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| Fact Sheet Title Fact Sheet |
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| Megrim - West of Scotland and Rockall |
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Megrim in Sub-area VI (West of Scotland and Rockall)
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| | Data Ownership | | This document provided, maintained and owned by International Council for the Exploration of the Sea (ICES) , is part of ICES Advice data collection. |
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| ident Block | ident Block | | | | Species List: | | Species Ref: en - Megrim, fr - Cardine franche, es - Gallo del Norte |
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| ident Block Megrim - West of Scotland and Rockall
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| fao Div |
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| 27.6.a | Northwest Coast of Scotland and North Ireland or as the West of Scotland (Division 27.6.a) |
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| 27.6.b | Rockall (Division 27.6.b) |
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| Aq Res | Biological Stock: Yes
Value: Sub-Regional
Management unit: Yes
Reference year: 2008
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| Considered a management unit: An aquatic resource or fishery is
declared as [Fishery] Management Unit if it is
effectively the focus for the application of selected
management methods and measures, within the broader
framework of a management system. According to the FAO
Glossary for Responsible Fishing, "a Fishery Management
Unit (FMU) is a fishery or a portion of a fishery
identified in a Fishery Management Plan (FMP) relevant
to the FMP's management objectives." FMU's may be
organised around fisheries biological, geographic,
economic, technical, social or ecological dimensions ,
and the makeup and attribute of a fishery management
unit depends mainly on the FMP's management
objectives. |
| Jurisdictional distribution: Jurisdictional qualifier (e.g.
"shared", "shared - highly migratory") of the aquatic
resource related with its spatial distribution. |
| Environmental group: Classification of the aquatic
resource according to the environmental group (e.g.
pelagic invertebrate, or demersal fish) to which the
species belong. |
| Reference Year: The Reference Year is the last year considered in the stock assessment and/or fishery status. |
| | | | | | Aq Res State Trend
| Spawning biomass in relation to precautionary limits | Fishing mortality in relation to precautionary limits | Fishing mortality in relation to high long term yield | Fishing mortality in relation to agreed target | Comment | | Unknown | Unknown | Unknown | NA | |
The state of the stock is unknown. There are major uncertainties about catch and effort data for megrim, as well as limited knowledge about population dynamics.
Habitat Bio Depth Zone: Shelf (50 m - 200 m). Vertical Dist: Demersal/Benthic. Geo Dist Geo Dist: National Water Area Overview Spatial Scale: Sub-Regional Water Area Overview  | | Water Area Overview Megrim - West of Scotland and Rockall
| fao Div | 27.6.a: Northwest Coast of Scotland and North Ireland or as the West of Scotland (Division 27.6.a) | | 27.6.b: Rockall (Division 27.6.b) |
| | | | | | Water Area Overview |
Water Area OverviewMegrim - West of Scotland and Rockall | fao Major | 27:
Atlantic, Northeast | | Large Marine Ecosystem Areas (LME) | 22: North Sea | | 24: Celtic-Biscay Shelf | | 60: Faroe Plateau |
Aq Res Struct Biological Stock: Yes Exploit
Factors affecting the fisheries and the stock
The effects of regulations
New mesh regulations introduced in Division VIa which have increased the mesh size from 100 to 120 mm (vessels >15 m) will result in an increase in the length of first capture. This measure, coupled with further effort restrictions associated with the long-term management plan for cod (Council Regulation (EC) No 1342/2008) is likely to result in further effort displacement away from the shelf fisheries in Division VIa, with indications of effort switching to Rockall (Division VIb). However, at this stage it is not possible to quantify this until an integrated analysis of VMS and logbook data is conducted.
Changes in fishing technology and fishing patterns
Effort restrictions and changes in fishing patterns associated with the long-term management plan for cod (Council Regulation (EC) No 1342/2008) are described in more detail in section 5.4.21. Mesh size increases implemented in 2009 are expected to benefit the megrim stock in Division VIa. The expected increased effort in Division VIb may increase exploitation on the Division VIb megrim population.
No information is available on changes in the French and Spanish fleets operating in this area.
Bio Assess Assess Models Methodology
Scientific basis
Data and methods
The information basis for megrim is being developed, with improvements to both industry-related data and surveys. There is currently only four years of survey data and that is considered not long enough for an assessment of the state of the stock.
Uncertainties in assessment and forecast
The quality of the available landings data (specifically the area misreporting), discard information, lack of effort data and cpue data for the main fleet in the fishery, severely hampers the ability of ICES to carry out an assessment for this stock. For stocks like megrim and anglerfish on the Northern Shelf, there is a general need for improved spatio-temporal resolution of commercial catch and effort data through integration of VMS and logbook data.
Comparison with previous assessment and advice
In recent years there has been no analytical assessment for this stock and the management advice has been based on average landings. This year the advice is based on effort.
Results
Table 5.4.28.4
Table 5.4.28.5
Ref Point
No precautionary reference points have been defined for this stock.
Sci Advice
Single-stock exploitation boundaries
ICES advises on the basis of exploitation boundaries in relation to precautionary considerations that the effort in fisheries that catch megrim should not be allowed to increase.
