Demersal fish live on or near the seabed and feed on bottom-living organisms and other fish. Although fisheries may be directed towards particular species or species groups, demersal fish are often caught together and comprise a mixed demersal fishery.
How are Demersal Fish Caught?
Scottish fisheries for cod, haddock and whiting take place in shelf waters throughout the northern and central North Sea, to the west of Scotland in both coastal and offshore waters, and include a targeted haddock fishery at Rockall. Various fishing methods are used, with towed gears such as trawls and Scottish seine predominating.
Monkfish are found at a wide range of depths, from shallow inshore waters to below 1,000 metres. They are taken in mixed demersal fisheries in the northern North Sea, and in a more specialised fishery in deeper waters off the shelf edge to the north and west of Scotland. Cod, haddock, whiting and monkfish are also caught to varying degrees in the Nephrops trawl fishery.
Other demersal species of importance to the Scottish fleet include saithe (Pollachius virens), which are distributed widely in seas around Scotland, and ling and blue ling which are taken mainly in deeper shelf edge waters to the west of Scotland.
Some demersal species are taken as a by-catch in the Scottish demersal trawl fisheries. These include plaice, lemon sole, dogfish, skates, witch, megrim, redfish, dab, hake, and turbot with lesser quantities of catfish, forkbeard, grenadier, tusk, halibut, Greenland halibut, brill and pollack.
How are Demersal Fisheries Managed?
Demersal fisheries in the North Sea and to the west of Scotland are managed under the Common Fisheries Policy (CFP) using a combination of quotas and technical measures, such as regulations on minimum landing and fishing gear configuration, including minimum mesh sizes.
Regulations are complex, and differ depending on gear, target species and fishing area, reflecting the interactions between and the mixed nature of the fisheries. Fisheries for cod and associated species have recently become subject to management measures including fishing effort limitation which restricts the number of days fishing vessels are allowed to spend out of port.