Coasts and estuaries are dynamic areas and of great economic and environmental importance and are the final recipient of much of the pollution carried by rivers. They are also affected by pollution which occurs at sea and from our beaches.
Coastal areas are used for fishing, aquaculture, mineral extraction, industrial development, energy generation, tourism and recreation, and for waste disposal. They are also important for protecting the land from the influence of the sea.
An estuary is a partially enclosed area of water on the coast where saltwater from the sea mixes with fresh water from rivers and streams. The movement of tides causes coastal areas and estuaries to be either under water or exposed to the air at different times of the day. These characteristics create an environment which is different from both the freshwater river and the sea. These areas are known as transitional waters.
Why are Coasts and Estuaries important?
Estuaries are among the most biologically productive ecosystems on earth. More than two-thirds of the fish and shellfish consumed by humans spend some part of their lives in estuaries.
These ecosystems also provide many other important ecological functions, including acting as filters for terrestrial pollutants and providing protection from flooding.
They also have economic importance as tourist destinations and shipping routes. Millions of people visit the coast each year to boat, swim, bird watch and fish.
The vast majority of goods imported and exported by the UK are transported by sea.
This Information Note provides an introduction to the key issues associated with the management of this environment. A selection of website links has been provided to guide readers to relevant organisations and initiatives.
Pressures and Impacts
The coasts and estuaries of the UK are important environmental, cultural and economic assets. Around 50% of the UK’s biodiversity (some 40,000 species including corals, sea horses, fish and mammals such as dolphins and whales) is to be found in the sea. In 1998, 51% of people in England visited the seaside supporting the local economy. However, coastal areas are under extreme pressure from a wide range of sources and this is reflected in the rapid deterioration of many habitats. In Essex alone, 25% of all saltmarsh has been lost in the last 25 years and, in some estuaries, the rate of loss has increased over the last decade.
Since 1984, nitrogen inputs to the sea around the UK have risen by 20% while the estimated total fish stock in the North Sea has declined by 35% in the last 25 years and plaice stocks are now 25% of the size they were in 1902 (Source: English Nature).
The countryside agencies within the UK have collaborated on an EU LIFE funded project to develop management schemes for marine Special Areas of Conservation (marine SAC) - the UK Marine SAC project (see below). A key output from this project has been a series of reports which assess the interactions that can take place between human activities and the marine environment, in order to provide better management of marine SACs and other non-designated coastal areas. This will be achieved by defining those activities that may have a beneficial, neutral or harmful impact and by giving examples of management measures that will prevent or minimise adverse effects. Each of these activities is described below and links to the reports provided.
Recreation and Tourism
Recreation and tourism bring economic benefit to areas which are often in economic decline. However, litter, footpath erosion and habitat disturbance are often the accompanying negative side of the financial gains, such that the very aspect that attracts visitors is degraded.
Tourist accommodation, amenities and boat marinas are all built on the coastal margin, increasing the area of hard coastal engineering and interfering with the natural coastal processes of erosion and deposition. The effects of boating include engine exhaust emissions, oil and fuel spills, release of biocides in the form of anti-fouling and noise nuisance. Boat wash and anchoring cause erosion and damage to marginal and underwater vegetation. Very few boats in the UK have holding tanks, therefore sewage and wastewater is discharged directly overboard. Fishing can lead to loss of tackle, lines and nets which frequently kill fish and mammals. The following report provides a summary of these problems and how they may be alleviated: ‘A review of the effects of recreational interactions within UK European marine sites’.
Sand, gravel and marl is extracted from both the seabed and the coast. Significant habitat loss can occur as a result. Damage may be done to areas adjacent to the extraction zone and not just the extraction site.
Impacts include, among other things, increased sediment load in the water, changes in water chemistry and changes in water movement and sediment transport associated with altered seabed profile. These changes may be associated with reduced diversity and numbers of marine fauna and flora. The following report provides a summary of the impacts of aggregate extraction and how they may be mitigated: ‘Guidelines on the impact of aggregate extraction on European marine sites’.
Some 97% of goods are imported in to the UK by sea, hence shipping is economically vital. Dredging of the sea bottom in key areas is conducted on a regular basis in order to maintain shipping channels. This produces disturbance both at the dredged site and in the locations where dredged sediment is deposited. The effects are similar to those associated with aggregate extraction but chemical impacts can be greater since sediments which have received long-term inputs of contaminants from shipping, such as heavy metals and anti-fouling, are being disturbed and dumped in areas of lower contamination. However, the effects of dredging are not always negative as evidenced by the project DECODE, or the Determination of the Ecological Consequences of Dredged-material Emplacement. The main aim is to help harmonise efforts and increase information transfer between the many beneficial use-related research projects coming on-stream within the UK.
