GENETIC TAGGING OF HUMPBACK WHALES

The ability to recognize individual animals has substantially increase d our knowledge of the biology and behaviour of many taxa(1). However, not all species lend themselves to this approach, either because of i nsufficient phenotypic variation or because tag attachment is not feas ible. The use of genetic markers ('tags') represents a viable alternat ive to traditional methods of individual recognition, as they are perm anent and exist in all individuals. We tested the use of genetic marke rs as the primary means of identifying individuals in a study of humpb ack whales in the North Atlantic Ocean. Analysis of six microsatellite loci(2,3) among 3,060 skin samples collected throughout this ocean al lowed the unequivocal identification of individuals. Analysis of 692 ' recaptures', identified by their genotype, revealed individual local a nd migratory movements of up to 10,000 km, limited exchange among summ er feeding grounds, and mixing in winter breeding areas, and also allo wed the first estimates of animal abundance based solely on genotypic data. Our study demonstrates that genetic tagging is not only feasible , but generates data (for example, on sex) that can be valuable when i nterpreting-the results of tagging experiments.