Title: The importance of seasonal flooding on the food-chain link between zooplankton and juvenile fish in the Okavango Delta, Botswana.
Student: Siziba Nqobizitha
Country of origin: Zimbabwe
University: University of Botswana Degree: PhD (Natural Resources Management)
Supervisor: Prof. Lars Ramberg; Prof. Moses Chimbari and K. Mosepele
Year of registration: 2009
Student number: 200808215

There is growing recognition of seasonal flooding as a driver of biological productivity in aquatic systems of semi-arid climates. Seasonal flooding of the Okavango Delta is largely influenced by the inflow from Okavango River. During flooding, nutrients are mobilised from inundated floodplains thereby stimulating biological productivity of the system. However, effects of water developments, climate change and variability are likely to reduce the seasonally flooded areas thereby negatively impacting on fish production and affecting people whose livelihoods depend on this resource. Field sampling will be conducted in primary, secondary and rarely flooded plains of the Delta. The objectives of the proposed study are to:

• determine the influence of temperature, dissolved oxygen, conductivity, turbidity, total nitrogen, total phosphorus, total dissolved organic carbon, chlorophyll a and macrophytes on zooplankton distribution, composition and abundance;
• determine the effect of flooding frequency on abundance and composition of zooplankton that emerges from floodplain sediments;
• determine food composition of selected juvenile and small fish species that utilise different study floodplains;
• determine the abundance and distribution of juvenile fish relative to the abundance and composition of zooplankton;
• determine the influence of macrophyte density, small fish species and zooplanktivorous macroinvertebrates on juvenile fish growth and survival rates.

The study will be conducted in the context of a multi-disciplinary programme at HOORC that seeks to address linkages between hydrology, ecology, livelihoods and policy in the Okavango Delta at different flooding regimes. The results of the proposed study will contribute towards improved fisheries management strategies through better understanding the relationship between zooplankton and fish production at different flooding regimes.

Last Modified: Tue, 18 Aug 2015 11:37:46 SAST