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Hake - West European Basin, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Hake - West European Basin, 2008
Fact Sheet Citation  
Hake - Northern stock (Division IIIa, Sub-areas IV, VI and VII and Divisions VIIIa,b,d)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
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Species:
FAO Names: en - European hake, fr - Merlu européen, es - Merluza europea, ru - Мерлуза восточноатлантическая
Geographic extent of Hake - West European Basin
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.  

Geographical Distribution
Jurisdictional distribution: National

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

A number of regulations have been introduced in recent years, to promote the recovery of the stock. The most important of these are listed below:

The minimum mesh size for trawls in the Bay of Biscay was increased from 55 mm (“Nephrops fishery”)/65 mm (“otter trawlers”) to 70 mm in 2000. The minimum landing size is 27 cm.

Two areas where a 100 mm minimum mesh size is required for all otter-trawlers, regardless of the amount of hake caught were introduced in 2002 (EC Reg. 494/2002), one in Subarea VII (SW of Ireland) and the other in Subarea VIII (Bay of Biscay).

Measures to limit fishing effort in a ‘biologically sensitive area’ in Subareas VIIb, VIIj, VIIg and VIIh were introduced in 2003 (EC Reg. 1954/2003).

The hake recovery plan (EC Reg. No. 811/2004) came into operation in 2004.

These regulations and others have contributed to stabilise the fishing mortality since 2001. The effect of these measures cannot be precisely quantified.

Changes in fishing technology and fishing patterns

Since the introduction of the high opening trawls in the mid-1990s, no significant changes in fishing technology have been introduced.

In the French Nephrops fishery in the Bay of Biscay, the use of a squared mesh panel to reduce discarding of undersized hake has been enforced since 2006.
Assessment
 
Assessment Model
Methodology

Scientific basis

Data and methods

An age-based assessment (XSA) was performed using four commercial cpue series and four surveys for tuning.

Discards were not included in the assessment due to data quality.

Information from the fishing industry

The fishing industry and scientists have, at national level, discussed information that can be used in the assessments. However, national industries have not provided any additional quantitative information for use in the assessment.

Uncertainties in assessment and forecast

Age from otolith readings may be overestimated. Further studies, extensive tag-recapture studies, complementary ageing and growth methodologies, and even alternative non-age-based assessment methods are required to draw any firm conclusions on these matters. Analyses indicate that stock trends are robust to uncertainties in growth (ICES, 2006). However, if growth of hake is underestimated, reference points would need to be revisited.

Discards are not included in the assessments. The available data are patchy and noisy and discard rates of several fleets are still simply not known. Even, when data are available, it has not yet been possible to incorporate them in a consistent way.

The historical performance of the assessments shows consistent overestimation of SSB and underestimation of fishing mortality for the last few years in the assessment. SSB for 2008 has been revised downwards by 3% and F for 2007 upwards by 4%.

There are large uncertainties associated with the most recent recruitment estimates; these are only estimated by a single survey. In the absence of reliable 2007 and 2008 recruitment estimates, geometric mean recruitment has been used.

There is no biological basis for the current stock definition of northern and southern hake.

Comparison with previous assessment and advice

The assessment and the basis for advice are consistent with last year.
Overall Assessment Results


Figure 9.4.1.1. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Summary of stock assessment: landings, fishing mortality, recruitment, and SSB (weights in ‘000 tonnes). 2007, 2008 and 2009 recruitments were replaced by geometric mean (1990-06).


Figure 9.4.1.2. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Stock-recruitment plot, yield per recruit analysis, and PA plot.


Figure 9.4.1.3. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Comparison between current and previous assessments (predicted intermediate years are included).


Table 9.4.1.2. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Estimated landings, discards, and catches (‘000 tonnes) by ICES area.


Table 9.4.1.3. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Summary of stock assessment.
Year Recruitment SSB Landings Mean F
  Age 0     Ages 2–6
  millions tonnes tonnes  
1978 311 206100 49500 0.212
1979 283 243900 50600 0.193
1980 359 228800 56500 0.208
1981 276 246900 53900 0.205
1982 223 248700 55000 0.225
1983 228 238200 57500 0.223
1984 200 253800 63300 0.226
1985 214 349600 56100 0.143
1986 199 320900 57100 0.174
1987 207 265900 63400 0.230
1988 213 206600 64800 0.286
1989 195 185500 66500 0.327
1990 252 148700 64300 0.353
1991 204 120400 52400 0.292
1992 240 104100 56600 0.380
1993 212 102100 52100 0.293
1994 179 95500 51300 0.382
1995 199 98900 57600 0.432
1996 201 95600 47200 0.355
1997 158 98300 42600 0.307
1998 147 94000 35000 0.286
1999 158 91800 39800 0.322
2000 150 94600 42000 0.328
2001 138 103600 36700 0.245
2002 149 107700 40100 0.263
2003 181 110000 43200 0.278
2004 195 121600 46400 0.272
2005 192 120500 46500 0.275
2006 228 129800 41500 0.233
2007 184* 126700 45100 0.263
2008 184* 136600 47800 0.243
2009 184* 145900    
Average 208 163791 51045 0.273
*2007, 2008 and 2009 recruitment estimates replaced by geometric mean (1990-06)

