THE INVASION BIOLOGY OF THE AFRICAN SHARPTOOTH CATFISH, CLARIAS GARIEPINUS, IN SOUTHEAST ASIA

Abstract

The African sharptooth catfish, Clarias gariepinus, is a highly invasive species that has become widely established in Southeast Asia. Despite its potential far-reaching consequences, little is known about its life history and impacts in the region. My thesis aims to address these knowledge gaps, and elucidate the potential risks of this invasive species on native freshwater communities.

Using quantitative surveys and landscape models, I investigated drivers of Clarias gariepinus establishments in the Malay Peninsula and presented evidence that the species has adversely impacted native congeners. I then addressed taxonomic problems in the Clarias batrachus species complex, a native taxon which has declined in recent years partially owing to Clarias gariepinus introductions. Ecological niche models were subsequently utilized to investigate the potential global distribution of Clarias gariepinus. Finally, I elucidated the origins and invasion genomics of Clarias gariepinus in Southeast Asia, and patterns of gene flow with native counterparts.