Occurrence and feeding of three shark species,Carcharhinus brachyurus,C. obscurus and Sphyrna zygaena,on the Eastern Cape coast of South Africa |
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| Abstract: | The shark species Carcharhinus brachyurus, C. obscurus and Sphyrna zygaena, which attain more than 2 m when adult, occur in coastal waters of the Southern Cape as juveniles. They use these coastal waters as nursery areas and their relative abundance there varies through the year, possibly because of seasonally varying oceanographic conditions. Adult C. brachyurus occur in the same geographic area but usually deeper, although there is some overlap in juvenile and adult depth ranges. Adult C. obscurus prefer the warmer subtropical and tropical waters north of the study area. Adult S. zygaena are found over deep reefs at the edge of the continental shelf. There was considerable dietary overlap between the three species, the prey of all three being dominated by small schooling fish, such as pilchard, and squid. For the three species, animals of total length >2 m took larger prey, such as elasmobranchs, with greater frequency, although they continued to prey on squid and schooling fish. It is postulated that the nursery areas are in the study area because of the abundance of food there, and that avoidance of cannibalism would be enhanced by the use of such nurseries. |
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| Keywords: | fishery management locally managed marine area (LMMA) Octopus cyanea |
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