Fishery Resources Monitoring System

Français
Mackerel - Bay of Biscay and Portuguese waters, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Mackerel - Bay of Biscay and Portuguese waters, 2008
Fact Sheet Citation  
Mackerel in Divisions VIIIc and Ixa (Southern component)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Atlantic mackerel, fr - Maquereau commun, es - Caballa del Atlántico, ru - Скумбрия обыкновенная
Geographic extent of Mackerel - Bay of Biscay and Portuguese waters
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

Mackerel is mainly exploited in a directed fishery for human consumption. This fishery tends to target bigger fish and there is evidence that this causes discarding of smaller, less marketable fish.

In June 2009, an agreement was concluded between contracting parties to the Coastal States on mackerel banning highgrading, discarding, and slipping from pelagic fisheries targeting mackerel, horse mackerel, and herring beginning in January 2010.

Regulations and their effects

During 1998–2008, management aimed at attaining a fishing mortality for mackerel in the range of 0.15–0.2. The realized fishing mortality during this period ranged between 0.22 to 0.45. The current assessment shows reductions in fishing mortality and increases in biomass from 2003 onwards.

Prior to the late 1960s, spawning biomass of North Sea mackerel was estimated to be above 3 million tonnes. Due to overexploitation, recruitment has failed since 1969 leading to a marked decline in the stock size. The measures advised by ICES have been aimed at protecting the North Sea spawning component and promoting stock recovery. The North Sea spawning component has increased since 1999, but continued protection is needed as the abundance remains low.

The closure of the mackerel fishery in Divisions IVb,c and IIIa throughout the whole year is designed to protect the North Sea component in this area, and also protect juvenile Western mackerel which are numerous, particularly in Division IVb,c during the second half of the year. Unfortunately, the closure has resulted in increased discards of mackerel in the non-directed fisheries (especially horse mackerel fisheries) in these areas as vessels are currently permitted to take only 10% of their catch as mackerel bycatch. As estimates of mackerel bycatch are not available, the reported landings of mackerel in Divisions IIIa and IVb,c from 1997 onwards underestimate catches because they do not include discarded bycatch.

The advised fishery closure of Division IVa during the first half of the year is based on the perception that the Western mackerel enter the North Sea in July/August, and stay there until December before migrating back to their spawning areas. Updated observations in the late 1990s suggest that this return migration actually begins in mid- to late February. This is believed to result in large-scale misreporting from the northern part of the North Sea (Division IVa) to Division VIa. As a consequence, ICES recommended that the closure for Division IVa be extended to the 15th of February (This is incorrectly stated as 1 February in the 2002 ICES Advice). This was adopted for the 1999/2000 fishing season onwards. However, misreporting from Division IVa to VIa continues to occur.

Changes in fishing technology and fishing patterns

In recent years significant catches have been taken in Icelandic waters, an area where almost no catches have been previously reported. In 2008 and 2009, catches in this area constituted approximately 18% of the total catch.

In the southern part of the distribution area, Atlantic mackerel (Scomber scombrus) can be caught together with Spanish mackerel (Scomber colias). In recent years, catches of Spanish mackerel have increased. The catch in 2005 was the highest since 1982. Catches of both species are landed separately. ICES advice applies to Atlantic mackerel only.

Impacts of environment on the fish stock

Survey data and catch information suggest distributional changes of both juveniles and adult mackerel. This indicates an expansion of mackerel further west and less north compared to previous years, illustrating the interannual dynamics of a fast moving species. The distribution pattern coincided with considerably warmer surface waters in 2009 than in earlier years in both the western part of the Norwegian Sea and in the northern part of the Icelandic zone. Together with temperature, feeding opportunities seem to affect the distribution of the mackerel stock.

