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Herring - North Sea, Eastern Channel and Skagerrak, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Herring - North Sea, Eastern Channel and Skagerrak, 2008
Fact Sheet Citation  
Herring in Sub-area IV Division VIId and Division IIIa (autumn spawners)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Atlantic herring, fr - Hareng de l'Atlantique, es - Arenque del Atlántico, ru - Сельдь атлантическая
Geographic extent of Herring - North Sea, Eastern Channel and Skagerrak
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: Shared between nations

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

In EU waters, slippage and high grading of herring is now prohibited in the North Sea herring fishery (EC Council Reg No 43/2009) as long as the fish are above minimum landing size and quota is available. The consequences of new regulation are unknown but to thought have little impact on the catch estimates. In the Norwegian purse seine fisheries, slipping is permitted under conditions where the fish is assumed to be viable (likely to survive). This rule is currently under revision. High grading and discarding is not permitted.

Changes in fishing technology and fishing patterns.

There have been no major changes to fishing technology and fishing patterns of the fleets that target North Sea herring.

Impacts of the environment on the fish stock

North Sea herring has recently produced six poor year classes in a row, which has never been observed before at this SSB. Indications suggest that the 2008 year class has is slightly higher but still lies within the bounds of the recent series of poor year classes. The survival of the larvae has been poor (Payne et al., 2009). The specific reasons for this are not known. The trends in herring recruitment are similar to the warming of the water on the spawning grounds and changes in the hydrography. These changes may be linked to the AMO (Atlantic Multidecadal Oscillation), and they are also associated with changes in the zooplankton community. Further investigation of the causes of the poor recruitment will require targeted research projects.Scientific basis

Data and methods

The stock assessment and projections used data from the landings and from four survey time-series of North Sea herring. Each of these surveys targets a different life stage of the herring. The landings and catch-at-age data is collated from Subarea IV and Divisions VIId and IIIa. Some national catch estimates were corrected for unallocated and misreported catch.

Denmark and Norway provided information on bycatches of herring in the industrial fishery. These are the main countries conducting these fisheries.

Information from the fishing industry

Representatives from the pelagic industry after the ICES expert group express concern that for the last 2-3 years the fishermen’s observations of the abundance of juvenile herring in the Eastern, Central and Southern part of the North Sea were higher than anticipated given the results of the assessment. The working group has found underestimation of the 2007 year class and corrected for this in the current assessment, however, other year classes are still estimated at the same low level.

Uncertainties in assessment and forecast

ICES carried out a benchmark assessment of the North Sea autumn-spawning herring stock in 2006, checking the appropriate use of the survey indices and catch. The present assessment is an update of the bench mark assessment. Surveys show slightly divergent signals. The occurrence of misreported and unallocated catches leads to uncertainties in the assessment. The overall assessment gives a consistent basis for advice (Figure 6.4.16.4).

There is no evidence that discarding of herring is a major problem at present for the estimation of population dynamics or conservation of North Sea herring.

Comparison with previous assessment and advice

The assessment is consistent with the assessment of 2008. The new assessment has revised the size of the 2007 year class but it is still estimated as poor and comparable with the other recent year classes.

The basis advice is different from last year. Last year ICES advised to implement a new management plan, this year it advises to follow the new management plan.
Assessment
 
Overall Assessment Results


Figure 6.4.16.1 Herring in Subarea IV, Divisions VIId & IIIa (autumn spawners), stock summary. Fishing mortality is expressed as averages over ages 2–6 (dots) and 0–1 (line). Bpa (Btrigger in the previous Harvest control rule) and Blim, Fpa (2-6) and Fpa (0-1) are shown. Recruitment is expressed as one year olds (0 winter ring).


