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Roundnose grenadier - Rockall, West of Scotland, Irish and Celtic seas, Porcupine Bank, English and Bristol Channels, Faroes grounds and Western Hatton Bank
Marine Resource  Fact Sheet
ICES Advice 2009
Roundnose grenadier - Rockall, West of Scotland, Irish and Celtic seas, Porcupine Bank, English and Bristol Channels, Faroes grounds and Western Hatton Bank
Fact Sheet Citation  
Roundnose grenadier in Subareas VI and VII and Divisions Vb and XII b
Owned byInternational Council for the Exploration of the Sea (ICES) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Roundnose grenadier, fr - Grenadier de roche, es - Granadero de roca, ru - Макрурус тупорылый
Geographic extent of Roundnose grenadier - Rockall, West of Scotland, Irish and Celtic seas, Porcupine Bank, English and Bristol Channels, Faroes grounds and Western Hatton Bank
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Sub-Regional
Reference year: 2008
 
 
Biological State and Trend
State & Trend Descriptors
PartnerFIRMS
Exploitation rateUndefined
Abundance levelUndefinedUncertain/Not assessed

Overall the stock status is uncertain, but there is some evidence of biomass depletion for Vb, VI and VII (Figure 9.4.15.2.2).

Survey data from the west of Scotland (Division VI) indicate that grenadier does not occur in the shallower waters (Figure 9.4.15.2.3). Length distribution of French landings indicates a change towards smaller fish. The results of an exploratory age-structured assessment of the stock in Subareas VI and VII and in Division Vb indicate that the total biomass has declined consistently since 1996.
Habitat and Biology
Depth zone: Slope (200 m - 1000 m).   Vertical distribution: Demersal/Benthic.  

Water Area Overview
Spatial Scale: Sub-Regional

Geo References
Resource Structure
Considered a single stock: Yes
Exploitation
 

Factors affecting the fisheries and the stock

Regulations and their effects

There is a licensing scheme for European Community vessels in community and international waters. Effort limitations apply in the NEAFC regulatory area (international waters) for all NEAFC contracting parties.
Assessment
 
Assessment Model
Methodology

Scientific basis

The status of this stock is based on available abundance indices from commercial and research vessel data, mean length data in catches and, to a lesser extent, on the preliminary results from exploratory separable VPAs.

The abundance index from the commercial fishery is derived from directed lpues of a French reference fleet in a reference area from trips where roundnose grenadier is more than 10% of the total landings. The reference consists of large high-sea trawlers (>45 m overall length) that were already fishing in the early 1990s. The number of vessels in the reference fleet have declined over years and the mean age of the vessels has increased. Several factors (month, depth, rectangle, vessel, skipper) are shown to have explanatory power on cpue, but they are not included in the calculation of the cpue.

Information from the fishing industry

In collaboration with the French industry, IFREMER has carried out investigations to refine cpue series for French trawlers. A new time-series starting in 2000 and based on haul-by-haul data was initiated by the French industry. It shows that 82% of the hauls dedicated to deep-sea fisheries catch roundnose grenadier at depths between 700 and 1400 m. The ‘deep-sea’ hauls where no roundnose grenadier is reported are at lower depths (500–1100 m).

Comparison with previous assessment and advice

Past advice has stated that a 50% reduction in fishing effort was needed to permit stock rebuilding, and that the expansion of fisheries should not be allowed until reliable assessments indicate that increased harvests are sustainable. The present advice is consistent with previous advice since a 50% reduction in effort is considered to lead to a 50% decrease in landings.
Overall Assessment Results


Table9.5.15.2.1. Working group estimates of landings (tonnes) of roundnose grenadier.
Roundnose grenadier in Vb
Year Faroes France Norway Germany Russia/USSR UK (E+W) UK (Scot) TOTAL
1988       1       1
1989 20 181   5 52     258
1990 75 1470   4       1549
1991 22 2281 7 1       2311
1992 551 3259 1 6       3817
1993 339 1328   14       1681
1994 286 381   1       668
1995 405 818           1223
1996 93 983   2       1078
1997 53 1059           1112
1998 50 1617           1667
1999 104 1861 2     29   1996
2000 48 1699   1   43   1791
2001 84 1932           2016
2002 176 774       81   1031
2003 490 1032       10   1532
2004 508 986 0 0 6 0 76 1576
2005 903 912 1 0 1 0 48 1865
2006 900 875 0 0 0 0 0 1775
2007* 867 636 0 0 0 0 0 1503

