Principles of Genetics and Breeding

15.1.2 Hatchery management

Hatchery management can be of single species or of multi-species. In multi-species hatcheries, broodstocks are kept separately by species or together as mixed species and often maintain Chinese and Indian major carp broodstocks.

Broodstock is a prerequisite for all types of hatchery production and proper broodstock management will lead to better breeding responses and increased fecundity, fertilization, hatching and larval survival rates and more viable fish seed.

Hence, the broodstock management has assumed great importance in hatchery management. The broodstock management process can be divided into two broad categories:

the pre-spawning process and

the post-spawning process.

• The pre-spawning process includes procedures for broodstock selection and procurement, maintenance, maturation, acclimatization, spawning and hatching.
• The post-spawning process includes facility maintenance, water quality management, broodstock handling; washing, selection, holding and transfer/transport of spawn, rearing of spawn, maintenance, health management, assessment of condition, selection and risk assessment for stocking, documentation and record keeping.

Since selective breeding and hybridization programmes of pedigreed fish are not carried out in fish hatcheries, procurement of broodstocks are done by collecting individuals from the wild, purchasing from cultured stocks in neighbouring farms or hatcheries, or developing new broodstocks through selection from previous fish populations.

One of the most common problems in selecting fish from fingerling production ponds to develop broodstock is that only undersized and slow growing fingerlings are left for selection purposes since larger and fast growing fingerlings are sold.

Therefore, positive mass selection procedure where the largest individuals with correct body shape, colour and free from external deformations cannot be practiced.

Selection of female and male fish from two independent ponds to raise as broodstock is advisable as it will reduce the possibility of pairing relatives that could lead to inbreeding problems.

Nevertheless, this practice is largely ignored in small-scale hatcheries due to lack of pond space.

The good practice of transferring spawners after spawning to a resting pond without mixing with ripe males and females is ignored too in many small-scale hatcheries for the same reason.