Sarah Welton

Dorset’s marine and coastal environments are the county’s chief environmental and economic assets. The marine environment is a natural resource (see Dorset’s Marine and Coastal Habitats, Dorset’s Underwater World and Marine Ecology), which has been exploited by generations of Dorset inhabitants. The recent discovery of archaeological evidence of an Iron Age port in Poole Harbour (see History on the Seabed) demonstrates the significance of the sea as a resource over 2000 years ago.

Understanding the value and sensitivity of the marine environment and the impacts of our use of the sea is far more complex under the sea than on land. On land, ecologists can see what is there and surveys can be carried out easily. Underwater it is much more challenging. Divers must wear bulky equipment, can only spend a limited period underwater, visibility is often reduced to a metre and even making field notes takes on a whole new meaning. Despite these difficulties, underwater surveys have been carried out in Dorset by marine biologists, by volunteer divers through the Seasearch project and by mapping the seabed, using echo sounding, side scan sonar and underwater video (see Dorset’s Underwater World). A good picture of the distribution of subtidal habitats around Dorset’s coast now exists but there is still much more to learn. A Marine Biodiversity Database and Marine Literature Database have been established at the Dorset Environmental Records Centre, collating all this information.

Current human activities using Dorset’s marine resources are:

Fisheries
Tourism and recreation
Mineral extraction
Transport
Waste disposal and pollution

In managing a coastal zone, it is important to consider the ‘whole coast’ – the sea as well as the land. The sea cannot be addressed separately from the land. Activities that take place on land in the coastal zone affect the marine environment and vice versa (see Who’s Who in Coastal Management). The marine environment is integrated throughout the Dorset Coast Strategy.

Fisheries

Fishing has always been an important use of Dorset’s coastal zone (see photograph below). Today, a fleet of some 300 vessels is based in Dorset’s ports and harbours, and a larger number fish beyond the 6-mile limit. It is estimated that the total employment numbers, dependent on fishing in Dorset, are between 500 and 800 full-time and part-time jobs. The fleet targets a mixed fishery, with crabs and lobsters the staple for many boats. Shellfisheries are important in sheltered harbours.

Photograph showing net fishing on Chesil Beach (DCM).

The main fishing ports are Mudeford, Poole, Weymouth, West Bay and Lyme Regis but boats also operate from Swanage, Kimmeridge, Lulworth and Portland. Many fishing vessels work a wide variety of fishing gear, and they switch methods several times a year according to seasonal movements of species or changes in market demand. In the shallow, sheltered waters of Poole Harbour, fishing activity is intense. There are no major fish markets in the area. The majority of the catch landed is sold through local wholesalers to meet the demand from local hotels and caterers. The ferry port at Poole gives good access to continental markets.

Off the Dorset coast, boats fish for:

Edible crabs and lobsters on the rocky ledges. Strings of baited pots are laid on the seabed, marked with buoys and flags.

Prawns in shallow harbours and bays e.g. Poole Bay.

Fin fish - trawling for flatfish, such as Dover Sole, Brill and Plaice and for Cod and Bass. Poole Harbour and the Fleet are important nursery areas for Bass and other fish species. Mackerel fishing takes place off Chesil Bank and further west.

Scallops are hand picked by divers off Lulworth Cove and dredged in Lyme Bay.

Oysters – in Poole Harbour and the Fleet.

Clams in Poole Harbour – Licensed clam fishermen fish from November to January using a pump and scoop for sieving sediments. Research is being undertaken to ascertain the effects on other animals in the sediments and therefore feeding birds

Cockles – the cockle fishery is unlicensed and therefore difficult to control. Cockles are removed from mudflats at low tide and pumped from the shallows.

In addition to these fisheries, bait is dug from muddy shores and ‘dragged’ from the shallows in Poole Harbour. Although the Southern Sea Fisheries Committee (SSFC) is responsible for Dorset’s fisheries, it has no control over bait-digging, as it is not a ‘fishery’. The concern is the damage to intertidal shore habitats by not infilling holes and the potential damage to the seabed by ‘dragging’.

