Genetic structure of the beaked whale genus Berardius in the North Pacific, with genetic evidence for a new species

International audienceThere are two recognized species in the genus Berardius, Baird’s and Arnoux’sbeaked whales. In Japan, whalers have traditionally recognized two forms of Baird’sbeaked whales, the common “slate-gray” form and a smaller, rare “black” form. Previouscomparison of mtDNA control region sequences from three black specimensto gray specimens around Japan indicated that the two forms comprise differentstocks and potentially different species. We have expanded sampling to include controlregion haplotypes of 178 Baird’s beaked whales from across their range in the North Pacific. We identified five additional specimens of the black form from theAleutian Islands and Bering Sea, for a total of eight “black” specimens. The divergencebetween mtDNA haplotypes of the black and gray forms of Baird’s beakedwhale was greater than their divergence from the congeneric Arnoux’s beaked whalefound in the Southern Ocean, and similar to that observed among other congenericbeaked whale species. Taken together, genetic evidence from specimens in Japan andacross the North Pacific, combined with evidence of smaller adult body size, indicatepresence of an unnamed species of Berardius in the North Pacific