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Fish investigations in the Barents Sea Winter 2022

Forord

Annual catch quotas and other regulations of the Barents Sea fisheries are set through negotiations between Norway and Russia. Assessment of the state of the stocks and quota advice are based on survey results and international landings statistics. The results from the demersal fish winter surveys in the Barents Sea are an important source of information for the annual stock assessment.

The development of the survey started in the early 1970s and focused on acoustic measurements of cod and haddock. Since 1981 it has been designed to produce both acoustic and swept area estimates of fish abundance. Some development has taken place since then, both in area coverage and in methodology. The development is described in detail by Jakobsen et al . (1997), Johannesen et al . (2009) and in Appendix 2, and the current survey design and methods for survey index calculation are presented in Appendix 1. At present the survey provides the main data input for several ongoing projects at the Institute of Marine Research, Bergen:

  • monitoring abundance of the Barents Sea demersal fish stocks

  • mapping fish distribution in relation to climate and prey abundance

  • monitoring food consumption and growth

  • estimating predation mortality caused by cod

This report presents the main results from the surveys in January-March 2022. The surveys were performed with the Norwegian research vessels “Helmer Hanssen” and “Johan Hjort”, and the Russian research vessel “Vilnyus”. Annual survey reports since 1981 are listed in Appendix 4, and names of scientific participants in 2022 are given in Appendix 3.

1 - Survey operation

Table 1.1 presents the vessels participating in the survey in 2022 and IMR trawl station series numbers, and Figure 1.1 shows survey tracks, trawl stations and ice cover.

  Period Series no.
Johan Hjort 27.01-18.03 70001-70216
Helmer Hanssen 18.01-16.02 70301-70457
Vilnyus 21.01-22.02 70501-70645
Table 1. 1. Vessel participation by period and trawl station series numbers by vessel for the winter survey in 2022.

 

Survey tracks and all trawl stations in the winter survey 2022. Data source for the ice cover: https://cryo.met.no/archive/ice-service/icecharts/quicklooks/2022/ (18.01.22, the first day of the survey).
Figure 1.1.Survey tracks and all trawl stations in the winter survey 2022. Data source for the ice cover: https://cryo.met.no/archive/ice-service/icecharts/quicklooks/2022/ (18.01.22, the first day of the survey).

 

Main area Trawl type  
 
A B1 B2 P 51 1 3
B B1 B2 P 36 - -
C B1 B2 P 18 - -
D B1 B2 P 132 1 3
D' B1 B2 P 61 - 1
E B1 B2 P 34 1 5
S B1 B2 P 72 - 3
Inside standard strata system B1 B2 P 404 3 15
N B1 B2 P 69 - 1
     
Outside strata system B1 21
  B2 P - -
Total B1+B2 P 497 16
Table 1.2. Number of trawl stations by main area in the Barents Sea winter 2022. B1= swept area bottom trawl (quality=1 and condition<3), B2 =other bottom trawl, P=pelagic trawl, N=trawl stations in new strata. Refer to Figure 1.1. or Appendix 1 for a map of the main areas.

The coverage of the most northern and most eastern strata differs from year to year. The areas of these strata are therefore calculated according to the coverage each year. Table 1.3 gives the area covered by the survey every year since 1981. In that table “Extrapolated area” reflects the size of areas where some kind of extrapolations/adjustments have been made to take account of incomplete coverage (see also section 3.1). Table 1.4 summarizes the degree of coverage and main reasons for incomplete coverage in the whole period.