Figure 6.4.16.2 Herring in Subarea IV, Divisions VIId & IIIa (autumn spawners). Stock and recruitment, yield, and precautionary approach


Figure 6.4.16.3 North Sea herring. Agreed management plan for adult fishery (A-fleet, ages 2-6) including trigger biomass points (Blim and Btrigger) and Bpa. Black dots represent realised estimated fishing mortalities from 2002 until 2008. Fishing mortality in 2009 is estimated based on the agreed TACS for the A-fleet from the short term prediction


Figure 6.4.16.4-Herring in Subarea IV and Divisions IIIa and VIId (North Sea autumn spawners North Sea herring. Comparison of current assessment with previous assessments

Reference Point
 


  Type Value Technical basis
Precautionary approach Blim 800 000 t < 0.8 million t; poor recruitment has been experienced
  Bpa 1.3 million t B trigger in the previous harvest control rule
  Flim not defined  
  Fpa

F0-1 = 0.12

F2-6 = 0.25

Target Fs in the previous harvest control rule
Targets Fmt

F0-1 = 0.05

F2-6 = 0.25

If SSB >1.5 million tonnes, B trigger (based on simulations)
   

F0-1 = 0.05

F2-6 = 0.25 – (0.15*(1500000-SSB)/700000)

If SSB between 0.8 and 1.5 million tonnes (based on simulations)
   

F0-1 = 0.04

F2-6 = 0.10

If SSB <0.8 million t (based on simulations)
Precautionary reference points unchanged since 1999, target reference points since 2009.




Yield and spawning biomass per Recruit F-reference points (2009):
  Fishing Mort Ages 2-6 Yield/R SSB/R
average last 3 years 0.31 0.018 0.05
Fmax 0.47 0.013 0.024
F0.1 0.13 0.011 0.075
F35%SPR 0.16 0.012 0.065



HCR evaluation has shown than candidates for reference points which are consistent with high long-term yields and a low risk of depleting the productive potential of the stock are around the target values in the management plan.
Projection

Catch forecasts are presented below for different scenarios of sharing the catch amongst fleets, producing the total fishing mortality given in the table headings. The forecasts are based on an assumption of the fisheries in 2009, taking the TAC with an overshoot by the A-fleet of 13% corresponding to the overshoot seen in the last three years, and by-catches following the agreed management plan.

The seven scenarios presented below are based on an interpretation of the harvest control rule or other options and show the range of options for differing overall exploitation rates. The distribution of catches among the fleets is only illustrative, and other options with similar overall exploitation rates are possible:

  1. No fishing;
  2. Catches that are estimated lead to SSB>Bpa in 2011;
  3. A 15% decrease in A fleet in TAC between 2009 and 2010;
  4. The EU-Norway management plan with larger catches of approximately 40% for the C and D fleet
  5. The EU–Norway management plan;
  6. A roll over TAC from 2009 to 2010 of 171 kt for the A fleet;
  7. A 15% increase in A fleet in TAC between 2009 and 2010;


Since the current management plan only stipulates overall fishing mortalities for juveniles and adults, making fleet-wise predictions for four fleets that are more or less independent provides different options for 2010. The consequence of other combinations of catch options can be explored on request.


Outlook assuming a TAC constraint for fleet A in 2009 Basis: Intermediate year (2009) with catch constraint. R09 (ICA)=32832 million; R10-11=GM(YC 2001-2007)=21465 million

F

fleet A

F

fleet B

F

fleet C

F

fleet D

F0-1F2-6

Catch

fleet A

Catch

fleet B

Catch

Fleet C

Catch

fleet D

SSB 2009
0.1840.0210.0060.0040.040.189194.27.46.52.7971


Scientific Advice

Single-stock exploitation boundaries

ICES advises on the basis of the agreed EU–Norway management plan. Following the agreed management plan implies catches of 164 300 t for fleet A and 10 400 t for fleet B in 2010 in the North Sea.


