This report is a contribution to the Strategic Environmental Assessment (SEA3) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change) and is an addendum to "SEA2 Technical report 008 - North Sea Geology, covering subsurface geology, sea-bed sediments, sediment mobility and seismicity." by same authors. 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.

As part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment SEA7, a seabird and cetacean survey was undertaken. The track passed through the Firth of Clyde, the North Channel and the adjacent continental shelf before covering the Rockall Trough as far as the eastern margin of the Rockall Bank and the southern margins of Anton Dohrn Seamount. For much of the survey the weather was unseasonably poor and data was frequently collected in marginal conditions. At total of 7578 birds of 37 species were recorded. Of these 26 species were seabirds and the remainder were migrant passerines, hirundines and geese. Fulmars were the most abundant birds seen during the survey, followed by gannets and great shearwaters, which were recorded in unusually high numbers. The latter species may have been more abundant because of atypically strong westerly winds. Five species of cetacean were seen, with short-beaked common dolphins being the most abundant, followed by long-finned pilot whales and sperm whales. Other sightings included one blue shark and one sunfish. Seabird and cetacean densities were low in much of the study area but were elevated on the continental shelf, especially near the Stanton Bank, at the southern margins of the Anton Dohrn seamount and along the eastern margin of the Rockall Bank.

This report is a contribution to the Strategic Environmental Assessment (SEA6) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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.

This report is a contribution to the Strategic Environmental Assessment (SEA7) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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 based 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 is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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.

This report is a contribution to the Strategic Environmental Assessment (SEA2) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). SEA2 focuses on the mature areas of the North Sea UK continental shelf which is divided into 3 areas - Northern, Central and Southern North Sea. 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 is a contribution to the Strategic Environmental Assessment (SEA6) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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 is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change) . 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. 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. This report provides an overview of these surveys. 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. Additional files (xls, doc, cdr) are also available.

This report is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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.

Cruise report for Multibeam swath bathymetry, sidescan sonar and underwater video survey in the vicinity of Portland Bill as part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment (SEA8) . Emu Ltd was commissioned by Geotek Ltd on behalf of the DTI to perform hydrographic and ecological surveys within the vicinity of Portland Bill to further understand regional processes around a tidal headland. Survey work was required specifically to investigate the sediment processes and seabed habitats present.