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
Aquaculture
Research, 32(9): 717-725
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%.
(National Institute of Water and Atmosphere, PO Box
14-901, Kilbirnie, Wellington, New Zealand)