Fish and Shellfish Stocks 2012

WHITING STOCKS — NORTH SEA

Whiting ( Merlangius merlangus) is caught all year round, mainly in mixed demersal fisheries with some bycatch taken in the industrial fisheries. It's found throughout the North Sea, but is known to occur exclusively in some localised areas. Discarding of this species is still quite high.

2012 position : UK share 10,539 tonnes
Last Year : 8,933 tonnes
Landed into Scotland in 2010 : 6,291 tonnes
Value for 2010 : £8 million

Biology

Whiting is one of the most numerous and widespread species found in the North Sea. High numbers of immature fish occur off the Scottish coast, in the German Bight and along the coast of the Netherlands. Tagging experiments, and the use of a number of fish parasites as markers, show that the whiting found to the north and south of the Dogger Bank form two virtually separate populations. It is also likely that the whiting in the northern North Sea may contain populations including 'inshore' and 'offshore' groups.

At four years old, a single female fish of reasonable size produces more than 400,000 eggs. By two years old, however, most whiting are mature and able to spawn. The spawning season lasts from late January until June. The spawning season of an individual female lasts at least ten weeks, during which time she releases many batches of eggs.

Like many other fish, whiting spend their first few months of life in the upper water layers before moving to the seabed. They grow very quickly for the first year, after which the growth rate becomes much slower. There are large differences between the growth rates of individual fish and a 30 cm fish can be as young as one year or as old as six. The whiting in the northern North Sea usually grow faster than their more southern counterparts.

Adult whiting feed mainly on juvenile fish and crustaceans (shrimps and crabs). The exact composition of the diet depends on the size of the fish, the area and the time of the year. In the North Sea, whiting is one of the main predators of other commercially important species of fish. Norway pout, sandeel, haddock, cod and even whiting themselves are frequently eaten. It has been estimated that each year the North Sea whiting population consumes several hundred thousand tonnes of these species.

ICES ADVICE ON MANAGEMENT

Information Source: ICES advice 2011 ( http://www.ices.dk/committe/acom/comwork/report/2011/2011/whg-47d.pdf). Quoted text in italics.

MSY and precautionary approach reference points

State of stock and advice

• Fishing mortality in 2010 was estimated to be 0.27: this means that approximately 24%, by number, of all fish aged between 2 and 6 years were caught.
• Spawning stock biomass in 2011 was estimated to be approximately 205,000 tonnes.
• Fishing mortality and biomass cannot be determined in relation to the precautionary approach, as reference points have not been defined for this stock
• The advice is in accordance with the EU-Norway interim management plan, recommending a human consumption TAC in 2012 of 21,300 tonnes for Subarea IV and Division VIId.

ICES considers that maintaining the level of fishing mortality at 0.3 would be consistent with long-term stability as long as recruitment is not poor. The EU and Norway adopted this level of fishing mortality for the interim management of the stock for 2011. ICES are in the process of developing and evaluating the management plan.

There are no reference points to give advice on TACs for the MSY or precautionary approaches.

Whiting abundance estimations from surveys suggest that the northern component is declining, whereas the southern component is increasing or stable. The increase in the southern component is broadly in line with the industry's perception of the stock. However, their perception of increasing abundance of whiting in the northern North Sea is at odds with the evidence gathered from the surveys.

Management outcomes for 2012

At the December 2011 meeting in Brussels, the Council of Ministers decided that the EU Total Allowable Catch for North Sea (IV and IIa) whiting should be 15,750 tonnes. The UK quota for 2012 was set at 10,539 tonnes.

This quota decision reached was in line with the scientific advice based on an interim EU Norway management plan. Hague preference was invoked which adjusted the final outcome.