Recreational angling is a highly popular activity, supporting a large number of charter boats and angling retail outlets. Although the amount of fish taken by recreational fishing is small in comparison with commercial catches, it is still significant (3 tonnes of fish is quoted as the total catch of the larger competitions (Dorset Coast Forum 1998)) and conservation measures should apply to both.

The impacts of fishing on the marine environment include the effects on target species. During recent years, there has been widespread concern, nationally and internationally, over crises in fish stocks, especially the implications of over-fishing on cod stocks. Sustainable fishing ensures that, although fishermen remove fish or shellfish from the sea, populations are kept at a healthy level. The restriction on vessel size in Dorset’s inshore waters provides some control on over-fishing of target species and it is generally thought that Dorset’s fisheries are sustainable. However, there has been a dramatic reduction in numbers of mackerel coming into inshore waters as a result of huge commercial fishing efforts in the Western Approaches, over which Southern Sea Fisheries Committee has no control.

By-catch describes non-target species, accidentally caught during fishing activities. The main concern in Dorset in recent years is over the numbers of dead cetaceans, washed up on beaches during the winter. In 2003, 38 dolphins were found dead on Dorset's beaches. That year, over 300 Common Dolphins and Harbour Porpoises were washed up in Devon and Cornwall and many more along the French coast. In 2004/5, however, there has been a significant reduction in strandings. The number of carcasses reported is believed to be a small percentage of the animals that actually die at sea as we only tend to see the problem when strong onshore winds blow the bodies on to our beaches. Post-mortem examinations of some of these animals indicate fishery by-catch as a likely cause of death. Recent research by the UK Fisheries Department has shown the mid water pair trawl fishery for bass in the Western Approaches to be particularly prone to incidental by-catch.
Defra-funded research by the Sea Mammal Research Unit is currently looking at cetacean by-catch and the bass fishery and will include an assessment of factors contributing to the recent reduction.

Common Dolphin and Harbour Porpoise are protected by Act 12 of the EU Habitats Directive which requires member states to monitor incidental capture and take measures to reduce the number of animals being killed as a result of by-catch to below 1.7% of the total population.

Fishing methods, deployed off the Dorset coast, which are potentially damaging to seabed communities, are trawling for flatfish, scallop dredging, pump method of cockle and clam harvesting and bait digging and dragging. There is particular concern about scallop dredging in Lyme Bay, where sensitive species e.g. the Pink Sea Fan are being destroyed, and about pump/scoop methods used in Poole Harbour, from the point of view of seabed damage and noise and disturbance. It is crucial that research and monitoring is carried out to ascertain whether damage and disturbance are a problem.

The Marine Conservation Society's annual Beachwatch survey of marine debris in 2005, attributed 14.6% of debris found on Britain's beaches to the fishing industry (MCS 2005). Abandoned net and line are a potential threat to wildlife, causing entanglement. Monofilament net, lost at sea, continues to ‘ghost fish’.

Responsibility for the management of fisheries in coastal waters rests with the Commission for the European Union (EU), which delegates it to member states under the Common Fisheries Policy (CFP). EU regulations are implemented through UK law. Currently in Dorset, the Southern Sea Fisheries Committee (SSFC) manages the sea fisheries from High Water Mark out to 6 nautical miles. The SSFC has bylaws that restrict vessels to a maximum length of 12m and require such vessels to register if they want to fish commercially (to sell their fish). SSFC bylaws set minimum landing sizes, gear to be used, location restrictions and close seasons for the different species. Oyster and clam fisheries are regulated by licensing.

There are several Fishery Conservation and Awareness Initiatives, notably

Lyme Bay Reefs Project is led by the Devon Wildlife Trust in partnership with fishermen, funded by the environment Action Fund, English Nature, East Devon District Council, Devon County Council, Dorset County Council and the Fishmongers Trust. The project has carried out research into the effects of scallop dredging on reef habitats and regeneration of the habitat after dredging. Results showed that increasing scallop-dredging effort decreases species abundance and diversity as well as decreasing habitat cover and structure on rocky reef habitat. The regeneration survey after 12 months found little evidence of recovery from the impact of scallop dredging. The majority of the scallop dredging in the bay occurs on habitats other than rocky reefs – gravel, sand and shingle. Due to the natural mobility of these habitats, the impacts are thought to be considerably less. Voluntary agreements with South West Fish Producers have resulted in closed areas for dredging. Monitoring is being carried out to reveal whether the agreements are achieving the necessary protection of biodiversity (Devon Wildlife Trust 2001).

