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Open Access
Abstract:
A Bayesian Belief Network, validated using past observational data, is applied to conceptualize
the ecological response of Lake Maninjau, a tropical lake ecosystem in Indonesia, to
tilapia cage farms operating on the lake and to quantify its impacts to assist decision making.
The model captures ecosystem services trade-offs between cage farming and native fish
loss. It is used to appraise options for lake management related to the minimization of the
impacts of the cage farms. The constructed model overcomes difficulties with limited data
availability to illustrate the complex physical and biogeochemical interactions contributing to
triggering mass fish kills due to upwelling and the loss in the production of native fish related
to the operation of cage farming. The model highlights existing information gaps in the
research related to the management of the farms in the study area, which is applicable to
other tropical lakes in general. Model results suggest that internal phosphorous loading
(IPL) should be recognized as one of the primary targets of the deep eutrophic tropical lake
restoration efforts. Theoretical and practical contributions of the model and model expansions
are discussed. Short- and longer-term actions to contribute to a more sustainable
management are recommended and include epilimnion aeration and sediment capping.
