Information

Fish and Shellfish Stocks: 2013

Information on the state of fish and shellfish stocks of commercial importance to the Scottish fleet, inclduing Total Allowable Catches (TACs) for each stock.


Saithe Stocks (North Sea and West of Scotland)

Saithe ( Pollachius virens) is mainly taken by demersal trawl as part of a directed fishery along the Northern Shelf edge and Norwegian Trench. Saithe are also taken as part of the mixed demersal fishery. They are, by weight, the second most landed roundfish species caught by Scottish fishermen.

2013 position : UK share 10,527 tonnes
Last Year : 9,472 tonnes
Landed into
Scotland in 2011 : 14,577 tonnes
Value for 2011 : £13.12 million

Biology
Adult saithe can be caught in almost any sea area but occur mainly around the 200m depth contour. In late summer and autumn young saithe are found in large numbers within Scottish and Norwegian coastal waters, usually on grounds which are unsuitable for commercial fishing. The adult stock can occur in dense shoals which move around the water column and are often caught hundreds of metres above the seabed.

Saithe reach maturity between the ages of four and six years. A medium sized adult female can produce about 2.5 million eggs during a spawning season. Spawning takes place between January and April near to the edge of the continental shelf to the north and west of the Outer Hebrides. Initially the young fish live near to the surface but by mid-summer they can be found close inshore, in bays and harbours. In their second year they live along the shoreline before eventually moving to deeper water. This offshore migration usually occurs in springtime. Saithe grow quickly, averaging around 15cm per year for the first three years and 10cm for the next three, reaching 100cm by the time they are eleven years old.

Saithe are active predators, feeding on the bottom and in mid-water. By weight, fish prey dominate their diet at all times of the year. Herring, Norway pout and sandeel are the main fish species eaten.

Left: Spawning Grounds. Right: 2010 Distribution of Landings by Scottish Vessels (Tonnes).

ICES Advice on Management

Information Source: ICES advice 2012 ( http://www.ices.dk/sites/pub/Publication%20Reports/Advice/2012/2012/sai-3a46.pdf). Quoted text in italics.

Landing, Recruitment (age 3), Fish mortality and Spawning Stock Biomass

MSY and precautionary approach reference points

Type Value
Management Plan SSB MP 200,000 t
F MP 0.3
MSY Approach MSY B trigger 200,000 t
F MSY 0.3
Precautionary Approach B lim 106,000t
B pa 200,000t
F lim 0.6
F pa 0.4

State of stock and advice

  • Fishing mortality, F, has generally increased since 2004 and is currently just below F pa and F MSY.
  • The status of the stock has deteriorated in the last few years. The spawning stock is estimated to have been above B pa from 2001-2008 but has since declined to below B pa.
  • Fishing mortality and biomass are both below their precautionary limits. However, fishing mortality is above the level which is consistent with achieving maximum sustainable yield (F2011< F MSY).
  • This year's advice is in accordance with the EU-Norway management plan, with the 15% TAC constraint imposed, resulting in an advised TAC of 100,684 tonnes in 2013 for the whole assessment area.

There has been a southern shift in geographical distribution in fishing pattern for at least the German fleet. This is probably due to EU fleets coming under the effort regime of the EU cod management plan, and may shift the distribution of catches toward younger aged fish.

The current assessment estimates SSB in 2012 to be 30% higher than estimated in November 2011, and fishing mortality in 2010 is estimated to be 25% lower. The change was caused mainly by the revision of age distribution in the Norwegian catches. The basis for the advice is the same as last year: the management plan.

In 2012, ICES put forward mixed-fisheries advice for the first time ( ICES, 2012c). In contrast to single-species advice there is no single recommendation but a range of plausible options, assuming fishing patterns and catchability in 2012 and 2013 similar to those in 2011. Major differences between the outcomes of the various scenarios indicate potential unbalance between single-species fishing opportunities. The consequences of this unbalance in terms of changes in fleet dynamics cannot be ascertained.

Cod is the limiting species for the North Sea demersal fisheries in 2013. Following the 'cod' scenario (full implementation of the cod management plan), the saithe management plan catch options could not be fully utilized.

Management outcomes for 2013
At the December 2012 meeting in Brussels, the Council of Ministers decided that the international Total Allowable Catch for North Sea and west of Scotland saithe should be 100,684 tonnes. The UK quota for 2013 was set at 10,527 tonnes.

This quota decision was reached in accordance with ICES advice and the saithe long term management plan and represents a reduction in fishing opportunity in 2013.

Contact

Back to top