More clarity on the main problems

Chapters 2 to 6 and particularly Chapter 7, have identified the main problems that are preventing us from achieving the vision for the UK seas and in many cases their probable causes across the eight UK regions. This helps us to prioritise our efforts to improve our understanding of the relationships between the pressures and the impacts and informs regulators of where additional measures might be necessary.

Better criteria to determine whether the seas are clean, healthy, safe, productive and biologically diverse

All the Evidence Groups stressed the need to have clearer criteria and targets for defining what we mean by clean, healthy, safe, productive and biologically diverse seas. For this assessment we have used thresholds set in International and European frameworks or those under development at national level, which indicate whether a desired quality has been achieved. For example, to assess whether the seas are clean with respect to particular contaminants, we took measurements of the concentrations of the contaminants in water, biota and sediment, and compared them with concentrations that cause no adverse effects to humans or sea life according to experiments. However, there are no clearly established criteria for some aspects of the vision, for example, the impacts of noise and litter on marine organisms, making it difficult to measure our progress in some areas. The EU Marine Strategy Framework Directive will help with the development of such criteria at European level.

Setting appropriate baselines and targets

A related issue is the question of the state we want our seas to reach in order to be clean, healthy, safe, productive and biologically diverse within a framework of sustainable development. Some of the thresholds used (for example those derived from the EU Water Framework Directive) use a state that was ‘natural’ before human pressures were introduced as a reference. Others, for example, those for the fisheries assessment undertaken by the Productive Seas Evidence Group are based on the EU Common Fisheries Policy, which aims for the harvesting of fish at sustainable levels. When assessing habitats and species, we have sometimes found it difficult to determine what a natural state is; ecosystems are dynamic, and change due to natural causes, and in some cases monitoring programmes have started too recently to provide accurate records of natural conditions. The Charting Progress 2 assessment has used the assessment criteria that are widely used for assessing the state of the seas, and has not attempted to resolve this issue. Policy makers will need to address this tension between natural conditions and sustainable use, particularly when developing the targets needed to achieve Good Environmental Status under the EU Marine Strategy Framework Directive.

A truly integrated approach to assessments remains a challenge

Significant progress has been made in understanding the impacts of individual pressures on sea areas, but assessing the impacts of multiple pressures and determining the most important human impacts have still to be realised. Adopting an ecosystem-based approach requires an understanding of how the various pressures contribute to any change in the structure and functioning of ecosystems. An appropriate methodology is needed. However, some thought for the scale at which these assessments must be made, which will vary in relation to the species being assessed or the pressure being investigated, will be required as part of this process. Furthermore, care is needed to avoid the possibility of aggregating data to an inappropriate scale.

More coverage

In many cases, our assessments of state are based on limited data sets or expert judgement. For example, we have habitat maps available for around only 10% of the UK continental shelf. One way we have tried to address this is to carry out risk- or pressure-based monitoring programmes, involving sampling where we expect to find problems, based on our knowledge of where the main pressures will be. However, for a more robust picture, we will need better information. Chapters 2 to 6 have highlighted a number of gaps in our knowledge of various aspects of the marine environment which limit our ability to assess its real status.