Noth sea fish stocks

[warriorwitch]

Fish have traditionally formed an important food resource for many people in the United Kingdom. They are also vital elements of ocean ecosystems. While there is emerging evidence that some species, notably cod and hake, are declining in numbers in the seas around the United Kingdom, stocks of other species, such as herring, have been increasing in recent years. After declining to very low levels in the 1970s, stocks of herring have recovered strongly, while haddock stocks have fluctuated dramatically since the 1960s, and continue to do so: they quadrupled between 2000 and 2002. Stocks of cod in the North Sea and elsewhere are causing particular concern to the Government and other interested parties. After increasing in the 1960s, and fluctuating somewhat in the 1970s, North Sea stocks ...

[warriorwitch]

The North Sea is situated to the east of Britain and to the west of continental Europe. It extends to about 625,000 km2. To the north, it is bounded by the continental shelf edge marking the limits of the Norwegian Sea. There is a relatively deep (600 m) trench off the coast of Norway, otherwise it is generally less than 200m in depth, becoming shallower to the south. The seafloor is comprised mostly of mixed sediments with mud in some more northerly areas, and coarser sands in the shallower tidally active south. Areas close to Scottish and Norwegian coasts are rocky.

In addition to fishing grounds, there are heavily used shipping lanes (particularly in the south) and exploitation of extensive reserves of oil and gas beneath the sea floor.

Fisheries
The main demersal fisheries target a mixture of roundfish species (cod, haddock, and whiting) or flatfish species (plaice and sole) with a bycatch of roundfish. There is also a fishery for Saithe. Pelagic fisheries mainly target herring and mackerel. These are all predominantly for human consumption, although a proportion of the pelagic fisheries are used for fishmeal and fish oil production. In addition, there are industrial fisheries for sandeel, Norway pout and sprat which are used in the production of fishmeal. Besides these finfish fisheries there are also fisheries for the crustaceans Nephrops, Panadalus borealis and brown shrimp (Crangon crangon). Norway, Denmark, UK and The Netherlands are the major North Sea fishing nations.

Status of the stocks
Information on the status of the stocks has been derived from the International Council for the Exploration of the Seas (ICES) who have a commitment to undertake annual stock assessments in European waters.

North Sea cod stocks are in a very poor state with constant high levels of fishing mortality in recent years combined with low spawning stock biomass. Currently the stock is outside safe biological limits and a zero fishing mortality level is recommended. A cod recovery plan has been proposed, with the aim of long term management of the species for the future. In February 2004, the European Union introduced new regulations affecting cod fishing in the North Sea. The aim is to increase the quantity of mature fish to more than 150,000t (North Sea, Skagerrak and eastern Channel) over the next five to ten years. These measures included controls for the setting of total allowable catch (TAC), fishing effort limitation (number of days at sea and gear restrictions) and restrictions on landing ports, stowage and transport of cod.

The stock size of haddock has historically shown large variations due to the occasional occurrence of a very strong year class. Although the stock is considered within safe biological limits, currently it is the 1999 year class alone that supports the haddock fishery. Until another strong year class recruitment, which in not predicted for several years, the haddock fishery will continue to rely on the 1999 year class recruitment for its future. The status of the whiting stock is unknown, but with declining landings and poor recruitment in recent years, the stock is considered outside safe biological limits. Most flatfish stocks are outside the safe biological limits. Plaice is estimated to be near the lowest observed level and exploitation rates are considered to be too high. The development of a recovery plan for this species has been recommended. For sole the spawning biomass reached a historic low in 1998 and although some recovery has been observed, recent recruitment is very poor. The fishing mortality for this species is also considered to be too high. In contrast to the previous stocks, the abundance of saithe has increased in recent years whilst fishing mortality has decreased, and the stock is considered to be within safe biological limits.

Herring stocks have recovered since the closure of the fishery in the 1970s and 1980s. Recruitment from several year classes has been above average, although the 2003 recruitment was poor. The population is currently thought to be stable in the short term. The North Sea part of the mackerel stock has all but disappeared; fish caught in the North Sea now come predominantly from a larger western group which spawn outside the North Sea and are only present in the northern North Sea in the second half of the year. The sandeel stocks have fluctuated with recent recruitment being amongst the lowest recorded. Consequently the status of the stocks is very uncertain. Recruitment to the Norway Pout stocks has been very poor in recent years and landings declined. Since 1995, landings have fluctuated about a low level. However, the stocks are thought to be within safe biological limits. The sprat stocks are considered to be in good condition, with biomass increasing in recent years.

The Nephrops stocks within the North Sea are generally thought to be exploited at sustainable levels, and may even be under-exploited in the northern North Sea. The Panadulus borealis stocks appear to be stable in some areas (e.g. Norwegian Deep and Skagerrak) but are uncertain in others (e.g. Farn Deep and Fladen Ground). Stocks of some shellfish in the Wadden Sea have been overfished.

Environmental problems
Besides the current parlous state of many fish stocks, particular environmental problems caused by fisheries in the North Sea are:

Non-sustainable bycatch of harbour porpoises in bottom-set gill nets. Current figures indicate that more than 2% of harbour porpoises in the central-south North Sea are caught per year. This is thought to be greater than the rate of population growth. In addition, there is an unmeasured bycatch in similar nets fished by Norwegians. Recently regulations have been introduced by the EC to help combat this. However, the mandatory use of 'pingers' will only apply to gear deployed by vessels greater than 12m in length and there will be no on-board observer scheme for fisheries using 'pingers'.
Extinction of several species of skate and ray (elasmobranchs) in the southern and central North Sea.
Very high bycatch levels in beam trawls and shrimp fisheries in the south-eastern North Sea.
Management of sandeel fishing near Shetland and off eastern Scotland needs to avoid risking depletion of the stocks due to their importance to seabirds and other predators (including fish).