The Weymouth and Portland Fish Festival provided an opportunity to promote sustainable fisheries.

‘Seafood from the Dorset Coast’, a sustainable fish cookbook was produced by the Dorset Wildlife Trust and the Dorset Coast Forum, in co-operation with local fishermen and restaurants.

Fish and Chip Wrapper Project was launched in March 2003. Greaseproof bags with a sustainable fisheries message will be used by fish and chip shops throughout the county, supported by a website on sustainable fishing and posters.

All these initiatives are achieving an effective partnership between marine conservationists and fishermen.

Tourism and Recreation

Tourism is Dorset’s predominant industry, and the coast is arguably Dorset’s most important single tourism asset (see Leisure Hours). There is no question that visitors place a high value on the attractiveness of the Dorset Coast. This quality was ranked first among the area’s assets as a holiday destination in visitor surveys across the county in 1997 (source: Dorset Tourism Data Project). Although the dramatic coastal landforms, varied geology and associated terrestrial wildlife habitats and coastal settlements play an important part in the coast’s attractiveness, it is the sea and the beaches that are the main attraction to tourists to Dorset.

Historically seaside resorts developed in the wake of the Georgian and Victorian vogue for sea bathing. In the seaside resorts of Christchurch, Bournemouth, Poole, Swanage, Weymouth and Lyme Regis, the main attractions are the beaches and the attainment of high standards of water cleanliness and beach management are a major priority. Other heavily visited sites include:

Studland and Shell Bays - owned by the National Trust. Up to 1.5 million visitors a year, who are attracted by the fine sandy beaches and a range of beach and water-based activities.

Lulworth Cove - privately owned. Up to ¾ of a million visitors a year to see the nationally and internationally recognised geomorphological features of the Cove, Stair Hole and Durdle Door. The pebble beaches of Lulworth Cove, Man O’War Cove and Durdle Door are popular for beach activities, rock-pooling, bathing and water sports.

Charmouth is most famous for fossils, for which it attracts many visitors to the area. In addition to fossil collecting, Charmouth is used for beach activities, bathing and rock-pooling.

The main impacts on the marine environment of beach tourism are:

Tourism related development – coastal squeeze.

Water quality issues relating to the increase in population size in the tourist season.

Beach cleaning and the removal of strandline material.

Tourism-related litter.

In addition to general beach activities, many visitors to the Dorset coast want to discover more about the marine environment. Several beaches, e.g. Kimmeridge and Charmouth, provide the opportunity for rock-pooling and a chain of interpretive centres along the coast interpret different aspects of the marine world, including

The Purbeck Marine Wildlife Reserve, Kimmeridge, managed by the Dorset Wildlife Trust) runs rocky shore walks and events and interpretation at the Fine Foundation Marine Centre at the Bay, which includes a touch pool, aquaria and marine interpretive displays on all aspects of the marine reserve.

These and other coastal visitor centres including Charmouth Heritage Coast Centre, Lulworth Heritage Centre, Chesil Beach Centre and the National Trust Studland Education Centre work together through the network group Dorset Coastlink on joint initiatives which include marine aspects in their interpretive programmes. Marine Week and Seafest have become annual events in August

Interpreting the marine environment encourages exploration of vulnerable intertidal habitats. At the Purbeck Marine Wildlife Reserve, careful consideration has been given to the ‘pros’ and ‘cons’ of marine interpretation for conservation and the conclusion reached was that the benefits of increasing public awareness of the marine environment and marine conservation issues outweigh the costs. Impacts on rocky shores include:

Disturbance to rocky shore communities – trampling, stone turning;

Collecting – winkles, limpets for bait, crabbing.

Management initiatives include:

Voluntary Marine Conservation Areas. There are a number of voluntary areas in the South West, focusing on different aspects of the marine environment. Although protection is by voluntary agreement, these areas are a focus for education.

