Selection of Dosages of Oxytetracycline for Age Validation Studies

Abstract

Oxytetracycline (OTC), injected to mark the otoliths of sablefish (Anoplopoma fimbria), causes mortality directly in proportion to the dosage administered. The selection of an appropriate dosage requires minimizing mortality while maximizing the number of fish that have a usable OTC mark. Laboratory studies could not be used to determine appropriate dosages. Dosages that substantially increased mortality in the ocean did not cause any mortality in the laboratory. For sablefish, we recommend a dosage of 25–35 mg OTC/kg fish.