World Aquaculture 2023

May 29 - June 1, 2023

Darwin, Northern Territory, Australia


Andrea Taylor*, Alexander Basford, Duong Duong, Josh Herrits, Matthew Osborne


Darwin Aquaculture Centre, Channel Island

Department of Industry, Tourism and Trade

Northern Territory Government of Australia

GPO Box 3000, Darwin NT 0801


Black jewfish Protonibea diacanthus is a commercially important fish to northern Australia’s wild catch fishery. Part of the croaker family Scienidae, it has an established market for its meat and high value swim bladder. This research presents the first successful hatchery production of black jewfish in Australia and documents ontogeny of early life stages of this species. Adult black jewfish were induced to spawn on four occasions in the Northern Territory, Australia, 25-30 hours after injection with LHRHa (Syndel) during the wild black jewfish spawning season. Eggs hatched 12 hours after fertilisation (Fig 1.) and day 1 larvae measured 2.4 mm standard length (SL). Larvae mouths opened 31 hours after hatch and first feeding was observed at 57 hours. Swim bladder inflation (92%) occurred between 40 and 62 hours after hatch. Larvae were progressively fed rotifers, Otohime microdiet and Artemia, and metamorphosis occurred between day 20 and day 25 (average 13.5 mm SL). Tail biting cannibalism occurred in larval stages from day 17 and increased with the onset of metamorphosis, causing mortalities until day 35. Juvenile handling methods were modified over four production runs to increase survival during this stage. Initiating size grading immediately after metamorphosis and low stocking density in nursery systems is showing promise as an effective strategy for minimising cannibalism mortality. Survival from day 1 larvae to metamorphosed juvenile has increased from 1.5% to 20% over the course of four production runs, and research is continuing. Juveniles grew on average 1.3 mm per day for the first 5 months in nursery tanks, and reached average 2 kg and 51 cm total length by 14.5 months of age. Juveniles displayed salinity tolerance of 5-35ppt. Black jewfish show promise as an emerging aquaculture species due to their fast growth and ability to be cultured using existing aquaculture technology. Primary points for refinement involve management of cannibalism, increasing larval survival and improving nursery and grow-out procedures.