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Acoustic monitoring of large whales in deep waters north and west of the British Isles: 1996-2005. Preliminary Report

Prepared by:

Russel A. Charif and Christopher W. Clark
Bioacoustics Research Program, Cornell Laboratory of Ornithology

UKCS Offshore Oil and Gas and Wind Energy Strategic Environmental Assessment: Archaeological Baseline

Prepared by:
Wessex Archaeology

Offshore SEA - Distribution, movements and foraging behaviour of grey seals off NE England and SE Scotland

Prepared by:

Dave Thompson, Beth Mackey and Nicola Quick
Sea Mammal Research Unit

National Grid Input into UK Offshore Energy SEA: Impact on Onshore Electricity Transmission System

Prepared by:

Ivo Spreeuwenberg
National Grid

Distributions of Cetaceans, Seals, Turtles and Ocean Sunfish recorded from Aerial Surveys 2001-2008

Prepared by:

WWT Consulting

Seabird and Marine Mammal Survey F.R.V. Scotia 5-29 August 2008

Prepared by:

Adam Batty
for Cork Ecology

Seabird and Marine Mammal Survey M.V. Englishman 17-30 September 2008

Prepared by:

Ciaran Cronin
for Cork Ecology

Seabird and Marine Mammal Survey R.V. Cefas Endeavour 11-22 August 2008

Prepared by:

Ciaran Cronin
for Cork Ecology

Report on seabird and marine mammal survey from MV Vos Rambler in the Dogger Bank area of the North Sea, 1-15 September 2008

Prepared by:
Genevieve Leaper
For Cork Ecology

Seabird and Marine Mammal Survey VOS Rambler 14-27 September 2008

Prepared by:

Adam Batty
for Cork Ecology

Offshore Energy Strategic Environmental Assessment (SEA) Seascape Study - Working Paper

Prepared by:

White Consultants with Arup and CESA

This paper provides an overview of cephalopods — squid, octopus, cuttlefish — in the SEA2 area. Cephalopods are short-lived, carnivorous animals that have rapid growth rates and play an important part in oceanic and coastal food webs.

They are preyed on by cetaceans, fish and seabirds, and are predators themselves, feeding on fish, crustaceans, molluscs and cephalopods.

Knowledge of cephalopod distribution in Scottish waters is mainly based on information from commercial whitefish vessels that catch squid as a by-catch.

The loliginid squid Loligo forbesi is the predominant species. English cephalopod landings are dominated by cuttlefish caught in the English Channel — outside the area of interest.

The benthic octopod Eledone cirrhosa, though a highly valued species in southern Europe, is usually discarded by fishermen in Scottish waters.

Fishery management statistics indicate that the areas of highest abundance of Loligo forbesi and of Eledone cirrhosa lie outside the SEA2 area.

Cephalopods naturally accumulate high levels of trace metals. The potential of drilling operations to introduce trace metals into the sea is discussed.

It is concluded that the overall impact on cephalopods and cephalopod fisheries in the SEA2 area by further oilfield development would be slight.

This report was prepared by Iain Young of the Department of Zoology, University of Aberdeen, where a group specialises in cephalopod research.

This report draws on a wide range of data sources to provide an overview of the chemicals used in the offshore oil and gas industry, of the chemicals already in the environment and of those released into the environment from other sources.

Considering the whole sea area, it should be noted that the water samples with the highest levels of chemical contamination are found at inshore estuary and coastal sites subject to high industrial usage.

Approximately 2,000 chemical products are used by the offshore oil and gas industry. In 1999 some 180,000 tonnes of chemicals were discharged into the UK sector of the North Sea.

Produced water is now the main source of contaminants, having overtaken drill cuttings since oil-based muds were replaced by less harmful alternatives.

24,286 tonnes of chemicals were reported as discharged to the UKCS in produced water in 1999.

The quantity of oil production water is greater than of gas production water. As oilfields mature, the amount of produced water increases.

The range of chemicals used by the offshore oil and gas industry, the means of regulating them and of monitoring their use, are discussed.

Evidence of biological effects caused by the release of contaminants into the sea is reviewed.

Man has been using the sea in manifold ways for many centuries. This report considers human activities in the North Sea which might have an impact on, or themselves be affected by, further oil and gas developments in the SEA2 areas.

The activities include shipping, energy (both existing oil and gas developments and renewable energy), telecommunications, military activities, waste disposal, dredging and aggregate extraction, marine archaeological sites and wrecks.

Commercial fishing is the subject of a separate report.

Some of the human activities cited above are largely confined to coastal regions, inshore of the SEA2 areas under consideration, for example waste disposal sites and sites for offshore wind power development.

Other activities overlap the SEA2 areas, for example shipping and telecommunications cables. In the southern North Sea shipping traffic is considerably busier than in the central and northern North Sea.

The future of the offshore oil and gas industry is also reviewed. It is now a mature industry and, while new installations are being established in some locations, the decommissioning of other installations is already in progress elsewhere.

After some three decades of operations in the North Sea, about half of the recoverable oil and gas has been produced.

The new fields being discovered are considerably smaller than those discovered in the 1970s.

This report was produced by Cordah Ltd, a multi-disciplinary environmental management consultancy.

This report reviews the impact of human activity on fish and fisheries in the North Sea. The North Sea is one of the world’s most important fishing grounds. In the central and northern parts there is a mixed demersal fishery that targets cod, haddock and whiting; plaice and sole are trawled in the southern and southeastern North Sea; there are extensive pelagic fisheries for herring and mackerel; crustaceans fisheries for Norway lobster, crab and scallop; and industrial fisheries for sandeel and Norway pout.

The recent Quality Status Report for the North Sea (OSPAR 2000) shows that commercial fishing itself has the highest impact on fish populations. The various impacts of the offshore oil and gas industry (e.g. seismic surveys, drilling discharges, produced water discharges…) are classified as intermediate in scale.

The biology of the commercially important fish and shellfish that occur in the offshore waters of the North Sea is discussed. Numerous maps, showing the location of spawning activity and the location of fishing effort, are included. This report is relevant to both SEA 2 and SEA 3 areas.

There is concern about the stocks of herring, cod, haddock, whiting, saithe, plaice and sole which are close to or outside Safe Biological Limits. Catch levels for many fish stocks are almost certainly not sustainable. Increasingly stringent fishery management actions are being taken by the European Commission to try to alleviate the problem of declining fish stocks. Such actions may lead to increasing conflict between the fishing and the offshore oil and gas industries, e.g. by displacing fishing activity away from traditional grounds towards oil and gas fields. However, well established means of liaison exist between the two industries.

This report was prepared by scientists from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) Lowestoft Laboratory with additional data supplied by the Fisheries Research Services Marine Laboratory in Aberdeen

The geology of the North Sea from the Palaeozoic era to the present day is reviewed, with reference to petroleum geology. Geological factors affect the environmental consequences of oil and gas exploitation in many different ways. For example, in the case of the Ekofisk oilfield in the Norwegian sector of the North Sea, oil production led to seafloor subsidence of a few metres due to its chalk reservoir, but production-related subsidence on this scale is atypical.

The evolution of the geomorphology and composition of the shallow and seabed sediments is discussed. The distribution of mud, sand, gravel and hard substrates influence the nature of the benthos and can affect the way in which contaminants are accumulated and transported. Shallow seabed sediments support the foundations of structures ranging from platforms to pipelines. Hydrogeological conditions and the risk of pollution to aquifers are also reviewed.

The Viking Graben, which lies in the northernmost of the SEA2 areas, is more seismically active than the southern areas. The periodicity of the seismic hazard is summarised with reference to offshore installations.

This report was prepared by scientists from the British Geological Survey (BGS). BGS carries out geological survey both onshore and offshore, is the national custodian for geoscience data and aims to provide the best and most up-to-date geoscience information and advice for the UK.

Eight marine mammal species occur regularly over large parts the North Sea: harbour seal, grey seal, harbour porpoise, bottlenose dolphin, white-beaked dolphin, Atlantic white-sided dolphin, killer whale and minke whale. A further 15 cetacean species and five pinniped species are reported less frequently in the region.

This report describes the distribution and abundance of these mammals and their ecological importance. The harbour porpoise the most numerous marine mammal in the North Sea, with a population estimated at 268,000 in summer 1994. The northern and central SEA2 areas are particularly important areas for the harbour porpoise.

Marine mammals make use of sound for a variety of purposes: finding prey, detecting predators, communication and probably navigation. The offshore oil and gas industry generates underwater noise at every stage of the process: during exploration seismic surveys, drilling, production and decommissioning. The effects of these different sources of underwater noise on marine mammals are discussed. The use of explosives for underwater cutting and demolition during the decommissioning of platforms and installations may pose a serious threat to some marine mammals.

The effects of pollution on seals and cetaceans are discussed, including the effects of oil spills. Large whales can be killed by being struck by ships; increased shipping traffic in an area would increase this threat.

The report was prepared by scientists from the Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews.

This paper gives an overview of the phytoplankton and zooplankton community composition in the North Sea and how this has fluctuated through the latter half of the 20th Century in response to environmental change. The study is based on a unique long-term dataset of plankton abundance in the North Atlantic and the North Sea acquired by the Continuous Plankton Recorder (CPR).

The dinoflagellate genus Ceratium dominates the phytoplankton community in the North Sea, but diatoms are also important, especially in the southern part. The normal annual blooms of plankton are discussed, as are harmful algal blooms (HABs), which appear to be on the increase, possibly due to a combination of climatic variability and eutrophication.

Among the zooplankton, copepods are particularly important and constitute a major food resource for many commercial fish species, such as cod and herring. Calanus is the dominant copepod genus in the North Atlantic.

Other important components of the plankton — meroplankton, picoplankton and megaplankton — are also reviewed. Very small picoplankton (~1 micron in diameter) and much larger gelatinous members of the megaplankton (e.g. jellyfish and ctenophores) are poorly sampled by the CPR. Although the picoplankton represents a sizeable fraction of total primary production, its role in the marine ecosystem is poorly understood.

The introduction of non-indigenous plankton in ship’s ballast water has been in progress for about a century. There is growing concern about the risk of alien species, and the importance of protecting native bio-diversity.

This report was prepared by scientists from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), which specialises in the study of plankton in the North Atlantic and the North Sea.

Pockmarks frequently contain unusual densities of fish, typically large gadoids such as cod, torsk and ling. High densities of fish otoliths have been found in one North Sea pockmark. The existence of cemented sediment in the base of pockmarks can provide a refuge for fish and a hard substrate for colonisation by epifauna such as anthozoa.

Deep active pockmarks, such as the three studied in block 15/25, are known to contain species dependent on high sulphide concentrations, originating from seepage or enhanced sedimentation. Some of these species are not found elsewhere in the open North Sea. The 20 m deep "Scanner" pockmark in block 15/25 is the only pockmark in the UK sector of the North Sea whose biology has been studied in detail. It is the only known habitat of the gutless nematode Astononema southwardorum. Further novel species may be discovered with more detailed investigations. Seeping pockmarks are also likely to contain potentially interesting bacterial associations.

This report was written by Professor Paul Dando (School of Ocean Sciences, University of Wales, Bangor), whose research has focussed on the environmental effects of fluid seepage through the seabed.

This report reviews the distribution and character of pockmarks - shallow seabed depressions - which are common in the area of the North Sea to the north-east of Scotland known as the Fladen Ground. Pockmarks are believed to be produced by the escape of fluids (gas or water, but generally gas in the North Sea) from the seafloor and are found in areas where the seabed sediments are soft, silty clays. Processes of pockmark formation, their geometry, age and distribution, and the sources of gas in the underlying geological strata are discussed.

The gas seepage which is believed to produce the pockmarks is probably episodic in nature and may have persisted for several thousand years. While the great majority of pockmarks are inactive at the present time, a few are observed to be actively seeping gas. The presence of bacterial mats or of methane-derived authigenic carbonate in pockmarks, which would indicate methane seepage over a considerable time, has been little studied in the UK sector of the North Sea.

