Abstract:
Integrated Multi-Trophic Aquaculture (IMTA) combines fed species such as fish with extractive species such as seaweed and sea cucumbers to recycle nutrients and reduce waste in the production system. Although IMTA is technically feasible in Zanzibar’s coastal waters, adoption by local farmers remains limited. This study set out to explore the socio-economic, organisational, and knowledge-related factors that shape stakeholders’ willingness to adopt IMTA in Zanzibar. We used a mixed-methods design, combining an aquaculture farmer survey (n=50), semi-structured interviews with traders (n=9) and organisational key informants (n=9), focus group discussions, and field observations. The research was conducted across seven coastal locations on Unguja Island, covering seaweed, fish, sea cucumber and sponge farmers, fish traders, fisheries and aquaculture officers, and hatchery staff. Only one-third of farmers had heard of IMTA, and three-quarters had no clear understanding of the concept. Yet, 72% said they would be very likely to adopt IMTA if training, materials and financial support were provided. The most cited barriers were setup costs (96%), technical complexity (74%), and environmental concerns (58%). Correspondingly, farmers requested credit or grants (98%), materials (92%), and training (64%). Statistical tests showed no single dominant predictor of adoption intention, a finding that is likely influenced by the sample size, the contextual characteristics and the limited variance in responses. Qualitative analysis revealed that regulatory officers focus on factors such as governance coordination, traders on market reliability, and farmers on daily operational realities that must be addressed together. Zanzibar’s aquaculture stakeholders are willing to adopt IMTA but are not yet ready. Bridging this gap requires demonstration sites, co-investment mechanisms, maintained exchange and joint learning spaces as well as sustained organisational coordination and not another short-term project. The findings of this study will provide information that can be integrated into Zanzibar’s Blue Economy Policy and Fisheries Master Plan.