The Limpet Protection Zone at Kimmeridge encourages visitors to ‘love them and leave them’ and ‘save their shells’ – a voluntary no-take area.

Blenny-friendly crabbing promotes crabbing without a hook by selling hookless crab lines.

One locally very important aspect of tourism is based on the large numbers of educational groups of all ages visiting the Dorset Coast. It is a classic field studies site, and many groups stay for up to a week in centres in Swanage, Weymouth and west Dorset. Although many geography groups (GCSE and above) come to study the geology and geomorphology of the area, intertidal ecology is widely studied in Dorset. The sandy shore at Studland and rocky shores at Kimmeridge, Osmington, Portland and Lyme Regis are popular sites. Younger groups, visiting Dorset on ‘school journeys’, generally include a shore study/rock-pooling.

Detailed trends in coastal recreation are difficult to establish. It is generally accepted that participation in water recreation is on the increase and has been for much of the 20th century. The most marked trend of the last 10 – 20 years has been the growth of active recreation. This has resulted from both the rapid expansion of minority sports such as sub-aqua diving and the establishment of new activities such as windsurfing and jet-skiing (Dorset Coast Forum 1998). Activities with potential impacts on the marine environment include Sub-Aqua Diving, Personal Watercraft (Jet-skis), Power Boating and Water Skiing, Sailing, Sea Angling and Windsurfing

Sub-Aqua Diving may cause damage through:

Collecting – particularly vulnerable species e.g. Pink Sea Fan and Ross Coral;

Damage to wreck sites;

Fin damage to vulnerable species.

In contrast to these negative impacts, the effort of sports divers provides a valued resource to help improve our knowledge of the marine environment. Seasearch is a national project to use volunteer divers in marine research and monitoring, with an active group in Dorset.

Personal Watercraft (PWCs ‘Jet-skis’), windsurfing, power boating and water skiing may each:

Disturb wildlife – noise e.g. waders feeding in Poole Harbour;

Damage wildlife e.g. to sea grass beds at Studland;

Put pressure on the coastal environment at access points.

In addition, PWCs may damage wildlife e.g. sea grass beds at Studland, and windsurfing may damage coastal habitats by trampling e.g. access across beach to Portland Harbour.

Sailing is often thought to be benign but it can impact on the marine environment through coastal marina developments, especially by reclamation, and by pollution from sewage, bilge water and litter. Sea angling may disturb wildlife, e.g. Little Terns nesting on Chesil Bank, and affect coastal plants by trampling and leaving litter. Other water-based activities include sea bathing, canoeing, sea rowing and surfing.

The management approach to watersports, identified in the Dorset Coast Strategy, is to adopt a zoning scheme in areas where several activities are taking place and there are potential conflicts and conservation and safety implications.

Poole Harbour Aquatic Management Plan

The Plan zones activities in the busy Harbour, identifying the southern reaches of the Harbour as a ‘Quiet Area’ and separating the commercial shipping channel, the main recreational craft channel and the small boat channel from the designated windsurfing area and the Jet-ski area. The Aquatic Management Plan can be successfully implemented because of policing by the Poole Harbour Commissioners’ Harbour Patrol boats. The plan has been re-written in 2006.

Mineral Extraction

The most economically valuable seabed resources in many coastal areas are marine aggregates and oil and gas extraction. In the past, shingle was collected from many of the west Dorset beaches for use in industry and construction with damaging effects on the beaches (see photograph below). There is currently no dredging activity for marine aggregates in the waters off the Dorset coast and this is unlikely to be an issue due to the lack of aggregate resources. Thinking ahead, marine-dredged (sand and gravel) and sea-borne aggregates need to be considered as a possible long-term source for Dorset’s construction and sea defence needs. These supplies might include materials dredged from the seabed or quarried elsewhere and imported by sea. The impacts of dredging for aggregates on the marine environment include immediate damage to the seabed substrate, smothering to surrounding seabed communities and increased turbidity.

Photograph of gravel extraction at West Bay (DCM).