Other factors

Stock components: ICES currently uses the term “Mackerel in Northeast Atlantic” to define the mackerel present in the area extending from ICES Division IXa in the south to Division IIa in the north, including mackerel in the North Sea and Division IIIa. The spawning areas of mackerel are widely spread, and only the stock in the North Sea is sufficiently distinct to be clearly identified as a separate spawning component. Tagging experiments have demonstrated that after spawning, fish from Southern and Western areas migrate to feed in the Norwegian Sea and the North Sea during the second half of the year. In the North Sea they mix with the North Sea component. Since it is currently impossible to allocate catches to the stocks previously considered by ICES, for practical reasons all mackerel in the Northeast Atlantic are considered to comprise a single stock (i.e. the mackerel in the Northeast Atlantic stock). Catches cannot be allocated specifically to spawning area components on biological grounds but by convention, catches from the Southern and Western components are separated according to the areas in which these are taken.

To keep track of the development of spawning biomass in the different spawning areas, mackerel in the Northeast Atlantic stock are divided into three area components: the Western Spawning Component, the North Sea Spawning Component, and the Southern Spawning Component:


Mackerel in Northeast Atlantic
Distributed and fished in ICES Subareas and Divisions IIa, IIIa, IV, V, VI, VII, VIII, and IXa.
Spawning component Western Southern North Sea
Spawning Areas VI, VII, VIIIa,b,d,e. VIIIc, IXa. IV, IIIa.



The Western Component is defined as mackerel spawning in the western area (ICES Divisions and Subareas VI, VII, and VIII a,b,d,e). This component currently accounts for 76% of the entire Northeast Atlantic stock. Similarly, the Southern Component is defined as mackerel spawning in the southern area (ICES Divisions VIIIc and IXa). Although the North Sea component has been at an extremely low level since the early 1970s, ICES considers that the North Sea Component still exists as a discrete unit. This component spawns in the North Sea and Skagerrak (ICES Subarea IV and Division IIIaN). Current knowledge of the state of the spawning components is summarised below.

Western Component: The catches of this component were low in the 1960s, but increased to more than 800 000 t in 1993. The main catches are taken in directed fisheries by purse-seiners and mid-water trawlers. Large catches of the western component are taken in the northern North Sea and in the Norwegian Sea. The 1996 catch was reduced by about 200 000 t compared with 1995, because of a reduction in the TAC. The catches since 1998 have been stable. The SSB of the Western Component declined in the 1970s from above 3.0 million t to 2.2 million t in 1994, but increased to 2.7 million t in 1999. A separate assessment for this stock component is no longer required, as a recent extension of the time-series of mackerel in the Northeast Atlantic data now allows the estimation of the mean recruitment from 1972 onwards. Estimates of the spawning-stock biomass, derived from egg surveys, indicate a decrease of 14% between 1998 and 2001 and a 6% decrease from 2001 to the 2004 survey. The results from 2007 indicated a 5% increased from 2004 to 2007.

North Sea Component: Very large catches were taken in the 1960s in the purse-seine fishery, reaching a maximum of about 1 milliont in 1967. The component subsequently collapsed and catches declined to less than 100 000 t in the late 1970s. Catches during the last five years are assumed to be about 10 000 t. The 2002 and 2005 triennial egg surveys in the North Sea both indicate similar egg production, but in 2008 egg production decreased by about 40%.

Southern Component: Mackerel is a target species for the hand line fleet during the spawning season in Division VIIIc, during which about one-third of the total catches are taken. Mackerel are also taken as a bycatch in other fleets. The highest catches (87%) from the Southern Component are taken in the first half of the year, mainly from Division VIIIc, and consist of adult fish. In the second half of the year catches consist of juveniles and are mainly taken in Division IXa. Catches from the Southern Component increased from about 20 000 t in the early 1990s to 44 000 t in 1998, and were close to 50 000 t in 2002. Estimates of the spawning-stock biomass, derived from egg surveys, are highly variable, and give average estimates of around 16-20% of the combined mackerel in the Northeast Atlantic stock (1995–2007).
Assessment
 
Assessment Model
Methodology

Scientific basis

Data and methods

This assessment is based on catch numbers-at-age for the period 1972–2008 and triennial egg survey estimates of SSB from 1992 to 2007. In the past, estimates of total mortality have been similar to those obtained from tag-recapture studies.

