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

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) and describes the hydrography of the SEA7 area. 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.

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 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 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 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 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 class Cephalopoda comprises three major 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 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 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 is a contribution to the Strategic Environmental Assessment (SEA7) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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. 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 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 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.

This report is a contribution to the Strategic Environmental Assessment (SEA5) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). Macrofuanal analysis was undertaken on 61 seabed samples from 13 locations to the southwest of Shetland that were contaminated by oil from the Braer tanker spill. The data report presents the resulting species list and abundance data, together with biomass data and the size measurements of selected taxa.

As part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment 5 (SEA5) a geophysical survey was undertaken on the survey vessel R/V Jean Charcot. The geophysical survey comprised the first phase of a scientific research project devoted to acquiring information about specific aspects of the North Sea Environment and its seafloor habitats. The geophysical survey was required to provide high resolution maps of the seafloor in SEA 5 areas of interest. Swath bathymetry, side scan sonar and shallow geophysical reflection data were acquired as part of the geophysical survey. No seabed samples were collected.