323
individuals·L
−1
. As the squid grow, the water depth is increased by 50 mm every day
or every second day. Squid are graded by size every 10 days, and squid of similar
size are grouped together for subsequent nursing. The density of squid is decreased
by about 20–25 % in each group after grading.
Feeding
S� lessoniana hatchlings begin to feed immediately after hatching and must be provided with live feed of appropriate size, which is 50–200 % of their ML. Wildcaught live mysids ( Mesopodopsis orientalis) that are about 6–7 mm in total length
are key to the successful nursing of hatchlings (Nabhitabhata 1978). The live feed
is stocked and fed to the squid ad libitum. Pygmy goby fry ( Stigmatogobius romeri)
are also a good feed organism (Chankaew et al. 2003a). Other wild zooplankton and
fish larvae are suitable food, but as the supply of these organisms is not consistent,
they are not reliable enough for the mass production of squid.
Feed organisms that are commercially produced can ensure more reliable and
consistent success of squid hatchery operations. Postlarvae of the penaeid shrimp
( Penaeus merguiensis) that are 5–10 mm in total length and sea bass fry ( Lates
calcarifer) that are 5 mm in length can be used as the primary foodstock. About 7
(1–22) postlarvae or fish are consumed daily by each squid hatchling (Chankaew
et al. 2003b; Nabhitabhata et al. 1996). Other crustaceans that have been tried did
not result in good squid production. The crab mysis Portunus pelagicus can initiate
seizures in squid hatchlings if fed in the first 2–3 days after hatching. Young squid
fed freshwater prawn mysis ( Macrobrachium rosenbergii) each consumed about
140 individuals per day, but only 8 % of the hatchlings survived longer than 10 days
(Nabhitabhata et al. 1992b). One reason for this low rate of hatchling survival was
that the prawn mysis could not survive in 30 psu seawater long enough to provide
the required quantity of feed for the squid hatchlings.
The survival rate of young squid fed shrimp postlarvae ( P� merguiensis) is approximately 80 % (22–100 %) from hatching to 10 days of age (Chindamaikul et al.
1994a; Nabhitabhata 1978; Nabhitabhata and Kbinrum 1981; Nabhitabhata et al.
1996). The survival rate during this period decreases if the supply of feed organisms
is insufficient (Nabhitabhata 1978, 1996; Nabhitabhata and Kbinrum 1981).
The daily feeding rate of squid hatchlings is about 28 % of their BW and the average conversion rate is more than 50 % (28–95 %; Nabhitabhata et al. 1992b, 1996).
The unit cost of production in Thailand has been estimated to be about US$ 10 for
100 hatchlings with a feed cost of about US$ 9 in 1996 (Nabhitabhata et al. 1996),
when US$ 1 is approximately equal to Thai Baht 25 (US$ 1 equals Thai Baht 30
in 2013). At 30 days after hatching, survival is about 60 % (10–74 %; Nabhitabhata
1978; Nabhitabhata and Kbinrum 1981; Nabhitabhata et al. 1996; Table 17.1).
Young squid can alternatively be nursed in a floating net cage. Ahmad and
Usman (1997) nursed their S� lessoniana from hatchlings in a net cage that was
1.5 × 1.5 × 1.5 m and provided Mesopodopsis mysids as feed organisms. The growth
was rapid with an increase of 2.9–4 g after 30 days, as compared to about 2 g in
17 Sepioteuthis lessoniana
individuals·L
−1
. As the squid grow, the water depth is increased by 50 mm every day
or every second day. Squid are graded by size every 10 days, and squid of similar
size are grouped together for subsequent nursing. The density of squid is decreased
by about 20–25 % in each group after grading.
Feeding
S� lessoniana hatchlings begin to feed immediately after hatching and must be provided with live feed of appropriate size, which is 50–200 % of their ML. Wildcaught live mysids ( Mesopodopsis orientalis) that are about 6–7 mm in total length
are key to the successful nursing of hatchlings (Nabhitabhata 1978). The live feed
is stocked and fed to the squid ad libitum. Pygmy goby fry ( Stigmatogobius romeri)
are also a good feed organism (Chankaew et al. 2003a). Other wild zooplankton and
fish larvae are suitable food, but as the supply of these organisms is not consistent,
they are not reliable enough for the mass production of squid.
Feed organisms that are commercially produced can ensure more reliable and
consistent success of squid hatchery operations. Postlarvae of the penaeid shrimp
( Penaeus merguiensis) that are 5–10 mm in total length and sea bass fry ( Lates
calcarifer) that are 5 mm in length can be used as the primary foodstock. About 7
(1–22) postlarvae or fish are consumed daily by each squid hatchling (Chankaew
et al. 2003b; Nabhitabhata et al. 1996). Other crustaceans that have been tried did
not result in good squid production. The crab mysis Portunus pelagicus can initiate
seizures in squid hatchlings if fed in the first 2–3 days after hatching. Young squid
fed freshwater prawn mysis ( Macrobrachium rosenbergii) each consumed about
140 individuals per day, but only 8 % of the hatchlings survived longer than 10 days
(Nabhitabhata et al. 1992b). One reason for this low rate of hatchling survival was
that the prawn mysis could not survive in 30 psu seawater long enough to provide
the required quantity of feed for the squid hatchlings.
The survival rate of young squid fed shrimp postlarvae ( P� merguiensis) is approximately 80 % (22–100 %) from hatching to 10 days of age (Chindamaikul et al.
1994a; Nabhitabhata 1978; Nabhitabhata and Kbinrum 1981; Nabhitabhata et al.
1996). The survival rate during this period decreases if the supply of feed organisms
is insufficient (Nabhitabhata 1978, 1996; Nabhitabhata and Kbinrum 1981).
The daily feeding rate of squid hatchlings is about 28 % of their BW and the average conversion rate is more than 50 % (28–95 %; Nabhitabhata et al. 1992b, 1996).
The unit cost of production in Thailand has been estimated to be about US$ 10 for
100 hatchlings with a feed cost of about US$ 9 in 1996 (Nabhitabhata et al. 1996),
when US$ 1 is approximately equal to Thai Baht 25 (US$ 1 equals Thai Baht 30
in 2013). At 30 days after hatching, survival is about 60 % (10–74 %; Nabhitabhata
1978; Nabhitabhata and Kbinrum 1981; Nabhitabhata et al. 1996; Table 17.1).
Young squid can alternatively be nursed in a floating net cage. Ahmad and
Usman (1997) nursed their S� lessoniana from hatchlings in a net cage that was
1.5 × 1.5 × 1.5 m and provided Mesopodopsis mysids as feed organisms. The growth
was rapid with an increase of 2.9–4 g after 30 days, as compared to about 2 g in
17 Sepioteuthis lessoniana