Ostracoda impairs growth and survival of Arapaima gigas larvae

Abstract

The practice of indoor larviculture can be an alternative to enhance the rearing of arapaima larvae, improving their survival and the supply of arapaima juveniles for the grow-out stage. We aimed to evaluate different live microcrustaceans as feed for arapaima larvae to verify groups that can be safely used in laboratory trials, as well as in commercial larviculture. Arapaima larvae (39.45 ± 7.04 mg and 2.09 ± 0.13 cm) were housed in 12-L circular tanks (n = 4 tanks; 30 larvae per tank) in a static water system. The tanks were cleaned twice a day, when 50% of the water was changed. Fish were fed three types of live feed 9 times/day: brine shrimp Artemia sp. nauplii (AR), Cladocera-rich zooplankton (CZ), and Ostracoda-rich zooplankton (OZ) for 15 days. Fish fed CZ and AR showed a similar fast growth rate with low mortality rates. The OZ fed Arapaima larvae presented intact Ostracoda in their rectums. This findins, demonstrates their poor digestibility, which resulted in poor growth and low survival. Ostracoda-rich zooplankton must be avoided in arapaima larviculture until 8 days after they begin swimming to the water surface or 17 days after hatching. © 2019