Observations on the food and status of the Cape clawless otterAonyx capensisat Betty’s Bay, South Africa

Abstract

The feeding ecology and status of Cape clawless otters were studied from April to December 1984 at Betty’s Bay, South Africa, and compared to similar studies along the Tsitsikama coast. Enough food, adequate cover and supply of fresh water were essential for the establishment of holts, while human disturbance was a limiting factor which caused an artificial clumping of holts. Analysis of 234 spraints indicated that fish was the most important prey category (59% of the biomass), then octopus (15% of the biomass), red rock crab Plagusia chabrus (13% of the biomass), Cape lobster Jasus lalandli (10% of the biomass) and the brown rock crab Cyclograpsus punctatus (0,8% of the biomass). The otters in the study area eat considerably more fish and lobster and less crab compared to those at Tsitsikama, although using the same foraging methods. Analysis of tracks, spraints and sightings indicated a population density of one otter per 2 km of coastline, approximately the same as found at Tsitsikama Coastal National ...