Features » Sub Antarctic notothenioid fish systematics


The suborder Notothenioidei includes several families of fishes that evolved in and inhabit the Southern Ocean. To be able to survive in the ice-laden waters around Antarctica and its associated islands these fishes developed a number of adaptations, including a group of organic molecules called antifreeze glycoproteins or AFGPs. These AFGPs help depress the freezing point of blood serum and other body fluids below that of the seawater thus preventing the freezing of these fishes. Over time several species have become widespread in the Southern Ocean and inhabited the waters around sub-Antarctic islands, including the South African Prince Edward Islands (PEI) in the south Indian Ocean.

The Prince Edward Islands are young islands, not older than one million years, and with a temperature range of 3-8°C their water is ice-free. Fishes inhabiting the waters surrounding these islands are living close to or at the limit of their metabolic systems. Because of this, they would be expected to have inactive AFGP genes, or even lose them altogether and evolve into different species.  In addition, having the AFGPs where they are not needed makes the sub-Antarctic populations vulnerable to predation and to environmental change such as global warming.

Past morphological studies divided populations from ice-laden waters and ice-free waters into sub-species or even species. However, Gon & Klages (1988) and DeWitt et al. (1990) found no justification for these actions and Gon et al. (1994) showed that Notothenia coriiceps at Marion Island most likely has AFGPs in its blood.

The objective of the current project, a PhD study by Ms Tshoanelo Moloi funded by the South African National Antarctic Programme (SANAP), is to determine the taxonomic status of the sub-Antarctic population using modern molecular genetics methods and investigating their AFGPs attributes.

Research Team:

Principal Investigator: Ofer Gon

Collaborator: Dr Monica Mwale 

Collaborator from the University of Illinois, USA: Prof Chi-Hing Christina Cheng

Student Assistant: SAIAB PhD Student Tshoanelo Moloi

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