The most commonly fishing technique utilised by the Scottish fleet is trawling. Most bottom trawls utilised by the Scottish whitefish and langoustine fleets skim just over, or just on, the seabed. Inevitably, this will cause some environmental impact, but the areas most often fished are ‘soft’ seabed types such as mud and sand, which are resilient to trawl disturbance and which are also highly dynamic environments in their own right, subject to natural physical processes such as strong currents. In most instances, it is not possible to bottom trawl over rocky reefs as this would damage the fishing gear, thus such areas are avoided.
Trawling is in many ways a close parallel to land use, where it is entirely appropriate to cultivate suitable land, but also to protect areas such as the national parks or nature reserves where appropriate.
It is important to point out that bottom trawlers have their own favoured fishing grounds, which they target year after year because they catch good quantities of fish in these areas. This is in itself is indicative of the limited impact bottom trawling must have on the benthic ecosystem as these fish will depend upon abundant invertebrates and other marine life to feed upon.
This assertion is backed by a study by the NAFC Marine Centre in Shetland, which describes an analysis of vessel monitoring system (VMS) data for Scottish whitefish fishing vessels in the area of the northern North Sea around Shetland. The results indicate that while a high proportion of the area was fished at some time over the six-year period from 2006 to 2011, only a much smaller area was fished on a regular or repeated basis. In addition, a high proportion of the fishing activity was concentrated in a relatively small proportion of the area.
Despite the northern North Sea being one of the Scottish fleet’s most important fishing areas, this report highlights that significant areas are only lightly fished, with less than a quarter of the area being targeted on an annual basis. It is a common misconception that large areas of our seas are heavily fished and this report provides confirmation that the reality is very different. The report An Estimate of The Area Fished Around Shetland and in the Northern North Sea can be downloaded at: http://www.nafc.ac.uk/WebData/Files/Report – 2013-04-08 – Area Fished.pdf