Shark Catch Trends and Effort Reduction in the Beach Protection Program, KwaZulu-Natal, South Africa (Elasmobranch Fisheries - Oral)

Shark nets have been set off the beaches of KwaZulu -Natal, South Africa, since 1952, to minimise risk of shark attack. Reliable catch data for each of the 14 shark species commonly caught are available from 1978 only. The nets fish in fixed localities very close to shore and there is an absence of fisheries independent data for most species. There is uncertainty about factors such as localised stock depletion and philopatry. Catch rates of seven species show a significant decline, but this figure drops to four with the exclusion of the confounding effects of the annual sardine run. Of the four, two are caught in very low numbers (Java Carcharhinus amboinensis and great hammerhead Sphyrna mokarran) and it is probable that any decline in population size reflects either local depletion or additional exploitation elsewhere. The other two species (blacktip C. limbatus and scalloped hammerhead S. lewini) are caught in greater numbers. C. limbatus appears to have been subject to local depletion. Newborn S. lewini are captured by prawn trawlers and discarded, mostly dead, adding to pressure on this species. As a precautionary measure, and in the absence of clarity on the question of stock depletion, in September 1999 a process of reducing the number of nets per installation was begun, with a view to reducing catches. In addition, a final phase of experimentation with drumlines (set lines, each with a single baited hook) began in March 2001. Once complete, it is hoped that some of the remaining nets will be replaced with drumlines. Drumlines are mo re selective than nets in terms of shark species caught, and take little non-shark bycatch. An essential consideration throughout the process is that bather safety remains the priority.