Some sampling for discards has been carried out since 2000 and a formal requirement was initiated in the EU in 2002. Estimating proportions of catch discarded and slipped is problematic in pelagic fisheries due to high variability in discard and slipping practices. In some fleets no sampling for discards is carried out. Recently, information on these practices has been improving; discards from sampled fleets (Scotland, the Netherlands, and Germany) in 2008 amounted to 27000 tonnes.

Recruit surveys provide information on the distribution of young mackerel, but are subject to high variability and have not proved useful in estimating year-class strength.

Information from the fishing industry

The fishing industry has informed ICES that in all the EU fishing fleets targeting mackerel, large quantities of juvenile and adult mackerel continue to be seen on the fishing grounds, as reported last year. This is not confined to one area or to one member state’s fleet. In addition, the abundance of mackerel in the entire distribution area is creating major problems with unwanted bycatches for some fleets not targeting mackerel. Furthermore, the industry has observed that the distribution seems to have changed in a westerly direction, giving more catches of larger fish in the earlier part of the season than usual. Stakeholders are actively seeking mechanisms that would allow inclusion of fishing industry information into the assessment process and are involved in a number of pilot projects in this regard.

Uncertainties in assessment and forecast

Due to the shortage of fishery-independent data, the absence of age-disaggregated information for the spawning-stock index and the uncertainty in the magnitude of catches, SSB estimates are uncertain, but fishing mortality and the trend in SSB are better estimated.

The estimated catch for 2009 used in the forecast is uncertain due to additional catches in excess of the TAC that cannot be quantified precisely at present.

Some information on the level of discards is available and was included in the assessment, but the number of fleets sampled is not sufficient to capture the full scale of discarding.

Comparison with previous assessment and advice

The perception of the stock based on the assessment results is very similar to last year's assessment. The basis of the advice this year is the precautionary management plan given above. , Faroe Islands, and the EU agreed to the plan in 2008, but it has not been agreed to by all of the participants in the fishery. Previous advice was based on a management plan agreed by , Faroe Islands, and the EU in 1999.
Overall Assessment Results


Figure 9.4.2.1. Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Summary of stock assessment: landings, fishing mortality, recruitment, and SSB.


Figure 9.4.2.2. Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Stock - recruitment plot, yield per recruit analysis, and PA plot.


Figure 9.4.2.3. Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Comparison of current assessment with previous assessments (solid blue line – Limit reference points; dashed blue line – precautionary reference points; and green lines management plan biomass trigger and upper and low limits).

Table 9.4.2.5a.
Table 9.4.2.5b. Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Catches by country 1988-2008 (cont.) (data submitted by Working Group members).
Country 2002 2003 2004 2005 2006 2007 2008
Belgium 22 2 5 1 3 1 2
Denmark 34376 27900 25665 23212 24219 25223 26726
Estonia              
Faroe Islands 19768 14014 13029 9769 12067 13429 11289
France 21878 22906 20266 16338 14953 20038 15602
Germany, Fed. Rep. 26532 24061 23244 19040 16608 18221 15502
Germany, Dem. Rep.              
Guernsey         10    
Iceland 53 122   363 4222 36706 112286
Ireland 72172 67355 61102 45687 40664 49260 44759
Jersey       9 8 6 7
Latvia              
Lithuania         95 7  
Netherlands 33444 30424 27532 25127 24157 24234 19972
Norway 184291 163406 157364 119678 121993 131691 121524
Poland       570   978  
Portugal 2934 2749 2289 1509 2620 2605 2381
Romania              
Spain 50123 23762 34455 52753 54136 62946 64648
Sweden 5232 445 4437 3204 3209 3858 3664
United Kingdom 194045 183008 174730 152801 95815 133688 112149
USSR (Russia from 1990) 45811 40026 49489 40495 33580 35408 32728
Misreported 6009   31        
Unallocated 50543 59172 46596 13171 4954 12453 1069
Discards 23774 9481 10972 19760 17970 8615 26766
Total 771007 668833 651206 543487 471283 579367 611074

