Researchers in geography and ecology together with an environmentalist association of Mayotte have recently conceived the citizen science project ‘Narisome muhoko’, meaning ‘We study the mangrove’. This project emerged at the end of an interdisciplinary research project on the resilience of two mangrove social-ecological systems (2018-2021) and at the time of the first Mangrove Management Plan (2019-2028) of the island. For each mangrove of Mayotte, the Plan is expected to be enforced by local authorities and/or associations. These stakeholders are particularly struggling with one of the tasks asking to “monitor the evolution of the ecological state and threats” in the absence of any instruction. The ‘Narisome muhoko’ project has two aims: 1. To operationalize this monitoring action by proposing relevant but easy to implement indicators that could be applied by citizens and/or technical agents; 2. To engage Mahore citizens in the management of the mangrove neighbouring their village using these indicators. It is planned to develop a set of indicators aimed at monitoring the evolution of the mangroves health state in response to different environmental pressures. Our experience allowed us to design a project based on the local ecological knowledge of inhabitants (Longépée et al., 2021) in a context where not all citizens have access to recent technologies or is a French speaker. The project first focuses on two mangroves of Mayotte, already studied by the team. In 2022, a team of trained citizens has started monitoring indicators of the phenology of mangrove trees and the regeneration of trees in several areas of the mangrove. At the same time, other indicators will be devised to assess the influence of waste and/or waste water on the mangrove ecosystem and to follow the practise of mangrove tree cutting. This project is in line with the complex systems thinking, aiming to encourage an adaptive management in the spirit of learning-by-doing (Berkes et al., 2003).