Reproduction, gamete
supply and larval rearing of New Zealand turbot Colistium nudipinnis (Waite
1910) and brill Colistium guntheri (Hutton 1873): a potential new
aquaculture species
M.J. Tait, R.W. Hickman-2001
Aquaculture Research, 32(9): 717-725
(from Current Contents)
Abstract :
New Zealand turbot Colistium nudipinnis (Waite 1910)
and brill Colistium guntheri (Hutton 1873) were studied to assess their
potential for aquaculture development. The reproductive cycle of wild fish
showed a long spawning season from winter to summer, during which it is
possible to obtain gametes. Both species have a diurnal ovulatory cycle, and
gamete collection, by stripping and fertilizing at sea, was most successful
within 2-3 h before and after sunset. Male reproductive anatomy suggests
that these flatfish spawn in close proximity and that pair formation is
highly likely. The eggs of both species have multiple oil droplets, turbot
eggs being slightly larger (0.99 mm diameter) with more droplets (18-55)
than brill eggs (0.97 mm, 13-26 droplets). Hatching occurred approximately
84 h after fertilization at 14°C. Newly hatched turbot averaged 2.2 mm in
length, and brill averaged 2.1 mm. First feeding began 4 days post-hatch
(DPH). During larval rearing, rotifers were replaced by Artemia nauplii at
10 DPH. Metamorphosis commenced at 12-15 DPH and was completed and the
larvae settled by 45 DPH. Weaning to inert foods began at 20-22 DPH (50 mg
weight) and was completed by 57 DPH. Survival of turbot was 22.8% from
fertilized egg to hatching, 7.3% through incubation to 22 DPH and 2.1%
through incubation to fully weaned juveniles. Weaning success for turbot
from metamorphosis to 57 DPH was 31.5%.
(NIWA Aquaculture, Mahanga Bay, Wellington, New
Zealand)