  Main Area     Extra- polated area
Year A B C D D' E S N Total excluding N excluding
1981-92 23299 8372 5348 51116 - - -   88135  
1993 23929 8372 5348 51186 23152 8965 16690   137642  
1994 27180 9854 5165 53394 36543 11417 17557   161110  
1995 26797 9854 5165 53394 58605 13304 24783   191904  
1996 26182 9854 5165 53394 54047 5738 11809   166190  
19971 27785 9854 5165 23964 2670 0 18932   88371 56200
19981 27785 9854 5165 23964 5911 3829 23931   100440 51100
1999 27785 9854 5165 43230 8031 5742 18737   118545  
2000 27173 9854 5165 52314 29438 14207 25053   163204  
2001 26609 9854 5165 53394 29694 15777 24157   164652  
2002 26594 9854 5165 53394 21914 15757 24689   157369  
2003 26621 9897 5165 52072 23947 6259 23400   147361  
2004 27785 9854 5165 53394 42731 4739 20760   164428  
2005 27785 9854 5165 53394 39104 19931 24648   179883  
20062 27785 9854 5165 53394 35302 13872 24691   170064 18100
20071 27785 9854 5165 23911 8498 20822 27858   123894 56700
2008 27785 9854 5165 53394 23792 18873 26313   165176  
2009 27785 9854 5165 53394 31978 15739 27858   171774  
2010 27785 9854 5165 53394 17882 18562 27858   160501  
2011 27785 9854 5165 53394 33432 16835 27858   174324  
20122 27785 9854 5165 53394 9917 17289 27858   151263 16700
2013 27785 9854 5165 53394 58183 21118 27858   203358  
20143 27785 9854 5165 53394 54800 29897 27858 58048 208754  
2015 27785 9854 5165 53394 45449 26541 27858 47263 196047  
2016 27785 9854 5165 53526 29266 20342 27630 54387 173568  
20172 27785 9854 5165 45493 12223 18524 27858 38786 146903 37460
2018 27785 9854 5165 53394 45193 23095 27630 44186 192117  
2019 27785 9854 5165 53394 56452 26788 27630 34035 207121  
20202 27785 9854 5165 53394 47002 11475 26881 21614 181557 25148
20212 27785 9854 5165 52848 33050 26897 27630 48777 183230 10933
2022 27785 9854 5165 53395 44972 26897 26095 27630 216297 194163
Table 1.3. Area (NM2) covered in the bottom trawl surveys in the Barents Sea winter 1981-2022, 1994-2022 are StoX estimates.

1 Russian EEZ not covered

2 Russian EEZ not completely covered (Strata 7 and 13 in 2006, Area D’ in 2012, strata 7, 13, 15, 7 and 20 in 2017, strata 17, 19, and 20 in 2020, and strata 16, 19, and 20 in 2021).

3 Additional northern areas (N) covered from this year.

Year Coverage Comments
1981-1992 ABCD  
1993-1996 ABCDD’ES  
1997 Norwegian EEZ, S Not allowed access to Russian EEZ
1998 Norwegian EEZ, S, minor part of Russian EEZ Not allowed access to most of Russian EEZ
1999 ABCDD’ES Partly limited coverage due to westerly ice extension
2000 ABCDD’ES Russian participation starts
2001-2005 ABCDD’ES Russian vessel covered where Norwegians had no access
2006 ABCDD’ES No Russian vessel, not allowed access to Murman coast
2007 Norwegian EEZ, S No Russian vessel, not allowed access to Russian EEZ
2008 ABCDD’ES Russian vessel covered where Norwegians had no access
2009 ABCDD’ES Reduced Norwegian coverage of Russian EEZ due to catch handling
2010 ABCDD’ES Reduced Norwegian coverage of Russian EEZ due to bad weather
2011 ABCDD’ES Russian vessel covered where Norwegians had no access
2012 ABCDD’ES No Norwegian coverage of Russian EEZ due to vessel problems
2013 ABCDD’ES No Norwegian coverage of Russian EEZ due to vessel shortage
2014 ABCDD’ESN Strata 24-26 (N) covered for the first time
2015 ABCDD’ESN Slightly reduced/more open coverage due to bad weather
2016 ABCDD’ESN No access to Russian EEZ, Russian vessel covered most of Russian EEZ
2017 ABCDD’ESN No Russian vessel, not allowed access to southwestern Russian EEZ
2018 ABCDD’ESN Russian vessel covered where Norwegians had no access
2019 ABCDD’ESN Russian vessel covered where Norwegians had no access
2020 ABCDD’ESN Reduced coverage of D’, E, and N due to bad weather, reduced survey time (medical emergency), and ice-cover
2021 ABCDD’ESN Reduced coverage of D’ and E due to ice cover and time constraints, and of area N due to ice cover.
2022 ABCDD’ESN Reduced coverage of D’ and E due to ice cover and time constraints, and of area N due to ice cover.
Table 1.4. Barents Sea winter surveys 1981-2022. Main Areas covered, and comments on incomplete coverage.