In order to provide a stronger basis upon which the significance of pockmarks within mature oil and gas provinces of the North Sea might be assessed, the Department of Trade and Industry commissioned the acquisition of new data directed towards increasing our scientific understanding of sandbanks and pockmarks as part of the SEA2 process. The survey vessel Kommandor Jack was chartered in April 2001 and, among other operations, conducted high-resolution geophysical surveys of pockmarks in the Fladen Ground. Preliminary results from that operation are included in this paper.

This report was prepared by Dr Alan Judd (University of Sunderland), one of the world’s foremost authorities on seafloor pockmarks.

Investigation of the origin of shallow gas in Outer Moray Firth open
blocks 15/20c and 15/25d (Scotia and Scanner pockmark areas).

The socio-economic effects of licensing the SEA2 area depend on the exploration, development, and production activities resulting from the new round. There are many underlying uncertainties involved in estimating these effects. The numbers of Blocks nominated and the number subsequently taken up constitute initial uncertainties. It is understood that around 70 Blocks may be on offer in the SNS, 90 in the CNS, and 70 in the NNS. Many of the Blocks on offer will have been relinquished from earlier rounds.

In the 18th Round the take-up was not very high in relation to the number of Blocks put on offer. This round coincided with a period of very low oil and gas prices which probably influenced the interest shown by the industry. The present price environment is very different though much uncertainty remains.

The numbers of commitment wells likely to be offered in the new round are also subject to considerable uncertainty. These will reflect both the numbers of Blocks sought and the perceptions of the expected success rates. Exploration success rates, while less than in the 1970s and 1980s, have held up quite well given the maturity of the North Sea acreage in question. One reason for this has been the advances in seismic technology.

In the present context it is also relevant that much data on previously licensed acreage will be available to new applicants. It is also relevant that in some of the acreage discoveries have already been made. This could enhance the overall success rate, taking into account appraisal as well as exploration.

This report was prepared by the University of Aberdeen

This report documents the known and likely occurrence of prehistoric archaeological remains across the whole floor of the North Sea including the SEA3 area, and makes suggestions on how to enhance the finding and reporting of such artefacts. 

Sea level change associated with the retreat of the last glaciation led to almost the whole floor of the North Sea being dry land at some time or another in the past 20,000 years. Similar exposure of the North Sea floor was also associated with earlier glacial cycles. Thus prehistoric submarine archaeological artefacts can occur over a wide area of the North Sea floor, as far north as the latitude of the Shetland Islands. While artefacts dating from the last 12,000 years are most likely, human or proto-human artefacts as old as half a million years may have survived in places.

Submarine archaeological studies in the Danish Archipelago have established that coastal sites were an optimal place for prehistoric human occupation. Similar coastal sites existed over many parts of the North Sea floor in the past.

The potential impact of oil and gas operations on submarine archaeological remains is discussed. Pipe entrenching is the most likely process to uncover prehistoric archaeological deposits.

This report draws on a wide range of data sources to provide an overview of the chemicals used in the offshore oil and gas industry, of the chemicals already in the environment and of those released into the environment from other sources. Considering the whole sea area, it should be noted that the water samples with the highest levels of chemical contamination are found at inshore estuary and coastal sites subject to high industrial usage.

Approximately 2,000 chemical products are used by the offshore oil and gas industry. In 1999 some 180,000 tonnes of chemicals were discharged into the UK sector of the North Sea. Produced water is now the main source of contaminants, having overtaken drill cuttings since oil-based muds were replaced by less harmful alternatives. 24,286 tonnes of chemicals were reported as discharged to the UKCS in produced water in 1999. The quantity of oil production water is greater than of gas production water. As oilfields mature, the amount of produced water increases.

The range of chemicals used by the offshore oil and gas industry, the means of regulating them and of monitoring their use, are discussed. Evidence of biological effects caused by the release of contaminants into the sea is reviewed.

This report was prepared by scientists from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS). CEFAS is a UK-based research and consultancy centre providing services in fisheries science and management, environmental monitoring and assessment, and fish health.

This report reviews the impact of human activity on fish and fisheries in the North Sea. The North Sea is one of the world’s most important fishing grounds. In the central and northern parts there is a mixed demersal fishery that targets cod, haddock and whiting; plaice and sole are trawled in the southern and southeastern North Sea; there are extensive pelagic fisheries for herring and mackerel; crustaceans fisheries for Norway lobster, crab and scallop; and industrial fisheries for sandeel and Norway pout.

The recent Quality Status Report for the North Sea (OSPAR 2000) shows that commercial fishing itself has the highest impact on fish populations. The various impacts of the offshore oil and gas industry (e.g. seismic surveys, drilling discharges, produced water discharges…) are classified as intermediate in scale.

The biology of the commercially important fish and shellfish that occur in the offshore waters of the North Sea is discussed. Numerous maps, showing the location of spawning activity and the location of fishing effort, are included. This report is relevant to both SEA 2 and SEA 3 areas.

There is concern about the stocks of herring, cod, haddock, whiting, saithe, plaice and sole which are close to or outside Safe Biological Limits. Catch levels for many fish stocks are almost certainly not sustainable. Increasingly stringent fishery management actions are being taken by the European Commission to try to alleviate the problem of declining fish stocks. Such actions may lead to increasing conflict between the fishing and the offshore oil and gas industries, e.g. by displacing fishing activity away from traditional grounds towards oil and gas fields. However, well established means of liaison exist between the two industries.

This report was prepared by scientists from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) Lowestoft Laboratory with additional data supplied by the Fisheries Research Services Marine Laboratory in Aberdeen.

This paper provides an overview of cephalopods — squid, octopus, cuttlefish — in the SEA2 and SEA3 areas. Cephalopods are short-lived, carnivorous animals that have rapid growth rates and play an important part in oceanic and coastal food webs. They are preyed on by cetaceans, fish and seabirds, and are predators themselves, feeding on fish, crustaceans, molluscs and cephalopods.

Knowledge of cephalopod distribution in Scottish waters is mainly based on information from commercial whitefish vessels that catch squid as a by-catch. The loliginid squid Loligo forbesi is the predominant species. English cephalopod landings are dominated by cuttlefish caught in the English Channel — outside the area of interest. The benthic octopod Eledone cirrhosa, though a highly valued species in southern Europe, is usually discarded by fishermen in the SEA2 and SEA3 areas. Fishery management statistics indicate that the areas of highest abundance of Loligo forbesi and of Eledone cirrhosa lie outside the SEA2 and SEA3 areas.

Cephalopods naturally accumulate high levels of trace metals. The potential of drilling operations to introduce trace metals into the sea is discussed. It is concluded that the overall impact on cephalopods and cephalopod fisheries in the SEA2 and SEA3 areas by further oilfield development would be slight.

This report was prepared by Iain Young of the Department of Zoology, University of Aberdeen, where a group specialises in cephalopod research.

This report provides an overview of the various management plans which have been developed for the coastal zone, coastal defence, estuaries, biodiversity and coastal habitats in the SEA3 area.

Numerous dynamic processes, both natural and man-made, affect the SEA3 coastline. After reviewing these processes, the report reviews the various coastal initiatives and management strategies which have been established to minimise their detrimental effects.

Various coastal fora provide a lead in developing management strategies for the enhancement and protection of the environment in their areas. Plans include European marine site management schemes, shoreline management plans prepared by coastal defence authorities, estuary management plans, coastal habitat management plans and biodiversity action plans.

This report summarises the large number of existing conservation sites and potential sites of conservation importance in the SEA3 area.

The SEA 3 area displays a wide variety of habitat types, from those of a coastal nature, such as estuarine mudflats and sandflats, saltmarsh, sea cliffs and reef habitats, to those associated with the offshore environment. Some of these habitats are rare in a national and/or international context, and many support important numbers of birds, insects and other animals.

Existing coastal and nearshore conservation sites are protected by international, national and local conservation designations. Statutory sites are legally protected whilst non-statutory sites rely on the planning process to confer protection.

The UK Government is currently taking steps to implement the EC Habitats Directive and the Birds Directive in offshore waters. A process to designate Special Areas of Conservation and Special Protection Areas, both within territorial waters and out to the limits of the UKCS, is under way. Potential offshore conservation sites are reviewed.

This report is a synthesis of information on human activities which might have an impact on, or themselves be affected by, further oil and gas developments in the SEA3 area. The activities include shipping, energy (both existing oil and gas developments and renewable energy), telecommunications, military activities, waste disposal, dredging and aggregate extraction, marine archaeological sites and wrecks.

The SEA3 area hosts a wide variety of different users. Some have been there for centuries, others are more recent arrivals. Among the older industries and activities are fisheries, ports and shipping, military activities and sea bathing. The offshore oil and gas industry has developed into a major player in the North Sea since the late 1960s, with considerable infrastructure of pipelines and coastal gas terminals in the SEA3 area. The number of submarine telecommunication cables across the North Sea has grown enormously in the past ten years, with the advent of the fibre optic cable and the growth of the Internet and e-commerce. The next twenty years may see considerable development of offshore wind farms in the SEA3 area.

The geology of the North Sea from the Palaeozoic era to the present day is reviewed, with reference to petroleum geology. Geological factors affect the environmental consequences of oil and gas exploitation in many different ways. For example, in the case of the Ekofisk oilfield in the Norwegian sector of the North Sea, oil production led to seafloor subsidence of a few metres due to its chalk reservoir, but production-related subsidence on this scale is atypical.

The evolution of the geomorphology and composition of the shallow and seabed sediments is discussed. The distribution of mud, sand, gravel and hard substrates influence the nature of the benthos and can affect the way in which contaminants are accumulated and transported. Shallow seabed sediments support the foundations of structures ranging from platforms to pipelines. Hydrogeological conditions and the risk of pollution to aquifers are also reviewed.

Apart from the addition of a new surficial sediment map of the North Sea, this document is identical to the report on North Sea Geology produced for SEA2.

This report was prepared by scientists from the British Geological Survey (BGS). BGS carries out geological survey both onshore and offshore, is the national custodian for geoscience data and aims to provide the best and most up-to-date geoscience information and advice for the UK.

Eight marine mammal species occur regularly over large parts the North Sea: harbour seal, grey seal, harbour porpoise, bottlenose dolphin, white-beaked dolphin, Atlantic white-sided dolphin, killer whale and minke whale. A further 15 cetacean species and five pinniped species are reported less frequently in the region.

This report describes the distribution and abundance of these mammals and their ecological importance. The harbour porpoise the most numerous marine mammal in the North Sea, with a population estimated at 268,000 in summer 1994. The northern parts of the SEA3 area are important for the three most abundant cetacean speciesin the North Sea: minke whale, harbour porpoise and white-beaked dolphin. Harbour seals occur widely in the SEA3 area.

Marine mammals make use of sound for a variety of purposes: finding prey, detecting predators, communication and probably navigation. The offshore oil and gas industry generates underwater noise at every stage of the process: during exploration seismic surveys, drilling, production and decommissioning. The effects of these different sources of underwater noise on marine mammals are discussed. The use of explosives for underwater cutting and demolition during the decommissioning of platforms and installations may pose a serious threat to some marine mammals.

The effects of pollution on seals and cetaceans are discussed, including the effects of oil spills. Large whales can be killed by being struck by ships; increased shipping traffic in an area would increase this threat.

The report was prepared by scientists from the Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews.

This report summarises sites which are protected for reasons other than nature conservation. They include sites of geological importance, archaeological importance, sites of designated water quality for bathing, and areas of bivalve shellfish production.

Sites of geological importance include Geological Conservation Review sites (GCRs), geological Special Sites of Scientific Interest (SSSI) and Regionally Important Geological and Geomorphological sites (RIGS).

