Gobies and hake in the hypoxic waters of the Benguela up-welling current

Our aim is to investigate how the goby (Sufflogobius bibarbatus) and the shallow water hake (Merluccius capensis) cope with the hypoxic waters of the Benguela current. Both are key species of the ecosystem. They show a remarkable tolerance to the hypoxic conditions found in this up-welling area, which is one of the five most productive marine ecosystems of the world. Due to high sedimentation rate, large areas of the shelf are covered with hydrogen sulphide sediments, making hypoxic conditions above and i n the water column. As key species with strong influence on the ecosystem functioning and productivity, these species ought to have evolved a very special physiology and behaviour making them so successful in this extreme marine environment. We will use new acoustic methods (developed by Norwegian partners) to find individual hake and goby, and track their swimming patterns in the field. This method allows us to investigate (in the field) how the two species respond to changes in oxygen, sulphide and pr edator-prey conditions. To test our field generated hypotheses, we will conduct laboratory experiments where we will study their physiology and behaviour. Controlled experiments allow us to control water conditions (oxygen, sulphide levels), as well as to monitor the individual fish's swimming speed and activity level. Our research questions are based on pure, curiosity-driven research but they have applications for fisheries management. We will use an interdisciplinary approach wherein marine ecologistst s, environmental biologists, physiologists, fisheries biologists and behavioural ecologists will meet and work together. The new acoustic knowledge that the project will deliver may be a big step forward for the South African fisheries management institut ions in their estimations of species abundance using acoustic techniques. Through the project we will provide common research opportunities for scientists and post graduate students in the South Africa and Norway