Determining the most suitable method of otolith preparation for estimating the age of tigerfish, <i>Hydrocynus vittatus</i> in the Pongolapoort Dam, South Africa

Abstract

This study compares sectioned and whole lapillus and asterisci otoliths as suitable  structures for ageing tigerfish, Hydrocynus vittatus. Fifty tigerfish were collected from the Pongolapoort Dam, KwaZulu-Natal, South Africa. Growth zone counts on sectioned lapilli showed the greatest percentage agreement (52%) and highest precision (APE = 4.77%, CV = 6.20%). Growth zone counts were symmetrically distributed between  structures (Bowker’s tests P > 0.125). Between-reader analysis also showed sectioned lapilli to have the highest percentage agreement (68%) and best precision (APE = 5.55%, CV = 7.85%).

Key words: age, asterisci, lapilli, otolith, tigerfish.