Validation of daily growth increments in otoliths of Anguilla rostrata (Lesueur) elvers

Abstract

The presence of daily growth increments in otoliths was validated for Anguilla rostrata. Elvers were captured at the freshwater–seawater interface of the Annaquatucket River, Rhode Island, immersed in a tetracycline hydrochloride solution to mark their otoliths, and maintained in stream aquaria for 10 or 20 d. Increment counts outside the tetracycline mark generally underestimated the number of days since marking by less than 5%. This underestimation was probably due to the time required for tetracycline incorporation after administration.