Statolith morphology of purpleback flying squid Sthenoeuthis oualaniensis in the central South China Sea

We studied the morphology, microstructure and demographic parameters of statolith of Sthenoeuthis oualaniensis from 90 individuals captured in the central South China Sea during September to October, 2012. The morphologic results show that the statolith had great lateral dome and wing dome, small dorsal dome and long narrow rostrum dome. S.oualaniensis in the central South China Sea could be devided intothree populations according to their statolith morphology. The total statolith length (TSL), wing length (WL), maximum width (MW) were logarithmically related to the mental length (ML) (P0.05); while the rostrum length (RSL) and dorsolateral length (DLL) were linearly related to the ML(P0.05). The absolute size and relative size of statolith gradually increased and decreased with increasing ML, respectively. The ratios of DLL, LDL, RSL and WL to TSL almost remained the same, being 48.05%, 60.05%, 35.44% and 67.59%, respectively; and the ratios of LDL and WL to TSL were relatively higher.