Larval rearing of a Hawaii rover (Emmelichthyid) species.

September 01, 2013

Family: Emmelichthyidae

Rovers (Emmelichthyidae) are slender, reddish, small to medium-sized, planktivorous, schooling fishes comprising 3 genera and 16 species. Juveniles occur near the surface, often with other schooling fishes, and adults live near the ocean bottom at depths of 300 to 1200 feet.  Although many rover species are excellent food fish, rovers have not been cultured in captivity. 

A rover species present in Hawaii waters was reared from a small number of eggs collected in waters off the west side of Oahu in May, 2012. Rover larvae are rather featureless and have limited specializations for pelagic life, aside from weak head spination. They look similar to the larvae of some damselfish (pomacentrid) and jack (carangid) species but are less pigmented in the early larval stages, e.g., pre-flexion and flexion. The pelagic juveniles have dark vertical bands on the body.  The larval development of this rover species is quite rapid with a larval period of only about 20-25 days.  The larvae have a large mouth at first feeding and easily feed on copepod nauplii. They do not have any special rearing requirements and can probably be raised quite well on a rotifer/artemia diet. Rovers could make good candidates for aquaculture based on their excellent flesh quality, their short larva period, fast growth and uncomplicated rearing requirements of the larvae.  Further studies to evaluate the efficacy of captive spawning adults, raising the larvae in numbers and growing out the juveniles to market size are needed.