Oxytetracycline Bath
The tetracycline series (tetracycline, chlortetracycline, oxytetracycline) of antibiotics can be used as a marker in fish. The chemicals are deposited in bones of fish submersed in a chemical bath resulting in yellow-gold fluorescence detectable with ultraviolet illumination. Oxytetracycline can be injected into fins to make florescent marks only visible with ultraviolet light.
Advantages:
- Marking of calcified structures can provide accurate aging techniques, growth rates, age at maturity, longevity predictions and estimates of age-specific data such as catch rates, fecundity, mortality, and growth rates
- A large number of fish of any size may be marked within a short time
- The mark is permanent and has little impact on fish health
Disadvantages:
- Analysis is expensive, time consuming, and requires special equipment for mark recognition