Chapter 3: Healthy and Biologically Diverse Seas

Introduction

The first report on marine stewardship, Safeguarding Our Seas, outlined a vision of clean, healthy, safe, productive and biologically diverse oceans and seas. In 2005, the first full assessment of the state of the UK seas, Charting Progress, showed that they were productive and supported a wide range of fish, mammals, seabirds and other marine life; however, it also reported evidence that human activities such as widespread commercial fishing practices were harming marine ecosystems, and that climate change was affecting the health of the seas.

This chapter builds on the outcome of Charting Progress, showing progress that has been made towards the vision of healthy and biologically diverse seas. Based on the Feeder Report prepared by the Healthy and Biologically Diverse Seas Evidence Group – the largest and most comprehensive assessment ever completed of the health of marine ecosystems in UK waters – Charting Progress 2 focuses on the biological aspects of the UK seas. The chapter begins with an assessment of benthic habitats, which are of interest for the communities and species they contain, moving on through the primary producers at the base of the food chain (microbes and plankton) up through fish to top predators such as seabirds and cetaceans. Figure 3.1 shows the six broad habitat types found in UK waters.

The chapter includes sections on two important groups that were not included in the Charting Progress assessment: microbes and turtles. In the past few years, microbes – bacteria, archaea, viruses and many protists – have become more widely recognised as vital parts of the marine ecosystem. All marine turtle species found in UK waters have international protection and the UK therefore has a responsibility to contribute to their conservation and report on their status. We have also added waterbirds to the assessment of marine birds as they depend on marine habitats for foraging and other activities.

Where there were sufficient data, the assessments are based on formal protocols. However, where the data and available assessment techniques were inadequate we have relied on the judgement of experts to fill the gaps. It is important to note that although we are reporting on change in the past five years we have also looked at data over the longer term to set this in context. The timeframe for each assessment varies depending on the information available for each topic. Full details concerning methodologies, data sources and assessment timeframes can be found in the Feeder Report.