Français
Herring - Gulf of Riga, 2005
Marine Resource  Fact Sheet
SearchSavePrint
Stock status report
Herring - Gulf of Riga, 2005
Fact Sheet Citation  
Owned byInternational Council for the Exploration of the Sea (ICES)   more>>
Related observationsLocate in inventorydisplay tree map
 
Species:
Clupea harengus
Species thumbnail
Fao Names :  en - Atlantic herring, fr - Hareng de l'Atlantique, es - Arenque del Atlántico
Distribution of Herring - Gulf of Riga
 Map legend

Area Details Advanced search
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Sub-Regional
Considered a management unit: Yes
 
Table of Contents
Habitat and Biology - Water Area Overview - Geographical Distribution - Exploitation - Assessment -  Management - Biological State and Trend - Source of information - Bibliography
 
Habitat and Biology
Depth zone: Shelf    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


The Gulf of Riga is a separate semi-enclosed ecosystem of the Baltic Sea characterised by low salinity that restricts the occurrence of marine species. Therefore, herring is the dominant species in the Gulf, unlike the Baltic Proper. The bycatch of sprat in this fishery has recently been about 10% of the total catch. There is also a lack of abundant predators in the Gulf since cod is found in the Gulf of Riga only in the periods when the cod stock is very high (last time in the early 1980s).

The environment


The year-class strength of Gulf of Riga herring depends strongly on the severity of the winter. Recruitment predictions are based on average water temperature in April, when the spawning starts and the abundance of zooplankton in May, when the hatching of larvae begins. The period since the end of the 1980s, when the majority of winters have been mild, has been favourable for the reproduction of Gulf of Riga herring.
Assessment
 
Assessment Model
Assessment Model Entry
Data

Scientific basis


Data and methods


The assessment is based on catch data, a commercial cpue index, and an acoustic index. Recruitment predictions are based on two environmental indices.
Overall Assessment Results

Comparison with previous assessment and advice


The current assessment has revised the value of SSB in 2004 downwards by 9% and fishing mortality in 2004 upwards by 14%.
Graphs 
Graphs 
Graphs 
Graphs 
Graphs 
Graphs 

Landing table


Herring catches in the Gulf of Riga by country.
Landing table
Year Estonia Latvia Unallocated Total
  -   landings  
1991 7420 13481 - 20901
1992 9742 14204 - 23946
1993 9537 13554 3446 26537
1994 9636 14050 3512 27198
1995 16008 17016 3401 36425
1996 11788 17362 3473 32623
1997 15819 21116 4223 41158
1998 11313 16125 3225 30663
1999 10245 20511 3077 33833
2000 12514 21624 3244 37382
2001 14311 22775 3416 40502
2002 16962 22441 3366 42769
2003 19647 21780 3267 44694
2004 18218 20903 3136 42257
2005 11213 19741 2961 33915

Herring in the Gulf of Riga.
Stock summary
Year Recruitment SSB Landings Mean F
- Age 1 - - Ages 3-7
  thousands tonnes tonnes  
1977 943316 54524 24186 0.6902
1978 1076601 49359 16728 0.3751
1979 977120 46743 17142 0.4309
1980 1110553 46720 14998 0.3498
1981 909000 47232 16769 0.4524
1982 1690925 42776 12777 0.4196
1983 1253087 50902 15541 0.4675
1984 2049739 39946 15843 0.7058
1985 1235975 52247 15575 0.5370
1986 1038622 62517 16927 0.5071
1987 3605778 49094 12884 0.4243
1988 525759 89607 16791 0.5298
1989 1230387 57524 16783 0.3867
1990 3428267 69320 14931 0.2677
1991 3650100 77418 14791 0.3148
1992 4253070 96815 20000 0.3274
1993 3277176 112923 22200 0.2732
1994 2875114 119547 24300 0.2631
1995 3556283 113921 32656 0.3729
1996 4891918 104359 32584 0.3908
1997 1627463 106453 39843 0.4867
1998 2895800 85704 29443 0.4210
1999 2973446 90529 31403 0.3767
2000 2752461 92029 34069 0.3861
2001 6749079 87416 38785 0.4457
2002 2266018 115788 39701 0.3822
2003 7924983 99107 40803 0.4355
2004 1532340 111549 39115 0.4490
2005 4422505 96707 32225 0.3733
2006* 3213330 -    
Average 2664541 79170 24131 0.4221

* RCT3 estimate.
Reference Point
 
Reference points
Yield and spawning biomass per Recruit
F-reference points
Reference points
  Fish Mort Yield/R SSB/R
  Ages 3–7    
Average last 3 years 0.419 0.009 0.026
F max 0.835 0.010 0.014
F 0.1 0.264 0.009 0.036
F med 0.297 0.009 0.033


Technical basisReference points
Projection

Short term implications


Outlook for 2007


Basis: F(2006) = Fsq = 0.42; Landings(2006) = 39.5; SSB(2006) = 106.4.
Outlook for 2007
Rationale TAC
(2007) 		F
(2007) 		Basis SSB
(2007) 		SSB
(2008) 		%SSB change %TAC change
Zero catch 0 0.0 F=0 106.4 132.1 24% -100%
Status quo 35.4 0.42 F sq 98.7 89.7 -9% -12%
Precautionary limits 3.9 0.04 F pa * 0.1 105.6 127.2 20% -90%
9.6 0.10 F pa * 0.25 104.5 120.3 15% -76%
18.4 0.20 F pa * 0.5 102.6 109.6 7% -54%
26.0 0.30 F pa * 0.75 100.8 100.0 -1% -34%
31.1 0.36 F pa * 0.9 99.8 94.7 -5% -22%
34.0 0.40 F pa 99.0 91.3 -8% -15%
36.8 0.44 F pa * 1.1 98.3 88.1 -10% -8%
40.9 0.50 F pa * 1.25 97.3 83.5 -14% 2%

Weights in ‘000 t.
Shaded scenarios are not considered consistent with the Precautionary Approach.
Scientific Advice

Single stock exploitation boundaries


Exploitation boundaries in relation to precautionary limits


Fishing in 2006 below Fpa (= 0.4) corresponds to landings of at most 33 900 t in 2007.

Management considerations


The assessment is based on landings of the Gulf of Riga herring taken both in and outside the Gulf. The TAC is applied only to herring caught in the Gulf of Riga, which includes some small percentage of open-sea herring, but not to Gulf of Riga herring taken outside the Gulf of Riga. Fishing at Fpa (0.4) is expected to reduce the SSB slightly in the short term. However, SSB will remain well above Bpa.
Management
Considered a management unit: Yes

Management Objectives

There are no explicit management objectives for this stock.

Catch and TACS
Catch and TACSWeights in ‘000 t. * The possible catch of open-sea herring is not included. ** The possible catch of open-sea herring is included.
Biological State and Trend
 
State of the stock
Based on the most recent estimates of SSB and fishing mortality, ICES classifies the stock as having full reproductive capacity and as being harvested sustainably. Based on high recruitment, SSB increased in the beginning of the 1990s and has remained high thereafter.
Source of information
 

Report of the ICES Advisory Committee on Fishery Management, Advisory Committee on the Marine Environment and Advisory Committee on Ecosystems, 2006.
ICES Click to open.
Bibliography
 

Report of the Baltic Fisheries Assessment Working Group. Rostock, 18 – 27 April 2006, ICES CM 2006/ACFM:24.
powered by FIGIS   © FAO, 2000-2008
crawl