Table 9.4.2.6.
Table 9.4.2.7. Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Summary of stock assessment.
Year Recruitment TSB SSB Fbar Catchs
  Age 0     age 4–8  
  (Thousands) (Tonnes) (Tonnes)   (Tonnes)
1972 2107710       361262
1973 4740947       570719
1974 3972009       607473
1975 4898680       784329
1976 4921339       828434
1977 959498       620016
1978 3224330     0.193 736519
1979 5293791     0.256 842739
1980 5545867 3170793 2109885 0.248 734950
1981 7223223 3294253 2137584 0.231 754045
1982 2025972 3227927 2061195 0.224 716987
1983 1564509 3348280 2357237 0.214 672283
1984 7381492 3123975 2377858 0.224 641928
1985 3304438 3310145 2325294 0.219 614371
1986 3431405 3316289 2348414 0.232 602201
1987 5119691 3183050 2342935 0.218 654992
1988 3570179 3261221 2352917 0.240 680491
1989 4397057 3342866 2432299 0.181 585920
1990 3176776 3130777 2299116 0.182 626107
1991 3706513 3423846 2559251 0.225 675665
1992 4716451 3536234 2577894 0.254 760690
1993 5562702 3466635 2413766 0.318 824568
1994 4745812 3339450 2233526 0.355 819087
1995 4275449 3542342 2423915 0.345 756277
1996 4050038 3369042 2447523 0.239 563472
1997 3014543 3514795 2560826 0.249 573029
1998 3014644 3337419 2470494 0.290 666316
1999 3452126 3375918 2486482 0.301 640309
2000 1980116 3098108 2222260 0.352 738606
2001 5064315 2983811 2158363 0.397 737463
2002 8427720 2664323 1765975 0.443 772905
2003 3330106 2958967 1775602 0.427 669600
2004 4204636 2825813 1909235 0.376 650221
2005 5655568 3256519 2378330 0.267 543486
2006 4703184 3441403 2476318 0.220 472652
2007 2740833 3491284 2505033 0.252 579379
2008 3858779* 3324007 2491963 0.237 611063
2009 3858779*   2591221    
* Geometric mean of recruitment series (1972–2006).

Reference Point
 


  Type Value Technical basis
Precautionary approach Blim 1.67 million t Bloss
  Bpa 2.3 million t Trigger reference point used in the precautionary management plan given above
  Flim 0.42 Floss
  Fpa 0.23 Flim * 0.55 (CV 36%)
Targets

Ftarget

Btriggert

Between 0.20 and 0.22

> 2.2 million t

Precautionary management plan given above
unchanged since 2008


Yield and spawning biomass per Recruit. F-reference points (2009):
  Fish Mort Yield/R SSB/R
  Ages 4-8    
Average last 3 years 0.24 0.15 0.62
F0.1 0.17 0.14 0.75
Fmed 0.22 0.15 0.65



Fmax is not well defined.
Projection


Outlook for 2010. Basis: Catch(2009) = 830 (rounded from 832) (TAC plus discards plus 70 TAC overshoot plus 112 TAC set by Iceland plus 36 new unilateral Norway and Faroe Islands declared quota and minus 18 that the UK and Ireland have agreed not to fish); F(2009) = 0.31; R08 = GM 72–06 = 3859 million; SSB(2009) = 2591.
Rationale Catch (2010) F(2010 & 2011) Basis

SSB(2010)

Spawning time

SSB(2011)

Spawning time

Implied change in catch1 Implied change in TAC2
Zero catch 0 0 F=0 2651 3090 -100% -100%
Status quo 611 0.24 F 2008 2440 2406 -26% +1%
Roll over TAC 605 0.23 TAC 2008 2442 2413 -27% 0%
  572 0.22 F(management plan upper bound) 0.22 2454 2448 -31% -5%
  550 0.21 F(management plan mid point) 0.21 2462 2472 -34% -9%
  527 0.20 F(management plan lower bound) 0.20 2470 2496 -37% -13%
  726 0.29 +20% TAC (management plan upper bound) 2397 2285 -13% +20%
  484 0.18 -20% TAC (management plan lower bound) 2486 2543 -42% -20%
  996 0.42 +20% catch 2293 2012 +20% 65
  664 0.26 -20% catch 2420 2350 -20% 10

Weights in ‘000 t.

