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Whiting - North Sea, Eastern English Channel, 2012
Marine Resource  Fact Sheet
ICES Advice 2012
Whiting - North Sea, Eastern English Channel, 2012
Fact Sheet Citation  
Whiting in Subarea IV (North Sea) and Division VIId (Eastern Channel)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Whiting, fr - Merlan, es - Plegonero, ru - Мерланг
Geographic extent of Whiting - North Sea, Eastern English Channel
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Sub-Regional
Management unit: Yes
 
 
Habitat and Biology
Depth zone: Shelf (50 m - 200 m).   Vertical distribution: Demersal/Benthic.  


Whiting are largely mature from age 2, which means recruitment can heavily influence the SSB in the following year at low stock sizes. The spatial distribution of whiting is considered to have changed over the last decade. This may represent a contraction to a sub-stock structure that coincides with the main spawning areas in the North Sea. The 2011 key run of the North Sea multispecies model (SMS), on which natural mortality estimates for this stock are based, indicates that whiting are a major prey component in the diet of many piscivorous fish and marine mammals.
Geographical Distribution
Jurisdictional distribution: Shared between nations

Water Area Overview
Spatial Scale: Sub-Regional


Ecoregion: North Sea
Geo References
Resource Structure
Considered a single stock: Yes
Exploitation
 

The fisheries


Whiting are caught in mixed demersal roundfish fisheries, fisheries targeting flatfish, the Nephrops fisheries, and as bycatches in the industrial sandeel and Norway pout fisheries. Cod recovery measures since 2002 have influenced the fisheries effort and local distribution as well as the selectivity by increasing minimum mesh sizes and implementing selective gear. Industrial fisheries have reduced considerably since 1995 due to low TACs. The Human Consumption TAC for this stock has been restrictive since 2000.
Catch distribution Total landings (2011) = 31.3 kt, where 18.4 kt are landings (~39% demersal trawls and seine with mesh >= 100 mm North Sea, 28% demersal trawls mesh size 70–99 mm North Sea, 28% demersal trawls mesh size 70–99 mm Eastern Channel, and 5% other gears), 11.8 kt discards, and 1.1 kt industrial bycatch.

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Assessment
 
Scientific Advice

ICES advises on the basis of precautionary considerations that landings should be no more than 26 000 t (human consumption for the combined area) in 2013. Management for Division VIId should be separated from the rest of Subarea VII
Overall Assessment Results
Figure 6.4.5.1 Whiting in Subarea IV (North Sea) and Division VIId (Eastern Channel). Summary of stock assessment (weights in thousand tonnes), including intermediate-year forecasts for 2012. Top right: SSB/F for the time-series used in the assessmentQuality considerations

The improvement of predation estimates as well as the quality of landings and discard data have led to a significant revision of the perception of the stock. Overall, the quality of the assessment is considered to have improved. While catch rates from local fleets may not represent trends in the overall North Sea and English Channel stock, and the localized distribution of the population results in substantial differences in the quota uptake rate (possibly resulting in local discarding problems), the catch and survey data appear to indicate consistent stock trends. This is due in part to the improvement in the provision of discard estimates from participating countries in recent years.
Figure 6.4.5.2 Whiting in Subarea IV (North Sea) and Division VIId (Eastern Channel). Historical assessment results (final-year recruitment estimates included). In 2012, natural mortality estimates changed substantially taking into account additional predation mortality (increase of around 50% for ages 2–8 based on ICES, 2011b).
Assessment Model

Scientific basis

Assessment type Age-based analytical (XSA).
Input data Two survey indices (IBTS Q1 & Q3 ages 1 to 5).
Discards and bycatch Included in the assessment for Subarea IV and Division VIId since 1990.
Indicators None.
Other information This assessment was benchmarked in 2009 (WKROUND), and is due to be benchmarked again in 2013.
Working group report WGNSSK


Management
Management unit: Yes


Management plans


In 2011 ICES considered an F target of 0.3 (with a 15% TAC constraint) to be consistent with long-term stability even when recruitment is poor for several consecutive years. Based on a considerable revision in the level of fishing mortality in 2012, the target F is no longer considered applicable and the management target needs re-evaluation.
Biological State and Trend
Exploitation rate: Undefined
Abundance level: Undefined
Source of information
 

The above excerpts are from the first two pages of the ICES advice, the supporting information to this advice can be read in full at the following reference:
ICES. Whiting in Subarea IV (North Sea) and Division VIId (Eastern Channel) Report of the ICES Advisory Committee, 2012. ICES Advice, WKNSSK 2012. Click to openhttp://www.ices.dk/committe/acom/comwork/report/2012/2012/whg-47d.pdf
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