Projections of climate change effects on Lake Tanganyika (CLEAT)

Info

Start date: 1 January, 2015 End date: 31 March, 2021 Project type: Research collaboration projects in Danida priority countries (Window 1) Project code: 14-08AU Countries: Tanzania Thematic areas: Aquatic environment and resources, Climate change, Lead institution: Aarhus University (AU), Denmark Partner institutions: Tanzania Fisheries Research Institute (TAFIRI), Tanzania University of Dar es Salaam (UDSM), Tanzania Illinois State University (ISU), USA Enavigo Consult, Denmark Project website: go to website (the site might be inactive) Project coordinator: Peter Stæhr Total grant: 9,985,685 DKK Project files:

Project summary

Lake Tanganyika is an important ecosystem in eastern Africa, which historically has supported one of the world’s most productive freshwater fisheries. However, stocks of important commercial fish have decreased significantly. Scientific evidence suggests that fisheries are partly threatened by climate driven reductions in lake productivity. This project will provide a better understanding of how sensitive Lake Tanganyika is climate change and evaluate future sustainable fisheries. Based on active engagement with local scientists, students, fishermen and lake managers, the project will build capacity on contemporary lake monitoring to provide a fundamental understanding of how environmental conditions relate to fish yields and improve decision-making capacity for fishermen. The gathered data will be used as a platform to inform Tanzanians about their unique lake via local workshops targeted to local poor fishermen, and to lake managers and larger scale fishermen via seminars and through a new lake website. The data will also be used to develop the first full scale biogeochemical model of Lake Tanganyika, and be used to verify a decadal time series of satellite based observations of water temperature, algal biomass and primary production. Coupling this information with knowledge on fish species traits will allow us to investigate how abundance of important pelagic and littoral fish responds to temperature-mediated changes and compare this with effects of intensified fisheries.

Outputs

Project Completion Report
The overarching objective of CLEAT was to build local and regional capacity in understanding
the impact of climate change on the functioning and productivity of Lake Tanganyika, in order
to help develop a more sustainable fisheries for the local communities. We addressed this
through a transdisciplinary approach which involved 1) Monitoring of lake functioning (physics,
chemistry, biology), 2) Modelling of climate effects on lake functioning, 3) Understanding of
Peter Stæhr R455-A35173 Danida Fellowship Centre 8/17
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drivers of lake productivity, 4) fisheries management and 5) Knowledge transfer and education.
Emphasis in the project has been on strengthening capacity in data analysis and presentation
of findings such as publication of research papers. This has involved developing routines and
guidelines for quality assurance of essential data on water quality, fish landings, and fish
growth along with data based on qualitative interview techniques. These data has been the
backbone of the 3 Ph.D. studies and 2 master studies produced by the project. Most of the
data has been used directly in thesis chapters and publications and other have been used to
setup advanced state-of-the art models of lake functioning, including a fish productivity model.
These models are now being applied by PhD student to make predictions about how the lake
ecosystem will change under future climate scenarios. The importance of fishing equipment
and practices were investigated and interviews with local fishermen and stakeholders has
provided a deeper understanding of the complex interactions affecting the declining fisheries of
the lake. Project findings have been disseminated efficiently both at the local, regional, national
and international scale.
An automated monitoring buoy was developed and successfully deployed in the lake and has
produced essential data for model calibration and understanding of lake productivity. A peer
reviewed manuscript based on these data has been produced and the buoy itself attracted a
lot of media attention, in both national media and internationally including the journal National
Geographic.
Overall, CLEAT partners, in particular the Ph.D. students and staff at TAFIRI, have gained a
much deeper understanding of the complex interactions between human and natural
conditions affecting the functioning and fisheries of Lake Tanganyika. Findings show that
fishermen perceive changes to the environment and fisheries consistent with climate impacts,
however their decisions and actions in relation to these changes are also strongly influenced
by cultural, economic, and religious variables. This important result from our project has been
presented at the highest political level in Tanzania and supported by a policy brief which clearly
states that regional lake management hinges on effective integration of knowledge from local
fishermen, stakeholders and policymakers. This will hopefully help promote alternative
livelihoods and more sustainable fishing practices that are grounded in locally and culturally
relevant systems.
Peter

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