Ecosystem approach to marine resources (EAMR)

Background

After decades focusing on the study and management of single species, fisheries management is evolving towards ecosystem based approaches. These regard the ecosystem as the most relevant unit, emphasising that resilient ecosystems are crucial to maintain the sustainability of marine goods and services. The FAO Reykjavik declaration of 2001, reinforced at the World Summit on Sustainable Development in Johannesburg in 2002, requires nations to use an ecosystem approach to develop policy governing the exploitation of marine resources by year 2010. Nations are further required to restore depleted fish stocks by 2015, and to establish representative networks of Marine Protected Areas by 2012.

To fulfil these requirements, a strategy based on innovative and integrated science is needed to address the complexity of marine ecosystems and to propose operational management frameworks. The Ecosystem Approach to Marine Resources is such a strategy.

EAMR must be built on a scientific rationale that links ecological processes to ecosystem-level patterns using models. The outputs of these models will be indicators of the state of the ecosystem, and will help managers to protect the integrity of the ecosystem without crossing ecological limits. This will support the maintenance of viable fisheries policies.

Ecosystem approach to marine resources: moving from ‘fisheries oceanography’ towards ‘ecosystem oceanography’

Puffin feeding on North Sea sandeels. The consequences of fishing extend beyond targeted species. Photograph: Akinori Takahashi, Centre for Ecology and Hydrology, UK.

Bycatch is inevitable for most fisheries. Management decisions that consider the whole ecosystem are thus essential. Photograph: Arnaud Bertrand, IRD, France.

The scientific objectives of the Ecosystem Approach to Marine Resources (EAMR) are to identify, quantify and model the major ecological mechanisms that control exploited populations, their responses to climate and anthropogenic forcing, and their role in the ecosystem. The EAMR must consider ecosystem knowledge and uncertainties to facilitate a move towards ecosystem oceanography. Ecosystem oceanography takes a holistic view, integrating food-web dynamics with environmental and anthropogenic forcing to understand and predict changes in marine ecosystems. Implementation of the EAMR would also help in balancing diverse societal objectives.

Under a context of climate change and overexploitation the EAMR aims to answer specific questions about the functioning of marine ecosystems:

• Under which circumstances does the removal of top predators result in fundamental changes at lower trophic levels?
• Under which circumstances does the heavy exploitation of forage species, such as anchovies, herring or sardines, cause fundamental changes in the functioning of marine ecosystems?
• What are the combined effects of climate change and heavy exploitation on marine resources and how reversible are these effects?

The key to answering these questions and exploring whether general principles can be applied lies in understanding the energy flow within a specific ecosystem, through three emerging questions:

• Can we quantify and model the interactions between all the relevant ecosystem components so that abrupt patterns (e.g. ecosystem state changes) can be predicted?
• What drives marine ecosystem dynamics – the ocean climate, exploitation patterns, species interactions or the combined effect of the three?
• How can ecosystem oceanography contribute to the development of EAMR approaches that balance different societal objectives?