Grouped Species Action Plan

There are six small dolphin species occurring regularly in UK waters.

Bottlenose dolphin Tursiops truncatus . Along the Atlantic seaboard of Europe, the bottlenose dolphin is locally frequent nearshore off the coasts of Spain, Portugal, north-west France, western Ireland, north-east Scotland, in the Irish Sea (particularly Cardigan Bay and south-east Ireland), and in the English Channel. The species also occurs offshore in the north Atlantic as far north as the Faroe Islands. Although overall population estimates do not exist, studies indicate a resident population of 130 bottlenose dolphins in the Moray Firth whilst the population in Cardigan Bay has been variably estimated at 130-350 bottlenose dolphins. Neither population is closed, and individuals may join up for periods of time from elsewhere. Numbers at most UK sites are greatest between July and October (with a secondary peak in some localities in March-April).

Risso`s dolphin Grampus griseus . Although present in UK waters throughout the year, numbers are greatest between May and September. The major UK population occurs around the Hebrides, with a regular presence in the Northern Isles, and in the Irish Sea, particularly around Bardsey Island. Elsewhere, it is fairly common in south-east Ireland and western Ireland, around the Iberian Peninsula and in the Mediterranean. A study in the North Minches of Scotland has identified at least 142 individuals but no population estimate has yet been made.

White-beaked dolphin Lagenorhynchus albirostris . This species occurs over a large part of the northern European continental shelf, its distribution extending northwards to Iceland, the Greenland Sea and central-west Greenland. It is common in UK and Irish waters, occurring most abundantly in the central and northern North Sea across to north-west Scotland, although it also occurs occasionally in southern Ireland, the Irish Sea and western Channel. A population estimate of between 4000-13,300 was made in July 1994 for the North Sea and Channel with a further estimate in the same area of 6000 to 18,500 small dolphins (both white-beaked and white-sided dolphins, but not differentiated). In UK waters, the species is most common in late summer (June to September) although present in northern Britain throughout the year.

Atlantic white-sided dolphin Lagenorhynchus acutus . This species is widely distributed mainly in offshore waters from central-west Greenland, Iceland and the southern Barents Sea, south to the Bay of Biscay. In UK waters, its distribution is concentrated around the Hebrides, Northern Isles and northern North Sea. The species also occurs regularly off western Ireland and in the south-west approaches to the English Channel, but is rare in the Irish Sea, the eastern Channel and southernmost North Sea. No population estimate exists for the species, although the estimate of 6000 to 18,500 referred to in paragraph 1.4, includes an unknown proportion of white-sided dolphins. In UK waters, the species is most common between July and September although this may reflect favourable observing conditions.

Common dolphin Delphinus delphis . The species is abundant and widely distributed in the eastern north Atlantic, mainly in deeper waters from the Iberian Peninsula north to western Scotland. In UK waters, it is common in the western approaches to the English Channel and the southern Irish Sea (particularly around the Celtic Deep, off Pembrokeshire) and around the Inner Hebrides north to Skye. It is also common west of Ireland. In some years, the species occurs further north and east - around Shetland and Orkney, and in the northern North Sea. It is generally rare in the southern North Sea and eastern portion of the Channel. No overall population estimate exists, but the population around the Celtic Deep was estimated to be between 23,000-249,000.

Striped dolphin Stenella coeruleoalba . A subtropical and warm temperate species, occurring in the north Atlantic in offshore areas to the west of the Iberian Peninsula and France. Records are also held for this species in the Mediterranean. In UK waters the species is rare, recorded mainly from the south-west approaches to the English Channel and off Southern Ireland, although occasional sightings and strandings have occurred as far north as Shetland. No population estimates exist for the region. Most records, nearshore to the UK, occur between July and December.

Status changes for all these six species cannot be readily assessed through lack of quantitative data. There is no clear evidence of recent population changes, although records of both striped and common dolphins are more frequent in northern Britain during the 1990s than they were in the 1980s. This suggests a possible recent northward extension of their range, whilst bottlenose dolphins are reported to be less frequent in the southernmost North Sea than they were in the 1960s and 1970s.

All species of cetaceans are given protection under the Wildlife and Countryside Act 1981 and the Wildlife (Northern Ireland) Order 1985. All cetacean species are listed on Annex IV (Animal and Plant Species of Community Interest in Need of Strict Protection) of the EC Habitats Directive. All cetacean species are listed on Annex A of EU Council Regulation 338/97 and therefore treated by the EU as if they are on CITES Appendix I thus prohibiting their commercial trade.

The bottlenose dolphin is listed in Annex II and IVof the EC Habitats Directive. Under Annex IV the keeping, sale or exchange of such species is banned, as well as deliberate capture, killing or disturbance. The Directive requires that member states monitor the incidental capture and killing of all cetaceans. Under Annex II candidate marine SACs (Special Areas of Conservation) for bottlenose dolphins are being established in the Moray Firth, (north-east Scotland) and in Cardigan Bay (west Wales).

An Agreement on the Conservation of Small Cetaceans in the Baltic and North Seas (ASCOBANS), formulated in 1992, has now been signed by seven European countries, including the UK. Under the Agreement, provision is made for protection of specific areas, monitoring, research, information exchange, pollution control and heightening public awareness. Measures are included aimed specially at protecting dolphins and porpoises in the North and Baltic Seas and cover the monitoring of fisheries interactions and disturbance, resolutions for the reduction of by-catches (below 2% of stock sizes), and recommendations for the establishment of specific protected areas for cetaceans.

