Age and growth of Argyrozona argyrozona (Pisces: Sparidae) in a marine protected area: an evaluation of methods based on whole otoliths, sectioned otoliths and mark-recapture

Argyrozona argyrozona is an important component of the South African commercial linefishery. The purpose of this study was to develop a reliable protocol for estimating age and calculating growth. Methods based on both otoliths and mark-recapture data were investigated. Transverse sagittal sections from the Tsitsikamma National Park (TNP) showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. The first translucent check was shown by daily increment counts to mark the completion of the first annulus (i.e. not a juvenile/false check). Within reader (between counts) and between readers average percentage error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly underestimated the age of fish older than 10 years ( P