Sites of archaeological importance include wrecks and scheduled monuments. A large number of wrecks exist in the SEA3 area, most uncharted. The majority of wrecks are found in coastal waters. Important historic wrecks in UK waters are protected under the Protection of Wrecks Act 1973.

Water samples are regularly taken from numerous beaches along the east coast for physical, chemical and microbiological analysis. Bathing beaches are classified according to national and European standards for quality.

In the UK, shellfish for human consumption must be harvested from designated production areas.

The SEA3 report has been written as an addendum to the more comprehensive SEA2 document. The two papers give an overview of the phytoplankton and zooplankton community composition in the North Sea and how this has fluctuated through the latter half of the 20th Century in response to environmental change. The study is based on a unique long-term dataset of plankton abundance in the North Atlantic and the North Sea acquired by the Continuous Plankton Recorder (CPR).

The dinoflagellate genus Ceratium dominates the phytoplankton community in the North Sea, but diatoms are also important, especially in the southern part. The normal annual blooms of plankton are discussed, as are harmful algal blooms (HABs), which appear to be on the increase, possibly due to a combination of climatic variability and eutrophication.

Among the zooplankton, copepods are particularly important and constitute a major food resource for many commercial fish species, such as cod and herring. Calanus is the dominant copepod genus in the North Atlantic.

Other important components of the plankton — meroplankton, picoplankton and megaplankton — are also reviewed. Very small picoplankton (~1 micron in diameter) and much larger gelatinous members of the megaplankton (e.g. jellyfish and ctenophores) are poorly sampled by the CPR. Although the picoplankton represents a sizeable fraction of total primary production, its role in the marine ecosystem is poorly understood.

The introduction of non-indigenous plankton in ship’s ballast water has been in progress for about a century. There is growing concern about the risk of alien species, and the importance of protecting native bio-diversity.

This report was prepared by scientists from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), which specialises in the study of plankton in the North Atlantic and the North Sea.

This study provides forecast information on probable activity levels, capital expenditure, tax revenues and employment resulting from exploration and production in the SEA3 area.

The SEA3 area comprises 330 blocks or part blocks in the Central and Southern North Sea. Estimates were made of the reserves which might be discovered or developed. A cautious view was taken of the number of new developments which might emanate from licensing the area. The related exploration, appraisal, development and decommissioning costs were then estimated.


Economic modelling was undertaken for different oil and gas prices to calculate for each development gross revenues, development costs, operating costs, and decommissioning costs. The taxation implications were also calculated.

The impact of licensing the SEA3 area on the level of employment in the UK has been calculated. The proposed licensing would make a modest but worthwhile contribution towards moderating the downward trend of employment in the North Sea industry.

This report discusses the potential for prehistoric archaeological remains to exist on the continental shelf part of the SEA4 area. The combination of post-glacial sea level rise and the subsidence of the shelf to the north of the Scottish mainland indicates that a large area of the present shelf, out to a water depth of about 150m on either side of the Orkney-Shetland Ridge, may have been dry land over 5000 years ago. 

Submarine archaeological studies in the Danish archipelago have established that coastal sites were an optimal place for prehistoric occupation. There is a great density of prehistoric sites in the Orkney and Shetland archipelagos, dating back to as early as 6000 years BP. Submerged sites could date back to about 9000 years BP.

While shelf sites exposed to strong currents and Atlantic storm conditions are unlikely to have survived, the survival of more protected sites is quite likely. Locations where prehistoric remains might occur and have a high chance of survival are discussed.

The potential impact of oil and gas operations on submarine archaeological remains is discussed. Pipe entrenching is the most likely process to uncover prehistoric archaeological deposits.

This report was prepared by Dr N C Flemming

The development of the deep-water oil industry to the west of Shetland led to extensive regional surveys of the seafloor environment, so that the deep-water benthos of the SEA4 area are now at least as well known as in any other deep-water area worldwide. Two papers have been prepared on the topic: a very accessible introduction and a more detailed technical report.

Extensive surveys of the Faeroe-Shetland Channel, funded by the Atlantic Frontier Environmental Network and by the Department of Trade and Industry, took place between 1996 and 2002. The ecology of the benthos in the SEA4 area is strongly influenced by the hydrography of the region, in particular the complex temperature regime, and by the nature of the seabed sediments.

This paper provides an overview of cephalopods - squid and octopus - in the SEA4 area. Cephalopods are short-lived, carnivorous animals that have rapid growth rates and play an important part in oceanic and coastal food webs. They are preyed on by cetaceans, seals, fish and seabirds, and are predators themselves, feeding on fish, crustaceans, molluscs and cephalopods.

Knowledge of cephalopod distribution in Scottish waters is mainly based on information from commercial whitefish vessels that catch squid as a by-catch. Fishery landings of cephalopods consist mainly of the loliginid squid Loligo forbesi. At present there are no commercial landings of the ommastrephid squids Todarodes sagittatus or Todaropsis eblanae. The benthic octopod Eledone cirrhosa, though a highly valued species in southern Europe, is usually discarded by Scottish fishermen.

Various deep-water squid are likely to be present in the Faeroe-Shetland Channel, of which the most important is probably the Arctic squid Gonatus fabricii.

Cephalopods naturally accumulate high levels of trace metals. The potential of drilling operations to introduce trace metals into the sea is discussed. But the most likely impact of oil industry activities on cephalopod populations is disturbance of spawning grounds. Although squid in spawning condition are caught every year in the SEA4 area, where they spawn is not known.

It is concluded that the overall impact on cephalopods and cephalopod fisheries in the SEA4 area of further oilfield development would be slight.

This report identifies coastal and near-shore conservation sites within the SEA4 area which are protected by international, national and local conservation designations as well as describing the sites and reasons for their protected status.

At the northern extremity of Britain, the SEA4 area combines very productive waters with spectacular and distinctive coastal scenery. The combination of rich food sources and relative lack of disturbance make it host to abundant bird populations, including rare species not found elsewhere in the United Kingdom. Among the conservation sites are sea inlets, mud and sand flats, lagoons, salt marshes, sand dunes, shingle, sea cliffs, fresh water bogs and marshes, heath, scrub and grassland.

This report is a synthesis of information on human activities which might have an impact on, or themselves be affected by, further oil and gas developments in the SEA4 area. The activities include fishing, mariculture, shipping, energy (both existing oil and gas developments and renewable energy), telecommunications, military activities, waste disposal, dredging and aggregate extraction, tourism, coastal and marine archaeological sites. 

The SEA4 area hosts a wide variety of different users. Some have been there for centuries, others are more recent arrivals. Among the older industries and activities are fisheries, ports and shipping and military activities; the oil and gas industry and mariculture are newer arrivals. Orkney and Shetland have provided major infrastructure for the North Sea oil and gas industry since the 1970s, and there have been producing oil fields to the west of Shetland since 1997. Finfish and shellfish farming are important industries in the coastal regions of the SEA4 area.

Fisheries are very important in the SEA4 area, the mixed demersal fishery for cod, haddock and whiting, the pelagic fisheries for herring and mackerel, and the industrial fishery for sandeel, being the most important. However, there are serious concerns about many fish stocks. This report discusses fish biology, the many different fisheries, trends in fish landings, management efforts to control fishing and achieve sustainable fish stocks, and the interaction between fishing and the oil and gas industry.

Relevant aspects of the biology of 28 species or species groups are described. Brief descriptions of the fishery for each species are given, including the method of fishing and long term trends in landings. Statistical information on fish landings available from the International Council for the Exploration of the SEA (ICES) and data for Scottish vessels supplied by Fisheries Research Services are presented. Problems of misreporting and under-reporting are discussed. Specific efforts to control fishing in the vicinity of Shetland and Orkney are mentioned.

Fish communities in the SEA4 area associated with the coast, shelf and shelf edge have affinities with communities elsewhere in the UK EEZ, such as to the west of the Hebrides, but the deep-water fish communities found in the very cold water below about 500m water depth in the Faroe Shetland Channel are unique to the UK EEZ.

The report concludes with a discussion of the interactions between fishing activity and the oil and gas industry. The reader should refer to the SEA2 North Sea Fish and Fisheries report for a more detailed discussion of this topic.

This report was prepared by Dr John Gordon, Honorary Fellow at the Scottish Association for Marine Science Laboratory at Dunstaffnage.

This report describes the field of mud diapirs in the northern part of the SEA4 area, known as the Pilot Whale Diapirs, which were mapped during a multibeam survey carried out in 2002. A diapir is a fold or dome caused by more plastic rocks at depth, such as salt or mud, intruding overlying denser rocks, generally driven by their own buoyancy. Sometimes a diapir breaks through to the seafloor.  

The diapir field extends over an area some 60 km across, creating a very variable seabed terrain. The largest diapirs have produced elevations at the seafloor of more than 120m.

The largest diapirs in the group are thought to have intruded to the seafloor from 500m or more beneath it. The evidence suggests that the diapirism was initiated between 5 and 1 million years ago, but it does not appear to be continuing at the present time.

The report was prepared by scientists from the Continental Shelf and Margins Group at the British Geological Survey.

This report describes the surficial seabed geology and geological processes affecting the continental shelf part of the SEA4 area, lying in water depths of less than 200 m. Roughly half of the SEA4 area lies in these water depths.

The report reviews the seabed geomorphology, near-bottom currents, types of rock outcrop, variations in the texture of the unconsolidated sediments, the variety and distributions of seabed bedforms and selected aspects of the inorganic geochemistry of the sediments. Variations in the seabed geology have a major influence on the organisms that live on the bottom, thus are important to understanding the modern seabed habitat.

The modern seabed environment now largely reflects the effects of reworking by near-bottom currents on the topography and the sediments that originated during the glaciations.

The report was prepared by scientists from the Continental Shelf and Margins Group at the British Geological Survey.

This report summarises the geological history of the SEA4 area from Pre-Cambrian times to the present day, sets the framework in which oil and gas fields have been discovered to the west of Shetland, and discusses the seismicity of the area.

A generalised geological map of the area is presented and three approximately NW-SE trending sections across the southern part of the SEA4 area are shown. The petroleum geology of the area is reviewed and the geological settings in which oil has been found at the Clair, Foinaven, Schiehallion and Loyal oilfields is described. Other hydrocarbon fields to the west of Shetland, for which there are no immediate development plans, are briefly touched on. The seismicity of the SEA4 area, which is very low, is discussed.

Twelve marine mammal species occur regularly in the SEA4 area: grey seal, harbour seal, hooded seal, harbour porpoise, white-beaked dolphin, Atlantic white-sided dolphin, Risso's dolphin, long-finned pilot whale, killer whale, minke whale, fin whale and sperm whale. A further eleven cetacean species and four pinniped species are occasional visitors. 

This report describes the distribution and abundance of these mammals and their ecological importance. The SEA4 area is an important area for cetaceans, but little is known about the abundance or seasonal distribution of many species.

Marine mammals make use of sound for a variety of purposes: finding prey, detecting predators, communication and probably navigation. The offshore oil and gas industry generates underwater noise at every stage of the process: during exploration seismic surveys, drilling, production and decommissioning. The effects of these different sources of underwater noise on marine mammals are discussed. The use of explosives for underwater cutting and demolition during the decommissioning of platforms and installations may pose a serious threat to some marine mammals. However, current understanding of the effects of noise on marine mammals is rudimentary.

The effects of pollution on seals and cetaceans are discussed, including the effects of oil spills. The diseases to which they are subject are briefly discussed, as are non-oil management issues such as fisheries bycatch. Finally, the national and international frameworks for the protection of marine mammals are reviewed.

The plankton community in the SEA4 area is similar to that in the North Sea, with variations in the abundances of some individual species. Emphasis in this review is put on trends in the abundances of major phytoplankton and zooplankton taxa over the last 40 years. The study is based on a unique long-term dataset of plankton abundance in the North Atlantic and the North Sea acquired by the Continuous Plankton Recorder (CPR). 

