Fishery Resources Monitoring System

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Hake - Bay of Biscay and Iberian Basin, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Hake - Bay of Biscay and Iberian Basin, 2008
Fact Sheet Citation  
Hake - Southern stock (Divisions VIIIc and IXa)
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 - Bay of Biscay and Iberian 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

Since 2006 a recovery plan has been implemented, aimed at recovering the SSB above Bpa and reducing F to 0.27. However, this plan has not been effectively implemented. Even so, a number of regulatory measures are adopted for fishing southern hake, including minimum mesh sizes, closed areas and seasonal restrictions (EC No.850/98).

Fishing effort limitations corresponding to a 10% reduction were initiated in 2005, with a reduction of allowed fishing days in order to establish a maximum number of days by fishing gear.

A TAC is set for all of the Atlantic Iberian Peninsula, including the Gulf of Cadiz. The TAC has been ineffective in regulating the fishery in recent years as landings greatly exceeded the TACs.

The minimum landing size of southern hake is 27 cm. There is no correspondence between minimum landing size and the current mesh size in force. This has resulted in high discards.

All of these regulations and others, which were expected to reduce fishing mortality and discarding, may have contributed to the improvement of the stock status in recent years, however improved recruitment appears to have been the most important factor. Fishing mortality, which had been reduced from 2004 to 2006 has been increasing since 2007. As such, the extent of the effect of the measures cannot be precisely quantified at this time.
Assessment
 
Assessment Model
Methodology

Scientific basis

Data and methods

A statistical catch-at-age model in Bayesian framework was used based on landings, three commercial lpue series, and two surveys.

Uncertainties in assessment and forecast

Recent estimates from the model of SSB, F and landings are uncertain. Current assessment shows a high retrospective pattern with a trend to overestimate F and landings, and underestimate SSB.

The model estimates of landings have been below the observed landings since 2005.

The main elements of uncertainty in this assessment include: (i) there is no biological basis for the current stock definition of southern hake; (ii) there may be a problem of overestimation of age from otolith reading. 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. If growth of hake is underestimated, reference points would need to be revisited; (iii) discards were not considered in the assessment, but preliminary estimates are approximately 3000 tonnes in 2008, representing approximately 20% of the total landings, concentrated on juveniles. Not considering discards provide a more pessimistic recovery view under a scenario of reducing F, like those expected with current effort reduction regulations; (iv) Gulf of Cadiz landings are not included in the assessment. Although Gulf of Cadiz landings were only 560 tonnes in 2008, these represent 7% of the landings by number, mostly younger ages.

Comparison with previous assessment and advice

The assessment and the basis for advice are consistent with last year. F in 2007 was revised 36% downwards, SSB in 2008 were revised 46% upwards and model estimates of 2007 landings were revised 19% downwards.
Overall Assessment Results


Figure 7.4.1.1. Hake in Divisions VIIIc and IXa (southern stock). Landings, fishing mortality, recruitment, and SSB. Observed landings are showed as dots while estimates landings are given by line (median) and dashed lines (5 and 95% credibility intervals of the model).


Figure 7.4.1.2 Hake in Divisions VIIIc and IXa (southern stock). Stock recruitment and PA-plot. Grey dots denote model uncertainty


Figure 7.4.1.3 Hake in Divisions VIIIc and IXa (southern stock).Yield and SSB per recruit. Three curves represent credibility intervals and median.


Figure 7.4.1.4 Hake in Divisions VIIIc and IXa (southern stock). Comparison of current assessment with previous assessments. The assessment in 2008 and 2009 is based on a Bayesian approach while earlier assessments are based on an XSA approach (predicted intermediate years are included).

Table 7.4.1.3
Reference Point
 


  Type Value Technical basis
Precautionary approach Blim 25 000 t The level below which there are indications of impaired recruitment.
  Bpa 35 000 t ~ Blim *1.4
  Flim 0.55 Floss
  Fpa 0.40 ~ Flim * 0.72
Targets Ftarget 0.27 Recovery plan (EC Reg. No. 2166/2005)
(Unchanged since 2004)


Yield and spawning biomass per Recruit F-reference points (2009):
  Fish Mort Ages 2-5 Yield/R SSB/R
Fsq 0.52 0.19 0.29
Fmax 0.18 0.23 0.96
F0.1 0.10 0.21 1.49
Median values



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 (median and 90% credibility intervals): F2009 = Fsq = mean F(06–08) rescaled = 0.52 [0.42; 0.65]; R09–11 randomized from 1989–2008: R09/11 =49.5 [35.6, 98.7] millions; landings (2009) = 16.5 [14.0; 19.4]; SSB (2010) = 24.6 [18.8; 31.9].
Rationale Landings1 (2010) Basis F(2010)2 SSB (2011)2 Risk of SSB (2011) below Blim Probability of SSB (2011) increasing 3 % TAC change 4
Zero catch 0 F=0 0.00 40.3 0.00 1.00 -100%
Status quo 16.2 Fsq 0.52 23.1 0.65 0.54 100%
Agreed management plan 15.0 10% F reduction 0.47 24.4 0.55 0.65 85%
  9.5 -10% F since 2006 0.27 30.0 0.16 0.52 18%
  9.3 15% TAC constraint 0.26 30.3 0.15 0.95 15%
Precautionary limits 7.4 Fpa*0.5 0.20 32.4 0.08 0.98 -9%
  10.5 Fpa *0.75 0.30 29.1 0.21 0.93 29%
  13.2 Fpa *1 0.40 26.2 0.41 0.79 63%
  15.7 Fpa *1.25 0.50 23.6 0.61 0.59 94%
  4.9 Bpa in 2011 0.13 35.0 0.03 1.00 -40%
Status quo 2.1 Fsq *0.1 0.05 38.0 0.01 1.00 -74%
  4.0 Fsq *0.2 0.10 35.9 0.02 1.00 -50%
  5.0 Fsq *0.25 0.13 34.9 0.03 1.00 -38%
  7.6 Fsq *0.4 0.21 32.1 0.09 0.98 -6%
  9.3 Fsq *0.5 0.26 30.3 0.15 0.95 15%
  10.8 Fsq *0.6 0.31 28.7 0.23 0.91 34%
  13.0 Fsq *0.75 0.39 26.4 0.39 0.81 60%
  13.7 Fsq *0.8 0.42 25.7 0.44 0.76 69%
  16.2 Fsq *1 0.52 23.1 0.65 0.54 100%
  17.4 Fsq *1.1 0.57 21.9 0.73 0.43 114%
  18.5 Fsq *1.2 0.63 20.8 0.80 0.33 128%
  19.0 Fsq *1.25 0.65 20.2 0.83 0.28 135%
  19.5 Fsq *1.3 0.68 19.7 0.86 0.25 141%

