Species separation and zoogeography of redfish and rockfish (genus Sebastes) by otolith shape analysis

Abstract

Interspecific otolith shape variation was investigated within the species-rich genus Sebastes (redfish, rockfish) as a tool for species separation, since morphological distinction has proven to be difficult. Otolith samples from all four North Atlantic redfish species, six commercially important rockfish species from the North Pacific, and Sebastes capensis from the South Atlantic were compared for differences in linear otolith measurements and elliptical Fourier-shape descriptors. A clear distinction between the North Atlantic and North Pacific / South Atlantic species (97% correct jackknifed classification) was achieved by univariate measurements and discriminant analysis of size-corrected Fourier descriptors. Overall species classification success was 91%, 94% within the North Pacific species and 88% within the North Atlantic samples. From the Pacific rockfish, Sebastes alutus otoliths showed the strongest affinity to the North Atlantic Sebastes. High similarity of otolith shapes of S. capensis to the North Pacific Sebastes and clear discrimination from North Atlantic species coincide with current zoogeographical and speciation theories, as well as with recently reported genetic results.