In the phytoplankton community, conspicuous trends are the steady increase in Phytoplankton Colour (an indicator of phytoplankton biomass) since 1960 and the mid 1980s peak in Thalassiosira spp. abundance. Among the zooplankton the decline in the abundance of Calanus finmarchicus and the increase in that of Calanus helgolandicus since 1960 are probably related to increasing sea surface temperatures in the northeast Atlantic.

Phytoplankton blooms are discussed, from the normal annual blooms to harmful algal blooms (HABs). Because of the extensive fish farm industry in coastal regions of SEA4, there is considerable interest and ongoing research into HABs, but there is no clear evidence that they are increasing in frequency or intensity due to anthropogenic eutrophication.

Other important components of the plankton meroplankton, picoplankton and megaplankton are also reviewed. For a more detailed discussion of the various components of the plankton community, the reader should refer to the SEA2 report.

This report was prepared by scientists from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), which specialises in the study of plankton in the North Atlantic and the North Sea.

This report describes the surficial sediments in the SEA4 area and the sedimentary processes that are active in the area at the present day.

The report focuses on the deeper water areas from the outer continental shelf to the floor of the Norwegian Basin in the northernmost part of SEA4.

The report is based on sidescan sonar images, multibeam bathymetry, sub-bottom profiles, seabed photographs and sediment samples.

The Holocene and late glacial events and processes that contributed to the present day seafloor morphology and sediment distribution are reviewed, as is the present day oceanographic regime.

It is concluded that the present day sedimentary environment, seaward of the continental shelf edge at about 200 m water depth, is dominated by low sediment input and deposition rates, and by reworking of surficial sediments by bottom currents.

The large scale seabed morphology was shaped mainly during the last glacial, when high sediment input resulted in glacigenic debris fan formation.

This report was prepared by Dr D G Masson and colleagues from the Southampton Oceanography Centre.

This report provides a summary of the benthic communities and assemblages which inhabit the shallow waters of the SEA4 area, from littoral to offshore areas.

A wide range of habitats exist in the area because of the heterogeneity of the seafloor environment, ranging from hard rock sites exposed to the full force of waves and tidal currents to muddy sediments in sheltered inlets. The shelf and offshore areas include varying bedforms of sand and gravel, some of high carbonate content, and considerable amounts of glacigenic material. The epifauna and infauna which inhabit these different environments are summarised.

A section of the report discusses the environmental impacts of anthropogenic activities in the area. These include the harvesting of algae from rocky shores, the release of radionuclides on the Caithness coast (Dounreay), dredging for sedimentary material, trawling and mariculture, in addition to the offshore oil and gas industry.

This report was prepared by Professor A. Eleftheriou of the Institute of Marine Biology of Crete.

Starting with scenarios of possible exploration and development activity in the area provided by the Department of Trade & Industry, this study provides forecasts of oil and gas production, expenditure, employment and tax revenues.

The impacts of future oil and gas developments in the SEA4 area on the local economies of Shetland and Orkney will be small in comparison to what has happened in the past. The main impact will be to postpone or to slow down the decline in UK oil production. Nevertheless, production from fields in the area could make significant contributions to overall UKCS production, employment and tax revenues, as well as extending the lives of facilities such as the Sullom Voe and Flotta terminals. It could help to retain employment and population in the area.

This report was prepared by Mackay Consultants

Prehistoric submarine archaeological remains back to a date of about 12,000 years ago, Palaeolithic, Mesolithic and Neolithic, could occur with low probability anywhere in the SEA5 area between the northern mainland coast and the eastern boundary of SEA5.

The existence and possible survival of prehistoric sites is complicated by the rapid and continuing uplift of the east coast of Scotland and the immediately adjacent shelf in the Moray Firth, the fact that ice sheet covered part of the seabed obliterating most artefacts earlier than about 20,000 years BP, and that the seabed towards the median line has subsided, and was associated with extensive sea-water lakes and floating sea ice during the glacial maximum.

The combination of post-glacial sea level rise which terminated about 5000 years ago, and the continuing subsidence of the outer shelf, with uplift of the mainland, creates a complex sequence at coastal sites, some of which may have been dry land over 5000 years ago, then covered by the rising sea, and are now uplifted again relative to a constant sea level.

Known submerged prehistoric sites in Orkney, Shetland, Viking Bank, the Yorkshire coast, and Denmark, show that prehistoric sites from the last 5-10,000 years can survive marine transgression.

The strong current conditions in the SEA5 area, the exposure to North Atlantic storms, the thin sediment cover in many places, and the large areas of exposed bedrock, make the exposed areas of the shelf statistically poor prospects for the survival of prehistoric deposits in situ, other than in submerged caves and gullies.

Within sheltered sea lochs and enclosed bays of the east coast of the Shetlands, Orkney and Fair Isle, in submerged gullies, and locally thick sediments, survival is quite likely. Deposits in open shelf gullies are likely to have been transported and re-deposited.

Evidence from the northern North Sea and the Russian Arctic suggests that some prehistoric peoples may have occupied the exposed shelf area during late glacial periods utilising Inuit-style survival methods, and butchering marine mammals. If this proves to be the case, there may be unexpected occurrence of earlier prehistoric sites, Late Palaeolithic, on the north-east shelf.

Pipe entrenching is the process in the oil and gas industry which is most likely to disturb prehistoric archaeological deposits. Commercial site investigation using acoustics and coring could provide beneficial new archaeological data. The paper concludes with tentative suggestions for discussion of protocols and a reporting regime.

This report was prepared by Dr N C Flemming.

The purpose of this report is to present an up-to-date synthesis of current information on the benthic environment and the benthic communities and associations in the Strategic Environmental Assessment (SEA) region 5 and, additionally, to highlight areas considered to be particularly vulnerable to anthropogenic influences.

The synthesis has been prepared from the information available on seabed habitats, species and communities to the east of Orkney and Shetland and extending down the east coast of Scotland.

The area includes the major east coast features, the Moray Firth, the Firth of Forth, and the Tay estuary, and the inner Firths of Dornoch, Cromarty and Inverness, the Ythan Estuary and the Montrose basin. It extends offshore to an irregular border at 1° west, east of Wick on the Scottish mainland, proceeds west to 1°45’ west off Fraserburgh and then offshore again to 0°45’east off the Tay estuary before rejoining the coast at the Scotland - England border.

Anastasios Eleftheriou, David Basford and Derek C Moore.

Cephalopods are short-lived molluscs, characterised by rapid growth rates, and are important predators and prey in oceanic and neritic environments. They can range in size from 1.5 cm in pygmy squid (Sepiolidae) to 20 m in giant squid (Architheutidae). Cephalopods exhibit the highest degree of development in invertebrate nervous systems, expressed through complex behaviour patterns such as the ability to learn and the display of complex colour changes. In contrast to other molluscs, most cephalopods lack an external shell, are highly mobile as adults and occupy similar ecological niches to predatory fish.

They are active predators at all stages of their life-cycle and generally regarded as opportunistic, taking a wide variety of prey. Cannibalism has been frequently recorded in cephalopod species. Cephalopods also sustain a number of marine top predators such as fish, birds and marine mammals, especially whales. Many species are powerful swimmers and carry out vast feeding and spawning migrations, thus influencing prey and predator communities strongly on a seasonal and regional basis.

As cephalopods are important elements in food webs they interact with commercial fisheries of finfish. Evidence exists that fishing pressure has changed ecological conditions and shifts in community structures have occurred with cephalopod stocks slowly replacing predatory fish stocks. Their commercial significance to world fisheries is of relatively recent, but growing, importance.

This report was prepared by Gabriele Stowasser, Graham J Pierce, Jianjun Wang and M Begoña Santos of the Department of Zoology, University of Aberdeen.

An integral element of any environmental assessment for offshore oil and gas exploration, and for possible nearshore renewable energy proposals, involves a review of potential sites of conservational importance within the region of interest. For the purpose of SEA 5, this is especially important given the scale of the area in question and the fact that it includes the coastal zone which is known to support a large number of conservation sites.

The SEA 5 area displays a wide variety of habitat types such as coastal cliffs, rock platforms, beaches and dunes. The area also includes major estuaries such as the Tay and the Forth. Some of these habitats are rare in a national and/or international context, and many support important numbers of bird colonies, seals and, in the Moray Firth, dolphins.

This report identifies and locates coastal and nearshore sites within the SEA 5 area which are protected by international, national and local conservation designations as well as describing the sites and reasons for their protected status. The coastal conservation sites are listed according to whether they are of international, national or local importance.

For internationally important sites, summary information describing the main features of the site is provided and there is also an assessment of the vulnerability of the site and any relevant management issues.

The ordering of the national sites in this report does not imply any formal ranking, but is a relative judgement of their scientific importance. The conservation sites described in this section are listed in Table 1.1 and brief descriptions of the statutory and non-statutory mechanisms responsible for site protection are presented in Appendix 2. Statutory sites are legally protected whilst non-statutory sites rely on the planning process and other local agreements to confer protection.

Prepared by Aberdeen Institute of Coastal Science and Management, University of Aberdeen with Hartley Anderson Limited.

A review of the distribution and abundance of divers, grebes and seaduck in the SEA 5 area was carried out by Cork Ecology at the request of the Department of Trade and Industry as part of the production of the SEA 5 Consultation Document. The study area was defined as the east coast of Scotland from the English border north to John O’ Groats, including Orkney and Shetland, and the offshore waters in the SEA 5 area.

Divers, grebes and seaduck are primarily inshore species typically wintering in sandy bays or estuaries although some e.g. great northern divers prefer rocky shorelines. Some species are resident while others are winter visitors to Britain.

This review considered thirteen species: red-throated diver, black-throated diver, great northern diver, great crested grebe, red-necked grebe, slavonian grebe, scaup, eider, long-tailed duck, common scoter, velvet scoter, goldeneye and red-breasted merganser.

Report prepared by Colin Barton and Claire Pollock, Cork Ecology, Cork, Ireland.

This report reviews published and newly-acquired seabed geological data in an area of 78,000 square kilometres extending from the coast to more than 200 m water depth to the east of the British Isles. While it can be argued that the modern environment is a product of past environmental conditions, the basis for the review is also that our understanding of the modern environment can be significantly improved if new techniques, data and ideas are applied to a revision of the existing research knowledge.

The purpose of the review is to place the characteristics of the seabed features that were surveyed by the DTI in 2003, and the processes forming them, into an improved understanding of their historical, local and regional context. In this way a strong element of the review is to include the results from exploration and discovery.

The intention of the report is to provide a technical basis for the DTI Strategic Environmental Assessment prior to a new round of licensing and consents for oil and gas. Results from this report are also relevant to scenarios for development of potential offshore renewable energy sites in less than 40-50m water depth.

Report prepared by the British Geological Survey.

Eight marine mammal species are known to occur regularly in this area: grey seal, harbour seal, harbour porpoise, white-beaked dolphin, bottlenose dolphin, Atlantic white-sided dolphin, killer whale, and minke whale. Long-finned pilot whales and Risso’s dolphins are regularly seen in waters around Shetland.

There are occasional at-sea records of at least a further five cetacean species (humpback whale, fin whale, sperm whale, striped dolphin and short-beaked common dolphin) and four pinniped species (hooded seal, bearded seal, ringed seal and walrus).

Report prepared by the Sea Mammal Research Unit, St Andrews University.

The SEA 5 area covers parts of the central and northern North Sea to the east of the Scottish mainland, Orkney and Shetland. The area supports different users and activities, many of which are focussed in particular coastal and marine areas.

The North Sea oil and gas industry has been particularly important in shaping the coastal development of the area over the last 30 years both in terms of industrial development and population demographics. Major developments include the receiving terminals on Shetland and Orkney; in the Moray Firth; at St. Fergus and within the Firth of Forth, as well as the substantial industry support network centred on key locations such as Lerwick, Peterhead and Aberdeen amongst others.

