Kittiwake Rissa tridactyla, taking off from water, Farne Islands, Northumberland

Marine environmental indicators review

We commissioned a review of marine environmental indicators reporting on the biodiversity aspects of ecosystem health.

Selecting environmental indicators

The review looked at the range of existing and proposed indicators the UK was signed up to, both domestically and internationally.

It identified those best suited to give an overview of marine ecosystem health and the sustainability of human activities.

The UK has a range of domestic policies and international commitments which include targets for environmental improvement. However, it is not always clear how effective the various actions taken by the government, or its bodies, are in achieving these particular conservation aims, if at all.

Therefore Governments, including the UK, now set environmental indicators, which can inform decision-making and help measure and report on changes in environmental status and progress towards achieving conservation goals and objectives.

Kittiwake pair standing on rock, Isle of May National Nature reserve

A 'suite' of indicators

In the marine environment, many of the targets and indicators we use to measure performance towards good conservation status are either directly from international commitments, or are domestic versions to be used at the national level.

Although many of these indicators are very similar they are not always exactly the same – this, and the numerous sources of indicators, can lead to confusion.

Traditionally, most environmental indicators describe the quality or status of a particular aspect of the environment. A clear message which emerges from examining the different approaches to selecting indicators is that it is preferable to reflect and report on the status of the whole ecosystem, and its structure and function.

Therefore a 'suite' of indicators rather than a single one will be needed to adequately report on marine ecosystem health, structure and function.

This approach supports the desire for a more holistic, ecosystem-based approach to the management of human activities. It also helps to deliver 'good environmental status', which is the aim of the EU Marine Strategy Framework Directive.

The ecosystem-based approach is being advocated by many forums and organisations, and is particularly relevant to the mobile marine environment where boundaries tend to be more arbitrary.

Proposed suite of marine indicators

As part of our report, a review of marine environmental indicators reporting on biodiversity aspects of ecosystem health, proposals for a coherent suite of indicators for the biodiversity aspects of marine ecosystem health for use in the UK were checked against six criteria.

This was to find those which effectively reported on ecosystem resilience, structure and vigour. The final suite was divided into three themes, covering fisheries, biodiversity and water quality and pollution. 


An indicator developed around the theme of fish community structure could be linked to the UK's objective of conserving and enhancing the status of marine biodiversity, while also monitoring the objective of achieving sustainable fish stocks.

Therefore, it would provide a link back to the impacts of fishing, ie human impacts, and hence should feed back into management actions which can improve the status of the indicator. An illustrative example is the indicator proposed by OSPAR - 'Changes in proportion of large fish'. 


An indicator developed around the theme of biodiversity community structure would report on the status of marine biodiversity and communities and would be useful for reporting on habitat complexity. An illustrative example is the UNCSD (United Nations Commission on Sustainable Development) indicator - 'Connectivity/fragmentation of ecosystems'.

Water quality and pollution 

An indicator developed around the theme of hazardous substances would measure the quality of the marine environment. It would also link to activities that are the subject of management measures (eg discharge consents), which makes it possible to influence the water quality trend(s) highlighted by this indicator. An illustrative example is the European Environment Agency indicator – 'Hazardous substances in marine organisms'.