1Catches in 2010 relative to estimated catches in 2009

2 Catches in 2010 relative to TAC 2009

Scenarios in italics are not considered consistent with the management plan.



Scientific Advice

Single-stock exploitation boundaries

ICES advises that total catches in 2010 should be between 527 000 tonnes and 572 000 tonnes.

Exploitation boundaries in relation to existing management plans

The precautionary management plan described above for Northeast Atlantic mackerel (F between 0.20 and 0.22) implies catches between 527000t and 572000 t in 2010. The SSB is expected to remain stable in 2011 for a catch in this range.

Exploitation boundaries in relation to precautionary considerations

ICES advises that the existing measures to protect the North Sea spawning component remain in place. These are:

  • There should be no fishing for mackerel in Divisions IIIa and IVb,c at any time of the year;
  • There should be no fishing for mackerel in Division IVa during the period 15 February–31 July;
  • The 30 cm minimum landing size at present in force in Subarea IV should be maintained.



Table 9.4.2.1. Mackerel in the Northeast Atlantic. Single-stock exploitation boundaries (advice), management, and catch data for the combined area.
Year

ICES

Advice

Predicted catch corresp. to advice

Total Agreed

TAC3

Official

Landings5

Disc.1

slip

ICES

catch2,4

1987Given by stock component 44261611655
1988Given by stock component 61062236680
1989Given by stock component 5325767590
1990Given by stock component 56258016628
1991Given by stock component 61260931668
1992Given by stock component 70772925760
1993Given by stock component 76778418825
1994Given by stock component 8377945821
1995Given by stock component 6457298756
1996Significant reduction in F-45250911564
1997Significant reduction in F-47051719570
1998F between 0.15 and 0.24985496278667
1999F of 0.15 consistent with PA 437562585n/a640
2000F=0.17: Fpa6426126552738
2001F=0.17: Fpa6656706601737
2002F=0.17: Fpa69468368524773
2003F=0.17: Fpa5425836009670
2004F=0.17: Fpa54553258711650
2005F=0.15 to 0.20[320–420]42244720543
2006F=0.15 to 0.20[373–487]444318618473
2007F=0.15 to 0.20[390–509]5025588579
2008F=0.15 to 0.20[349–456]45842027611
2009F=0.15 to 0.20[443–578]6057   
2010harvest control rule[527-572]    

Weights in ‘000 t.

1Data on discards and slipping from only two fleets.

2Landings and discards from Divisions and Subareas IIa, IIIa, IV, V, VI, VII, VIII, and IXa.

3All areas except some catches in international waters in Subarea II.

4Catches updated in 2003 with revisions from SGDRAMA in 2002.

5 Updated with ICES FishStats data.

6 Incomplete.

7 Does not includes the unilateral Norway/Faroe Islands TAC first declared in 2009 and Icelandic TAC.



Table 9.4.2.2. Mackerel in the Northeast Atlantic. Single-stock exploitation boundaries (advice), management, and catch data for Western component.
Year

ICES

Advice

Predicted catch corresp. to advice

Agreed

TAC1

Disc.

slip

ICES

catch2,4

1987SSB = 1.5 mill. t; TAC38040511633
1988F = F0.1; TAC; closed area; landing size43057336656
1989Halt SSB decline; TAC3554957571
1990TAC; F = F0.148052516606
1991TAC; F = F0.150057531647
1992TAC for both 1992 and 199367067025742
1993TAC for both 1992 and 199367073018805
1994No long-term gains in increased F83138005796
199520% reduction in F5306088728
1996No separate advice-42211529
1997No separate advice-41619529
1998No separate advice-5148623
1999No separate advice-5200597
2000No separate advice-5732703
2001No separate advice-6301694
2002No separate advice-64224723
2003No separate advice-5489644
2004No separate advice-50011615
2005No separate advice-39720494
2006No separate advice-418517420
2007No separate advice-4728519
2008No separate advice-43127551
2009No separate advice-569  
2010No separate advice-   

Weights in ‘000 t.