In general, significant coastal development is centred upon the large firths which cut into the east coast; Inverness in the Moray Firth, Dundee on the Firth of Tay and Edinburgh and associated towns on the Firth of Forth. The importance of these areas has lead to the development of coastal fora which seek to balance the environmental and economic characteristics of these areas.

Outwith these areas much of the SEA 5 coast is rural in nature with little industrial development. The fishing industry, whilst generally in decline, remains a key industry for many small east coast fishing towns and villages as well as industry centres such as Lerwick, Peterhead and Fraserburgh. Aquaculture is an important industry in Orkney and Shetland, the coasts of which abut SEA 4 and SEA 5, however, this industry is relatively unimportant in the rest of the SEA 5 area.

This report presents an initial overview of the coastal population of the SEA 5 area and the industries and activities which utilise the SEA 5 area including:

• Oil and gas activity
• Commercial fishing
• Fisheries for migratory species
• Ports and shipping
• Mariculture
• Military activity
• Telecommunication cables
• Renewable energy
• Aggregate extraction
• Marine disposal
• Tourism and leisure
• Locally important activities
• Coastal and marine archaeology
• Coastal and marine management initiatives


Report prepared by Hartley Anderson Limited with Aberdeen Institute of Coastal Science and Management, University of Aberdeen.

This report provides data on the plankton community in the SEA 5. Data for this report were provided by the Continuous Plankton Recorder Survey, as well as sourced from outside organisations.

The SEA 5 area is influenced by the Shelf Edge Current, which breaks off its main route in the form of the Fair Isle Current, the Dooley Current and the East Shetland Inflow. Oceanic water flows into the North Sea in this area, causing periodic incursions of associated planktonic organisms.

The report addresses the following issues:

• Phytoplankton and zooplankton community composition
• Phytoplankton blooms
• Abundance of the copepod Calanus
• Mero-, pico- and megaplankton
• Phytodetritus and vertical fluxes

Report prepared by the Sir Alister Hardy Foundation for Ocean Science.

The SEA5 review differs from previous assessments in that the zone includes a large coastal fringe, along the whole east coast of Scotland and the Northern Isles, and contains a diverse range of habitats, from inter-tidal rocky shores and sandy beaches, to the shallow sub-littoral and deepwater mud basins offshore.

These habitats support a wide range of invertebrate resources, of which six species of crustacean, four species of bivalve mollusc and two species of gastropod mollusc form the basis of a thriving shellfish fishing industry in Scotland. The landings of shellfish from the SEA5 zone were worth around £30 million in 2000-2002.

The landings are dominated by the Norway lobster, Nephrops norvegicus which occurs in four main areas, one of which, the Fladen ground, is in close proximity to mature oil fields. The fishery for this species in the North Sea is likely to increase, with diversion of effort from the demersal fisheries for cod and other whitefish.

Much of this expansion should take place at Fladen where the stock is at present under-exploited. It is likely, however, that trawl gear used in the Norway lobster (and pink shrimp) fisheries will be required to be more selective in order to reduce the by-catch of demersal fish, especially cod, and the wastage through discarding of under-sized fish.


Report prepared by Colin A Chapman.

This report assesses the socio-economic implications of licensing the SEA 5 area and sets out the results in relation to:

• oil and gas production, and reserves
• capital, operating and decommissioning expenditure
• employment
• tax revenue
• social impacts

The Department of Trade and Industry provided scenarios of possible exploration and development activity in the area and these scenarios were converted into optimistic and pessimistic scenarios. They were then used to produce forecasts of: oil and gas production; oil and gas reserves; expenditure; employment; and tax revenues. The implications for existing facilities in the area are discussed and the potential social impacts.

Report prepared by Mackay Consultants.

Potential impacts of offshore wind farms on swans and geese

Offshore wind farms may impact birds directly by mortality from collisions or indirectly by displacement from migratory flyways or local flight paths. At present there are very little data on the effects of offshore wind farms on swans and geese.

Whooper swan, pink-footed goose, European white-fronted goose, barnacle good and brent goose have been highlighted as potentially sensitive species to wind farms and these species are likely to be focal species for environmental assessment.

Key areas and species

Of the nine species reviewed, five species, whooper swan, mute swan, pink-footed goose, greylag goose and barnacle goose occur in internationally important numbers at coastal sites in the SEA5 area. Greenland white-fronted goose occur in nationally important numbers.

This report provides a synthesis of current knowledge of the benthic communities and seabed habitats in the SEA6 area. The area is a predominantly shallow, well flushed, fully saline, partially enclosed, temperate sea. The seabed is predominantly sedimentary, ranging between mud and cobbles but consisting mainly of sand. The coastal fringe hosts excellent examples of a broad range of habitat types including exposed rocky shores, sheltered rias, highly productive sand flats, estuaries and areas exposed to rapid tidal currents. This diverse range of habitats supports a broad range of animals and plants with numerous species.

The focus of the report is on dominant species and broad descriptions of community types (biotopes). The benthos associated with the littoral (intertidal) and sublittoral zones from the Mull of Kintyre and the Northern Irish coast in the north to Milford Haven, Pembrokeshire in the south are discussed. This area includes the important industrial estuaries of Morecambe, Liverpool and the Mersey, together with a number of minor estuaries, and the major islands of Anglesey and the Isle of Man. The deep water (depth >50 m) and offshore areas are also discussed.

Where appropriate, details of rare or unusual species are included, together with the threat offered by oil and gas related activities. Other major human activities in the SEA6 area that are currently affecting the benthos are also discussed.

The report was prepared by the Scottish Association for Marine Science.

This report provides a synthesis of current knowledge of the benthic communities and seabed habitats in the Clyde Sea, which abuts the northern end of the SEA6 area. The Clyde Sea is a fjordic system consisting of drowned, glacially over-deepened, valleys separated by sills. The southern limit of the area, and the ultimate sill for the Clyde Sea lochs, is formed by a broad sill termed the Great Plateau. The Great Plateau is predominantly <50 m deep and is overlooked by the volcanic plug of Ailsa Craig.

The report is presented in the context of the hydrography and sedimentology of the area. The focus is on dominant species and broad descriptions of community types (biotopes). It also reviews existing major human activities in the area that are currently affecting the benthos.

The report was prepared by the Scottish Association for Marine Science.

Historically there has not been a database of recreational use of the UK's marine environment. This lack of information was highlighted by the SEA which was carried out for the three strategic wind farm development areas: the Thames Estuary, Greater Wash and the North West (Liverpool Bay). In response the RYA published a document in 2004 entitled Sharing the Wind, which provided information on recreational boating in these strategic areas for consideration during the planning, design and approval process for wind farms. This report extends the work undertaken in Sharing the Wind to the SEA6 region.

The report provides information on cruising routes, general sailing and racing areas, anchorage areas, the intensity with which each route is used, and the location and size of shore based facilities. The work was produced as a result of consultation with a large number of clubs, regional committees and local experts throughout the SEA6 area, which are listed in the back of the report. There are a total of 143 clubs within 2 miles of the coast, with an estimated membership of 37,000, that use the SEA6 region for boating activities.

The report was compiled by the Royal Yachting Association.

Methane-derived authigenic carbonate (MDAC) is formed as a consequence of the anaerobic oxidation of methane by consortia of bacteria. MDAC develops as a rock-like concretion when a carbonate precipitate cements normal seabed sediment; the carbon of this carbonate is derived from methane. It occurs as crusts or slabs at the seabed, or as exposed lumps. The occurrence of MDAC is evidence of methane seepage, although the seepage is not necessarily going on at the present time. Large quantities of MDAC indicate that methane seepage has occurred over a prolonged period of time. 'Submarine structures formed by leaking gas' have been identified by the European Commission's Habitats Directive as habitats worthy of protection.

The distribution of MDAC in UK waters is poorly known. This report summarises the available information relevant to MDAC in the SEA6 area, including data acquired by surveys specifically conducted in support of this SEA in 2004. Carbon isotope data for samples recovered in 2004 have confirmed that the cemented hard grounds from two of the areas studied, Texel 11 and Holden's Reef, are composed of MDAC.

The report was prepared by Dr A. G. Judd.

Cephalopods are short-lived molluscs, characterised by rapid growth rates, and are important predators and prey in oceanic and neritic environments. They can range in size from 1.5 cm in pygmy squid (Sepiolidae) to 20 m in giant squid (Architheutidae). Cephalopods exhibit the highest degree of development in invertebrate nervous systems, expressed through complex behaviour patterns such as the ability to learn and the display of complex colour changes. In contrast to other molluscs, most cephalopods lack an external shell, are highly mobile as adults and occupy similar ecological niches to predatory fish.

They are active predators at all stages of their life-cycle and generally regarded as opportunistic, taking a wide variety of prey. Cannibalism has been frequently recorded in cephalopod species. Cephalopods also sustain a number of marine top predators such as fish, birds and marine mammals, especially whales. Many species are powerful swimmers and carry out vast feeding and spawning migrations, thus influencing prey and predator communities strongly on a seasonal and regional basis.

As cephalopods are important elements in food webs they interact with commercial fisheries of finfish. Evidence exists that fishing pressure has changed ecological conditions and shifts in community structures have occurred with cephalopod stocks slowly replacing predatory fish stocks. Their commercial significance to world fisheries is of relatively recent, but growing, importance.

From a commercial point of view, the most important cephalopod species in the SEA6 area is Loligo forbesi, which is landed as a by-catch of the demersal trawl fishery (82 tonnes in 2002). But the species Alloteuthis subulata, although of no commercial value, has an important ecological role in the coastal food webs, since it is the most commonly recorded cephalopod species in the stomach contents of demersal fish in UK waters.

This report was prepared by M. Sacau, G. J. Pierce, G. Stowasser, J. Wang, & M. B. Santos of the School of Biological Sciences, University of Aberdeen.

An integral element of any environmental assessment for offshore oil and gas development, and for possible nearshore renewable energy proposals, is a review of potential sites of conservational importance within the region of interest. For the purpose of SEA 6, this is especially important given the scale of the area (over 400 km from the tip of SW Wales to the Mull of Kintyre); its division into five separate states/provinces, each with their own nature conservation authorities and some differences in nature conservation legislation; the fact that it includes a very considerable length of coastal zone and that a very large proportion of those coasts are designated as nature conservation sites.

The report identifies and locates coastal and nearshore sites within the SEA 6 area which are protected by international, national and local conservation designations. The sites are briefly described and the reasons for their protected status are given. For internationally important sites, summary information describing the main features of the site is provided and there is also an assessment of the vulnerability of the site and any relevant management issues. The ordering of the national sites does not imply any formal ranking, but is a relative judgement of their conservation importance. Brief descriptions of the statutory and non-statutory mechanisms responsible for site protection are given. Statutory sites are legally protected whilst non-statutory sites rely on the planning process and other local agreements to confer protection.

The report was prepared by J. J. Moore of Coastal Assessment, Liaison & Monitoring.

This report considers the major sources of contamination to the Irish Sea from offshore energy installations and puts them in the context of other sources of contamination to the region. The report also considers contamination of the wider environment, making use of data provided by monitoring programmes and other specific studies.

The oil and gas industry in the Irish Sea is small by comparison to that of the North Sea, but bears comparison to that of the Southern North Sea which is dominated by gas production and for which many of the platforms are in relatively shallow water. The discharge of production and drilling chemicals, residual oil and compounds derived from the formation water co-produced with the oil or gas contribute to the contamination concentration in sediments and water. However, in Liverpool Bay and Morecambe Bay, where the oil and gas fields are located, the riverine inputs of major groups of organic contaminants and metals are found to be several orders of magnitude greater than those from the offshore oil and gas industry.

Inputs of artificial radionuclides into the Irish Sea are dominated by discharges from Sellafield on the Cumbrian coast. The distribution of radionuclides in seawater, in the sediment and in biota are reviewed.

