Abstract
M.Sc.
The tigerfish, Hydrocynus vittatus, is one of the most sought-after game fish in
Southern Africa, and a vital source of protein and income in contiguous communities.
Unfortunately, this species has been placed on the protected species list, alongside the
infamous great white shark (Carcharodon carcharias). The loss of this species will not only
be disadvantageous to local communities, but will also have a damaging impact on the
Southern African tourism industry.
After reviewing all available literature on tigerfish, it was noted that studies on the
genetics, morphology, distribution, age, growth and maturity were severely lacking. Research
on the Pongolapoort Dam and Phongolo River tigerfish was also practically nonexistent. The
aims of this study were therefore to: (1) analyse the genetic variation and diversity of five
Southern African tigerfish populations and comment on the use of the various populations as
possible candidates for restocking; (2) assess whether the genetic composition and caudal
colour can be linked to the biogeography of the species; (3) determine the growth patterns of
tigerfish otoliths and establish the best ageing technique for this species; and (4) determine
the age structure of tigerfish from the Pongolapoort Dam in KwaZulu-Natal, South Africa.
Before analysing the genetic composition of various tigerfish populations, it was
hypothesised that individuals from the Okavango and Phongolo systems would possess the
highest and lowest heterozygosity, respectively. Tigerfish from the Olifants River would be
the best choice of brood stock, should population restocking become necessary. The muscle
and liver tissues of 117 tigerfish from the Upper Zambezi, Okavango Delta, Olifants and
Phongolo Rivers and Pongolapoort Dam, were assessed by starch gel electrophoresis.