This document describes the general approach for the development of marine assessments or State of the Marine Environment reporting (SoME) under the Mami Wata project. The methodology follows the structure and approach described in the Integrated Environmental Assessment Training Manual (UNEP/IISD 2009) and offers, depending on availability of data and information, different options to develop SoME reports: literature-based, indicator-based or expert consultation approaches. The methodology has been adapted to the regional context in the member states of the Abidjan Convention by incorporating best practices, case studies and feedback.