Distribution and status of bottlenose dolphin Tursiops truncatus on the south coast of Natal, South Africa

Abstract

The offshore distribution and abundance of bottlenose dolphins Tursiops truncatus along the Natal South Coast was assessed aerially in May of 1989 and 1990. Unlike off the Natal North Coast and the Eastern Cape, a substantial proportion of sightings was made in water deeper than 30 m. This indicates that distribution on the South Coast may be different from that in other areas, possibly because of the presence there of offshore reefs, the continued degradation of the Natal inshore environment and the 1987 floods. There were probably fewer than 350 bottlenose dolphins off the South Coast, an apparent decline since the last survey of the area in 1985. Incidental captures of bottlenose dolphins on the South Coast average 24 animals per year, more than 7 per cent of the estimated maximum number. The consequences of this and also of the continued degradation of Natal's coastal zone are examined.