Scottish trawler

© Crown copyright 2010, Craig Davis

The Northern North Sea extends from Shetland in the north to Flamborough Head in the south with water depths of between about 50 m and 200 m. The coastline is predominantly rocky but there are intertidal sediments in the bays and inlets. The main offshore habitats are large expanses of sand and mud. Sea-surface temperature varies seasonally, ranging from 6 °C in winter to 14 °C in summer and much of the region becomes stratified in summer. There is a significant inflow of high salinity Atlantic water into the north of the region.

Climate change

Sea temperature is rising and has been linked to changes in the plankton community. The length of the phytoplankton growing season has increased and the distribution of some species of plankton and fish has shifted northward. These changes may have affected the marine food web.

Maritime economy

The oil and gas sector provides the greatest economic contribution to Region 1 because of the presence of major hydrocarbon fields – and this is the most economically important region for this industry in the UK. Although the industry is widely distributed, physical pressures are localised to installations and structures while contamination of the sea is declining due, for example, to a reduction in oil discharged with produced water. Shipping activity is important and provides links with northern Europe from ports in the Firth of Forth and the Port of Tees and Hartlepool. Cooling water abstraction has significant value because of the presence of a number of nationally important coastal power stations. Recreation is important locally, for example, the region supports bird watching on the East Lothian coast, cetacean watching in the Moray Firth and scuba diving at St Abbs-Berwickshire. Most industries using the seas are well regulated and create a low and localised pressure on the marine environment.

Fishing pressure

Fishing is a significant and widespread activity in this region. The Northern North Sea has the most valuable demersal and Nephrops fisheries in the UK, as well as fisheries for herring, mackerel and horse mackerel, and shellfish (e.g. lobster) near the coast. This intense fishing activity has an environmental impact. Assessed commercial fish stocks are either not at full reproductive capacity or are not being harvested sustainably. However, with the exception of stocks of haddock and saithe, the quality of demersal fish communities is improving; abundance, biomass and productivity are increasing but smaller fish still dominate. Coastal and seabed sediment habitats such as sands and muds are considered to be severely impacted by bottom trawling activity, which may damage ecosystem functioning.

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