The report concludes with a discussion of gaps in our understanding. More data on contaminant concentrations are needed within a few kilometres of oil and gas installations. In particular, compounds commonly detected in produced water should be characterised for both Morecambe Bay and Liverpool Bay in order to enable the accurate calculation of the contribution of the offshore industry to chemical loads. This may increase in importance as land based discharges come under greater control and produced water increases.

This report was prepared by scientists from CEFAS.

This "Economic and Social Baseline Study" provides baseline information on the key economic activities in the SEA 6 area, namely:

• offshore oil and gas
• offshore wind farms
• ports, ferries and other shipping services
• fishing
• tourism
• other marine-related activities.

A separate report (SEA6 Socio Economics) by the same authors assesses the socio-economic implications of further oil and gas licensing in the SEA6 area. This report may be used to assess the impacts of proposed offshore wind farms in the SEA6 area.

The report was prepared by Mackay Consultants.

This report deals with fishing activity in the SEA6 area over the period 1998 - 2003. The different types of fishing carried out are briefly described and the fishing effort is presented in annual and seasonal maps for the area, based on data acquired by aerial surveillance by regular British Fishery Protection flights. The major fleets in the Irish Sea are otter trawlers, beam trawlers, scallop trawlers and potters.

The report was prepared by Craig Mills and Paul Eastwood of CEFAS.

This report provides an up-to-date overview of all the relevant data concerning methane-derived authigenic carbonate (MDAC) and other features associated with shallow gas and seabed fluid flow in the Irish sector of the western Irish Sea. The report makes use of some previously published data, but mainly analyses the datasets held by the Petroleum Affairs Division of the Irish Department of Communications, Marine and Natural Resources. The report complements the MDAC report produced for the SEA6 area by Dr A. G. Judd.

The report was prepared by P. F. Croker, M. Kozachenko and A. J. Wheeler

This report discusses the seabed geology and the surficial geology and processes of the SEA6 region of the Irish Sea.

The East Irish Sea Basin is at a mature exploration phase, having produced oil and predominantly gas since 1985. The hydrocarbon geology of the region is reviewed. Other prospectivity plays in the SEA6 area are the Caernarfon Bay Basin and the Cardigan Bay Basin.

The seabed sediments, seabed sedimentary processes and the corresponding diverse range of seabed habitats in the area are described, drawing upon published data and on the new information acquired from surveys specifically conducted for this SEA in 2004.

The report was prepared by the British Geological Survey

This report describes the physical oceanography of the Irish Sea from St George's Channel in the south to the North Channel and the Clyde Sea in the north. The report covers the topography and depth of the sea floor, the tides, the impact of storms, stratification and its consequences and the mean circulation, all with a view to mean and extreme conditions.

The predominant dynamical process is the semi-diurnal tides, with areas of both high and low energy embraced. Superimposed on this is the full range of water column structure – areas that are well mixed throughout the year; areas that stratify thermally in summer; areas of freshwater influence from river discharges, leading both to nearshore density gradients and stratification; frontal regions between the well-mixed and stratified regions.

The movement of the water and the amount of mixing prescribe physical effects, such as forces on structures and the movement and dispersion of contaminants, but also significantly influence biogeochemical processes including sediment erosion / deposition and movement, particularly of suspended sediment, benthic exchanges and primary productivity (via stratification, nutrient exchanges and light levels).

This report was prepared by Dr M. J. Howarth of the Proudman Oceanographic Laboratory.

Seven marine mammal species are known to occur regularly in the SEA6 area. A relatively small but fairly discrete population of grey seals utilises all but the northwest Irish Sea. Harbour seals are found primarily in the far north of the area. Harbour porpoises are seen year round throughout the area and bottlenose dolphins are present year round off Wales. Minke whales, Risso's dolphins and short-beaked common dolphins are regularly seen in summer mainly in the far south. The report discusses the distribution and abundance of these mammals and their ecological importance.

Marine mammals make use of sound for a variety of purposes: finding prey, detecting predators, communication and probably navigation. The offshore oil and gas industry generates underwater noise at every stage of the process: during exploration seismic surveys, drilling, production and decommissioning. The effects of these different sources of underwater noise on marine mammals are discussed. The use of explosives for underwater cutting and demolition during the decommissioning of platforms and installations may pose a serious threat to some marine mammals.

The effects of pollution on seals and cetaceans are discussed, including the effects of oil spills. The prevalence of disease among the marine mammal populations is reviewed.

The report was prepared by the Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews.

In this report maritime archaeology refers to archaeology based on the investigation of the remains of ships, boats, maritime infrastructure and such other material remains as provide insights into past societies by way of their seafaring and sea-use. Archaeological issues relating to the wrecks of aircraft are not included.

Submerged prehistoric archaeology is the subject of another report in the Strategic Environmental Assessment of the SEA 6 region. Consequently, submerged prehistoric archaeology is not discussed in detail within this report, although it is alluded to when necessary to highlight the potential for maritime archaeological remains to be found within the submerged prehistoric environments.

After summarising the legislative framework applicable to maritime archaeology, e.g. Protection of Wrecks Act 1973, the history of maritime activity in the Irish Sea from the Palaeolithic times to the present day is reviewed. Examples of historic wrecks, some found in recent years by divers, are given. The spatial distribution of maritime archaeological remains is considered and the possible impacts of oil and gas activities are described. The report concludes with an outline of the methods used in investigating maritime archaeological remains.

The report was prepared by Wessex Archaeology.

This report is an assessment of the status of the beds of the Horse Mussel Modiolus modiolus on the tide swept sea floor off north and northwest Anglesey, based on three short cruises of the RV Prince Madog during January - March 2005. In some places Modiolus forms dense beds that can carpet the sea floor and build up as reef-like features or bioherms. Side-scan sonar, sampling with grabs or dredges, and sledge mounted cameras were used to investigate the seabed. Modiolus was found, in sufficient abundance to be considered as 'beds', at four localities within the area surveyed.

Modiolus beds are of considerable conservation interest, coming within the 'reef' category of the EU Habitats Directive, and they are listed under OSPAR. Modiolus beds are known to be highly vulnerable to physical disturbance; once destroyed, beds do not seem to recover naturally in the medium term.

In addition to describing the occurrences of Modiolus and analysing the specimens sampled, the epifauna associated with them and other benthos in their vicinity are described.

The report was prepared by Professor E. I. S. Rees.

The SEA 6 area supports different users and activities, many of which are focussed in particular coastal and marine areas. It is a mixture of sparsely populated rural areas and highly developed centres of population. The primary contributors to the national and regional economies are tourism and leisure, oil and gas, ports and shipping and locally naval defence. The renewable energy sector is growing and may provide significant local opportunities for the port and local construction industries in the future.

The report presents an overview of the coastal population of the SEA 6 area and the industries and activities using the SEA 6 area including:
• Oil and gas activity
• Ports and shipping
• Mariculture
• Military activity
• Telecommunication cables
• Renewable energy
• Aggregate extraction
• Marine disposal
• Tourism and leisure
• Locally important activities
• Coastal and marine archaeology
• Coastal and marine management initiatives

The report was prepared by L. Luddington and J. J. Moore of Coastal Assessment, Liaison & Monitoring.

This report summarises information on the ecology of planktonic species found in the SEA6 area. The Irish Sea is very diverse not only in the physical-chemical regimes operating upon it, but in the ecology of planktonic organisms found there.

Data on the nutrient chemistry of the Irish Sea shows that the eastern Irish Sea is more heavily impacted by nutrients owing to freshwater run-off from land, which is far greater than in the western Irish Sea. Nutrients increased from the 1950’s to the 1980’s after which time the concentrations have levelled off and in some case declined. The phytoplankton biomass appears to have mirrored the influence of the nutrients both in time and space. Highest biomass (inferred from chlorophyll analysis) is generally found in regions of low salinity and tends to be greatest in the eastern Irish Sea. The phytoplankton community has also been shown to vary throughout the seasons and also within different regions or ‘ecohydrodynamic’ domains of the Irish Sea.

The zooplankton community of the Irish Sea has also undergone significant change over the last thirty or so years. The most noticeable of these changes being a significant decrease in abundance of most of the species recorded. Some species distributions and abundances have been shown to be influenced by climate and it is highly likely that other species of plankton in the Irish Sea are also affected in this way. Climate, or more specifically the North Atlantic Oscillation (NAO), certainly has a major impact upon the physical-chemical environment of the region and this has a direct influence upon the ecology of planktonic organisms found in the Irish Sea.

The report was prepared by K. Kennington and W Ll. Rowlands of the Port Erin Marine Laboratory, University of Liverpool.

In order to understand and prioritise the nature of prehistoric archaeological sites, which might occur on the sea floor, this report considers the context of all the adjacent land masses, including the Irish Republic, and in the south the Celtic Sea and western Channel. Prehistoric submarine archaeological remains back to a date of about 225,000 years ago, Palaeolithic, Mesolithic and Neolithic, could occur with low probability in many parts of the SEA6 area.

Palaeolithic archaeological sites as old as 225,000 years Before Present (BP) occur at locations on the Welsh coast, with a great density of sites from the later Mesolithic and Neolithic. Some sites therefore pre-date the last interglacial high sea level, and although they were covered by the Devensian ice sheet, material inside caves survived.

The penultimate glaciation, the Anglian, covered the whole Irish Sea, southern Wales and Ireland. But the last one, the Devensian, left the southern Irish Sea, southern Wales and the southern rim of Ireland exposed. The deep channel known as the Celtic Trough is the cumulative effect of over-deepened scour by ice sheets and meltwater tunnelling, partially infilled by glacial and marine sediments. It is deepest at the northern end. Occupied caves co-existing with the last ice sheet have been found in southern Wales, but not in southern Ireland. Particular attention is given in this report to Oxygen Isotope Stage 3, 64,000-22,000 years BP, for which sophisticated reconstructions of the climate and vegetation of western Europe have recently been made.

There are also Palaeolithic sites in southern England, the Channel Islands, and Brittany. At the time of the maximum glaciation of the Devensian, people were probably living on the floor of the English Channel and the exposed plains of the Celtic Sea, as well as in Cornwall, and on the ice edge in southern Wales itself. Submerged prehistoric sites have been found in the English Channel. The re-occupation of Wales and Ireland could have been as much from the south, as from the east, when the ice retreated. This could explain some of the highly developed Mesolithic sites in Ireland which seem to pre-date the equivalent structures on the British mainland. The rising sea level separated Ireland from the rest of Britain at about 12,000 years BP, although brief land contact may have been re-established around 10.5-9.5 ka BP due to isostatic uplift.

Evidence from the northern North Sea and the Russian Arctic suggests that some prehistoric peoples occupied the exposed shelf area during late glacial periods utilising Inuit-style survival methods, and butchering marine mammals. If this proves to be the case, there may be unexpected occurrence of early prehistoric sites, Late Palaeolithic, on the Atlantic shelf and in the southern Irish Sea, where people could have been hunting marine mammals.

Pipe entrenching is the process in the oil and gas industry most likely to disturb prehistoric archaeological deposits. Commercial site investigation using acoustics and coring could provide beneficial new archaeological data. The paper concludes with tentative suggestions for discussion of protocols and a reporting regime.

This report was prepared by Dr N C Flemming.

This report assesses the socio-economic implications of further oil and gas licensing the SEA 6 area.

The Department of Trade and Industry provided scenarios of possible exploration and development activity in the area and these scenarios were converted into optimistic and pessimistic scenarios. They were then used to produce forecasts of: oil and gas production; oil and gas reserves; expenditure; employment; and tax revenues. The implications for existing facilities in the area are discussed and the potential social impacts. An underpinning report, Economic and Social Baseline Study, is also available.

The report was prepared by Mackay Consultants.