2 - Length and age material

Individual lengths are collected from all target species, while otoliths for age determination are taken from cod, haddock, and capelin. For cod and haddock, the otolith readings are key for splitting the survey indices by age.

For both the bottom trawl and acoustic estimates, cod with all otolith types (coastal cod included) are included in the estimations. Coastal cod is usually well under 5% of the total.

Table 2.1 gives an account of the sampled length- and age material from bottom hauls and pelagic hauls from 1994 onwards.

      Cod Haddock Golden redfish Beaked redfish Greenland halibut Blue whiting Capelin Polar cod
  Year   L A L A L L L L L A L
  1994   57290 3400 40608 1808 3157 12389 525      
  1995   66264 3547 37775 1692 3785 9622 583      
  1996   61559 3304 34497 1416 2510 10206 587      
  1997   35381 2381 30054 1003 5429 10997 675      
  1998   39044 2843 12512 859 1739 9664 649      
  1999   22971 2321 12752 926 1266 6677 397      
  2000   31543 2871 25881 1426 1161 8739 546   9172 1860 3702
  2001   36789 2998 30921 1657 1173 7323 499   8079 2402 5955
  2002   45399 3730 58464 2057 1143 6660 688   10643 2387 7283
  2003   59573 2857 54838 1883 1102 4654 657   10390 1742 2510
  2004   40851 3175 51705 1874 1438 5507 459   11633 1994 6080
  2005   33582 3216 67921 2060 835 5166 832   12482 1892 6052
  2006   19319 2683 23611 1899 728 3356 962   6851 2232 1362
  2007   16556 2954 26610 2023 798 4544 973 4657 5475 1186 203
  2008   26844 3809 50195 2490 897 8568 1020 1350 13772 886 3166
  2009   22528 3486 40872 2433 455 9205 807 891 7636 776 617
  2010   30209 4085 35881 2367 429 8564 984 626 12337 1189 551
  2011   26913 3959 29180 2260 286 6885 607 105 11073 829 1492
  2012   17139 3020 33524 1854 574 5721 354 2441 11047 1256 601
  2013   14525 2451 19142 1671 479 6087 263 1091 15962 1591 3517
  2014   22624 4501 35940 2586 563 9310 444 1846 32811 3647 6879
  2015   25401 3795 18483 2038 395 8933 541 1991 15578 300 408
  2016   16636 3368 25423 2067 614 8668 425 2396 11423 150 681
  2017   12402 2851 15689 1955 576 8898 448 4799 5140 671 578
  2018   42462 5178 43294 3307 1211 11500 548 1443 16219 788 876
  2019   16217 5260 15967 3072 761 8981 413 886 13771 821 748
  2020   19971 3770 11047 1641 1040 11853 711 866 16801 745 1569
  2021   13714 4020 15253 1950 810 11292 1076 1722 16179 1377 5567
  2022   20294 4160 25161 2288 1176 9826 945 1520 18371 2072 4115
Table 2.1. Number of fish measured for length (L) and age (A) in the Barents Sea winter survey 1994-2022.

Table 2.2. shows the number of age readings per age for cod from 1994 onwards, while table 2.3 shows the same for haddock. The number of age samples for fish age 10+ increased in the second half of the time series, reflecting changing age composition in the stocks.

