AQUACULTURE OF THE FRENCH GRUNT Haemulon flavolineatum: LARVAL GROWTH AND DEVELOPMENT, FIRST FEEDING, AND IMPACT OF PHOTOPERIOD.

Grunts of the family Haemulidae are economically and ecologically important fish found throughout the world. The French grunt, Haemulon flavolineatum, has emerged as a candidate species for aquaculture due to its popularity in public aquarium displays and recent success in captive larval rearing. Though grunts are primarily harvested by recreational anglers for their value as a food fish, many species of grunts are popular in public and private aquariums due to their schooling behavior and bright colorations; both valued characteristics for an ornamental species.

An initial larval rearing trial using a wild zooplankton diet yielded baseline survival rates of 47 ± 3% throughout larval development (38 day post hatch (dph)) and allowed for a first description of larval development (Figure 1 and 2). The effect of feeding regime on survival to 15 dph was then evaluated using three diet treatments: Brachionus plicatilis, Oithona colcarva (a marine cylcopoid copepod), and a combination of B. plicatilis and O. colcarva. Results showed that a combination of B. plicatilis and O. colcarva produced significantly higher survival (71.2 ±5.1%) compared to B. plicatilis (38.6 ± 5.6%) and O. colcarva (27.9 ±6.5%). Growth among treatments did not differ.

In addition, the effect of photoperiod (12L:12D, 18L:6D, 24L:0D) during larval culture (0-20 dph) was investigated. At the p<0.05 level of significance, no statistical differences were observed for growth (p=0.065) and swimbladder inflation (p=0.060). Additional research with abbreviated periods of darkness is needed to determine an optimal lighting regime.