♦ Scientific name: Acanthopagrus schlegeli

♦ Common name: Black sea bream

♦ Ecology

   The species is distributed in the coastal waters of southern parts of Korean peninsula, Japan, China, and Taiwan. The species inhabits the sandy and rocky coasts where water depth is within 50m. A mature female spawns several times on the sandy/gravel bottom in May to July. Males over 17 cm in body length and females over 20 cm can be used as a spawner.

♦ Aquaculture

    The fertilized eggs obtained from the spawning tanks are collected and then moved to hatching tanks. Mean egg diameter and oil droplet diameter was 0.84±0.02 mm, 0.21±0.01 mm respectively and the eggs became smaller while the spawning was in process and then got bigger in the late spawning season. The eggs hatch 36~41 hrs after fertilization.

The newly-hatched larvae were 2.05±0.15 mm in mean total length, and their mouth and anus were not open. In 5 days after hatching, the larvae grew to 2.95 mm in total length and their yolksac and oil globules were almost absorbed. Fry production can be divided into primary and secondary phases, that is, rearing of the larvae (TL, 2~10 mm) and rearing of the juveniles (TL, 11~30 mm). From a different angle, the primary phase is rearing with zooplankton (mainly the rotifer, Brachionus plicatilis) and the secondary phase is that with Artemia nauplii and artificial diet in land-based tank (mainly concreat and polypropylene tank). For rearing of the larvae, high density culture in a small tank (5~10 m³) was initially the major technique but today, rearing using large tanks (50~100 m³) is most common. For larval rearing, the depth of tank varies from 1 to 2 m. Most of the rearing tanks are rectangular and circlular. The suggested water temperature for the black sea bream larvae are 17~24°C. The densities of the newly hatched larvae range from 10,000 to 30,000 fish per ton and survival ratios vary with facilities.

Cultivation is mainly done with net caged culture located in the coastal water of southern sea of Korea where tidal currents are evident and water temperature remains over 10°C during the winter. The net cage capacity varies, the standard being 100m³ (6 ×6×3.5 m). During the initial feeding adjustment period, bream are fed with only artificial diets, thereafter they are fed mainly artificial diets and moist pellet. The density of seeds in net cage is nearly 5~10kg/m³, considering the possible sudden change of environmental condition such as red tide and shortage of oxygen. Black sea bream prefer 20~26°C, and show active feeding and growth rate. The feeding behavior decreases below 20°C, and feeding stops at 10°C. Feeding behavior of black sea bream tends to generally fluctuate at higher temperature. The survival rate for the rearing is approximately 30~50%. They grow relatively fast; up to about 400~600 g in body weight in 2 to 3years.

<The spawners of black sea bream>	<Fertilized egg>
<Just hatched lava>	<Juveniles for release>
<Net cage culture of black sea bream>	<Harvesting seeds>
<Seed releasing>