1TAC for mackerel taken in all Divisions and Subareas VI, VII, VIIIa,b,d, Vb, IIa, IIIa, and IVa.

2Landings and discards of Western component; includes some catches of North Sea component.

3Catch at status quo F.

4Catches updated in 2003 with revisions from SGDRAMA in 2002.

5Revised from previous year (was 392).



Table 9.4.2.3. Mackerel in the Northeast Atlantic. Single-stock exploitation boundaries (advice), management, and catch data for North Sea component.
Year

ICES

Advice

Predicted catch corresp. to advice1

Agreed

TAC2

ICES

catch3

1987Lowest practical levelLPL553
1988Closed areas and seasons; min. landing size; bycatch regulationsLPL556
1989Closed areas and seasons; min. landing size; bycatch regulationsLPL49.27
1990Closed areas and seasons; min. landing size; bycatch regulationsLPL45.210
1991Closed areas and seasons; min. landing size; bycatch regulationsLPL65.5-4
1992Closed areas and seasons; min. landing size; bycatch regulationsLPL76.3-4
1993Maximum protection; closed areas and seasons; min landing sizeLPL83.1-4
1994Maximum protection; closed areas and seasons; min landing sizeLPL95.7-4
1995Maximum protection; closed areas and seasons; min landing sizeLPL76.3-4
1996Maximum protection; closed areas and seasons; min landing sizeLPL52.8-4
1997Maximum protection; closed areas and seasons; min landing sizeLPL52.8-4
1998Maximum protection; closed areas and seasons; min landing sizeLPL62.5-4
1999Maximum protection; closed areas and seasons; min landing sizeLPL62.5-4
2000Maximum protection; closed areas and seasons; min landing sizeLPL69.7-4
2001Maximum protection; closed areas and seasons; min landing sizeLPL71.4-4
2002Maximum protection; closed areas and seasons; min landing sizeLPL72.9-4
2003Maximum protection; closed areas and seasons; min landing sizeLPL62.5-4
2004Maximum protection; closed areas and seasons; min landing sizeLPL57.7-4
2005Maximum protection; closed areas and seasons; min landing sizeLPL44.9-4
2006Maximum protection; closed areas and seasons; min landing sizeLPL47.1-4
2007Maximum protection; closed areas and seasons; min landing sizeLPL53.1-4
2008Maximum protection; closed areas and seasons; min landing sizeLPL48.6-4
2009Maximum protection; closed areas and seasons; min landing sizeLPL62-4
2010Maximum protection; closed areas and seasons; min landing sizeLPL  

Weights in ‘000 t.

1Subarea IV and Division IIIa.

2TAC for Subarea IV, Divisions IIIa, IIIb,c,d (EU zone), and Division IIa (EU zone).

3Estimated landings of North Sea component.

4No information.

LPL = Lowest Practical Level.



Table 9.4.2.4. Mackerel in the Northeast Atlantic. Single-stock exploitation boundaries (advice), management, and catch data for Southern component.
Year

ICES

Advice

Predicted catch corresp. to advice

Agreed

TAC1

ICES

Catch2

1987Reduce juvenile exploitation-36.5722
1988Reduce juvenile exploitation-36.5725
1989No advice-36.5718
1990Reduce juvenile exploitation-36.5721
1991Reduce juvenile exploitation-36.5721
1992No advice-36.5718
1993No advice-36.5720
1994No advice-36.5725
1995No advice-36.5728
1996No separate advice-30.0034
1997No separate advice-30.0041
1998No separate advice-35.0044
1999No separate advice-35.0044
2000No separate advice-39.2036
2001No separate advice-40.1843
2002No separate advice-41.1050
2003No separate advice-35.0026
2004No separate advice-32.3135
2005No separate advice-24.8750
2006No separate advice-26.1853
2007No separate advice-29.6163
2008No separate advice-27.0160
2009No separate advice-35.83 
2010No separate advice   

Weights in ‘000 t.

1Division VIIIc, Subareas IX and X, and CECAF Division 34.1.1 (EU waters only).