Poor practice on board ships can lead to chemical and oil spills and the discard of waste overboard. The UK Marine SAC Project report ‘Good Practice Guidelines for Ports and Harbours operating within or near marine SACs’ can be found at:
Ports and Environment, a part of the FP-6 DG Research Integrated Project ‘Effective Operations in Ports (EFFORTS)’, aims at sustainability of port infrastructure and operations by solving environmental conflicts but maintaining efficiency.
Shipping requires harbour facilities, the building of which causes the loss of coastal habitat and increases traffic movement, with its related pollution. Other commercial services develop in association with the port and housing developments soon follow, all located on the coastal margin and all degrading coastal habitats.
Coasts and estuaries are the final recipient of pollution from both the sea and inland sources. River contamination frequently ends up on the coast, whether litter, chemical spills or nutrients released from farmland and wastewater treatment works. Similarly, oil spills in coastal waters and harbour areas will tend to be deposited on the coast.
Even low concentrations of polluting chemicals can have a significant effect since they are taken up by organisms such as plankton which form the basis of the entire marine food chain. With each stage through the food chain, the chemical concentration is increased until it is highest in the top predators, such as dolphins and gannets, where it may have fatal effects, limit their capacity to breed or reduce resistance to disease.
Litter from shipping, from inefficient handling of waste in shore-based facilities and from carelessly discarded rubbish can lead to significant quantities of windblown litter. This eventually accumulates on the sea bottom and on the shore causing odour nuisance, loss of amenity and impacting habitat quality.
The Save the North Sea project estimates that 20,000 tonnes of litter is deposited in the North Sea annually. The project conducted a study of the plastic content of fulmars stomachs which showed that 98% of the birds inspected had plastic in their bodies, with the average quantity being twice that found in a similar 1982 study. Litter is also a significant nuisance to fishermen and can damage fishing nets.
The UK Marine SAC project has produced two reports on coastal water quality:
Sea Level Rise
Sea level rise is causing significant impacts on both natural and man-made sea defence structures. Where these fail, agricultural land, buildings and natural habitat can all be damaged. Nearly 2 million properties located in floodplains along rivers, estuaries and coasts are at risk from flooding. Significant areas of low-lying land will be lost completely by about 2030 due to sea level rise, at which point it is predicted that the Thames Barrier will no longer be an adequate defence for London.
The current loss of saltmarsh habitats is significant. This amounts to about 100 hectares a year as they are trapped in a ‘coastal squeeze’ between hard-engineered sea defences and rising sea levels. Without the hard engineering they would move inland in a natural process of rebalancing with the rising sea level. Mudflats are being similarly degraded.
In this environment a new approach to coastal defence needs to be developed. With this in mind, English Nature has looked at how future coastal defence activities can work with natural processes rather than against them as described in ‘Environmental opportunities in low-lying coastal areas under a scenario of climate change’. English Nature Research Report No 16.
The Foresight Flood and Coastal Defence project was designed to produce a challenging and long-term vision (30-100 years) for the future of flood and coastal defence in the whole of the UK. The project report was published in April 2004.
The mid- term review was published January 2011:
The increased inland flooding which may be the result of climate change is increasing the sediment and nutrient transport to the coast, in with an associated increase nutrient loading of coastal waters and reduction in water quality. The resultant excessive algal growth starves the marine ecosystem of oxygen, causing fish death and impacting higher up the food chain.
Fishing and Fish Farming
Fishing can negatively impact on the coastal environment in a number of ways, the most obvious being the extraction of the resource at a rate higher than its capacity to regenerate. This is not only unsustainable in economic terms but has significant effects elsewhere in the ecosystem, such as seabird and sea mammal survival. As the numbers of some fish species decline due to over fishing, typically the large and slow growing species, others become more dominant and the whole structure of the ecosystem is altered. The dumping of undersized fish is credited with increased numbers of scavenger fish, invertebrates and seabirds further distorting the natural balance.
No Take Zones (NTZ) are areas where specific fishery activities have been voluntarily temporarily halted, for example in St Agnes, Cornwall in order to give an over-exploited resource the opportunity to recover. Evidence suggests that NTZ may be used as part of measures to conserve fish stocks, marine biodiversity and the livelihoods of those in the fishing industry. NTZ are areas closed to extractive uses, including fishing and mineral extraction. Designating NTZs allows fish to grow bigger and more numerous in and around the NTZ and enhances catches close to reserves, due to ‘spill over’ of adults into the adjacent fishing grounds.