The oil and gas industry has been a feature of the Dorset Coast since the 1930s. The whole of the Dorset Coast, both onshore and offshore, has a geological history with the right ingredients to have formed oil deposits (see photograph below). This has resulted in extensive activity to explore the area, the discovery of a number of reserves, and the establishment of three producing onshore fields.

Photograph of an oil drilling rig at Kimmeridge (DCM).

Oil and gas activity within Great Britain, its territorial seas and on the UK Continental Shelf is controlled by the Government. The main regulatory mechanism is the issuing of licences for blocks, with an average size of around 230 square kilometres. Exploration licences allow survey work and shallow drilling. Production licences grant the holder exclusive rights to explore for and produce petroleum in one or more particular blocks. When specific blocks are offered in a so-called ‘Round of Licensing’, the process may involve the company agreeing commitments with the Government to carry out seismic surveying or well drilling. The situation has occurred in Dorset that a company was obliged to drill, when it was not economically sensible to do so.

There are 32 licence blocks and part-blocks between the Dorset coast and the limit of the UK Continental shelf in the English Channel, 20 of which lie at least partly within the 12-mile limit.

Although all three producing fields are onshore, the Wytch Farm Field, Western Europe’s largest onshore field operated by BP, discovered in 1974, is drawing oil from the Sherwood Reservoir, beneath Poole Bay. Historically, proposed methods of reaching oil reserves beneath Poole Bay included standard rig installations, floating installations and an artificial island. Modern technology now allows oil reservoirs to be reached by horizontal drilling.

The EU Environmental Assessment Directive (87/337/EEC) states that environmental assessment may be needed for oil and gas production and transmission projects, depending on the nature and scale of the proposal. The Directive was implemented as it applies to offshore oil and gas activity in 1998. The offshore regulations require a review of the potential environmental effects of all oil and gas exploration and production proposals, and the formal assessment of those thought likely to have a significant effect on the environment. Any new development off the Dorset coast would almost certainly require a full assessment (an Environmental Statement with full consultation) before Government consent was given.

All recent proposals for exploration off the Dorset coast have been subject to environmental assessment. The statements published have been important sources of information on the marine environment. All such information is now available on the Dorset Marine Biodiversity Literature Database at the Dorset Environmental Records Centre.

Oil and gas production is potentially hazardous and great care is taken to prevent the escape of oil. The scale of impact upon the marine environment of a spill would depend on a number of factors:

Geography and hydrography of the area;

Nature and sensitivity of marine communities present;

Weather conditions;

Type of oil;

Speed of response;

In the event of a spill, the Maritime Coastguard Agency is responsible for the clean-up and containment of the spill at sea. Dorset County Council’s Emergency Planning Department’s Oil spill contingency Plan underlines the processes, including clean-up operations in the event that a spill reaches the coastline. There are well established oil spill contingency plans for the oil and gas fields, with 24-hour field control room and 24-hour call-out for key staff. The principal sites in the field are designated as Control of Major Accident Hazard (COMAH) sites. There is a £1 million base for response equipment in Poole. The Poole Spill Contingency Plan, co-ordinated by Poole Harbour Commissioners, organises regular practical and tabletop exercises, involving all the relevant authorities and local and environmental groups (Poole Harbour Commissioners 2001).

The immediate effects of major oil spills on seabirds are well documented. The longer term impact on intertidal and subtidal communities – in particular the smothering effects of heavier oils on filter-feeders – can have far-reaching consequences for the whole marine food web. The potential impact on tourism could also have a major effect on the local economy. Although major oil spills hit the headlines – hopefully such a spill will never happen in Dorset – minor, preventable release of oil into the sea from tanker washings, bilge water from small boats and run-off from roads is a continuing problem.

The transport of oil and gas from well site to British Gas National Grid and oil terminals is potentially the most hazardous part of the production process. In Dorset, approval was given, following a Public Enquiry, for the Purbeck – Southampton Pipeline, which runs under the land rather than sea, as the safest option. Undersea routings were considered and detailed impact assessments prepared. During this research, rare and sensitive seabed habitats, e.g. Maerl beds and sea grass beds, were discovered in Poole Bay. The impact of removing sections of the seabed to lay the pipeline in such areas would have been significant.