Table 6.4.16.1 Herring caught in the North Sea (Subarea IV and Division VIId). Single stock exploitation boundaries (advice), management and catch/landings.
Year

ICES

Advice

Predicted catch

corresp.

to advice

Agreed

TAC1

Bycatch ceiling

Fleet B

ICES

Lndgs.4

IV, VIId

ICES Catch5

IV, VIId

ICES Catch

Autumn

spawners

              IIIa, IV, VIId
1987 TAC 610 600   625 625 792
1988 TAC 515 530   710 710 888
1989 TAC 514 514  

669

717 787
1990 TAC 403 415   523 578 646
1991 TAC 423 420   537 588 657
1992 TAC 406 430   518 572 716
1993 No increase in yield at F > 0.3 3401 430   495 540 671
1994 No increase in yield at F > 0.3 3461 440   463 498 571
1995 Long-term gains expected at lower F 4291 440   510 516 579
1996 50% reduction of agreed TAC2 1561 1563 44 207 233 275
1997 F = 0.2 1591 159 24 175 238 264
1998 F(adult) = 0.2, F(juv)< 0.1 2541 254 22 268 338 392
1999 F(adult) = 0.2, F(juv)< 0.1 2651 265 30 290 333 363
2000 F(adult) = 0.2, F(juv)< 0.1 2651 265 36 284 346 388
2001 F(adult) = 0.2, F(juv)< 0.1 See scenarios 265 36 296 323 363
2002 F(adult) = 0.2, F(juv)< 0.1 See scenarios 265 36 304 353 372
2003 F(adult) = 0.25, F(juv)=0.12 See scenarios 400 52 414 450 480
2004 F(adult) = 0.25, F(juv)=0.1 See scenarios 460 38 484 550 567
2005 F(adult) = 0.25, F(juv)=0.1 See scenarios 535 50 568 639 664
2006 F(adult) = 0.25, F(juv)=0.12 See scenarios 455 43 490 511 515
2007 Bring SSB above Bpa by 2008 See scenarios 341 32 361 388 407
2008 F(adult) = 0.17, F(juv)=0.08 (MP) See scenarios 201 19 228 245 258
2009 Adopt one of the new proposed HCRs See scenarios 171 16      
2010 F(adult) = 0.15, F(juv)=0.05 (MP) See scenarios          

Weights in ‘000 t.

1Catch in directed fishery in IV and VIId.

2Revision of advice given in 1995.

3Revised in June 1996, down from 263.

4 Landings are provided by the working group and do not in all cases correspond to official statistics.

5ICES catch includes unallocated and misreported landings, discards, and slipping.



Management
Management unit: Yes

Management Objectives

In November 2008 EU-Norway have agreed on an adjusted management plan (see annex 6.4.16 in the source of information) taking account of recent poor recruitment. ICES has evaluated this management plan (WKHMP ICES CM 2008 ACOM:27) and concluded that the plan is consistent with the precautionary approach.

Scenarios for prediction year (2010)
Table 6.4.16.2 - Herring caught in the North Sea (Subarea IV and Division VIId). Catch in tonnes by country, 1999–2008. These figures do not in all cases correspond to the official statistics and cannot be used for legal purposes. 1) Catches of Norwegian spring spawners removed (taken under a separate TAC). 2) Landings from the Thames estuary area are included in the North Sea catch figure for UK (England). 3) Caught in the whole North Sea, partly included in the catch figure for The Netherlands 4) These catches (including some local fjord-type Spring Spawners) are taken by Norway under a separate quota south of 62°N and are not included in the Norwegian North Sea catch figure for this area. 5) may include misreported catch from VIaN and discards. 6) Including any bycatches in the industrial fishery


Table 6.4.16.3 - Herring caught in the North Sea. Catch in tonnes in Division IVa West. These figures do not in all cases correspond to the official statistics and cannot be used for legal purposes. 1) Including any by-catches in the industrial fishery. 2) May include misreported catch from VIaN and discards. 3) Including 1057 t of local spring spawners