Age/Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1994 283 354 392 652 571 363 124 54 37 16 19 3 2 - - - - - - -
1995 409 360 461 528 714 532 268 47 16 13 8 6 - - - - - - - -
1996 304 564 359 400 462 584 384 108 23 8 6 5 3 1 - - - - - -
1997 257 322 321 224 264 310 310 108 27 5 2 - - - - - - - - -
1998 331 311 445 425 220 242 257 193 39 6 3 - 1 - 2 - - - - -
1999 250 323 365 450 334 185 159 110 38 5 1 1 1 - - - - - - -
2000 256 365 470 491 578 340 119 66 50 12 4 2 1 - - - - - - -
2001 437 259 440 544 513 484 201 44 19 13 3 - - - 1 - - - - -
2002 162 650 478 661 607 506 345 90 16 7 3 - - - 1 - - - - -
2003 246 108 545 391 434 456 304 175 48 7 3 - 2 2 - - - - - -
2004 311 493 260 599 368 407 387 254 87 17 6 1 1 - - - - - - -
2005 341 386 619 309 565 306 388 196 56 21 3 2 4 1 - - - - - -
2006 291 364 423 521 234 430 194 162 68 18 6 3 - - - - - - - -
2007 295 258 474 358 453 205 369 159 95 22 10 6 1 - - - - - - -
2008 169 366 676 866 471 532 246 300 72 17 2 1 1 - - - - - - -
2009 319 276 445 635 695 420 292 124 120 24 9 2 1 - - - - - - -
2010 429 369 292 489 571 745 371 247 93 64 25 2 2 3 - - 1 - - -
2011 373 526 484 319 436 621 677 226 76 34 14 7 4 2 1 - - - - -
2012 275 214 319 330 198 303 504 415 100 47 25 10 9 2 1 1 - - - -
2013 149 251 232 330 296 188 282 426 215 38 20 8 5 1 1 - - - - -
2014 414 301 571 387 415 341 186 368 308 89 18 12 4 1 2 1 - - - -
2015 479 413 369 589 396 457 290 173 267 176 51 11 3 2 1 - - - - -
2016 235 529 405 484 678 437 418 323 164 178 86 20 15 3 3 1 1 - - -
2017 296 248 449 299 323 494 274 191 110 44 37 33 9 7 1 1 - - - -
2018 508 762 592 901 438 491 673 338 186 91 45 51 23 4 4 3 1 - - -
2019 465 632 892 651 839 435 356 508 149 66 17 10 6 8 2 1 - - - -
2020 265 523 755 830 585 673 432 305 310 88 41 11 16 10 10 7 - - - -
2021 270 235 537 630 683 503 445 226 145 103 32 12 6 1 6 3 - - - 1
2022 709 340 293 450 550 530 460 378 128 53 28 17 7 - 7 1 1 3 1 -
Table 2.2. Number of age samples from cod by age in the Barents Sea winter survey 1994-2022. Year-age combinations with < five aged individuals are highlighted in yellow. Abundance indices are still presented for ages with < five age samples but note the uncertainty level (c. f. tables 5.4 and 5.8). Biological parameters by age are presented for ages with a minimum of three age readings (c. f. tables 5.10-5.13).
Age/Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
1994 212 192 250 432 219 40 4 5 8 5 13 1 - - - - - -
1995 289 177 131 241 543 156 15 1 2 1 - 5 1 - - - - -
1996 225 236 155 106 228 343 52 9 - 1 - 2 1 - - - - -
1997 169 62 147 86 44 113 163 19 4 - - - 2 1 - - - -
1998 151 178 68 147 74 38 73 112 12 1 1 - - - 2 1 - -
1999 251 112 238 81 98 44 19 23 24 1 - 1 - - - - - -
2000 327 321 138 344 64 72 16 3 20 9 2 1 1 - - - - -
2001 388 339 430 99 315 26 23 3 3 3 8 1 2 - - 1 - -
2002 445 354 382 450 84 123 19 7 1 2 5 3 2 - - - - -
2003 376 234 154 268 298 42 32 5 3 3 3 1 1 - - - - -
2004 303 464 254 232 277 251 50 22 7 4 3 1 2 3 - - - -
2005 487 263 437 247 189 284 125 4 4 1 - - - - - - - -
2006 458 516 141 356 166 108 104 45 4 2 - 2 - - 1 1 - -
2007 422 404 372 116 257 107 51 34 15 4 2 - - - 1 - - -
2008 317 525 584 470 168 237 46 23 8 1 2 1 - - - - - -
2009 298 318 562 488 473 114 78 13 2 5 - 1 - - - - - -
2010 448 190 272 519 462 294 41 19 8 7 2 2 - - - - - -
2011 337 394 123 205 494 440 159 15 3 - - 2 1 - - - - -
2012 355 112 338 58 116 408 291 73 4 6 1 3 - - - - - -
2013 176 377 134 328 56 75 286 204 35 3 - - - - - - - -
2014 449 116 455 98 202 57 96 202 90 11 4 - - 1 - - - -
2015 429 371 88 524 81 160 43 110 123 55 6 3 1 - - - - -
2016 430 282 430 99 452 88 126 87 175 129 39 6 - 2 2 1 - -
2017 449 385 250 294 43 236 54 62 21 68 48 26 3 - - - - -
2018 704 696 596 372 424 62 160 45 44 35 56 48 19 3 - - - -
2019 644 630 679 486 211 187 39 46 14 24 7 12 8 3 - 1 - 1
2020 219 359 498 622 339 141 80 22 16 10 8 13 15 10 1 - - -
2021 439 68 244 373 501 172 51 19 5 5 4 3 6 2 - 1 - -
2022 618 301 68 243 305 437 99 16 4 4 6 - - 2 - - - -
Table 2.3 . Number of age samples from haddock by age in the Barents Sea winter survey 1994-2022. Year-age combinations with < five aged individuals are highlighted in yellow. Abundance indices are still presented for ages with < five age samples but note the uncertainty level (c. f. tables 6.4 and 6.8). Biological parameters by age are presented for ages with a minimum of three age readings (c. f. tables 6.10-6.13).

