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Report of the Working Group on Assessment of New MoU Species (WGNEW), 5–9 March 2012

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posted on 2023-03-13, 11:10 authored by ICESICES

The ICES Working Group on Assessment of New MoU Species met at ICES Head-quarters in Copenhagen, Denmark, during 5–9 March 2012. There were 14 participants from 7 countries. The main task of WGNEW is to provide information on the new species of the MoU between ICES and the EC: sea bass, striped red mullet, red gurnard, grey gurnard, turbot, brill, dab, flounder, lemon sole, witch flounder, Pollack, and Blue jack mackerel. For most stocks, this information includes total international landings and research vessel survey data that are indicative of abundance trends. The International Bottom Trawl Survey (IBTS) was used often along other internationally coordinated surveys. The IBTS is held annually in the first and the third quarter of the year.    
In addition, the Working Group was asked to prepare the benchmark assessment for turbot and sea bass that is planned in October 2012 and to evaluate the stock struc-ture for the stocks listed above. Below, the main conclusions are summarised per species.
Witch flounder (Glyptocephalus cynoglossus): This species is particularly important in the Skagerrak-Kattegat area where it is a valuable bycatch in fisheries by Denmark and Sweden. Two different assessment models were run in an attempt to assess witch flounder in IV and IIIa. The results of these methods were considered as an exploratory analysis. However, the estimated landings in the last years (2007–2011) are considered accurate, although discard were not included in the analysis.
Flounder (Platichthys flesus): In the North Sea flounder is a bycatch in fisheries for flatfish. The information on flounder was updated. A considerable part of the catch is being discarded; landings are 3000 to 4000 t. Mainly data for surveys are available. Recently a market sampling programme started in The Netherlands, the main coun-try landing flounder. The abundance of North Sea flounder in the IBTS quarter 1 survey increased between 1980 and 1990, and decreased again. In the last four years, 2008 to 2011, abundance was high.
Sea bass (Dicentrarchus labrax): The main countries landing sea bass are France (2/3 of the European landings) and the UK. The WG collated a large amount of data in preparation of the benchmark, including landings data, tagging data, genetics data, and survey data.  
Striped red mullet (Mullus surmuletus): Landings were around 1500 t in 1985 and have increased to around 5000 t in recent years. The majority of the landings are by France and most fish is caught in the Eastern Channel. For management purposes, two areas could be considered for this species: the north area (III, IV and VIId), and the south area (VI, VIIa,e,g,h,j-VIIIa,b and IXa)
Red gurnard (Aspitrigla cuculus): The species is mainly found in the Channel and on the shelf around the British Isles. Between 2001 and 2010 landings fluctuated around 4000 t.
Grey gurnard (Eutrigla gurnardus): Only survey data are available. The species is widely distributed in Western Europe. In a pragmatic approach, the population could be split between 3 Ecoregions: North Sea including VIId, Celtic Seas and South Euro-pean Atlantic. Both in the North Sea and in Skagerrak-Kattegat the IBTS survey indicates an abundance increase since the late 1980’s.  

Common dab (Limanda limanda): Common dab is a very common flatfish in the North Sea, where it is probably also the species with the highest discarding rate. Landings from the North Sea are around 10 000 t. Survey indices, e.g. the IBTS quar-ter 1 survey, indicate an increase in abundance in the 1980s.
Brill (Scophthalmus rhombus): brill is mainly a bycatch in the fishery for flatfish and demersal species. Many data on surveys and landings are available, but age data only exist for several short periods. Most of landings come from the North Sea, where between 1000 and 1600 t are caught annually in the last 10 years.  Due to time con-straints no assessment could be made.
Turbot (Psetta maxima): Turbot is mainly a bycatch in the fishery for flatfish and demersal species. For turbot many data from surveys and landings are available, but age data only exist for several short periods. The North Sea accounts for the major part of the landings. In the North Sea, landings have been decreasing in the last 10 years from about 4000 t to about 3000 t annually. Like for sea bass, the WG collated data in preparation of the benchmark, including landings data, tagging data, genetics data, and survey data.  
Lemon sole (Microstomus kitt): Lemon sole is a bycatch in several demersal fisher-ies. In the North Sea recent landings were 2500 to 4000 t. The IBTS index in the first quarter has increased between 1980–2000, and is now fluctuating at a high level.   
Pollack (Pollachius pollachius): Pollack is mainly a bycatch in various fisheries. For several areas, these landing estimates are clearly incomplete and erratic. WGNEW proposes to distinguish three different stock units: the southern European Atlantic shelf (Bay of Biscay and Iberian Peninsula), the Celtic Seas, and the North Sea (in-cluding VIId and IIIa). For most of the areas, very little information is available that can be used to infer stock trends, For Division IIIa (Skagerrak and Kattegat), the stock biomass of pollack is suggested to have increased from 1940 and to have reached a peak in the late 1950s. Since then the biomass has shown a decrease to reach a very low value around 2000. 

History

Published under the auspices of the following ICES Steering Group or Committee

  • ACOM

Published under the auspices of the following ICES Expert Group or Strategic Initiative

WGNEW; SSGSUE; WGNSSK; WGCSE; WGHMM; WGHANSA

Series

ICES Expert Group Reports

Meeting details

5 - 9 March 2012; Copenhagen

Recommended citation

ICES. 2012. Report of the Working Group on Assessment of New MoU Species (WGNEW), 5 - 9 March 2012, . ICES CM 2012/ACOM:20. 258 pp. https://doi.org/10.17895/ices.pub.8202

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