Large marine ecosystems (LMEs) are regions of the world's oceans, encompassing coastal areas from river basins and estuaries to the seaward boundaries of continental shelves and the outer margins of the major ocean current systems. They are relatively large regions on the order of 200,000 km² or greater, characterized by distinct bathymetry, hydrography, productivity, and trophically dependent populations. Productivity in LME protected areas is generally higher than in the open ocean.
Although the LMEs cover mostly the continental margins and not the deep oceans and oceanic islands, the 66 LMEs produce about 80% of global annual marine fishery biomass. In addition, LMEs contribute USD 12.6 trillion in goods and services each year to the global economy. Due to their close proximity to developed coastlines, LMEs are in danger of ocean pollution, overexploitation, and coastal habitat alteration.
Since 1997, IOC has promoted the Large Marine Ecosystem approach from a scientific point of view as well as in regions by contributing to the formulation and implementation of Global Environment Facility (GEF) LME projects. The Global Environment Facility has provided support (USD 285 million, leveraging USD 1.14 billion in financing from other partners) to 124 recipient countries to work together within 23 of the world’s 66 LMEs.
The GEF LME:LEARN (Large Marine Ecosystems Learning Exchange and Resource Network) is a project financed by GEF, implemented by UNDP and executed by IOC-UNESCO, aiming to improve global ecosystem-based governance of LMEs and their coasts by generating knowledge, building capacity, harnessing public and private partners and supporting south-to-south learning and north-to-south learning. The hitherto implementation of the project has contributed, inter alia, to the High Level Objective 1: Healthy Ocean Ecosystems and Sustained Ecosystem Services, of the IOC Medium-Term Strategy for 2014–2021, by building local and regional capacities, in terms of knowledge and tools, for implementing ecosystem based approaches in the marine environment.