Scottish Fisheries Statistics, 2001
Notes
1. Scottish based and registered vessels
The statistics in this volume are produced mainly from the Scottish Executive Rural Affairs Department's database, which records details of sea fish landings into Scotland and landings by Scottish based vessels abroad (i.e those which are licensed by Scottish ports). Under devolution, a Scottish vessel is one, which is registered on the UK register of Seamen and Shipping at a Scottish port.
2. Base district/ creek
Defined as the geographical area in which most of the owners of a vessel live and which includes the fishery office responsible for the issue of licences for that vessel. A creek is subdivision of a district
3. Fishing Methods
Demersal trawl
The gear consists of a net in the shape of a funnel attached to the vessel by wire ropes or 'warps'. As the net is towed over the sea floor the mouth it kept open by a combination of boards. floats and weights. The tail end of the net where the fish are trapped is the 'cod end'. The length of the warp is normally about three and a half to four times the depth of the water and can he used in depths of 100 to 450 metres from the stem of the vessel. Other single vessel trawling methods (lndustrial Queen Scallop. Shrimp and Nephrop) follow the same principal. Nephrop trawl is used by 'inshore' vessels in the 10-25 metre length group, many of which are multi-purpose and may also use seine nets; if so rigged, a vessel can tow 2 or more smaller type trawls (Nephrop twin/multiple trawls).
Pair (two boat/mid-water) trawl
Used to fish at depths between the surface and the sea floor. The net is towed by two vessels which may he up to 400 metres apart the depth of the net being mainly controlled by the length of the warps and the vessels' speed . The method is used by vessels in the inshore fleet for catching both demersal and pelagic Species.
Pelagic trawl
Also used at depths between surface and sea floor. but vessel's (Or vessels') speed when towing nets is greater than demersal trawling.
Seine Nets
Another bottom fishing method. The gear consists of a sac of netting with wings on either side kept in position vertically by floats and weights. Long warns are attached to the net .one of which is initially fastened to a flagpole paused through a buoy ('dahm buoy'). The vessel steams forward paying out warp, then the net itself, then more warp to form a triangle back to the dahm. which may he 1 to 3 km from the net. The vessel then steams ahead causing the warps to herd the fish into the path of the net, which is then winched aboard.
Pnrse seine
This method involves complete encirclement of a shoal or an area known to contain fish. The net, which may he up to 1.2 km long and 240 metres deep, is shaped like a purse. One end is first attached to a buoy. and the vessel then steams round the shoal paying out the net as it goes. On return to the buoy. the net is closed at the foot or 'pursed'. It is then winched to the side of the vessel and the fish taken on board by meant of a fish pump. This gear requires relatively heavy equipment and is not generally suitable for vessels below 20 metres. It is used to catch pelagic species (mainly Herring. Mackerel, Sprats, Ring nets are similar except that the net is much smaller and operated by two vessels. although the use of ring nets is now uncommon.
Beam Trawl
The beam trawl is a bottom fishing trawl net, used mainly for catching flatfish with the headrope attached to a beam towed along the bottom on runners at either end. The net is heavily weighted with a chain on the underside and has tickler chains running in front.
Gill Nets
Sheets of nesting, each about 35 metres long and totalling up to 1,500 metres or more. are paid out to forms a curtain or barrier in the path of on-coming fish. The net is kept vertical by floats on the headrope and a heavy footrope. the fish being caught in the mesh by their gills. For white fish the nets are anchored near to the sea floor from which they are made to stand upright (by floats) likes fence.
Great Lines
These are lines of thin rope totalling 1 5,000 metres long with hooks attached at intervals. The hooks are baited and the lines then laid along the sea floor. their position being marked by floats at each end. This method is particularly suitable for rocky and uneven grounds where other methods maybe impractical. It is used by vessels in the 25 so 30 metre group, although few use the method now.
Small Lines
Work on the same principal as Great Lines. but the vessels using this method are smaller and are usually at sea only one day ass time.
Creels
These are traps or pots used to catch shellfish, especially lobsters. nephrops and crabs. The pots are generally made from a combination of wood cane and netting. They are normally arranged on the sea floor in Iota between 10 and 50, depending on the capacity of the vessel.
Mechanical Dredge
Used to catch scallops. queen scallops and cockles. The gear consists of a steel-firmed mouth attached to a bag of light metal link chain. As the dredge is towed along the sea floor. metal teeth attached to the underside of the mouth rake the shellfish into a bag. The number of dredges on the vessel - which maybe up to 20 metres - may vary depending omits power and size.
Suction Dredge
Consists of a sledge dredge , which is towed along the sea bottom and a suction pipe, which transfers the cockles from the dredge to the vessel. Another method uses the suction pipe to blow used clear of the shellfish, which are then gathered by hand by divers.