Need for Genetically Selected Fish

The fishes from mass selection are not found to be successful for faster growth rate, or with better FCR value. In other hand in captive condition there is the chance of inbreeding. So we need genetically improved stock for following purposes –
Selective breeding and formation of improved species with better growth rate, low mortality and resistance to the diseases
To obtain better fertilisation rate
To achieve better fertilisation rate
To achieve better FCR value
To achieve better flesh content and shape of the fish

Selection Methods:

· The fishes are to be selected from different rivers to avoid close relatives of the fishes. Reservoirs should be avoided, because there is a chance of inbreeding.
· Genetically superior and pure lines are used for this purpose
· Mutant fish with superior character are used
· The brooders from different parental families much have deeper bodies with desirable qualities, like small heads, greater fatty make up.
· The population can be separated from original sources from at least two generations
· The brooders should have fastest growth rate, grater disease tolerance capacity and adaptable to extreme environment
· By chromosomal manipulation – Gynogenesis or Androgenesis
· Hormonal manipulation – Feminisation or Masculisation
· By genetic engineering – trangenesis or mutation

The fishes are selected by following criteria –

1. Body and development of fins
2. Better growth rate and better FCR value
3. Better disease tolerance capacity
4. Fatty make up (larger size and heavier growth rate)
5. Greater longevity
6. Higher fecundity
7. Greater adaptability in different stages and temperature variations
8. Hardier etc