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 009 - Cephalopods, covering overview of cephalopod population, ecology, fisheries, sensitivity" by same authors. This paper provides an overview of cephalopods - squid, octopus, cuttlefish - in the SEA2 and SEA3 areas of the North Sea. 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 is a contribution to the Strategic Environmental Assessment (SEA6) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 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.

This report is a contribution to the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment SEA2. 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 is 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.

This report is a contribution to Strategic Environmental Assessment SEA2 conducted by the Department of Trade and Industry (now Department of Energy and Climate Change) and it 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 SEA2 areas cover the Northern North Sea (NNS), the Central North Sea (CNS) and the Southern North Sea (SNS). 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.

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). It is a synthesis of information describing the seabed habitats, species and communities on the continental shelf of the west of Orkney and Shetland relevant to the SEA 4 area. It 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 is a contribution to the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environment Assessment SEA2 for the North Sea. It 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. 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 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 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.