This report reviews the many different sources of underwater noise, both natural and anthropogenic, that combine to provide the background noise levels in which marine organisms need to survive throughout the SEA6 region. The sources of sound combine together in a complex manner resulting in significant spatial and temporal variations in the noise field.

A map of the dominant noise sources in the Irish Sea is shown, indicating that man-made noise is the dominant source of noise over about 70% of the area. Shipping noise is likely to be dominant across large parts of the SEA6 area.

To fully characterise the ambient noise field in the SEA6 area would require multiple measurements at a large number of locations over a period of a year. However, a considerably lower cost approach would be to characterise each sound source and to use this with occurrence statistics for each source to model the ambient noise field across the region. The advantages and disadvantages of the acoustic modelling approach are discussed.

This report was prepared by QinetiQ.

SEA7 Technical Report - Archaeology

The report concentrates on reviewing existing data and published sources, rather than attempt a quantitative baseline of wrecks and casualties.

There is a comprehensive corpus of legislation, plans and polices concerned with the protection of the submerged maritime archaeological resource within the SEA 7 study area.

The study outlines the known history of maritime activity within the SEA 7 area. Despite being an extremely large body of water that at times can produce dangerous sea and weather conditions, and encompasses the rugged coastlines of western Scotland and Northern Ireland, the area has been used extensively by seafarers from at least the Mesolithic (from 9000 BC) up to present times.

During each time period there has been evidence of human activity within the SEA 7 area, often demonstrated by the discovery of maritime archaeological remains. The waters between the north east of Ireland and Scotland have been used as a means of communication throughout the centuries.

Previous investigations of maritime archaeological remains within the SEA 7 area are discussed in the report.

The spatial distribution of submerged archaeological remains is discussed, and comments are made on the limitations of any mapped baseline of data.

The study concludes with a comment on the potential impacts of oil and gas activities on the submerged maritime archaeological resource and suggests possible monitoring methodologies.

This report was produced by Wessex Archaeology

SEA7 Technical Report - Benthos

The SEA 7 area, especially the Hebrides slope and areas of the Rockall Trough have been significant in the development of deep-sea biology since the 19th century. In recent decades intensive sampling has been undertaken by researchers from UK institutions such as the Scottish Association for Marine Science (formerly the Scottish Marine Biological Association) and the National Oceanography Centre, Southampton (formerly Southampton Oceanography Centre and the Institute of Oceanographic Sciences).

The entire SEA 7 area is contained within the biogeographic region known as the Atlantic Deep-Sea Province, with the major oceanographic variables defined by the passage of North Atlantic Deep-Water. To the south, concentrated research efforts have taken place in areas such as the southern Rockall Trough, Porcupine Seabight and Porcupine Abyssal Plain. These encompass similar hydrographic and oceanic conditions to those of the SEA 7 area and form a basis for comparison.

A brief overview of the history of deep-sea research in the SEA 7 area is provided here, along with a summary of the physical environment. In this report, however, the main focus is the ecology of seafloor-dwelling organisms. To assist the reader, a section has been provided describing some of the techniques that are used in sampling deep-sea benthic communities. The ecology of benthic communities is described with respect to large-scale trends and is discussed in the context of how anthropogenic influences may affect the benthos. The final section discusses future planned research that may fill some of the gaps in our current knowledge.

This report was prepared by Andrew J Davies, Bhavani E Narayanaswamy, David J Hughes, and J Murray Roberts of the Scottish Association for Marine Science.

SEA7 Technical Report - Cephalopods

The class Cephalopoda comprises three maor divisions, of which two: Decapoda (squids and cuttlefish) and Octopoda (octopods) are represented in the SEA 7 Area. They are highly developed, but short-lived molluscs with rapid growth rates. They are important elements in marine food webs and interact significantly with marine mammals, seabirds and commercially exploited finfish species. They also represent a promising future fishery resource in terms of market value, abundance and growth potential.

At present, only an estimated 10% of exploitable stocks are utilised worldwide. There are six marketable squid species that occur in the SEA 7 Area. These belong to the long-fin (loliginid) and short-fin (Ommastrephid) squids – the two most important exploited families of decpods. In the SEA 7 Area, only one species, Loligo forbesi is commercially exploited on a regular basis, although there are significant landings of other species on occasion. The closely related Loligo vulgaris sometimes appears in catches and the small Alloteuthis subulata is thought to be naturally abundant and an important food item in the marine ecosystem.

There are other important species represented in the SEA 7 Area. These include cuttlefish, octopods, sepiolids and a number of deep-water species. Most of these are marketable and may be ecologically important. Large fisheries for some of these species, particularly octopods and cuttlefish operate in European waters further south, but they are not currently exploited in the SEA 7 Area.

This report was prepared by Lee C Hastie, Graham J Pierce and Jianjun Wang of the University of Aberdeen.

SEA7 Technical Report - Conservation

The coastal and marine areas within the SEA 7 boundary are very extensive, longer and more varied than any other SEA area. Stretching westwards into the Atlantic Ocean, the region includes a very large area of relatively shallow continental shelf. There are also a few uninhabited islands to the west of the Outer Hebrides, including St. Kilda with its multiple conservation designations.

The Outer Hebrides form one of the oldest geological provinces in Europe and is mainly absed on Lewisian Gneiss. A major geological fault runs parallel to the east coast (The Minch coast), whereas the western side is normally a continuation of the continental shelf. These features are prominent in the southern islands, notably the Uists. Harris and Lewis present different topographies which include the high massif with Clisham at its centre and the low peat-covered plateaux of most of Lewis to the north. The east Minch coastline is generally steeper and falls to deeper inshore waters. It is also characterised by several transverse sea lochs which resemble similar fjords on the west mainland coast.

Although the legacy of glacial processes are complex, the main effect has been to over-deepen sea lochs and inter-island straits (e.g. Sound of Harris) and deposit great masses of glacial debris, especially sands, on the shallow continental shelf to the west where, with the prevalence of strong onshore Atlantic waves and winds, vast beaches were formed in this post glacial period.

Large quantities of organic sand (crushed shells) were added to this volume; as a consequence some of the larger beach and sand dune systems in Britain are found along the west coast. These extensive blown sand systems are called machairs, and provide a unique series of environmental and ecological systems with very high conservational status at European and international levels.

The west coast of the Outer Hebrides contains many sites of archaeological interest and retains a distinctive cultural landscape as one of the last strongholds of a historical system of land tenure and working found nowhere else in Europe. This way of life is considered to be one of the prime reasons for the creation and maintenance of many of the significant conservational attributes of the Outer Hebrides.

This report was prepared by Aberdeen Institute of Coastal Science and Management, University of Aberdeen with Hartley Anderson Limited.

This "Economic and Social Baseline Study" provides baseline information on the key economic activities in the SEA7 area, namely:

• offshore oil and gas
• ports, ferries and shipping services
• fishing
• aquaculture
• tourism
• other marine-related activities.

A separate report (SEA7 Socio-economics) by the same authors assesses the socio-economic implications of further oil and gas licensing in the SEA7 area.

The report was prepared by Mackay Consultants.

SEA7 Technical Report - Fish & Fisheries

The SEA7 area includes the west coast of mainland Scotland with its numerous sea lochs, the continental shelf with the Hebridean Islands, the continental slope of the northern Rockall Trough, the Rockall Trough and its seamounts, the Rockall and Hatton Banks and the abyssal depths to the west of Hatton Bank. All these areas, except the abyssal depths support a diverse variety of fisheries using demersal, pelagic and static gears. SEA7 lies within ICES Sub areas VI and XII. These areas were devised for shallow-water fisheries and have been recently subdivided to take into account the expansion of fisheries into deep-water and to allow separate reporting of fish landings from national and international waters. The primary fishery management tool in the SEA7 area is the Total Allowable Catch (TAC) and when quotas become restrictive misreporting of catches can seriously distort landings data for some species. In the SEA7 misreporting has been and is prevalent between the west of Scotland (ICES Sub-area VI) and the North Sea (Sub-area IV) and between west of Scotland and Irish waters (ICES Sub-area VII). ICES Working Groups often make adjustments for what are termed “unallocated landings” and these data are used in this report.

A wide variety of data sources have been used in this report ranging from literature reviews, site specific surveys, fishery surveys and ICES reports.

Relevant aspects of the biology of 39 species or species groups have been described. Brief descriptions are given of the fishery for each species, including the method of fishing and the long term trends in the landings from each of the management areas are described.

This report was prepared by John D M Gordon, Honorary Fellow of the Scottish Association for Marine Science.

SEA7 Technical Report - Geology

Investigations of the hydrocarbon prospectivity and earthquake activity include the whole of SEA7 but in this report investigations of the sea-bed sediments are restricted to the Hebrides Shelf, Rockall Trough and east Rockall Bank.

On the Hebrides Shelf, Hebrides Slope, east Rockall Bank and in the deep-water Rockall Trough the modern sea-bed sediments are mainly composed of mixtures of former glacial deposits and grains of modern interglacial biogenic carbonate shell. Former glacial deposits and modern biogenic carbonate are now mainly mixed and transported by wave-orbital currents and residual currents on Rockall Bank and by combinations of wave-orbital currents, tidal currents and residual currents on the Hebrides Shelf and upper Hebrides Slope. Below approximately 300 metres water depth in the Rockall Trough the sea-bed sediments are mainly transported by circulating deep-water residual currents.

Sea-bed sediments with slopes of approximately 3 degrees or more are prone to gravity-driven instability and downslope sea-bed sediment movement. This means that there are large areas on the Hebrides Shelf , Rockall Bank and and other margins around the Rockall Trough where the combined influences of gravity and currents regulate sea-bed sediment movement and composition.

This report was prepared by Richard Holmes, Ken Hitchen and Lars Ottemoller of the British Geological Survey.

SEA7 Technical Report - Hydrography

SEA7 lies across the northern end of the Atlantic Meriodional Overturning Circulation and contains a number of major oceanic currents carrying surface water northward across the whole region and returning cold Artic water around the foot of some of its slopes.

In general both ocean current and depth averaged tidal velocities are small, of order 5 cm s-1. Maximum speeds are about 15 to 20 cm s-1 in some local regions such as the Rockall Bank and parts of the European shelf edge.

Mesoscale eddies, internal tides and internal waves can enhance these background current velocities quite significantly, particularly in the Rockall Trough where large non-linear internal waves have been observed.

The mean wind speed over the region is about 7.7 m s-1 in summer rising to about 11.2 m s-1 in winter. The most frequent surface wave has, on average, a height of 2.4 m and a period of 8.5 s, although in winter this height increases to about 3m and in summer it decreases to about 1.5 m.

The continental slope represents a transition between the oceanic and shelf systems, and a persistent northward slope current with speeds in the range of 15 to 30 cm s-1, centred approximately over the 500 m isobath, is the physical manifestation of this transition.

To the east of the slope current in water shallower than 200 m we enter the Malin and Hebrides Shelf Seas. Here, though the net flow is still wind driven and northward (with a typical speed of 5 cm s 1), the tides dominate the flow fields with current velocities up to 4.3 m s-1 in some of the channels.

The principal tidal components are the semi-diurnal (twice daily) tides although in some limited regions the diurnal (daily) tides are significant.

The physical structure of the shelf seas is largely determined by a balance between the stratifying influences of solar radiation and fresh water run-off from the land, and the mixing influences of the strong tidally and wind driven flows, themselves shaped by the intricate and irregular bathymetry and coastline of the SEA7 region.

This report was prepared by M E Inall and T J Sherwin of SAMS Research Services Ltd.

SEA7 Technical Report - Marine Mammals

Twenty-one cetacean species have been recorded in the SEA7 region. Of these, ten species are known to occur regularly: harbour porpoise, bottlenose dolphin, short-beaked common dolphin, Risso’s dolphin, white-beaked dolphin, Atlantic white-sided dolphin, long-finned pilot whale, killer whale, sperm whale and minke whale.

