Talk description

Ecosystem models, such as Ecopath with Ecosim (EwE), integrate ecological processes, environmental dynamics, and human activities, making them valuable tools for developing ecosystem-based management strategies. With its new Habitat Foraging Capacity module (E-HFC), EwE can even offer a full spatial and temporal resolution of marine ecosystem dynamics. This makes EwE a powerful tool for the exploration of management strategies in tropical, small-scale fisheries allowing for the evaluation of socio-economic trade-offs.  However, time-series data and a clear understanding of what drives the distribution of organisms in the system are prerequisites for using EwE reliably. This information is usually missing for tropical, small-scale fisheries hampering the use of EwE for the exploration of management strategies.

A model case study is Chwaka Bay – a tropical bay system in East Africa (Zanzibar), where local communities heavily rely on fisheries resources, and concerns about overfishing have led to a need for more sustainable fisheries management. We used a recently developed Chwaka Bay Ecopath model to examine various gear and spatial management strategies. Faced with the lack of time-series data on biological and environmental variables, we explored different approaches for parameterizing the spatial-temporal capabilities of EwE and examined the use of local ecological knowledge to assess model outputs.