Lyme Bay is proposed as one of two regulated ship-to-ship oil transfer areas in Britain, designated by the Maritime Coastguard Agency. This area has been used for this practice for many years on an unregulated basis and, beyond the 12 mile limit to UK Territorial Waters, there is no national jurisdiction. The principle of achieving a regulated rather than unregulated activity is welcomed. However, there are concerns about the level of risk and environmental impact so close to a coastline of international importance. Transfers are being monitored and discussions continue over the transfer agreements, in the light of the revised Marine Environmental High Risk Areas report (MEHRAs).

There is growing awareness that underwater noise could have an impact on marine wildlife, in particular cetaceans. The Durlston Marine Project, Swanage is carrying out an underwater acoustic monitoring programme (see Dorset’s Underwater World).

Transport

Dorset’s ports are important economic assets to the county. Dorset has three cargo and passenger handling ports (see for example Portland and Weymouth Harbours):

Port of Poole is managed as a non-profit making Trust Port by Poole Harbour Commissioners, handling over 400,000 tonnes of cargo, over 70,000 units of roll-on/roll off freight traffic and around 700,000 ferry passengers per year.

Portland Port is managed by a private company, Portland Port Ltd., following the withdrawal of the Royal Navy. It is building up its business, attracting cargo, freight and cruise vessels to this large, deep harbour - up to 16 metres depth in the Inner Harbour and up to 40 metres depth of water in the Outer Harbour – and offering various marine services.

Weymouth is managed by the local authority, Weymouth and Portland Borough Council. In addition to recreational moorings and fishing harbour and a few cargo vessels, over 250,000 passengers use the ferry routes to St. Malo and the Channel Islands.

The smaller harbours, such as Lyme Regis, West Bay, Swanage and Mudeford cater mainly for the recreation and fishing interests.

In addition to their business interests, Dorset’s ports have wider statutory responsibilities as Harbour Authorities.

Poole Harbour Commissioners Environmental Policy Statement

………. It further recognises the special position of Poole Harbour as a natural asset and will continue to promote its sustainable use, balancing the demands of its natural resources and resolving conflicts of interest.

Poole Harbour Commissioners’ statutory duty is to Conserve, Regulate and Improve Poole Harbour
(Poole Harbour Commissioners 2002)

Both Poole and Portland Harbours are designated as European Wildlife sites. The mudflats of Poole Harbour are designated as a Special Protection Area (SPA) and the Fleet, a Special Area of Conservation (SAC).

In addition to the shipping entering Dorset’s ports – passenger and cargo ferries, cargo vessels and cruise ships – offshore, over 2000 ships pass Dorset’s coast every day, en route to and from ports in the UK, Europe and worldwide. A planned fuel bunkering facility in Portland Port will attract a greater number of vessels closer inshore.

Ports activity may cause noise impacts from machinery and traffic creating disturbance to nearby bird roosting and feeding sites. Oil and chemical pollution is a hazard from shipping when in port, through cargo or fuel loading operations. Tri-butyl tin (TBT) is used for anti-fouling on large commercial shipping. Its use is banned on all small vessels. TBT is highly toxic to marine wildlife and can enter the marine environment as a result of maintenance of ships in port.

In relation to passing shipping:

Litter is thrown overboard, much of which gets washed up on Dorset’s beaches;

Oil enters the sea as a result of dumping of fuel washings;

The potential risk of collision might result in fuel, oil or hazardous cargoes threatening Dorset’s marine environment.

The shallow Poole estuary requires regular maintenance of the shipping channels. Dredged materials are either disposed of, under licence, at the designated dumping ground in Poole Bay or utilised to replenish Poole and Bournemouth’s beaches. Potential impacts might include:

Disturbance to surrounding seabed communities;

Release of pollutants, e.g. heavy metals, from the sediments to the water column;

Noise impacts arising from machinery, creating disturbance to nearby bird roosting and feeding sites;

Increased turbidity within the vicinity of the operation and at the dumping ground;

Smothering and reduced light levels within the vicinity of the dumping ground. Two sensitive marine habitats, identified in the UK Biodiversity Action Plan – Maerl Beds and Sabellaria spinulosa reefs - have been discovered recently in Poole Bay. DEFRA and English Nature are reviewing the siting of the current designated dumping ground in the light of these new findings.

