New Technique for the Study of Sperm Whale Migration

Abstract

IN the southern hemisphere, female and young male sperm whales (up to about 39 feet long) are not normally found in higher latitudes than 40° S while large males occur in Antarctic waters^1–3; clearly many large bulls must migrate from the breeding areas into colder regions. Evidence of the return of large bulls to lower latitudes rests upon marking them in the Antarctic⁴ or external infestation by Antarctic Cocconeis or Cyamus⁵. Only a single mark⁵ has been recovered which provides direct evidence for the return north from Antarctic waters. This mark (USSR No. 650203) was fired on December 25, 1967, at 62° 22′ S 26° 25′ E and the whale was killed on May 13, 1968, off Durban. The small size of the male concerned (35 feet at death) makes this record rather surprising although Jonsgård⁶ did mention that the smallest whales from Antarctic waters were about 35 feet. Marking can provide information on only a small part of the whale population at considerable cost, freshness of the whale restricts the value of infestation as an indicator but the study of food remnants in sperm whale stomachs provides another method without these disadvantages.