Evaluation of Thermal and Chemical Marking Techniques for Tilapia

Abstract Hot, freeze (liquid nitrogen), and chemical (silver nitrate and potassium permanganate) brands were applied to juvenile and adult Tilapia nilotica. Application efficiency was considered and the persistence and the clarity of marks were evaluated for a 61-d period. For juvenile fish (initial weight 2.2 g), freeze brands were most effective, heat brands were less satisfactory, and chemical brands failed all criteria. No brands, regardless of the application method, persisted when they were applied to adults (mean weight 100 g), or when they were obscured by scale regeneration.