Table 6.4.16.4 - Herring caught in the North Sea. Catch in tonnes in Division IVa East. These figures do not in all cases correspond to the official statistics and cannot be used for legal purposes. 1) Including any by-catches in the industrial fishery. 2) Catches of Norwegian spring spawning herring removed (taken under a separate TAC). 3) Negative unallocated catches due to misreporting into other areas. 4) These catches (including some fjord-type spring spawners) are taken by Norway under a separate quota south of 62°N and are not included in the Norwegian North Sea catch figure for this area


Table 6.4.16.5 - Herring caught in the North Sea. Catch in tonnes in Division IVb. These figures do not in all cases correspond to the official statistics and cannot be used for legal purposes. 1) Including any by-catches in the industrial fishery. 2) Discards partly included in unallocated landings. 3) Negative unallocated catches due to misreporting from other areas. 4) May include discards. Negative unallocated due to misreporting into other areas


Table 6.4.16.6 - Herring caught in the North Sea. Catch in tonnes in Divisions IVc and VIId. These figures do not in all cases correspond to the official statistics and cannot be used for legal purposes. 1) Landings from the Thames estuary area are included in the North Sea catch figure for UK (England). 2) Discards partly included in unallocated landings. 3) May include misreported catch and discards. 4) Thames/Blackwater herring landings: 107 t, others included in the catch figure for The Netherlands.


Table 6.4.16.7 HERRING in Subarea IV, Division VIId and Division IIIa. Figures in thousand tonnes.(a bigger version can be seen in the source of information)


Table 6.4.16.8 Herring in Subarea IV, Divisions IIIa and VIId (autumn spawners). Summary of the assessment.
Year

Recruitment

Age 0*

(thousands)

TSB

(tonnes)

SSB

(tonnes)

Fbar

(2-6 wr)

Fbar

(0-1 wr)

Landings

(tonnes)

1960 12087837 3723796 1861453 0.339 0.141 696200
1961 1.09E+08 4343827 1643371 0.436 0.074 696700
1962 46275907 4385355 1103051 0.536 0.047 627800
1963 47657598 4611329 2172543 0.227 0.069 716000
1964 62784953 4783461 2018320 0.344 0.161 871200
1965 34894783 4332831 1438153 0.694 0.127 1168800
1966 27858148 3310426 1274731 0.62 0.103 895500
1967 40255855 2816512 921824 0.798 0.162 695500
1968 38698462 2520863 412347 1.336 0.168 717800
1969 21581503 1905376 424149 1.105 0.169 546700
1970 41072449 1921915 374690 1.106 0.152 563100
1971 32306362 1849388 266027 1.408 0.318 520100
1972 20858534 1549403 288267 0.697 0.318 497500
1973 10102036 1155880 233324 1.135 0.36 484000
1974 21688511 911745 161930 1.053 0.263 275100
1975 2814491 679921.7 81542 1.473 0.423 312800
1976 2720374 358115 77673 1.451 0.199 174800
1977 4326038 209911.7 47180 0.815 0.198 46000
1978 4594665 224320.4 64421 0.054 0.123 11000
1979 10600186 381521.6 106648 0.065 0.125 25100
1980 16716729 629858.8 130506 0.285 0.12 70764
1981 37860685 1158012 195088 0.353 0.384 174879
1982 64740217 1842378 277945 0.264 0.28 275079
1983 61794951 2717821 431973 0.338 0.326 387202
1984 53439842 2863511 678583 0.456 0.216 428631
1985 80893853 3460696 698559 0.644 0.234 613780
1986 97583821 3470897 678431 0.573 0.189 671488
1987 86180225 3934292 899264 0.553 0.267 792058
1988 42262187 3618637 1192606 0.539 0.353 887686
1989 39173461 3307320 1247533 0.547 0.281 787899
1990 35871987 2973566 1182522 0.443 0.256 645229
1991 33634923 2712273 978026 0.491 0.213 658008
1992 62138096 2433999 701221 0.584 0.342 716799
1993 50250988 2515706 470816 0.692 0.399 671397
1994 34500565 2022344 508453 0.709 0.236 568234
1995 41602863 1841589 460948 0.739 0.308 579371
1996 49747245 1623068 462153 0.402 0.165 275098
1997 28730419 1946579 560344 0.421 0.035 264313
1998 27373602 2066499 733708 0.486 0.088 391628
1999 67697220 2331906 857946 0.37 0.043 363163
2000 40678164 2858801 865448 0.362 0.062 388157
2001 90678376 3236723 1301315 0.294 0.051 374065
2002 30444152 3933140 1587054 0.244 0.04 394709
2003 19069558 3647278 1708980 0.245 0.063 482281
2004 23729100 3343288 1752878 0.298 0.062 587698
2005 16141706 2862232 1615686 0.366 0.075 663813
2006 27136239 2340941 1233800 0.349 0.072 514597
2007 17358063 2085122 952774 0.339 0.07 406482
2008 20044858 1868927 999336 0.236 0.049 257870
2009 32832169   971000**      

