249
14 Sepiella japonica
should be adapted accordingly. The cages should be shaded by black mesh on the
top to avoid stress by bright light, which may cause the individuals unrest, or even
eject ink and die. The height of the net should be convenient for feeding operation.
In order to avoid attacks by the birds, net cover should be provided.
14.5.2.2 Juvenile Size and Density
Active, healthy juveniles of 15–20 mm ML can be introduced to the ongrowing process in 13–32 °C, optimally 27 ± 2°C, and salinity of 20–35 psu. Stocking density
depends on the size of the individuals. A 3 m × 3 m × 3 m cage can accommodate
2,000–2,500 juveniles of 0.7–1 cm total length (TL), or 1,200–1,500 juveniles of
3–5 cm TL, or 800–1,000 juveniles of 6–8 cm TL or 300–500 (> 9 cm TL).
14.5.2.3 Feeding
Wild fresh small shrimp ( N� awatschensis) and fish ( P� parva) are the major feed for
the juveniles during the ongrowing period. Daily feed quantity should be 10–15 %
of total body weight of juveniles. Besides, lamp light can be used to attract wild
preys, or if conditions permit, use lamps on top of the cages to attract zooplankton
(such as copepods, cladoceran) as supplement
14.5.2.4 Daily Management
During the ongrowing period, the fouling on the cage should be cleared and mesh
of suitable size should be changed periodically. Water flow in the cage should be
maintained. Water exchange must be guaranteed to ensure that there is always fresh
water in the cage, but the mesh size should be appropriate to prevent individuals
from escaping.
During the period 2006–2007, a total of 50,000–60,000 S� japonica adult individuals were reared in cages in the seas off the coast of Ningde and Putian counties,
Fujian Province, at a total survival rate of 60 %. Meanwhile, the outdoor ponds
were also used to S� japonica ongrowing in East China Sea (Wang et al. 2006); the
survival rate of the species was 26.7 % in 2005, and mean wet weight was 250 g; the
survival rate was up to 47.4 % in 2006, and the maximum weight reached was 400 g.
14.6 Harvest
After 3–4 months of ongrowing, S� japonica reaches commercial size and can be
harvested for marketing. The spineless cuttlefishes are active when water temperature is over 15 °C. Cuttlefish fishing traps which are cylinders of 20–30 cm height
by 30 cm diameter, covered with the polyethylene net of 10–20 mm mesh diameter
14 Sepiella japonica
should be adapted accordingly. The cages should be shaded by black mesh on the
top to avoid stress by bright light, which may cause the individuals unrest, or even
eject ink and die. The height of the net should be convenient for feeding operation.
In order to avoid attacks by the birds, net cover should be provided.
14.5.2.2 Juvenile Size and Density
Active, healthy juveniles of 15–20 mm ML can be introduced to the ongrowing process in 13–32 °C, optimally 27 ± 2°C, and salinity of 20–35 psu. Stocking density
depends on the size of the individuals. A 3 m × 3 m × 3 m cage can accommodate
2,000–2,500 juveniles of 0.7–1 cm total length (TL), or 1,200–1,500 juveniles of
3–5 cm TL, or 800–1,000 juveniles of 6–8 cm TL or 300–500 (> 9 cm TL).
14.5.2.3 Feeding
Wild fresh small shrimp ( N� awatschensis) and fish ( P� parva) are the major feed for
the juveniles during the ongrowing period. Daily feed quantity should be 10–15 %
of total body weight of juveniles. Besides, lamp light can be used to attract wild
preys, or if conditions permit, use lamps on top of the cages to attract zooplankton
(such as copepods, cladoceran) as supplement
14.5.2.4 Daily Management
During the ongrowing period, the fouling on the cage should be cleared and mesh
of suitable size should be changed periodically. Water flow in the cage should be
maintained. Water exchange must be guaranteed to ensure that there is always fresh
water in the cage, but the mesh size should be appropriate to prevent individuals
from escaping.
During the period 2006–2007, a total of 50,000–60,000 S� japonica adult individuals were reared in cages in the seas off the coast of Ningde and Putian counties,
Fujian Province, at a total survival rate of 60 %. Meanwhile, the outdoor ponds
were also used to S� japonica ongrowing in East China Sea (Wang et al. 2006); the
survival rate of the species was 26.7 % in 2005, and mean wet weight was 250 g; the
survival rate was up to 47.4 % in 2006, and the maximum weight reached was 400 g.
14.6 Harvest
After 3–4 months of ongrowing, S� japonica reaches commercial size and can be
harvested for marketing. The spineless cuttlefishes are active when water temperature is over 15 °C. Cuttlefish fishing traps which are cylinders of 20–30 cm height
by 30 cm diameter, covered with the polyethylene net of 10–20 mm mesh diameter