed herbivore pellets. Juvenile urchins displayed nocturnal feeding and foraging behavior irrespective of diet types and presence/absence of coral structure. Presence/absence of coral structure did not affect growth and diel pattern of feeding and foraging behavior, but modulated habitat usage patterns. Survival of juveniles was neither affected by diet types nor the presence/absence of coral structure. This study concludes that dried nori is a superior diet to herbivore pellets for juvenile urchin culture. Since the presence of coral structure influenced habitat usage patterns, provision of rugose structure in captivity has the potential to convey the innate shelter seeking behavior of juvenile urchins.