Reference Point
 


(unchanged since: 2003)
  Type Value Technical basis
Precautionary approach Blim 100000 t Blim = Bloss the lowest observed biomass in the 2003 assessment
  Bpa 140000 t Bpa ~ Blim * 1.4
  Flim 0.35 Flim = Floss
  Fpa 0.25 Fpa ~ Flim * 0.72
Targets Ftarget 0.25 Recovery plan (EC Reg. No. 811/2004)


Yield and spawning biomass per Recruit F-reference points (2009):
  Fish Mort Yield/R SSB/R
  Ages 2–6    
Average last 3 years 0.25 0.31 0.91
Fmax 0.18 0.32 1.21
F0.1 0.10 0.29 1.88
Fmed 0.34 0.29 0.64



Candidates for reference points consistent with taking high long-term yields and achieving a low risk of depleting the productive potential of the stock are in the range of F0.1–Fmax.
Projection


Outlook for 2010 Basis: Fsq = mean F(06–08) =0.25; R(07–10) = GM 1990–2006 = 184 millions; landings (2009) = 50.1 ; SSB(2010) = 161.6.
Rationale Landings (2010) Basis F total (2010) SSB (2011) %SSB change 1 %TAC change 2
Zero catch 0.0 F=0 0.00 233.2 44% -100%
High long-term yield (candidate) 41.6 Fmax 0.18 186.4 15% -19%
Status quo 54.5 Fsq *1 0.253) 171.9 6% 6%
Agreed recovery plan 6.4 F(recovery plan) *0.1 0.03 226.0 40% -88%
  15.6 F(recovery plan) *0.25 0.06 215.6 33% -70%
  29.9 F(recovery plan) *0.5 0.13 199.4 23% -42%
  43.1 F(recovery plan) *0.75 0.19 184.7 14% -16%
  50.5 F(recovery plan) *0.9 0.23 176.5 9% -2%
  55.2 F(recovery plan) 0.25 171.2 6% 7%
  59.7 F(recovery plan) *1.1 0.28 166.1 3% 16%
  66.3 F(recovery plan) *1.25 0.31 158.8 -2% 29%
Precautionary limits 6.4 Fpa *0.1 0.03 226.0 40% -88%
  15.6 F(prec limits) *0.25 0.06 215.6 33% -70%
  29.9 F(prec limits) *0.5 0.13 199.4 23% -42%
  43.1 F(prec limits) *0.75 0.19 184.7 14% -16%
  50.5 F(prec limits) *0.9 0.23 176.5 9% -2%
  55.2 Fpa 0.25 171.2 6% 7%
  59.7 F(prec limits) *1.1 0.28 166.1 3% 16%
  66.3 F(prec limits) *1.25 0.31 158.8 -2% 29%
  76.5 F(prec limits) *1.5 0.38 147.5 -9% 49%
  86.0 F(prec limits) *1.75 0.44 137.1 -15% 67%
  95.1 F(prec limits) *2 0.50 127.0 -21% 85%
  107.0 F(prec limits) *2.25 0.56 113.8 -30% 108%
All weights in ’000 tonnes.1) SSB 2011 relative to SSB 2010.2) Predicted landings 2010 relative to TAC 2009 (51.5 thousand tonnes).3) Fsq = 0.246, rounded to 0.25 in the table.Scenarios in italics are not considered consistent with the precautionary approach.


Scientific Advice

Single-stock exploitation boundaries

Considering the options below, ICES advises on the basis of the exploitation boundaries in relation to precautionary limits that landings for 2010 should not exceed 55200 t.

Exploitation boundaries in relation to existing management plans

A fishing mortality of F = 0.25 as indicated in Article 5.2 of the agreed recovery plan is expected to lead to an SSB of 171200 t in 2011 (the highest SSB since 1989), with estimated landings in 2010 of 55200 t. This implies an increase in TAC of 7%.

Exploitation boundaries in relation to high long-term yield, low risk of depletion of production potential and considering ecosystem effects

The fishing mortality in 2008, estimated at 0.24, is above fishing mortalities that are expected to lead to high long-term yields and low risk of stock depletion (F0.1 = 0.10 and Fmax = 0.18). This indicates that long-term yield is expected to increase at fishing mortalities well below the historic values. Fishing at such a lower mortality is expected to lead to higher SSB and therefore lower the risk of observing the stock to be outside precautionary limits.

