Geographic Variation in Opisthonema oglinum (Lesueur, 1818) in the Southeastern Brazilian Bight Inferred from Otolith Shape and Chemical Signatures

The thread herring Opisthonema oglinum (Lesueur, 1818) is a small pelagic fish distributed in the western margin of Atlantic Ocean from United States to Argentina. It target species for diverse commercial fisheries, including Brazilian industrial purse seine fleets that operate Southeastern Bight. To investigate geographic variation populations this fishing ground, sagittal otoliths were collected two areas: Rio de Janeiro (RJ: 23°04′ S, 44°03′ W) and Santa Catarina (SC: 26°05′ 48°18′ W). Otolith shape analyses multi-elemental signatures statistically evaluated using elliptical Fourier descriptors elemental/Ca ratios. Remarkable differences between areas found. previous scenario which constitutes single panmictic population now debatable. implications these results terms rational fisheries management are highlighted.