Breeding of milkfish
12.1. Distribution and importance
- Milk fish belongs to the Family Chanidae and Order Clupeiformes
- It is distributed in the Indo-Pacific region; commonly cultured in
Indonesia, Taiwan, Philippines, etc.
- Found in both the coasts of India, but is more abundant on the east
coast.
- Milk fish is hardy, highly resistant to diseases, euryhaline,
herbivorous and easy to culture.
- Can be cultured in freshwater, brackishwater and marine waters.
- It is not only an excellent food fish, but also an ideal bait fish
for tuna.
- Grows to 400-500g in 5-6 months.
- Improved culture methods have led to higher demand for fingerlings,
the main source being the natural waters.
Identifying characters
- Mouth small and inferior.
- Dorsal origin midway between front border of eye and caudal base.
- Anal small; Caudal deeply forked.
- Body bluish-grey above, sides and abdomen silvery.
- Dorsal and caudal dusky.
- Pectoral, pelvic and anal dotted with black along their margins.
12.2. Brood-stock development
- Milk fish is heterosexual (no incidence of hermaphroditism).
- Both wild and captive broodfish respond to hormone injection.
- Captive broodstock is managed in brackish-water earthen
ponds/cement ponds/cages.
- Fed with supplementary diet.
- Gonadal development is synchronous and six stages gonadal maturity
are found.
- Males mature at 4+ years, while females take 5+ years to mature.
- Does not spawn naturally in captivity.
- Spawns naturally in open sea during May-August.
- Difficult to identify ripe brooders based on morphological
characters.
- Ova-diameter (0.70 - 0.89 mm) indicates ripe ova.
- Fecundity – 2-8 million/kg b.w.
12.3. Induced spawning
- No. of injections – mostly two, sometimes only one; interval
between the two – 8-12 h
- Water quality requirements: Salinity – 14-34 ppt, temperature -
21-310C
- Interval between injection and striping : 6-17 h; stripping and
artificial fertilization
- Natural spawning is preferred as it is very sensitive to handling;
repeated spawning is possible.
- Hatching period : 20-25 h.
Hormones and dosage are as follows
|
Hormone |
Dosage |
|
|
Female |
Male |
|
|
Salmon Pituitary homogenate |
6-10 mg/kg |
1/3 dose |
|
HCG |
180-2500 IU/kg |
1/3 dose |
|
Carp Pituitary homogenate |
5-25 mg/kg |
1/3 dose |
|
sGnRH-a/mLHRH-a |
10-20 ug/kg |
- |
Larval
rearing
- One-day-old hatchlings are fed with Chlorella spp.
- From the 2nd day, rotifer (Brachionus plicatilis) and
Artemia nauplii are given .
- In about 20 days, the larvae reach 12-18 mm.
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