Table 5.4.28.1 Megrim (Lepidorhombus spp) in Subarea VI. Single-stock exploitation boundaries (advice), management, and landings
| Year | ICES Advice / from 2004 Single-stock exploitation boundaries | Predicted catch corresp. to advice | Predicted catch corresponding to single-stock boundaries | Agreed TAC1 | Official Landings2 | ICES Landings3 | | 1987 | Not assessed | - | | 4.4 | 3.9 | - | | 1988 | Not assessed | - | | 4.84 | 4.5 | - | | 1989 | Not assessed | - | | 4.84 | 2.7 | - | | 1990 | Not assessed | - | | 4.84 | 2.7 | 3.7 | | 1991 | No advice | - | | 4.84 | 3.2 | 3.7 | | 1992 | No advice | - | | 4.84 | 3.2 | 4.8 | | 1993 | No long-term gain in increased F | - | | 4.84 | 3 | 4.3 | | 1994 | No long-term gain in increased F | - | | 4.84 | 3 | 4.3 | | 1995 | No advice | - | | 4.84 | 3.3 | 4.6 | | 1996 | No advice | - | | 4.84 | 2.9 | 5.3 | | 1997 | No advice | - | | 4.84 | 2.8 | 4.6 | | 1998 | Adequate catch controls | - | | 4.84 | 2.7 | 4.2 | | 1999 | Maintain current TAC | 4.84 | | 4.84 | 2.5 | 3.8 | | 2000 | Maintain current TAC | 4.84 | | 4.84 | 2.4 | 3.6 | | 2001 | Maintain current TAC | 4.84 | | 4.36 | 2.4 | 3.3 | | 2002 | Maintain current TAC | 4.36 | | 4.36 | 1.6 | 2.3 | | 2003 | Maintain current TAC | 4.36 | | 4.36 | 1.7 | 2.3 | | 2004 | 4 Reduce TAC to recent landings | | 3.6 | 3.6 | 1.4 | 1.8 | | 2005 | 4 Reduce TAC to recent landings | | 2.3 | 2.88 | 0.9 | n/a | | 2006 | 4 Reduce TAC to recent landings | | 2.3 | 2.88 | 0.9 | 1.1 | | 2007 | Reduce TAC to recent landings | | 2.1 | 2.88 | 1.01 | 1.3 | | | | | | | | | | | | | | | | | | | | | | | | | | 2008 | Reduce TAC to recent landings | | 1.4 | 2.59 | 1.38 | 1.6 | | 2009 | Same advice as last year | | 1.4 | 2.79 | | | | 2010 | No increase in effort | | - | | | | | Weights in ‘000 t. 1 Division Vb(EC) and Subareas VI, XII, and XIV. 2 Divisions VIa and VIb. 3 Landings in Divisions VIa and VIb and unallocated landings from Subarea IV. Landings in Vb (EC), XII, and XIV are negligible. 4 Single-stock boundaries and the exploitation of this stock should be conducted in the context of mixed fisheries protecting stocks outside safe biological limits. |
Table 5.4.28.2 Megrim (Lepidorhombus spp) in Subarea IV. Single-stock exploitation boundaries (advice), management, and landings.
| Year | ICES Advice / from 2004 Single-stock exploitation boundaries5 | Predicted catch corresponding to single-stock boundaries | Agreed TAC2 | Official Landings3 | ICES Landings4 | | | | | | | | | 2004 | na1 | na1 | 1.89 | 1.16 | 0.739 | | 2005 | na1 | na1 | 1.74 | 0.99 | n/a | | 2006 | na1 | na1 | 1.74 | 1.39 | 1.18 | | 2007 | na1 | na1 | 1.48 | 1.52 | 1.05 | | 2008 | na1 | na1 | 1.59 | 1.57 | 1.32 | | 2009 | na1 | na1 | 1.59 | | | | 2010 | No increase in effort | - | | | | | Weights in ‘000 t. 1 Not applicable - IV not considered by ICES. 2 Divisions IV and IIIa. 3 Division IV. 4 Landings in Division IV less misreported landings into Subarea VIa. 5 Single-stock boundaries and the exploitation of this stock should be conducted in the context of mixed fisheries protecting stocks outside safe biological limits. |
Table 5.4.28.3 Megrim (Lepidorhombus spp) in Subareas IV and VI. Single-stock exploitation boundaries (advice), management, and landings
| Year | ICES Advice / from 2004 Single-stock exploitation boundaries4 | Predicted catch corresponding to single-stock boundaries | Agreed TAC2 | Official Landings3 | ICES Landings | | | | | | | | | 2004 | na1 | na1 | 5.49 | 2.56 | 2.59 | | 2005 | na1 | na1 | 4.62 | 1.89 | n/a | | 2006 | na1 | na1 | 4.62 | 2.29 | 2.40 | | 2007 | na1 | na1 | 4.36 | 2.53 | 2.45 | | 2008 | na1 | na1 | 4.18 | 2.95 | 2.96 | | 2009 | na1 | na1 | 4.38 | | | | 2010 | No increase in effort | - | | | | | Weights in ‘000 t. 1 Not applicable – combined VI and IV not considered by ICES. 2 Divisions VI, IV and IIIa. 3 Divisions IV and VI. 4 Single-stock boundaries and the exploitation of this stock should be conducted in the context of mixed fisheries protecting stocks outside safe biological limits. |
Management Management unit: Yes Objectives
No explicit management objectives have been set for this stock.
Advice
Management considerations
A recently developed fishery independent survey suggests an increasing trend in biomass in both areas VI and IV since 2005.
Since 2009, ICES also provides advice on megrim in Subarea IV (North Sea). This is because the spatial distribution of landings data and survey catches provide good evidence to suggest that megrim population is contiguous between Divisions IVa and VIa.
Recent reductions in effort in Scotland and Ireland are considered to have contributed to the decline of landings in Subarea VI. Landings in VI are well below the TAC. Uptake by France, who account for 44% of the TAC, is very low (~11%). Official landings in Subarea IV and Division IIa in recent years are close to the TAC.
Area misreporting has been prevalent as megrim catches were misreported from Subarea VI into Subarea IV, due to restrictive quotas for anglerfish (i.e. vessels targeting anglerfish misreported all landings including megrim from Subarea VI into Subarea IV). The extent of this problem is unknown and should be quantified through integrated logbook and VMS analysis.
Sources
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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