Determination of most reliable bony structure for ageing of aspius vorax inhabiting Karakaya Dam Lake (Malatya-Turkey)

The target of this study is to determination of the most reliable bony structure for ageing of Aspius vorax (Heckel, 1843) in Karakaya Dam Lake (Malatya, Turkey). The age determination method and its accuracy are the most important subjects for the evaluation of age, weight, sex and length relationships in fisheries biology. In this study, different kinds of "bony structures" are used such as scales, vertebrae, operculum otoliths and dorsal spine of A. vorax removed from each fish were examined by two readers three times each without reference to any data except the date of capture. A total of 73 specimens (27 female and 46 male) were examined. The highest percentage agreement (PA) and lowest index of avarage percentage error (APE) and coefficient of variance (CV) values were found between vertebrae and opeculum estimates and they were most suitable ageing structure in A. vorax. It was understood that operculums were the best bony structure for the age determination of A.vorax followed by vertebrae, dorsal spine and scale. In this work, we didn't preferred the otolith for detect age because of it was impossible for ageing.