* Age 1 (0 winterrings (wr))

** Predicted value



Management Advice

Management considerations

A reduction in fishing mortality to close to the target fishing mortality is expected to be achieved in 2009 (Figure 6.4.16.1). The SSB is expected to increase slightly both in 2010 and further in 2011, indicating that the current management has the potential to reverse the decline in the stock and stabilize it above the present level. The 2008 year class is estimated to be within the range of recent low recruitments. ICES assumes that the recruitment will remain at the low level. Delay in implementing substantial reductions in catch by not following the management plan has resulted in the SSB being at greater risk of being below Blim and lower catches (Figure 6.4.16.3).

Landings of herring taken in the North Sea but reported from other areas such as Divisions IIa and IIIa and from Division VIaN have increased in 2008 compared to 2007. The total amount of catch in excess of the TAC in the human consumption fishery has increased as a proportion of the TAC to 17% (35 000 t).

Management of the autumn-spawning herring must be considered together with the Western Baltic Spring-Spawning herring. The options selected for the C- and D-fleets are compatible with the advised exploitation of Western Baltic Spring Spawners assuming a catch for 2010 of 39800 tonnes (see Section 6.4.7) and are 7.4 and 3.7 thousand tonnes of North Sea autumn spawning herring for C and D fleets respectively.

Downs herring

The sub-TAC for Divisions IVc and VIId was established for the conservation of the spawning aggregation of Downs herring. The Downs herring has returned to its pre-collapsed state and is now again a major component of the stock. It is probable that exploitation of Downs herring has been relatively high. In the absence of data to the contrary ICES proposes that a share of 11% of the total North Sea TAC (average share 1989–2002) would still be appropriate for Downs herring.

Management plan evaluations

The new management plan has been evaluated and the plan is consistent with the precautionary approach.

Impact of fisheries on the ecosystems

Herring is considered to have a major impact on most other fish stocks as prey and predator and is itself prey for seabirds and sea mammals. Herring spawning and nursery areas, being near the coasts, are particularly sensitive and vulnerable to anthropogenic influences. The most serious of these is the increasing extraction of marine sand and gravel and the development of wind farms on existing and historic spawning beds.

The human consumption fisheries for herring are considered relatively clean, with little bycatch of other fish and almost no disturbance to the seabed. The limited evidence from observer programmes suggest that discarding of herring is not wide-spread. Juvenile herring are bycaught in the industrial fisheries.
Biological State and Trend
Exploitation rate: Harvested sustainability
Abundance level: Increased risk


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
Increased risk Harvested sustainably Overfished Above target  



Based on the most recent estimates of SSB and fishing mortality, ICES classifies the stock as being at risk of having reduced reproductive capacity and harvested sustainably. The SSB in autumn 2008 was estimated at 1.0 million t, and is expected to remain below Bpa (1.3 million t) in 2009. F2-6 in 2008 was estimated at 0.24, above the management target F2-6 (for this state of the stock = 0.14). The year classes since 2002 are estimated to be among the weakest since the late 1970s.
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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