In 2005/6 Poole Harbour Commissioners carried out a major capital dredge to deepen the main shipping channels, after exhaustive environmental impact assessments and consultation. Sand and silt was dredged from the approach channels to the Harbour and the Port and a large proportion was used for beach recharge at Swanage, Poole and Bournemouth and the remaining dredge material disposed of at the designated dumping ground

All ports have comprehensive emergency and pollution contingency plans. They are required to provide reception facilities for garbage and to produce and implement a waste management plan. Sites where TBT is used must be licensed by the Environment Agency. The Poole Harbour Steering Group (PHSG) was set up to assist with the management and implementation of the Poole Harbour Aquatic Management Plan and associated Poole Harbour Management Policies. It also acts as the forum to co-ordinate the management of the Poole Harbour Special Protection Area (SPA), which is a European Marine Site for nature conservation, in accordance with the requirements of the Habitats Directive (Poole Harbour Commissioners 2002).

Waste Disposal and Pollution

‘Accessible beaches and clean coastal waters are two of the main attractions of the Dorset coast. The public’s health and environmental expectations are increasing and it is important that the quality of the coastline is maintained.’ (Dorset Coast Forum 1998).

Pollutants enter the sea from the land from many different sources. Some are deliberately disposed of at sea, others enter the sea accidentally.

Bathing water quality in nearshore waters is measured by the amount of bacteria within water samples. The EC Bathing Water Directive (currently being reviewed) sets out two standards, against which water cleanliness is measured: Mandatory Standards and Guideline Standards. All Dorset’s bathing waters meet the Mandatory Standards and most the Guideline Standards, which are 20 times stricter.

Improving sewage schemes is hugely costly. Since 1990, Southwest and Wessex Water have spent well over £100 million on improving their coastal sewage schemes in the county. See photograph below showing sewer outfall construction work.

Photograph showing sewer outfall construction work (DCM).

Poor water quality is generally considered to threaten human health rather than marine wildlife. Some marine species thrive on our sewage! It is a concern, however, as the increased nutrients can upset the normal ecological balance and affect the marine food web. The water quality can have a marked effect on both the location and survival of fish stocks. This is especially important to shellfish beds, where the stock is unable to locate elsewhere. The location of sewage outfalls is critical, especially in designated shellfish areas. Shellfish can be quickly affected in areas of poor water quality.

Although the discharge into the sea of all plastics, synthetic fishing nets, garbage bags and other materials in specified areas of the sea is restricted (MARPOL (Annex V), the annual Great Dorset Beach Clean clearly indicates that the key polluters are shipping, beach users, the fishing industry and pleasure craft. These findings are backed up by the Marine Conservation Society’s Beachwatch Project (Marine Conservation Society 2005). Litter disposed at sea gets washed up on our beaches. Litter can be lethal to marine wildlife through entanglement and ingestion – a plastic bag looks much like a jellyfish to a predator. Litter is unsightly and a health hazard on Dorset’s beaches.

Abnormal algal blooms, which occur because of the nutrient enrichment of the water, can change the balance of life in an area. These blooms should not be confused with the natural increase of algae in the early summer (‘May and June water’), caused by sunlight. The main source of nutrient enrichment in Dorset is from agricultural run-off. Manure and fertilizers, used on arable land, enter the sea. Discharges from industry are another source. There is concern about nutrient enrichment in the Fleet.

Potential effects of nutrient enrichment include

Eutrophication, changing the equilibrium and hence ecology of an area.

Potentially toxic red-tide algal blooms.

The recent ‘Nitrates Directive’ imposes increased regulation on the release of nutrients into the sea. Water quality in Dorset is monitored by the Environment Agency, DEFRA and local authorities. The Dorset Coast Forum Pollution and Water Quality Working Group have addressed many of the issues. Public awareness initiatives include the preparation of a marine conservation handbook for coastal visitors to highlight what to look out for.