Geographical variation of harp seal underwater vocalizations

Abstract

Underwater vocalizations of harp seals (Phoca groenlandica) were recorded during the breeding season in the Gulf of St. Lawrence and north of Jan Mayen Island. Each herd had one unique call type and shared (often in different proportions) an additional 17 call types. Of these 17, 13 common call types had sample sizes large enough to permit statistical analysis of five duration, repetition, and pitch features. Only one of these call types exhibited no interherd differences; the others exhibited 1 – 5 different features. The average and maximum numbers of elements per call were higher in the Gulf than the Jan Mayen herd. Within each herd there were no differences in the call types and numbers of call elements over a 19-year period. An implication of these findings and other separate tagging studies is that the two herds are reproductively isolated.