Mpilonhle Nyawo


Mpilonhle Nyawo


 

Do submarine canyons influence the diversity and structure of benthic fish assemblages occurring on the continental shelf edge?

Submarine canyons are steep­walled valleys that cut across continental margins around the world. Characterised by a complex topography, canyons have the ability to influence current patterns and provide a heterogeneous set of habitats. They also play an important role in providing goods and services to human population. Most importantly, these goods and services include supporting fisheries. The evidence of higher complexity and species abundance, biomass and diversity around canyons, compared with areas away from canyons is emerging and points to canyons being hotspots for biodiversity. Off the eastern seaboard of South Africa, the heads of the numerous deep canyons that are carved into the shelf edge emerge relatively close inshore. This suggests that the ecological role of these canyons may be important not only to the deep­sea environment that they extend down into, but that they may also be strongly connected ecologically to the adjacent inshore zones. Being close to the shore also suggest that these canyons are easily accessible by small boats and there is evidence to suggest that they are actively targeted for both pelagic and bottom fishing. Regarding marine geology, the east coast submarine canyons have been mapped, however, very little research has been focused on the ecological functioning of South Africa’s submarine canyons. Thus, the importance of canyons for biodiversity, conservation and the provisioning services that they support is not well understood. The aim of this study is to then generate an understanding of the role of canyons in influencing benthic fish community structure at the continental shelf edge. The results presented by this study will contribute to a comprehensive documentation of benthic fish that inhabit canyons. The findings will further contribute to understanding the importance of submarine canyons as biodiversity hotspots that are ecologically linked to inshore areas. Lastly, the results will aid in understanding the variability amongst submarine canyons, which will support the design of the Marine Protected Area (MPA) network and zonation of individual MPAs that include canyon heads. 

Registered at: Rhodes University (Dept. Ichthyology and Fisheries Science)

Supervisor: Dr Anthony Bernard (SAIAB)
Co-Supervisor: Tamsyn Livingston (Ezemvelo KZN Wildlife)