Large marine ecosystems

Background

Large Marine Ecosystems (LMEs) are regions of ocean space encompassing coastal areas from river basins and estuaries to the seaward boundary of continental shelves and the seaward margins of coastal current systems. Fifty of them have been identified. They are relatively large regions (200 000 km2 or more) characterized by distinct bathymetry, hydrography, productivity and trophically dependent populations.

Types of LMEs

Several LMEs occupy semi-enclosed areas, such as the Black Sea or the Mediterranean. They can be divided into subareas (e.g. the Adriatic Sea). Others are limited by open continental margins (e.g. the Northwestern Australian shelf). Their seaward limit extends usually beyond the continental shelf. As they are defined by natural parameters, they often straddle political boundaries. They have been identified for the purpose of comprehensive monitoring of their condition. They could be used as a basis for ecosystem-based management of shared natural resources.

LME Project

The LME project was launched after the 1992 Earth Summit (UNCED, Rio de Janeiro, 1992) as one of the ways to halt, and even reverse, the deterioration of coastal waters. The primary objective of the LME project is to improve global prospects for the long-term sustainability of international and coastal aquatic resources and environments. This entails preventing, reducing and controlling degradation of the marine environment; developing and increasing the potential of marine living resources to meet human nutritional needs as well as social, economic and development goals; promoting the integrated management of coastal areas and the marine environment.

The project provides scientific and technical assistance to developing countries committed to monitor the state of the LMEs and to adopt new policies and actions for eliminating practices leading to degradation of coastal environments and losses in biodiversity and food security.

The LME approach uses five modules:

  • a productivity module considering the oceanic variability and its effect on the production of phyto and zooplankton;
  • a fish and fishery module concerned with the sustainability of individual species and the maintenance of biodiversity;
  • a pollution and ecosystem health module examining health indices, eutrophication, biotoxins, pathology, and emerging diseases;
  • a socio-economic module integrating assessments of human forcing and the long-term sustainability and associated socio-economic benefits of various management measures;
  • a governance module involving adaptive management and stakeholder participation.

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