West Coast of Scotland - Key Species
Cod
Atlantic cod, Gadus morhua, has a wide distribution in the north Atlantic stretching from the Celtic Sea to the Barents Sea and from the east coast of the USA and Canada to the western coast of Europe . On the west coast of Scotland, juveniles are frequently found in coastline shallow waters and sealochs and generally spend the first winter close inshore . As they reach maturity they move off into deeper water to join adult stocks, although Hawkins, et al. reported that cod up to 4 years old may remain localised in shallow Scottish sealochs.
Haddock
Haddock, Melanogrammus aeglefinus, is a highly commercial gadoid species. It is found up to a depth of 300m close to the bottom . Juvenile haddock can be found in shallower water.
Whiting
Historically whiting, Merlangius merlangus, has been a key commercial species in the west coast of Scotland . The species is associated with shallow seas around the UK. In particularl, the juveniles that settle into shallow water and sealochs close to the shore.
Monkfish
Two species of monkfish are caught off the west coast of Scotland, the monkfish, Lophius piscatorius and the black bellied angler fish, Lophius budegassa. L. piscatorius is the larger (can grow up to 2 m) and more common of the two and can be found from shallow water down on to the continental slope . L. budegassa is less common and generally found between depths of 100 and 300 m. CPUE from the 1st Quarter International Bottom Trawl Survey (IBTS) indicated that the biomass of the group is dominated by L. piscatorius, which accounts for 93 % of the total biomass for the group.
Herring
Traditionally, herring, Clupea herengus, has been a key fishery species in the waters around Scotland, particularly during the 19th and early 20th century . However the fishery has seen a dramatic decline, largely as a result of overfishing. Herring are distributed throughout the north east Atlantic and from the English Channel to as far north as the Arctic Ocean. Most herring populations spawn in autumn. Larvae from the spawning grounds off the west and north coast of Scotland are known to move into the nursery grounds in the North Sea . Some of the larvae remain on the west coast where the juveniles can be found in inshore waters and sea lochs. Eventually the juveniles will join the adult stocks which are found in the deeper waters of the continental shelf.
Sandeel
Four species of sandeel are prevalent in the waters off the west coast of Scotland - sandeel, Ammodytes marinus, smoothed sandeel, Gymnammodytes semisquamatus, greater sandeel, Hyperoplus lanceolatus, and Corbins sandeel, Hyperoplus immaculatus. They are known to burrow in shell and sand beds but can also be found schooling in the water column .The species of this group are a major prey item for many fish species as well as sea-birds such as puffins . Using the ratios of CPUE in the West Coast IBTS for these species, we define the group composition to be 36 % A. marinus, 35 % greater sandeel and 26 % Corbins sandeel.
Mackerel
Mackerel, Scomber scombrus, is a highly commercial species with an annual value of £64 million to the Scottish fishing fleet . It is a migratory fish and individuals only spend part of the year in ICES area VIa. Following spawning, the fish migrate towards their main feeding grounds in the Norwegian Sea.
Nephrops
The Norway lobster, Nephrops norvegicus, is assessed in three Functional Units on the West Coast of Scotland: the Firth of Clyde and the North and South Minches . Although Nephrops do occur elsewhere within area VIa, including on the shelf edge, the vast majority of the biomass is believed to be accounted for by these areas, with less than 3% of the landings since 1985 coming from elsewhere. The assessment has been carried out since 1995 using an Underwater TV Survey. The density of burrows is calculated and this is scaled to give an abundance estimate.