Fishery Resources Monitoring System

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Anchovy - Bay of Biscay, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Anchovy - Bay of Biscay, 2008
Fact Sheet Citation  
Anchovy in Sub-area VIII (Bay of Biscay)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
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Species:
FAO Names: en - European anchovy, fr - Anchois, es - Boquerón, ru - Анчоус европейский
Geographic extent of Anchovy - Bay of Biscay
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: Pelagic.  

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

Presently the fishery is closed. Usually the fisheries for anchovy are targeted by trawlers and purse-seiners. The Spanish and French fleets fishing for anchovy in Subarea VIII are spatially and temporally well separated. The Spanish fleet operates mainly in Divisions VIIIc and VIIIb in spring, while the French fleets operate in Division VIIIa in summer and autumn and in Division VIIIb in winter and summer.

Impacts of the environment on the fish stock

Anchovy is a prey species for other pelagic and demersal species, and also for cetaceans and birds.

Although recruitment depends strongly on environmental factors, recruitment predictions based on environmental variables are not yet sufficiently accurate to estimate the population one year in advance.
Assessment
 
Assessment Model
Methodology

Scientific basis

Data and methods

A two-stage Bayesian biomass dynamic model (BBM) assessment was used, based on the Daily Egg Production Method (DEPM) (survey since 1987), acoustic surveys (since 1989) and catches from the French and Spanish fisheries. The assessment method is consistent with that used last year.

Uncertainties in assessment and forecast

This year the assessment indicates a reduction of SSB (by about 20 %) despite the apparent stability in the survey SSB estimates. The low fraction of age 1 in both surveys, both in 2008 (implying a low estimate of age 2 in 2009) and in 2009 implies the small drop in SSB suggested by the model.

The current assessment is mainly driven by inputs provided by the surveys (SSB and proportion of 1-group). For the DEPM survey, uncertainties include the assumed spawning frequency (which is under revision) and the daily mortality rate of egg. For the acoustic estimate, even though commercial vessels were used during the survey to explore the coastal area, there may still be problems with the coverage of coastal areas where age 1 dominates.

The main uncertainties of the model are that the growth and natural mortality of anchovy are assumed independent of age. Similarly, there is no age differential catchability in the surveys. The assumption that DEPM survey data measures the spawning biomass in absolute terms might also increase uncertainty. Stock assessment modelling results do not reflect the additional uncertainty stemming from these factors.

The current model provides an estimate of the precision of the results and these are translated into risk that can be included in harvest rules. The 95% credibility intervals indicate that SSB in 2009 is between 15 and 32 thousand tonnes. The uncertainty in recruitment and harvest rate is relatively low. There is also low uncertainty about the current state of the SSB which is among the lowest in the time-series starting in 1987.

Comparison with previous assessment and advice

The assessment results are consistent with last year. The perception of the stock and the advice are unchanged.

SSB in 2008 has been revised upwards by 9% compared to last year.
Overall Assessment Results


Figure 7.4.6.1 Anchovy in Subarea VIII (Bay of Biscay). Catches (in tonnes).


Figure 7.4.6.2 Anchovy in Subarea VIII (Bay of Biscay). Posterior median (solid line) and 95% credible intervals (dashed lines) for the recruitment series (top panel, in tonnes), the spawning-stock biomass (middle panel, in tonnes), and the harvest rates (Catch/SSB, bottom panel) from the BBM.


Figure 7.4.6.3 Anchovy in Subarea VIII (Bay of Biscay). Distribution of SSB in 2010 constructed from the posterior distribution of SSB in 2009 and the recent years recruitment scenario in the absence of fishing. The vertical dashed line represents Blim (21 000 t).


Figure 7.4.6.4 Anchovy in Subarea VIII (Bay of Biscay). Comparison of current assessment for SSB with previous assessments.


