AGE, GROWTH AND SEXUAL DIMORPHISM OF THE STRIPED DOLPHIN (STENELLA COERULEOALBA) OFF THE SOUTH-EAST COAST OF SOUTHERN AFRICA
Amy Bishop, William Froneman and Stephanie Plön
Rhodes University, Department of Zoology and Entomology, Nelson Mandela Metropolitan University

 

Abstract
The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin that is found worldwide in tropical to warm temperate waters. Globally populations are threatened by direct fishing, by-catch and pollution. Little is known about the life history of this species within South African waters and thus it is currently listed as Data Deficient by the IUCN. Critical to the conservation of this species is an understanding of basic life history parameters, including age, growth and morphometrics. The ages of 59 (34 males and 25 females) striped dolphins stranded along the south-east coast of South Africa were determined by counting the number of growth layer groups (GLG’s) in their teeth. A von Bertalanffy growth curve indicated that males attain physical maturity at about 21 years of age and 231.8 cm in length, while females reach physical maturity earlier at 18 years of age and 224.4 cm in length. Morphometric measurements of 104 individuals (63 males and 41 females) indicated the absence of any sexual dimorphism between males and females, with the exception of girth at the axilla, maximum girth, and pectoral fin length. This study has provided valuable information on the life history of the striped dolphin which can be employed in the management and conservation of the species in South African coastal waters.

 

Presentation Topic
AGE, GROWTH AND SEXUAL DIMORPHISM OF THE STRIPED DOLPHIN (STENELLA COERULEOALBA) OFF THE SOUTH-EAST COAST OF SOUTHERN AFRICA
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