SHARK RESEARCH PROGRAMME DEPARTMENT OF ZOOLOGY UNIVERSITY OF STELLENBOSCH PRIVATE BAG X1, MATIELAND 7602, SOUTH AFRICA.

E-mail: dsadie@maties.sun.ac.za

BACKGROUND INFORMATION

The University of Stellenbosch is one of the oldest universities in South Africa. Its Department of Zoology was founded in 1903. Under leadership of with the scientific giants, Robert Broom and later Con de Villiers it achieved international recognition as one of the best schools of comparative anatomy in the world. In recent years it also branched out into the fields of comparative physiology, herpetology, ecology, ethology, ecotoxicology and molecular biology.

Our shark research programme was initiated in 1997 and is growing rapidly despite a very restricted research budget. It now involves several staff members and their postgraduate students. From 1999 onwards we will also be able to accommodate a limited number of postgraduate students from overseas universities (no more vacancies for 1999).

CURRENT PROJECTS 

Assessment of the possible impact of cage-diving operations on the behaviour and activity patterns of white sharks at Dyer Island (an offshore seal island near Gans Bay, South Africa)

Gathering of information on the operating procedures of South African white shark cage-dive operators, their role in the local economy and the pros and cons of regulating/permitting continued cage-diving.

Gathering of quantitative data on the numbers of sharks that visit cage-dive sites, the frequency and nature of potential disturbances/injuries to the sharks and how cage-diving operations affect their abundance, short-term and long-term movements, feeding patterns and behaviour.

Gathering of information on the behaviour of white sharks towards boats, surfers, scuba divers, abalone divers, spearfishers and commercial divers at cage-dive sites and sites where cage-diving is not allowed.

Comparative studies on smaller shark species (mostly in captivity but also some field studies at selected undisturbed sites) to determine how long it takes to condition sharks and whether repeated disturbances of the sharks affect their growth, reproduction, behaviour or blood chemistry (cell counts; pH; lactate levels; inorganic ion levels; glucose, lipid and protein levels; growth hormone levels; catecholamine and other stress hormone levels). 

A comparative study of the hematology and blood chemistry of common South African shark species

Documentation of normal species differences in blood cell counts, hematocrit (packed cell volume), haemoglobin levels and oxygen carrying capacity of the blood; correlation (if possible) of the observed differences to the taxonomy, evolutionary history or current life style of the various species.

Microscopic and electron-microscopic studies of red blood cell and white blood cell size, shape and structure in these shark species.

Comparative studies of the normal (unstressed) blood chemistry of these species (osmolarity and pH of the blood, concentrations of various inorganic and organic ions etc)

Effects of handling, angling stress and live transport on the blood chemistry of common South African sharks.

Investigation of the levels of stress hormones in the blood of sharks captured during tag-and release angling competitions and comparison with stress hormone levels in unstressed sharks (project 2)

Investigation of post-release mortality of sharks (if any) caught in angling competitions

Recommendations, if necessary, to reduce tag-and release mortality in angling competitions