Figure 9.5.15.2.1. Continued.
Table 9.5.15.2.1. Continued. Working group estimates of landings (tonnes) of roundnose grenadier (cont.).
Roundnose grenadier in Subarea VII and unallocated landings in Vb, VI & VII
Year Faroes France Ireland Spain UK (Scot) TOTAL   Year Unallocated landings in Vb, VI, VII
1988           0   1988  
1989   222       222   1989  
1990   215       215   1990  
1991   489       489   1991  
1992   1556       1556   1992  
1993   1916       1916   1993  
1994   1922       1922   1994  
1995   1295       1295   1995  
1996   1051       1051   1996  
1997   1033   5   1038   1997  
1998   1146   11   1157   1998  
1999   892   4   896   1999  
2000   859       859   2000  
2001   938 416     1354   2001 208
2002 1 449 605   3 1058   2002 504
2003   373 213   1 587   2003 952
2004 0 247 320 0 0 567   2004  
2005 0 146 55 0 0 201   2005 5003
2006   248 138 0 0 386   2006  
2007*   177 28 0 0 205   2007*  

Figure 9.5.15.2.1. Continued.
Figure 9.5.15.2.1. Continued. Working group estimates of landings (tonnes) of roundnose grenadier (cont.).
Working group estimates of landings of roundnose grenadier in Vb, VI, VI, and XIIb
Year Vb VI VII Unallocated Vb, VI, VII XIIb Total Vb, VI,VII,XIIb
1988 1 32 0 0 0 33
1989 258 2218 222 0 52 2750
1990 1549 5515 215 0 0 7279
1991 2311 7304 489 0 172 10276
1992 3817 6782 1556 0 13 12168
1993 1681 8205 1916 0 328 12130
1994 668 5938 1922 0 486 9014
1995 1223 6472 1295 0 644 9634
1996 1078 6044 1051 0 1528 9701
1997 1112 6032 1038 0 2725 10907
1998 1667 5207 1157 0 3964 11995
1999 1996 5642 896 0 6493 15027
2000 1791 8956 859 0 13822 25428
2001 2016 14773 1354 208 31774 50125
2002 1031 11538 1058 504 5394 19524
2003 1532 6598 587 952 18745 28413
2004 1576 5992 567 0 10067 18203
2005 1865 3696 201 5003 6012 16778
2006 1775 2088 386 0 5286 9535
2007* 1503 1437 205 0 2 3146
* Preliminary.


Figure 9.4.15.2.1. Total international landings of roundnose grenadier in Vb, VI, VII, and XIb (data for 2007 are incomplete).


Figure 9.4.15.2.2. Roundnose grenadier lpues in the reference area. Directed lpue of the French reference fleet (landings for fishing trips where roundnose grenadier comprise >10% of total landings vs corresponding effort).


Figure 9.4.15.2.3. Catch rates of roundnose grenadier in FRS survey, 1998–2006 per depth band.

Reference Point
 

No reference points have been defined for this stock.
Scientific Advice

Single-stock exploitation boundaries

Due to its low productivity, roundnose grenadier can only sustain low rates of exploitation. Cpue in the areas has been at a reduced level. ICES recommends that catches should be constrained to 6000 t (50% of the level before the expansion of the fishery, 1990–1996). The fishery should not be allowed to expand unless it can be shown that it is sustainable.
Management
 
Management Objectives

There are no management objectives for this stock.
Management Advice

Management considerations

The relative abundance index for this stock has declined to about 20% of its initial level. As the start of the cpue series is not believed to correspond to the start of the fishery, the true decline is likely to be greater than this. In general, biomass associated with MSY is about 40% of the unexploited biomass. The average catch during the time period of the decline in cpue must have generated a fishing mortality greater than Fmsy. Therefore, catches should be reduced by more than 50% to reduce F to Fmsy.

The period before the expansion of the fishery is equal to the years 1990–1996.

Roundnose grenadier is taken as one of the target species in a mixed-species fishery, along with other deep-water species (black scabbard and deep-water sharks in Division Vb, Subareas VI and VII). Any measures taken to manage the stocks of grenadier should take account of the advice given for all the species taken in the same deep-water mixed fishery.

Recent (2004–2005) information on discards shows that about 30% by weight and 50% by number of the catch of roundnose grenadier is discarded due to small size. These figures are higher than the ones estimated for 1997–1998. This increase is due to a combination of changes in the depth distribution of effort and a decrease in the abundance of larger fish in the landings.

The apparent decline in cpue in the reference area appears inconsistent with the presence of older fish in the current landings. However, this fishery in Vb, VI, VII and XIIb has expanded spatially with time and it is possible that sequential depletion of components of the stock may be occurring. Little is known about migration or mixing within the stock.

Historical landings data for this stock have been substantially revised to take into account landings reported in Statlant. It should also be noted that total international landings in 2007 are incomplete and do not include landings from Spain, which are likely to be substantial.
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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