Table 7.4.6.2 Anchovy in Subarea VIII (Bay of Biscay). Annual catches (in tonnes) (Subarea VIII) as estimated by the Working Group members.
Year France
VIIIab
Spain
VIIIbc, Landings
Spain
Live Bait Catches
International
VIII
1960 1,085 57,000 n/a 58,085
1961 1,494 74,000 n/a 75,494
1962 1,123 58,000 n/a 59,123
1963 652 48,000 n/a 48,652
1964 1,973 75,000 n/a 76,973
1965 2,615 81,000 n/a 83,615
1966 839 47,519 n/a 48,358
1967 1,812 39,363 n/a 41,175
1968 1,190 38,429 n/a 39,619
1969 2,991 33,092 n/a 36,083
1970 3,665 19,820 n/a 23,485
1971 4,825 23,787 n/a 28,612
1972 6,150 26,917 n/a 33,067
1973 4,395 23,614 n/a 28,009
1974 3,835 27,282 n/a 31,117
1975 2,913 23,389 n/a 26,302
1976 1,095 36,166 n/a 37,261
1977 3,807 44,384 n/a 48,191
1978 3,683 41,536 n/a 45,219
1979 1,349 25,000 n/a 26,349
1980 1,564 20,538 n/a 22,102
1981 1,021 9,794 n/a 10,815
1982 381 4,610 n/a 4,991
1983 1,911 12,242 n/a 14,153
1984 1,711 33,468 n/a 35,179
1985 3,005 8,481 n/a 11,486
1986 2,311 5,612 n/a 7,923
1987 4,899 9,863 546 15,308
1988 6,822 8,266 493 15,581
1989 2,255 8,174 185 10,614
1990 10,598 23,258 416 34,272
1991 9,708 9,573 353 19,634
1992 15,217 22,468 200 37,885
1993 20,914 19,173 306 40,393
1994 16,934 17,554 143 34,631
1995 10,892 18,950 273 30,115
1996 15,238 18,937 198 34,373
1997 12,020 9,939 378 22,337
1998 22,987 8,455 176 31,617
1999 13,649 13,145 465 27,259
2000 17,765 19,230 n/a 36,994
2001 17,097 23,052 n/a 40,149
2002 10,988 6,519 n/a 17,507
2003 7,593 3,002 n/a 10,595
2004 8,781 7,580 n/a 16,361
2005 952 176 n/a 1,128
2006 913 840 n/a 1,753
2007 140 ** 1.2 ** n/a 141
2008 0 0 n/a 0
AVERAGE (1990-2004) 6,394 26,337 318 32,824
** Experimental Fishery

Table 7.4.6.3 Summary of the assessment
Reference Point
 


Type Value Technical basis
Precautionary approach Blim 21 000 t Blim: Bloss = 21 000 t (1989 SSB).
Bpa 33 000 t Bpa = Bloss × exp(1.645σ).
Flim - Not defined.
Fpa 1.0–1.2 Fpa: = F for 50% spawning potential ratio, i.e. the F at which the SSB/R is half of what it would have been in the absence of fishing.
Targets Fy - Not defined.
(unchanged since 2003)



Because the assessment provides the probability distributions for the SSB, it is possible to estimate directly the risk of the SSB falling below Blim. Bpa and Fpa reference points may become unnecessary.
Projection

Basis: R(2010) from distribution of recruitment at age 1 in biomass (2002–2009) = 17400 t. (median). Total catch: 50% allocated to second half of 2009 and 50% to first half of 2010.
Outlook for 2010

Catch (t)

(1st July 2009–30 June 2010)

Probability

(SSB2010<Blim)

Median SSB 2010
0 0.37 25550
1000 0.40 24962
3000 0.44 23785
5000 0.47 22609
7000 0.49 21432
9000 0.52 20256

Weights in tonnes

Shaded scenarios are not considered consistent with the precautionary approach



Scientific Advice

Single-stock exploitation boundaries

There is a 37% risk that SSB in 2010 will be below Blim even with no catch. ICES advises on the basis of exploitation boundaries in relation to precautionary limits that the fishery should remain closed until the stock condition has improved. The stock condition can be re-evaluated when estimates of the 2010 SSB and 2009 year class are available based on the spring 2010 acoustic and DEPM surveys. This implies a closure of the fishery until at least July 2010.


Table 7.4.6.1 Anchovy in Subarea VIII (Bay of Biscay). Single stock exploitation boundaries (advice), management and landings
Year