The NTZs act as a nursery ground, with increased production of eggs and larvae and export of these to fishing grounds. Bigger fish produce more young. NTZs are also easier to enforce compared to traditional fisheries management. Read more about NTZ at:
Natural England have reported on the Lundy No-Take Zone – ten years on.
Ten years on, Lundy has helped establish the foundations for marine conservation nationally and is a great example of a marine site managed using the most up to date science and evidence to inform decisions. The NTZ lies within a wider protected area, designated as a Marine Conservation Zone (MCZ), in which some forms of fishing and other activities are permitted.
Defra held a public consultation on proposals to designate a further 31 MCZs giving stakeholders the opportunity to comment on the recommendations for site designation and supporting evidence. This consultation closed on 31 March 2013. Of the 31 sites proposed, 27 are being designated in November 2013, 2 will be subject to further consideration and possible designation in the future, and 2 will not be designated.
Costing the impact of demersal (close to, or on the sea bed) fishing on marine ecosystem processes and biodiversity (COST-IMPACT) is a project funded under the European Union Quality of Life and Management of Living Resources programme.
It is investigating how demersal fishing impacts the biodiversity of marine benthos and the associated goods and services, such as the nutrient cycling that they provide, how these impacts influence other marine ecosystem processes and what the likely values of marine ecosystem goods and services are and how these values are affected by fishing.
Fish and shellfish farming can help reduce pressure on wild stocks, but can also have an impact due to the waste detritus generated by producing a large number of fish in a small area, the chemicals used to keep the fish healthy in a relatively intensive production system, and the accidental or deliberate loss of ground tackle, cages and lines associated with these facilities. Discarded commercial and recreational fishing tackle, lines and nets are also a navigational hazard and dangerous to wildlife whether in the sea or on the shore.
The following two reports provide a summary of the effects of fisheries on maritime habitat quality:
‘A review of the effects of fishing within UK European maritime sites’
‘Guidelines for managing the collection of bait and other shoreline animals within UK European marine sites’
Conservation of Coastal and Marine Environment
The conservation of the UK coastline is the responsibility of a wide range of organisations, most notably Defra, English Heritage, Joint Committee for Nature Conservation (JNCC), Countryside Commission, Countryside Commission for Scotland, Environment and Heritage Service Northern Ireland, Environment Agency, Scottish Environment Protection Agency, Countryside Council for Wales, Scottish Natural Heritage and local authorities.
The current main priority is to develop common standards for monitoring the habitat condition of the four coastal Priority Habitats specified within the UK Biodiversity Action Plan.
The UK Boiodiversity Action Plan (UKBAP) is the UK Government’s response to the United Nations Environment Programme Convention on Biological Diversity signed in 1992. It describes the UK’s biological resources and defines a detailed plan for the protection of these resources. There are 391 Species Action Plans, 45 Habitat Action Plans and 162 Local Biodiversity Action Plans with targeted actions.
The 'UK Post-2010ﾠBiodiversity Framework', published in July 2012, has now succeeded the UK BAP.
The UK BAP lists of priority species and habitats remain, however, important and valuable reference sources.
The Coastal Priority Habitats are:
European Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora (Habitats Directive) is designed to protect the most valuable parts of Europe’s natural heritage. To achieve this, it has identified 189 habitat types and 788 species known as Annex I habitats and Annex II species which require special conservation measures to be taken by Member States. A selection of these habitats and species are given priority status in the Directive because they are considered to be particularly vulnerable and are mainly, or exclusively, found within the European Union.
Areas which match with the specifications in Annexes I or II are designated as Special Areas of Conservation (SACs). Read more about SAC designation at:
The Habitats Directive complements the Birds Directive, Council Directive 79/409/EEC on the conservation of wild birds, which requires Member States to protect rare or vulnerable bird species through designating Special Protection Areas (SPAs). Together, the terrestrial and marine SPAs and SACs are intended to form a coherent ecological network of sites of European importance, referred to as Natura 2000.
About 25 different types of coastal habitats have been identified as requiring protection as Special Areas of Conservation. These are listed and described on the following website:
Read more on UK coastal habitats at:
You are here:
Tel: +44 (0 1628 891 589 Fax: +44 (0) 1628 472711
Registered Office: Allen House, The Listons , Liston Road, Marlow,
Buckinghamshire SL7 1FD, UK © 2015 FWR All rights reserved.
The Foundation for Water Research is a company limited by guarantee,
registered in England, No 525927 and a registered charity No 108685.