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.

Haddock Stocks - West of Scotland (VIa & Vb)

Haddock ( Melanogrammus aeglefinus) to the west of Scotland is, by weight, one of the most important demersal species landed from this area. It is caught mainly by bottom trawlers which target mixed demersal fish assemblages. Discarding is still quite high in this area, with nearly 51% of the catch estimated to be thrown back.
2013 position : UK share 3,278 tonnes
Last Year : 4,683 tonnes
Landed into
Scotland in 2011 : 1,373 tonnes
Value for 2011 : £1.8 million

The haddock is widely distributed around the west coast of Scotland and can be caught in most areas within the 200 m depth contour. The stocks occurring off the north-west coast of Scotland are usually identified according to the regions which support a fishery, but genetic and biological marker studies suggest the possibility of different populations of haddock. A continuous population of haddock is thought to extend from the west coast around to the north of Scotland. Results from tagging experiments and larval transport studies suggest that there may be links between west coast haddock and those in the North Sea.

The majority of haddock now mature at age two with usually all mature by age three. However, mature age two haddock spawn fewer eggs for a given size than an age three haddock. A three year old female of good size is able to produce around 300,000 eggs in a season and releases her eggs in a number of batches over many weeks. Spawning usually occurs in February and March and occurs in almost any area. There is major spawning between the Butt of Lewis and Shetland. Some larvae from the west coast Spawning Grounds can be transported to the North Sea, which they enter through the Fair Isle/Shetland Gap or to the north east of Shetland. Young haddock then spend the first few months of life in the upper water layers before adopting the demersal way of life. The survival rate of young haddock is very variable from year to year.

The diet of haddock varies with the size of the fish, the time of year, and with the locality. In the winter months haddock of all sizes feed mainly on worms, small molluscs, sea urchins and brittle stars. In the spring and summer, fish prey, especially sandeels, are important, particularly for the larger haddock. At other times Norway pout is the most common fish eaten. During the herring spawning season haddock will feed heavily on their eggs.

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

ICES Advice on Management

Information Source: ICES advice 2012 ( Quoted text in italics.

Landings, Recruitment (age 10), Fish mortality and Spawning Stock Biomass

MSY and precautionary approach reference points

Type Value
MSY Approach MSY B trigger 30,000 t
F MSY 0.3
Precautionary Approach B lim 22,000 t
B pa 30,000 t
F lim Not defined
F pa 0.5

State of stock and advice

  • Fishing mortality in 2011 has been estimated at about 0.22: this means that approximately 20%, by number, of all fish between 2 and 6 years of age were caught.
  • The relatively strong 2006 and 2009 year classes have contributed to the rise of the spawning stock biomass in 2012, which is estimated to just be above B lim at 24,800 tonnes.
  • Fishing mortality and biomass are below and above, respectively, their precautionary limits. However, fishing mortality is just below the level which is consistent with achieving maximum sustainable yield ( F 2010F MSY).
  • The advice is in accordance with the MSY approach which recommends human consumption landings in 2013 of 3,100 tonnes for haddock in Division VIa.

ICES evaluated an EU management plan proposal and considered it to be precautionary. Following the plan would result in a 25% TAC decrease. This would result in removals from the stock of 8100 tonnes, and landings of 4,500 tonnes in 2013. This is expected to lead to an SSB of 21,700 tonnes in 2014.

The management plan should offer maximum protection to the haddock while recognising that they are caught in a mixed fishery. Attention should be given to the sporadic nature of recruitment in to the stock and how to manage the periods of poor recruitment interspersed with the larger, occasional pulses. In recent years around 50% of the total catch in weight has been discarded, so restricting landings alone may not achieve the necessary increase in SSB.

As in previous years, the majority of discards occurred in the Nephrops fleet (TR2) (~80% of all discards). Most of the fish discarded are one year olds. Any measure to reduce discarding and to improve the fishing pattern should be actively encouraged. Such measures should include the adoption of a sorting grid as well as appropriately located square-meshed panels.

Management outcomes for 2013
At the December 2012 meeting in Brussels, the Council of Ministers decided that the international Total Allowable Catch for West of Scotland (VIa and Vb) haddock should be 4,211 tonnes. The UK quota for 2013 is set at 3,278 tonnes.

To realise the TAC, adjustments to the existing bycatch regulations affecting haddock in previous years have been applied by the Commission. There are requirements to manage the haddock TAC uptake spatially in order to avoid increases in mortality on cod.

West of Scotland, the UK also committed to evaluation of its 2012 demersal fish selectivity measures, to exploring further selectivity developments in the light of findings, and to conducting additional surveys in 2013.


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