Exploitation boundaries in relation to precautionary limits

A fishing mortality of Fpa = 0.25 is expected to lead to landings of 55200 t in 2010 and an SSB of 171200 t in 2011, which is above Bpa.


Table 9.4.1.1. Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d) (Northern stock). Single stock exploitation boundaries (advice), management, catch, and landings.

Year
ICESAdvice / Single-stock exploitation boundaries (from 2004 onwards) Predicted catch corresp to advice Predicted catch corresp to single-stock exploitation boundaries AgreedTAC1 ICESlandings Disc.slip. ICESCatch***
1987 Precautionary TAC; juvenile protection -   63.5 63.4 2.0 65.3
1988 Precautionary TAC; juvenile protection 54   66.2 64.8 2.0 66.8
1989 Precautionary TAC; juvenile protection 54   59.7 66.5 2.3 68.8
1990 Precautionary TAC; juvenile protection 59   65.1 59.9 1.5 61.4
1991 Precautionary TAC; juvenile protection 59   67.0 57.6 1.7 59.3
1992 If required, precautionary TAC 61.5   69.0 56.6 1.7 58.3
1993 Enforce juvenile protection legislation -   71.5 52.1 1.5 53.6
1994 F significantly reduced <46   60.0 51.3 1.9 53.1
1995 30% reduction in F 31   55.1 57.6 1.2 58.9
1996 30% reduction in F 39   51.1 47.2 1.5 48.8
1997 20% reduction in F 54   60.1 42.6 1.8 44.4
1998 20% reduction in F 452   59.1 35.0 0.8 35.8
1999 Reduce F below Fpa <362   55.1 39.8 0.8 40.6
2000 50% reduction in F <202   42.1 42.0 0.6 42.6
2001 Lowest possible catch, recovery plan -   22.6 36.7 0.5 37.2
2002 Lowest possible catch / recovery plan -   27.0 40.0 0.3 40.3
2003 Lowest possible catch / recovery plan -   30.0 43.1 - ** -
2004 70% reduction in F or recovery plan* * <13.8 39.1 46.4   -
2005 F=0.19   33 42.6 46. 6    
2006 F=0.25   44 43.9 41.5    
2007 Recovery plan limits   50.5 52.7 44.4    
2008 Recovery plan limits   54 54 47.8    
2009 F =0.25 = Fpa   51.5 51.5      
2010 F =0.25 = Fpa   55.2        
Weights in ‘000 t.1Sum of area TACs corresponding to northern stock plus Division IIa (EC zone only).2Landings. *Single-stock boundary and the exploitation of this stock should be conducted in the context of mixed fisheries.**In 2003 onwards, no estimations of discards were available.***ICES catch not used in the assessment. Assessment based on landings only.


Management
Management unit: Yes

Management Objectives

There are explicit management objectives for this stock in the EU recovery plan (EC Reg. No. 811/2004) (Annex 9.4.1.1). The aim is to increase the SSB to above 140000 t. The agreed fishing mortality of F lower than 0.25 is constrained by a year-to-year change in TAC not to exceed 15% unless the SSB is below 100000 t. In this case a lower TAC than implied by the 15% constraint will be applied. The recovery plan has not been evaluated by ICES.
Management Advice

Management considerations

ICES advice for 2010 coincides with the maximum landings implied by the existing recovery plan.

Discards of juvenile hake can be substantial in some areas and fleets. The spawning biomass and the long-term yield can be substantially improved by reducing mortality of small fish. This could be achieved by measures that reduce unwanted bycatch through shifting the selection pattern towards larger fish.

The northern hake SSB is for 2009 estimated to be above the recovery plan target (140000 t). Article 3 of the recovery plan prescribes that a management plan should be implemented when the target is reached in two consecutive years. ICES considers that SSB has been approximately 140000 t in the last two years.

Stable fishing mortalities since 2001 at about Fpa (0.25) and the 2006 year class that is above average have contributed to the recent increase in SSB.

Impacts of fisheries on the ecosystems

Hake is caught in a variety of fisheries which use a range of gears. Many of these are mixed fisheries. The impact of the fisheries on the ecosystem has not been assessed.
Biological State and Trend
Exploitation rate: Harvested sustainably
Abundance level: Full reproductive capacity


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
Full reproductive capacity Harvested sustainably Overfished Appropriate  



Based on the most recent estimates of SSB (in 2009) and fishing mortality (in 2008) ICES classifies the stock as being at full reproductive capacity and being harvested sustainably. SSB is estimated to be just above Bpa in 2009, and F has been around Fpa since 2001. Recruitment has been relatively stable over the last decade.
Source of information
 
ICES. 2009. Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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