Distribution of beaked whales (Cetacea: Ziphiidae) off Southern New Zealand

Abstract

Sightings of 40 beaked whales (Cetacea: Ziphiidae) in waters to the east and south of New Zealand are discussed in relation to surface temperatures. (Only Mesoplodon layardi was specifically identified, once.) All but two sightings were recorded within a temperature range of 11.6°c to 16.9°c with a mean of 15.11 ± 0.53°c, which suggests that these animals were distributed adjacent to the Subtropical Convergence (approximately delineated by the 15°c isotherm in summer). The distribution of sightings indicates fewer ziphiids south of the Subtropical Convergence. Possibly this boundary marks the lower temperature tolerance of most species. The two anomalous sightings at 55° S in 7.3°c of water were probably close to the Antarctic Convergence (near the 4°c isotherm in summer).

Notes

Present address: Department of Zoology, University of Guelph, Guelph, Ontario, Canada.