Five further species, though not very often recorded, and primarily associated with deep water, probably also occur regularly: striped dolphins, fin whales, northern bottlenose whales, Cuvier’s beaked whale and Sowerby’s beaked whale.

There are occasional at-sea records of a further 6 species: Sei whale, humpback whale, blue whale, northern right whale and false killer whale. Pygmy sperm whales and at least three further species of beaked whale might also be expected in the general area on occasion.

Quantitative abundance is limited to areas of overlap with the NASS surveys, conducted in North Atlantic waters by Iceland, the Faroes and Norway.

The most recent NASS survey (2001) was denied access to UK waters, so there are no recent abundance estimates available for these waters. The NASS-95 survey resulted in estimates of some of the large whale species that may be relevant to this area.

The SCANSII survey, conducted during the summer of 2005, covered the continental shelf zone of the SEA-7 area. Abundance estimates from this survey are not yet available, but will be by the summer of 2006.

Relative abundance data are available from platform of opportunity sightings data (see Reid et al., 2003), as well as some small-scale coastal survey work conducted by organisations such as the Hebridean Whale and Dolphin Trust (HWDT).

In this report, each of the more abundant species is briefly described with particular reference to its distribution and abundance in the SEA-7 area.

This report was prepared by P S Hammond, S P Northridge, D Thompson, J C D Gordon, A J Hall, C D Duck, G Aarts, L Cunningham, C B Embling and J Matthiopoulos of the Sea Mammal Research Unit.

SEA7 Technical Report - Ambient Noise

This report initially gives a general introduction to underwater ambient noise and the underlying mechanisms that generate sound.

The report then identifies a number of sources of underwater acoustic noise, describes the characteristics of the noise including frequency content, levels and variability, and also identifies the current state of knowledge on each source. In all cases the sources are considered in the context of the SEA 7 area. Mechanisms that can modify the ambient sound levels are described. The dominant noise sources in the SEA 7 area are identified.

Recommendations are then made for the methodology to be used to obtain meaningful characterisation of noise levels in order to establish baseline levels.

The report then goes on to present an analysis of measured ambient noise data in the SEA 7 area, model predictions of spectrum levels, and compares the measured and modelled data.

It should be noted that the comments on noise sources are appropriate for the shallow and deep waters of the SEA 7 area and may not be appropriate for other SEA areas or where the water is very shallow.

This report was prepared by E J Harland and S D Richards of QinetiQ.

SEA7 Technical Report - Other Users

The purpose of this report is to provide an initial assessment of what is termed the “Other Users” of the SEA 7 area. These other users include those significant human activities and infrastructure occurring in the marine and coastal zone, and not addressed by other SEA 7 data reports. Fisheries and maritime archaeology (wrecks) are therefore excluded.

The report summarises current activity in the area, and where possible discusses likely future trends. It also summarises the relevance of each activity to any future proposed oil and gas activity. Where appropriate, comment is made about the potential sensitivity of an “Other User” to oil and gas development, or the potential restrictions to oil and gas development presented by existing users.

This report was prepared by Richard Stocks and Jillian Hobbs of Metoc Plc.

SEA7 Technical Report - Plankton

The purpose of this report is to provide the DTI with an assessment of the plankton ecology for the Strategic Environment Assessment (SEA) of area 7.

Owing to the size of the area being assessed this report divides the region into two sections. The basis of this division follows the 200m depth contour generally accepted as being the boundary between the shelf edge and oceanic realms. The first section being waters found on the continental shelf and are therefore more prone to freshwater runoff from land and anthropogenic inputs. The second section represents waters off the shelf edge, these waters are of a more oceanic origin and are less impacted by inputs from land-based sources.

Information on the nutrient biogeochemistry (nitrate, phosphate and silicate) are presented for three geographical provinces, the oceanic and shelf edge realms outlined above and also for the Clyde Sea area this being a region noted as having elevated nutrient loadings from anthropogenic sources.

The major sources of information on the nutrients of the SEA7 region come from the ICES and BODC data sets as well as from data presented in the scientific literature.

Information on the phytoplankton (the plant members of the plankton) comes from several sources including ICES, SAMS and the NIO at Southampton. This data is augmented by specific case-studies of the SEA7 region taken from the scientific press. Zooplankton (the animal component of the plankton) data is also presented as geographic plots from the Continuous Plankton Recorder (SAHFOS) data-set held by the Sir Alistair Hardy Foundation for Ocean Sciences.

This report was prepared by K Kennington of Port Erin, Isle of Man and D Johns of SAHFOS.

SEA7 Technical Report - Prehistoric Archaeology

There is a high likelihood of surviving prehistoric archaeology (10,000 – 5000 years old) in certain areas of SEA7, most notably to the west of the Outer Hebrides for a distance of some 10km, to a depth of -20m, and in and among the islands elsewhere (particularly around Islay, Jura, Mull and the Small Isles) along the coast and between S Scotland and N Ireland.

The reasons comprise a complex interplay of changing sea level and the rebound of the land once freed from the compression of ice at the end of the last Ice Age. The net result of these physical effects is that 10,000 years ago relative sea level has been up to 45m lower along much of the coast and this corresponds with the period of early human settlement in the area. In places this means that considerable areas of submerged land exist. An investigation of bathymetric, sedimentary and tidal data for the area suggests that the prehistoric land surface, including archaeological remains, may survive in many places.

Any archaeological remains that might be found would be highly significant because early remains are so far rare on the islands. Elsewhere in Scotland, archaeological material from this time indicates the importance of the coast suggesting that it is along those submerged coastlands that one might expect to find indications of early settlement, and thus, incidentally, providing one reason why so few remains have been found among the outer islands and coast of SEA7.

Cooperation between existing extraction companies and renewable industries and archaeologists elsewhere in Britain shows how the recording and investigation of archaeological material could be beneficial to both parties should work take place in SEA7. The final sections provide a preliminary examination of how matters might be taken forward to safeguard the archaeological knowledgebase without prejudicing commercial interests.

This report was prepared by C R Wickham-Jones and S Dawson.

SEA7 Technical Report - Seabirds

The aims of this study were:

• To provide an overview of individual species offshore distribution in SEA 7.
• To identify, where possible, offshore areas in SEA 7 that are important for seabirds.
• To assess offshore seabird vulnerability to surface pollution in SEA 7.
• To provide a brief outline on the potential for offshore SPAs in the offshore waters of SEA 7.
• To highlight major gaps in understanding and survey coverage in the offshore waters of SEA 7.

Methodology

• Ship-based and aerial survey data for the SEA 7 area collected between 1979 and 2005 were provided by ESAS.
• Offshore waters were defined as greater than 200 m in depth and the offshore distribution of seventeen species of seabirds were reviewed.

Species accounts

• Northern Fulmar, Northern Gannet and Black-legged Kittiwake were the most abundant species recorded on ESAS surveys in offshore waters of the SEA 7 area.
• The SEA 7 area was also important for European Storm-petrel and Leach’s Storm-petrel.

Important offshore areas in SEA 7

• Generally seabird densities were low in offshore waters. Important areas were along the shelf break, Rockall Trough and Rockall Bank.
• Species diversity of seabirds was low in offshore waters compared to inshore waters, although more species were recorded during the summer months.

This report was prepared by Claire Pollock and Colin Barton of Cork Ecology.

SEA7 Technical Report - Sediments

This report describes some of the more significant geomorphology and sedimentary features within the SEA7 area of the United Kingdom continental shelf.

The report makes use of specific targeted cruises undertaken for the UK Department of Trade and Industry as well as using data collected for other specific objectives. Data collected and used included multibeam bathymetry, processed for backscatter as well as depth, and seafloor photography.

The most significant discoveries here were:

• The occurrence of en-echelon fault scarps and mounds over areas of Hatton Bank which have subsequently acted as the focus for carbonate reef formation.
• Polygonal faults delineated by their bathymetric expression at the seafloor in the centre of the Rockall-Hatton Basin.
• Large-scale erosive features such as scours along the margins of George Bligh Bank and the northern margin of Rockall Bank.
• The definition of a highly eroded and sculpted upper continental slope/shelf edge along the eastern Rockall Bank margin.
• Lower on the slope the formation of the Feni Ridge and the identification of sites of small-scale slope failure.

Anton Dohrn Seamount was completely mapped using multibeam and reveals a domed summit with rock outcrop at its centre, and there is evidence of opposing currents on its east and western summit flanks.

The summit of Rosemary Bank was also surveyed, meaning that the entire seamount is now surveyed to a high degree of accuracy. The summit of Rosemary is home to three distinct areas of parasitic cones, though there appears to be little outcrop.

This report was prepared by Colin L Jacobs of the National Oceanography Centre, Southampton.

SEA7 Technical Report - Shellfish

This report deals with the shellfish resources and their commercial fisheries within SEA7. Exploited species of shellfish are found in the SEA7 zone occupying all types of habitat and distributed over a considerable range of depths, from the littoral zone down to 1000m. These species provide important fisheries and make vital contributions to the economy of remote communities on the west coast of Scotland.

The main species reviewed in this report are:

• Norway lobster
• European Lobster
• Crawfish
• Edible crab
• Velvet swimming crab
• Shore crab
• Red crabs
• Giant scallop
• Queen scallop
• Cockle
• Common mussel
• Razor shells
• Whelks
• Periwinkle

This report was prepared by Colin J Chapman.

This report assesses the socio-economic implications of further oil and gas licensing the SEA7 area.

The Department of Trade and Industry provided scenarios of possible exploration and development activity in the area and these scenarios were converted into optimistic and pessimistic scenarios. They were then used to produce forecasts of: oil and gas production; oil and gas reserves; expenditure; employment; and tax revenues. The implications for existing facilities in the area are discussed and the potential social impacts. An underpinning report, Economic and Social Baseline Study, is also available.

The report was prepared by Mackay Consultants.

Synthesis of Information on the Benthos of Area SEA 8

Prepared by:

Jennifer Pinnion and Andrew S. Y. Mackie
Marine Biodiversity, Amgueddfa Cymru - National Museum Wales

Paul J. Somerfield and Richard M. Warwick
Plymouth Marine Laboratory Applications Ltd

Identifying Recreational Cruising Routes, Sailing and
Racing Areas within the SEA 8 Area

Prepared by:

The Royal Yachting Association (RYA)

A Review of the Contaminant Status of SEA 8 covering the Western Approaches, Celtic Sea and English Channel

Prepared by:

David Sheahan, Steven Brooks, Angela Raffo, Carol Smedley and Robin Law
CEFAS

Fish and fish assemblages of the British Isles

Prepared by:

Cefas

DTI (DECC) Strategic Environmental Assessment Area 8, Superficial Seabed Processes and Hydrocarbon Prospectivity

Prepared by:

Tappin, D. R. and Rocks, K.
British Geological Survey

Mason, T.
Channel Coastal Observatory

SEA 8 Technical Report - Hydrography

Prepared by:

R. J. Uncles and J. A. Stephens
PML Applications Ltd.

SEA8 Technical Report: Marine Archaeological Heritage

Prepared by:

Maritime Archaeology Ltd in conjunction with Dr Nic Flemming

Background information on marine mammals for Strategic Environmental Assessment 8

Prepared by:

P. S. Hammond, S. P. Northridge, D. Thompson, J. C. D. Gordon, A. J. Hall, S. N. Murphy and C. B. Flemming
Sea Mammal Research Unit

Technical Report on the Other Users of the SEA 8 Area

Prepared by:

Jillian Hobbs and Nick Morley
Metoc plc

The Plankton Ecology of the SEA 8 area

Prepared by:

David Johns
The Sir Alistair Hardy Foundation for Ocean Science

Technical report on offshore seabirds and waders in the SEA 8 area (including an update of inshore seabird species)

Prepared by:

Colin Barton and Claire Pollock
Cork Ecology