ICES

Advice

Predicted catch corresp. to advice Agreed TAC Official landings ICES landings
1987 Not assessed - 32 14 15
1988 Not assessed - 32 14 16
1989 Increase SSB; TAC 10.01 32 n/a 11
1990 Precautionary TAC 12.3 30 n/a 34
1991 Precautionary TAC 14.0 30 n/a 20
1992 No advice - 30 n/a 38
1993 Reduced F on juveniles; closed area - 30 n/a 40
1994 Reduced F on juveniles; closed area - 30 n/a 35
1995 Reduced F on juveniles; closed area - 33 n/a 30
1996 Reduced F on juveniles; closed area - 33 n/a 34
1997 Reduced F on juveniles; closed area - 33 n/a 22
1998 Reduced F on juveniles; closed area 33 n/a 32
1999 Reduced F on juveniles, closed area 33 n/a 27
2000 Closure of the fishery 0 33 n/a 37
2001 Preliminary TAC corresponding to recent exploitation 18 33 n/a 40
2002 Preliminary TAC corresponding to recent exploitation 33 33 n/a 17.5
2003 Preliminary TAC corresponding to recent exploitation 12.5 33 n/a 10.6
2004 Preliminary TAC corresponding to recent exploitation 11 33 n/a 16.4
2005 Rebuilding SSB 5 30 n/a 1.1
2006 Closure of the fishery* 0 5 1.8
2007 Closure of the fishery* 0 0 - 0.12
2008 Closure of the fishery * 0 0 - 0
2009 Closure of the fishery * 0 0 - 03
2010 Closure of the fishery * 0

Weights in ‘000 t.

1Mean catch of 1985–1987.

2Experimental fisheries.

3Preliminary estimate of catches up to 1st of July.

n/a: not available.

* to be reconsidered after new information from Spring survey.



Management
Management unit: Yes

Management Objectives

There are no explicit management objectives for this stock. The present closure of the fishery aims at protecting the remaining stock until a strong year class recruits to the stock.
Management Advice

Management considerations

Anchovy is a short-lived species, with the fishable stock consisting primarily of one-year-old fish. The estimate of recruitment at age 1 is a key factor in determining a TAC.

Stock biomass has been low because recruitment has been low since 2002. The fishery has been stopped from 2005 onwards. There are no indications how long the low recruitment period will last and whether continued low SSB will reduce future recruitments. ICES advice is made in the frame of the precautionary approach, therefore, in the present situation, the catch forecast is made under the assumption that the recent low recruitment will continue. The recruitment in 2010 in the forecast is assumed to be similar to recent low recruitments (2002–2009). The forecast indicates that the probability of SSB in 2010 being below Blim is 37% without any catches. The forecast is relatively insensitive to the allocation of catches to different seasons

The closure of the fishery for the last four years has led to an increase in the abundance of older anchovy. If recruitment persist to be low, the contribution of older fish to spawning becomes crucial.

In the past, a TAC was set independent of the state of the stock in the range of 30 000 t to 33 000 t, and this had limited impact in regulating catches in the fishery.

Recent developments in management have been moving towards an in-year monitoring regime, as recommended previously by ICES. The assessment of anchovy is based on the survey results in the spring and the catch data. Hence, the most up-to-date assessment can be obtained in June as done in this assessment. TACs may be set for the whole period July–June, as the only input data for the time being are available in spring.

Harvest control rules (HCR) for anchovy are currently under development outside ICES, to be implemented when the stock has recovered. The results of an ICES benchmark assessment planned for anchovy in September 2009 may be useful in the evaluation of proposed management measures. ICES notes that the criterion for accepting HCR as precautionary would include rules that imply a low risk of reducing the SSB to a level which may imply further reduction in recruitment. Supplementary measures (area closures, minimum landing size) may be considered in addition to TACs.

Surveys to estimate juvenile abundance in autumn have now been conducted for six years. ICES considers these surveys as a promising approach to providing the information necessary to revise the TAC at the beginning of the year. However, the series so far covers only a period where the recruitment has been low. It is not known how a medium or strong year class will show in the survey. Therefore, until at least one medium or strong year class has been both measured in the survey and confirmed in the subsequent assessment, ICES will not be in the position to advice on a revised TAC for the first half year on the basis of the survey.
Biological State and Trend
Abundance level: Increased risk


Spawning biomass in relation to precautionary limits Fishing mortality in relation to precautionary limits Fishing mortality in relation to highest yield Comment
Increased risk Not harvested Undefined Fishery closed since July 2005



Based on the most recent estimates of SSB, ICES classifies the stock as being at risk of reduced reproductive capacity. Although median SSB in 2009 is estimated to be above Blim, this estimate has a 47% probability of being below Blim. Low recruitment at age 1 since 2002 and almost complete recruitment failure of the 2004 year class are the primary causes of the low stock size. The recruitment at age 1 in 2009 is at the same level as last year but lower than in 2006 and 2007.
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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