213
Nursing of young pharaoh cuttlefish in a floating net cage is feasible. Chiampreecha
(1983) reared young cuttlefish from hatching to 63 days in a steel-framed net cage of
600 × 800 × 400 mm. The cage had a water depth of 300 mm. The survival decreased
to 63 %, and the initial density of 26 individuals m
−2
decreased to a final density of 17
individuals m
−2
. However, the cage in this study is floated in a large concrete tank of
unknown volume with a flow-through seawater system.
In closed seawater systems, nitrogenous compound levels can rapidly increase
and should be monitored. Although young cuttlefish can tolerate up to 0.6 mg L
−1
of
ammonia (NH 4 –N) and 0.02 mg L
−1
nitrite (NO 2 –N) at 28 °C (Chindamaikul et al.
2001), it is recommended to maintain ammonia below 0.1, nitrite below 0.1 and
nitrate (NO 3 –N) below 20 mg L
−1
(Minton et al. 2001; Nabhitabhata 2000). Salinity
in the system should be monitored daily and be adjusted with synthetic or sterile
natural sea salt. In addition, pH should be maintained within the range of 5.9–8.4
for hatchlings (Nabhitabhata et al. 1991).
12.5.3 Feeding
Hatchlings have small external yolk sacs and these are abandoned on the first day.
Hatchlings still have some yolk reserves enabling them to survive without food
for 3–7 days or even up to 23 days (Nair et al. 1985), and the digestive activities will begin after 3 days, which is similar to what is observed in S� officinalis
(Boucaud-Camou and Roper 1995).
Various kinds of live food organisms, with corresponding sizes, are fed to the
hatchlings. The cuttlefish hatchlings are benthic and begin feeding on the first day,
6–12 h after hatching. The list of accepted food organisms includes live mysid,
Mesopodopsis orientalis (7 mm in total length and 10 mg body weight) and a mix
of fish larvae (10 mm in total length) that are collected from the wild. Other crustacean food organisms can also be used with success, e.g. the mysid Eurobowmanilla
simulans (4–6 mm), postlarvae of the shrimps Penaeus indicus, Metapenaeus dobsoni (Anil et al. 2005), the mysid Mysidopsis sp., the grass shrimp Palaemonetes
pugio and guppies Poecilia reticulata (Minton et al. 2001). The live food is stocked
and provided ad libitum to cuttlefish. The daily feeding ration of the hatchlings
is 20–28 % of their body weight, which equals 13 mysids or 10 shrimp postlarvae (Nabhitabhata et al. 1996). Cuttlefish hatchlings prefer crustaceans to fish as
food. Newly born hatchlings recognise, attack and eat mysids demonstrating that
such behaviour is innate in sepiid cuttlefish as described by Messenger (1977). The
attempts to feed young S� pharaonis with live food other than crustaceans and fishes
have not succeeded (Nabhitabhata 1978; Toll and Strain 1988). Adult Artemia spp.
are accepted but yield lower growth and survival. They should only be used as a
supplementary or reserve food when other crustaceans are in short supply.
Food organisms obtained from commercial hatcheries are more reliable and
consistent in supply. The postlarvae of the penaeid shrimp, Penaeus merguiensis
(8–10 mm) and sea bass, Lates calcarifer, fries (7.5 mm) are two of the available
species. The cuttlefish consume about 10 mysids or 2 sea bass fries daily (Chankaew
12 Sepia pharaonis
Nursing of young pharaoh cuttlefish in a floating net cage is feasible. Chiampreecha
(1983) reared young cuttlefish from hatching to 63 days in a steel-framed net cage of
600 × 800 × 400 mm. The cage had a water depth of 300 mm. The survival decreased
to 63 %, and the initial density of 26 individuals m
−2
decreased to a final density of 17
individuals m
−2
. However, the cage in this study is floated in a large concrete tank of
unknown volume with a flow-through seawater system.
In closed seawater systems, nitrogenous compound levels can rapidly increase
and should be monitored. Although young cuttlefish can tolerate up to 0.6 mg L
−1
of
ammonia (NH 4 –N) and 0.02 mg L
−1
nitrite (NO 2 –N) at 28 °C (Chindamaikul et al.
2001), it is recommended to maintain ammonia below 0.1, nitrite below 0.1 and
nitrate (NO 3 –N) below 20 mg L
−1
(Minton et al. 2001; Nabhitabhata 2000). Salinity
in the system should be monitored daily and be adjusted with synthetic or sterile
natural sea salt. In addition, pH should be maintained within the range of 5.9–8.4
for hatchlings (Nabhitabhata et al. 1991).
12.5.3 Feeding
Hatchlings have small external yolk sacs and these are abandoned on the first day.
Hatchlings still have some yolk reserves enabling them to survive without food
for 3–7 days or even up to 23 days (Nair et al. 1985), and the digestive activities will begin after 3 days, which is similar to what is observed in S� officinalis
(Boucaud-Camou and Roper 1995).
Various kinds of live food organisms, with corresponding sizes, are fed to the
hatchlings. The cuttlefish hatchlings are benthic and begin feeding on the first day,
6–12 h after hatching. The list of accepted food organisms includes live mysid,
Mesopodopsis orientalis (7 mm in total length and 10 mg body weight) and a mix
of fish larvae (10 mm in total length) that are collected from the wild. Other crustacean food organisms can also be used with success, e.g. the mysid Eurobowmanilla
simulans (4–6 mm), postlarvae of the shrimps Penaeus indicus, Metapenaeus dobsoni (Anil et al. 2005), the mysid Mysidopsis sp., the grass shrimp Palaemonetes
pugio and guppies Poecilia reticulata (Minton et al. 2001). The live food is stocked
and provided ad libitum to cuttlefish. The daily feeding ration of the hatchlings
is 20–28 % of their body weight, which equals 13 mysids or 10 shrimp postlarvae (Nabhitabhata et al. 1996). Cuttlefish hatchlings prefer crustaceans to fish as
food. Newly born hatchlings recognise, attack and eat mysids demonstrating that
such behaviour is innate in sepiid cuttlefish as described by Messenger (1977). The
attempts to feed young S� pharaonis with live food other than crustaceans and fishes
have not succeeded (Nabhitabhata 1978; Toll and Strain 1988). Adult Artemia spp.
are accepted but yield lower growth and survival. They should only be used as a
supplementary or reserve food when other crustaceans are in short supply.
Food organisms obtained from commercial hatcheries are more reliable and
consistent in supply. The postlarvae of the penaeid shrimp, Penaeus merguiensis
(8–10 mm) and sea bass, Lates calcarifer, fries (7.5 mm) are two of the available
species. The cuttlefish consume about 10 mysids or 2 sea bass fries daily (Chankaew
12 Sepia pharaonis