An Original Theoretical Framework for Modelling the Economic Value of the Nigerian Blue Economy and Its Marine Engineering Dimensions

The blue economy concept, encompassing economic activities derived from oceans and coastal resources, has gained significant policy traction in Nigeria, yet the theoretical frameworks available for comprehensively valuing its constituent sectors and their interdependencies remain underdeveloped for the African coastal context. This study develops an original theoretical framework for modelling the economic value of the Nigerian blue economy, with particular attention to the marine engineering-intensive sectors of maritime transport, offshore energy, port services, and marine environmental services. The research employs a theoretical framework development methodology drawing on environmental economics, maritime economics, ecological economics, and systems thinking literature. A value accounting structure is proposed that integrates market-price-based valuation, non-market ecosystem service valuation, and dynamic computable general equilibrium modelling of sector interdependencies. The framework introduces the concept of the marine engineering value chain as a structural organising principle for mapping the contribution of marine engineering activities to blue economy value creation. Application of the framework using available national accounts data and survey-based sector estimates produces the first comprehensive estimate of the total economic value of the Nigerian blue economy at approximately fourteen percent of GDP, substantially higher than existing partial estimates. Theoretical contributions include novel methods for accounting for the value of marine safety services and the opportunity cost of environmental degradation in blue economy accounting. Keywords: blue economy, economic valuation, marine engineering, Nigerian maritime sector, computable general equilibrium