Weight in ‘000 tonnes

1 median of stochastic projections corrected with Gulf of Cadiz (factor applied = 1.0425).

2 median of stochastic projections.

3 relative to SSB in 2008.

4 landings in 2010 relative to TAC 2009.

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 4 900 t.

Exploitation boundaries in relation to existing management plans

According to the recovery plan, the reduction in F of 10% would result in a TAC increase greater than 15%. Therefore, landings in 2010 should not exceed 9 300 t, corresponding to a 15% increase of the 2009 TAC.

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

The status quo fishing mortality is estimated at 0.52, well above levels that could support sustainable long-term yield (Fmax = 0.18).

Exploitation boundaries in relation to precautionary limits

For SSB to reach a Bpa in 2011 an F of 0.13 in 2010 should be applied. The corresponding yield (including Gulf of Cadiz) is 4.9 thousand tonnes in 2010.


Table 7.4.1.1 Hake in Divisions VIIIc and IXa (southern stock). Single stock exploitation boundaries (advice), management, and landings.
Year

ICES

Advice

Predicted catch corresp. to advice

Agreed

TAC

ICES

Landings

1987 Precautionary TAC; juvenile protection 15.0 25.0 16.2
1988 TAC; juvenile protection 15.0 25.0 16.4
1989 TAC; juvenile protection 15.0 20.0 13.8
1990 TAC; juvenile protection 15.0 20.0 13.2
1991 Precautionary TAC 10.0 18.0 12.8
1992 Precautionary TAC 10.3 16.0 13.8
1993 F = 10% of F 91 1.0 12.0 11.5
1994 F lowest possible, at least reduced by 80% 2.0 11.5 9.9
1995 F lowest possible - 8.5 12.2
1996 F lowest possible - 9.0 9.9
1997 F lowest possible - 9.0 8.5
1998 60% reduction in F 4.0 8.2 7.7
1999 Reduce F below Fpa 9.5 9.0 7.5
2000 20% reduction from 1994–98 average landings < 7.7 8.5 7.3
2001 Reduce F below Fpa; no increase in landings 8.5 8.9 7.6
2002 F below Fpa < 8.0 8.0 6.7
2003 Lowest possible catch / rebuilding plan 0 7.0 6.9
2004 Zero catch 0 5.95 6.8
2005 Zero catch 0 5.968 8.3
2006 Zero catch 0 6.661 10.7
2007 Zero catch 0 6.128 14.9
2008 Zero catch 0 7.047 16.7
2009 Zero catch 0 8.104  
2010 Reach Bpa in 2011 4.9    

Weights in ‘000 t.



Management
Management unit: Yes

Management Objectives

There are explicit management objectives for southern hake under the EC Reg. No. 2166/2005 to recover the stock to a spawning-stock biomass above 35 000 tonnes by 2016 and a goal of reducing fishing mortality to 0.27 (see Appendix 7.4.1 in source of information). The main elements in the plan are a 10% annual reduction in F and a 15% constraint on TAC change between years. This plan has not yet been evaluated by ICES.
Management Advice

Management considerations

The implementation of the recovery plan has not been effective. Fishing mortality has been increasing and the TAC has been overshot every year of the plan. Furthermore discard rates are high. If a 10% annual reduction in fishing mortality has been achieved since 2006 according to the recovery plan, the fishing mortality in 2010 would be at target F of 0.27. The recovery plan has not been evaluated by ICES.

Hake is caught in mixed fisheries together with megrim and anglerfish. The present advice for megrims and anglerfishes are significant reductions in TAC and zero catches, respectively. Therefore management measures for hake should also aim to reduce catches of those species. These measures could include selective gears, gear restrictions, area closures, etc.

Recent increases in SSB and yield are due to above average recruitment during 2003-2007, but at Fsq there is a high probability of reversing the upwards trend in SSB in medium term. Recruitment in 2008 is lower than in previous years, which will contribute to the decrease in SSB in medium term.

Discards of juvenile hake are 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 by shifting the selection pattern towards larger fish.
Biological State and Trend
Exploitation rate: Increased risk
Abundance level: Reduced 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

Reduced reproductive capacity Increased risk Overfished

Above target

 



Based on the most recent estimates of SSB (in 2009), ICES classifies the stock as suffering reduced reproductive capacity. Based on the most recent estimate of fishing mortality (in 2008) ICES classifies the stock as at risk of being harvested unsustainably. Fishing mortality has increased in recent years and is currently near Flim. SSB and recruitment have increased in recent years, but recruitment in 2008 is lower than in previous years and estimated to be poor (the lowest in the 27-year time series).
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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