Finfish Breeding and Hatchery Management (2+1)

Unit 5 - Fish seed rearing techniques

5.1. Fish spawn rearing techniques – nursery pond

In India, carp culture is carried out in three phases (three-tier system) comprising:

1. Nursery phase (rearing three-day-old spawn to fry),
2. Rearing phase (rearing fry to fingerling stage) and
3. Grow out phase (rearing fingerlings to adult stage).

Of the three phases the nursery rearing is crucial and needs greatest attention of fish hatchery managers.

• Jhingran and Pullin (1985, 1988) have reviewed the subject of nursery and rearing pond management.
  The allocation of land for different types of ponds and other purposes is shown below : under Indian conditions a 4 ha farm should be divided into nursery ponds, 0.2 ha; rearing ponds, 0.8 ha and stocking ponds, 3 ha.
• Considering the enhanced rate of stocking and survival of spawn, fry and fingerlings, the ratio of nursery to rearing to stock ponds should be 1:40:1280.
• The preparation of nursery, rearing and stocking ponds before releasing the stocking material is an important step for successful rearing of carp spawn to fry, fry to fingerlings and fingerlings to table-sized fish.
• The occurrence of large scale mortality of stocked spawn in unprepared nurseries is a common experience of fish culturists throughout the country.
• Basavaraja and Joseph Antony (1997) obtained survival as high as 100% in the IMC nursery.
• The average survival of carp fry in nursery ponds does not normally exceed 30% (Basavaraja, 1994), which is attributed to poor nursery practices.
• The three-day-old spawn normally accept natural or artificial feed and can be transferred to nursery pond where predatory fishes and insects, algal blooms and poor water quality are major causes of mortality.