The six dolphin species covered in this plan are protected under ASCOBANS' parent Convention, the Bonn Convention. The North and Baltic Sea populations of the bottlenose, Risso's, white-beaked, Atlantic white-sided and common dolphin are included on Appendix II of the Bonn Convention. The western Mediterranean population of the striped dolphin is included on Appendix II of the Bonn Convention.

The present status for each of the dolphin species occurring in UK waters is not known sufficiently to evaluate properly the extent to which population changes have taken place. However, four main human activities are recognised as currently likely to be detrimental to dolphins: activities leading to ecosystem changes; interactions with fisheries; boat activities; and contaminant inputs.

Ecosystem changes resulting from the widespread over-exploitation of marine biological resources in European waters have the potential to affect energy budgets and thence reproduction and survival of all UK dolphin species.

All the dolphin species considered here have been recorded as by-catches of various fisheries. There is evidence of substantial numbers of dolphins (mainly common and Atlantic white-sided dolphins) caught in pelagic trawls (targeting tuna, hake, bass, horse mackerel, mackerel and herring) in the south-west approaches to the English Channel and Celtic Sea. Annual by-catch estimates of 1200 striped dolphins and 400 common dolphins were obtained in 1992-93 in French drift-net fisheries for albacore tuna operating between the Azores and southern Ireland. The small UK tuna drift net fleet operating in the Bay of Biscay was estimated in 1995 to have a by-catch of 100 striped dolphins and 60 common dolphins in 1995. Post-mortem studies of 138 common dolphins washed ashore on UK coasts (mainly south-west England) between 1990 and 1995 revealed at least 62% of animals died as a result of by-catch.

Boat activities (merchant shipping, seismic, military and recreational) in coastal waters pose threats to dolphins by direct physical damage (collisions, and propeller damage) and by the sounds introduced into the environment, where potential harm may be caused by direct auditory damage at close distances and interference with navigation, food-finding, and communication further away. The English Channel is one of the most intensively used waterways in the world, and the North and Irish Seas are not far behind. In recent years, seismic activities have started in the Iris Sea, parts of the Channel, and along the Atlantic Frontier, west and north of Scotland and Ireland, following earlier emphasis on the northern and central North Sea.

Contaminants, including organocholorines, may impact the reproductive potential or cause immunesuppression in marine mammals, including dolphins. High concentrations of bioaccumulating chemicals have been detected in the tissues of marine mammals, and long-lived animals such as cetaceans are more at risk of accumulative heavy pollution burdens than shorter-lived ones. In Cardigan Bay, a few years ago the body of a dead bottlenose dolphin calf was found to have one of the highest levels of contaminants such as PCBs, DDT and mercury ever found in a mammal.

Global climate change may also have an effect on small dolphins but impacts on marine mammals are very difficult to predict.

In 1998, the EU Fisheries Council decided to ban the catching of tuna with drift-nets by 1 January 2002.

Before licences are awarded by the Department of Trade and Industry (DTI) to offshore blocks for oil and gas exploration, operators are required to conduct a preliminary assessment of the impact of their proposed operations using baseline data gathered and provided by government. In addition, restrictions on operating practices are included in the conditions attached to each licence to protect areas of sensitivity. For example, this may restrict the undertaking of seismic surveys to months when cetacean activity is known to be at its minimum. Following the award of licences, under the regulations implementing the Environmental Assessment Directive, operators are required to assess the potential impact of their actions. In cases where there is the possibility of significant impact they may be required to undertake a full environmental assessment seeking advice from consultees, both statutory and non-statutory. If the operation cannot be conducted without causing significant environmental impact, the operation may not be allowed to proceed.

Guidelines for seismic operators to minimise potential impacts of acoustic disturbance from seismic surveys were agreed with the oil and gas industry and published in 1995 by the then Department of the Environment and subsequently revised in April 1998. As a condition of licences awarded under the 16th and 17th Offshore Licensing Rounds, operators are required to conduct seismic activities in accordance with DETR Guidelines for the Minimisation of Acoustic Disturbance to Small Ceteceans. Member companies of the UK Offshore Operators Association (UKOOA) have indicated that they will comply with these Guidelines in all areas of the UK Continental Shelf and, in some cases, elsewhere. Under the guidelines there is a requirement for visual and acoustic surveys of the area prior to seismic testing to determine if cetaceans are in the vicinity, and a slow and progressive build-up of sound to enable animals to move.

A JNCC workshop in 1988 on the potential impacts of seismic activities on marine mammals was attended by representatives from the oil and gas industry, geophysical and environmental contractors, and identified information and concerns and discussed possible research needs and regulatory mechanisms.

Guidance has been drawn up by DETR and JNCC to encourage recreational users (including whale-watching operators) to minimise disturbance to dolphins. These include avoidance of sudden alteration in vessel speed or direction and pursuit of animals. Recommendations have also been made to limit the number of vessels in close proximity, and length of time of encounter.

Eunice Pinn, Joint Nature Conservation Committee Tel:01224 655718

The following LBAPs are working on Grouped plan for small dolphins:

Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume V: Maritime species and habitats (October 1999, Tranche 2, Vol V, p27)

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