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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.

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 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.

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.

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.

In advance of SEAs for areas 6, 7 & 8, a series of data assessment projects were instigated. The purpose of these projects was to assess the extent, quality and accessibility of data relating to specific environmental factors. In some cases, the project leaders produced brief explanatory notes describing the environmental factor being considered, in other cases the project was limited to a data search alone.

The contractors were asked, where possible, to enter the data onto an "End-Note®" database file in order that bibliographic searches may be made.

Please note that the boundary between SEAs 6 and 7 changed during the time these reports were produced, so may appear in a different position in some reports.

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.

In advance of SEAs for areas 6, 7 & 8, a series of data assessment projects were instigated. The purpose of these projects was to assess the extent, quality and accessibility of data relating to specific environmental factors. In some cases, the project leaders produced brief explanatory notes describing the environmental factor being considered, in other cases the project was limited to a data search alone.

The contractors were asked, where possible, to enter the data onto an "End-Note®" database file in order that bibliographic searches may be made.

Please note that the boundary between SEAs 6 and 7 changed during the time these reports were produced, so may appear in a different position in some reports.