Abstract: Otolith shape analysis has been widely used for stock discrimination. To examine population exchange between stocks in the East Antarctic, we computed six otolith shape indices (form factor, roundness, circularity, rectangularity, ellipticity, and aspect ratio) and elliptic Fourier coefficients for Dissostichus eleginoides from the Kerguelen Islands and the Crozet Islands. Prior to analysis, the influence of individual allometric effect on otolith shape was excluded. Principal component analysis was applied to select the components for subsequent discriminant analysis. We combined the shape indices with the elliptic Fourier coefficients and conducted a discriminant analysis, which had a success rate of 80.00% in the classification of our data. The otolith shape of D. eleginoides from the Kerguelen Islands are similar to those from the Crozet Islands; there are slight differences occur in between the outer edges of the otoliths from the two areas. Otolith shape analysis results and tagging and genetic data from previous studies support a preliminary inference of a population exchange between D. eleginoides from the Crozet Islands and those from the Kerguelen Islands. To elucidate the proportion and mechanisms of stock exchange between two areas, multiple approaches, including otolith chemistry and tagging, are needed.

Key words:  Dissostichus eleginoides, otolith shape, shape indices, elliptical Fourier analysis, discriminant analysis