2Catches updated in 2003 with revisions from SGDRAMA in 2002.



Management
Management unit: Yes

Management Objectives

ICES evaluated the following management plan for mackerel in the Northeast Atlantic:

  1. For the purpose of this long-term management plan, “SSB” means the estimate according to ICES of the spawning stock biomass at spawning time in the year in which the TAC applies, taking account of the expected catch.
  2. When the SSB is above 2 200 000 tonnes, the TAC shall be fixed according to the expected landings, as advised by ICES, on fishing the stock consistent with a fishing mortality rate in the range of 0.20 to 0.22 for appropriate age groups as defined by ICES.
  3. When the SSB is lower than 2 200 000 tonnes, the TAC shall be fixed according to the expected landings as advised by ICES, on fishing the stock at a fishing mortality rate determined by the following:


Fishing mortality F = 0.22* SSB/2 200 000

  1. Notwithstanding paragraph 2, the TAC shall not be changed by more than 20% from one year to the next, including from 2009 to 2010.
  2. In the event that the ICES estimate of SSB is less than 1 670 000 tonnes, the Parties shall decide on a TAC which is less than that arising from the application of paragraphs 2 to 4.
  3. The Parties may decide on a TAC that is lower than that determined by paragraphs 2 to 4.
  4. The Parties shall, as appropriate, review and revise these management measures and strategies on the basis of any new advice provided by ICES.


ICES concluded that the plan is precautionary under the assumption that the TAC equals the total removals from the stock. The plan was agreed by Norway, Faroe Islands and the EU in October 2008.
Management Advice

Management considerations

Catches in 2007 and 2008 have been considerably in excess of the ICES’ advice. The absence of effective international agreements on the exploitation of the stock (between all nations involved in the fishery) is a cause of concern and prevents control of the exploitation rate of the stock. According to the short-term forecast, the total estimated catch in 2009 results in an estimated fishing mortality of 0.31, which is above that stipulated in the management plan (it should be noted that this F would be lower without the significant additional catches in excess of the TAC). The 2010 TAC advice given above should apply to all areas fished.

The spawning stock biomass (SSB) has increased from a low of 1.8 million tonnes in 2002 to around 2.5 million tonnes in 2008, a level similar to that seen in the 1990s. Figure 9.4.2.1. indicates the current estimated stock level and recent stock development.

Available information indicates that the distribution of the spawning area and feeding areas of mackerel have expanded in recent years. Mackerel has been commercially fished in areas where it was previously not fished, particularly in the Icelandic EEZ.

An evaluation of unaccounted mortality in the mackerel fishery (Simmonds, 2007) suggested that both biomass and removals were significantly greater than those estimated using the standard assessment model. These analyses also suggested that the historic estimates of fishing mortality provided by the standard assessment are not affected by unaccounted mortality. These conclusions need further investigation. The results from the stock assessment provide the best estimates of biomass for mackerel in the Northeast Atlantic.

Management plan evaluations

In June 2008 ICES provided advice in response to a European Commission (EC) request on evaluation of management plan for mackerel in the Northeast Atlantic (Section 9.3.2.1 ICES, 2008). A number of precautionary harvest rules were presented to stakeholders, for both medium-term expectations and short term catch options. A management plan based on these options was agreed in October 2008.
Biological State and Trend
Exploitation rate: Increased risk
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 target fishing mortality

Comment

Full reproductive capacity Increased risk Overfished Above target  



Based on the most recent estimate of SSB (in 2009), ICES classifies this stock as having full reproductive capacity. Based on the most recent estimates of fishing mortality (in 2008), ICES classifies the stock as being harvested at increased risk.

Fishing mortality in 2008 is estimated to be just above Fpa. SSB has increased by 47% since 2002 and is currently estimated to be above Bpa. The 2002 year class is the highest on record. Subsequent year classes are estimated to be about average. There is insufficient information to confirm the sizes of the 2007 and 2008 year classes.
Source of information
 
ICES. 2009. Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
powered by FIGIS  © FAO, 2014
Powered by FIGIS
crawl