Use of otolith shape for stock identification of John's snapper, Lutjanus johnii (Pisces: Lutjanidae), from the Persian Gulf and the Oman Sea

Abstract

The otoliths of John's snapper (Lutjanus johnii) from the Persian Gulf and the Oman Sea were studied to evaluate whether otolith shape can be used to differentiate populations. John's snapper is a relevant commercially exploited species in the Arabian Sea, and the identification of different stocks is a major issue for fishery management. Otolith weight was used to examine the growth rate of both populations and as an indicator of similar ambient water composition. Otolith contours were obtained using wavelet functions, from the finest (WLT 1) to coarsest (WLT 9) scales, and then compared by principal components (PCA) using a canonical discriminant analysis (CDA) for each scale. No significant differences were noted in the otolith weight between the two populations (ANCOVA, P>. 0.05). The variability of the finest scales (WLT 1-3) was very high and showed a low percentage of classification (61%). The intermediate scales (WLT 4-6), and WLT 8 provided the best results; whilst the highest classification percentage was found in WLT 4 and WLT 8 (76% and 77%, respectively). The results of this study enable us to conclude that both populations should be considered separate stocks. © 2014