DNA
This is a mass marking technique that isolates genetic markers on entire populations and manipulates allele frequencies of groups. The genetic modification only needs to be applied once for the marker will be passed to subsequent cohorts. Selection of spawners with a particular genotype can permanently change the allele frequencies of a fish population. This marking technique can provide permanent identification of hatchery verses wild populations. Another application is using genotype at selected loci to identify individuals but this is a costly proposition.
Advantages:
- Mark is permanent
- Can mark entire population
Disadvantages:
- Not practical for marking or identifying individuals
- Specialized equipment and training to read marks
- Time consuming
- May require several generations to mark