Descriptions of three PhD studies related to CLEAT

PhD study on building local capacity of sustainable fisheries

This study will examine the perception of lake conditions and fisheries among local fishermen, their communities and local authorities. Investigations will be restricted to regions bordering the Tanzanian shorelines. Understanding of local skills, knowledge, needs, and socio-economic problems related to fisheries, will be investigated through interviews and historical analysis of demographic and economic conditions. The study will provide an understanding of social and economic issues related to environmental changes occurring in Lake Tanganyika. The gathered understanding will aid in the development of a plan for environmentally and economically sustainable management of lake resources. Importantly, the activities associated with this study will help activate, motivate and engage the local communities in development of a more sustainable use of lake resources.

PhD study on the physical and biogeochemical functioning of Lake Tanganyika

The main objective of this PhD study is to understand and quantify the importance of climate forcing for nutrient entrainment through the stratified layer in lakes and the linkages to primary production in the upper mixed zone. The PhD student will analyze temporal patterns in the physical and chemical data to assess changes in mixing and stability of the lake (WP1), and link this to biological data using models (WP2) to identify potential impacts of these changes. Data will be collected by the student in collaboration with local scientists. In addition, the student will use environmental sensors on a buoy system to provide coupled physical and meteorological data to understand the relationship between air temperature and wind speed and lake conditions. This will also be incorporated into a 3D hydroecological model. Together, these elements will help understand and quantify process- and mixing-rates in the lake, and thus elucidate the link between nutrient entrainment and pelagic primary production. Ultimately, the data will be incorporated into a 3D hydroecological model that the student will be able to utilize to quantify the effects of climate forcing on physical and ecological dynamics. Work with the model will be done through a 2 x 5 month stay at Aarhus University (AU) in Denmark, where the PhD student will work closely with AU researchers to learn how to run the model (a beta version will have been developed at this stage), how to parameterize model process rates, how to extract and validate data from the model, and how to make future projections using the model.

PhD study on fish biology and potential impacts of climate change on fish populations

This study will examine changes in fish biology as a means for identifying potential changes in fish populations due to climate. The main fishery focuses on three endemic pelagic fish species, whose catches have been declining. Two previous studies on fish biology conducted over the past few decades (1993-1994 and 2003-2007) provide historical data for comparison. Collaborating with local scientists, the student will collect data on fish 5 of 10 growth rates, mortality, fertility, and local yields (WP3 and 4). This modern dataset can then be compared with the previous data, which will allow the student to determine the magnitude and mechanisms of change (climate vs overfishing). In addition, the student will also assess population demographics of several near-shore fish species, which may be becoming alternative fish stocks with the decline in pelagic fish yields and increasing fishing pressure. The PhD candidate will also use the software EcoPath to model fish production in the lake under different climate scenarios. EcoPath will use output from the 3D lake model together with data collected by the PhD candidate for modeling. This will be done through a 2 x 5 month stay at Aarhus University (AU) in Denmark, where the PhD student will work closely with researchers to learn how to run the model.