Threat to South Africa’s Great White sharks comes from inbreeding

Inbreeding is threatening South Africa’s Great White shark population with a new study showing that the species has the lowest genetic diversity of all white sharks in the world.

The South African Great White Shark is suffering badly from inbreeding according to new research Image by James Mostert / CC BY 2.0

The research has found that only four genetic groups exist among the South African population but that in reality 90% belong to the same group. The South African Sunday Times reports that this kind of ‘inbreeding’ with an already highly threatened species, could make it very hard for these sharks to survive in future decades.

Great White Shark suffering from lack of genetic diversity  even worse than the endangered bottlenose dolphin Image by Lwp Kommunikáció / CC BY 2.0

The Stellenbosch University research project found only four maternal genetic lineages remaining in this indigenous population. Dr Sara Andreotti‚ who headed the research‚ stressed that in comparison to other marine species, the plight of the sharks was even below that of the “highly endangered bottlenose dolphin.” She believes the current low gene pool resulted from increased shark kills or because of the historical local extinction and re-colonization process.

The South African research, when compared to other studies in the US and Australia, concluded that the white sharks were stronger population-wise because they had greater diversity. Dr Andreotti called for further probes into the behaviour and migration patterns of these sharks so that a possible solution to their situation could be found.

The reality is that if these animals became extinct, it would have serious affects on the marine environment. As well as keeping Cape seal numbers down, sharks traditionally get rid of the sick among mammal and fish populations.