3 - Survey index calculation

Details on the calculation of survey indices, including StoX settings for different species are found in Appendix 1.

In 2022, the swept area and acoustic 1 estimation in StoX was based on the following biotic and acoustic snapshot files (versioned trawl and acoustic data):  

Cod and haddock   
biotic_cruiseNumber_0155_2022_UFJN_VILN_Vilnyus_2022-06-03T22.02.08.787Z    
biotic_cruiseNumber_2022204_Johan+Hjort_2022-03-28T22.02.52.009Z   
biotic_cruiseNumber_2022840_Helmer+Hanssen_2022-03-28T22.01.21.854Z    
echosounder_cruiseNumber_0155_2022_UFJN_VILN_Vilnyus_2022-08-01T22.00.00.044Z   
echosounder_cruiseNumber_2022204_Johan+Hjort_2022-03-18T23.00.12.395Z   
echosounder_cruiseNumber_2022840_Helmer+Hanssen_2022-03-17T23.00.00.935Z   
Redfish (three species)   
biotic_cruiseNumber_2022204_Johan+Hjort_2022-03-23T23.02.14.225Z  
biotic_cruiseNumber_2022840_Helmer+Hanssen_2022-03-23T23.01.02.197Z 
biotic_cruiseNumber_0155_2022_UFJN_VILN_Vilnyus_2022-06-07T22.02.26.378Z 
Greenland halibut 
biotic_cruiseNumber_0155_2022_UFJN_VILN_Vilnyus_2022-06-07T22.02.26.378Z  
biotic_cruiseNumber_2022204_Johan+Hjort_2022-03-23T23.02.14.225Z  
biotic_cruiseNumber_2022840_Helmer+Hanssen_2022-03-23T.01.02.197Z  
Blue whiting 
biotic_cruiseNumber_0155_2022_UFJN_VILN_Vilnyus_2022-06-07T22.02.26.378Z.xml 
biotic_cruiseNumber_2022204_Johan+Hjort_2022-08-15T22.01.45.892Z.xml  
biotic_cruiseNumber_2022840_Helmer+Hanssen_2022-08-18T22.02.26.845Z.xml  
Table 3.1 : Snapshot files used in the 2022 swept area and acoustic estimation, by species.

1 Acoustic estimation is done for cod and haddock only. The biotic files are used in the acoustic StoX projects to split the acoustic backscatter by age.

3.1 - Raising of indices

In 1997, 1998 and 2007 only the Norwegian exclusive economic zone (EEZ) and parts of the Svalbard area (S) was covered. The swept-area indices for cod, haddock, golden redfish, beaked redfish and Greenland halibut have therefore been raised to also represent the Russian exclusive economic zone (EEZ) (Mehl et al . 2016).

In 2006, there was not complete coverage in the southeast due to restrictions. The observations in the partially covered strata 7 were extrapolated to the full strata, and the observations in the partially covered strata 13 were extrapolated to the same area as covered in 2005.

In 2012 the coverage was incomplete in the eastern areas, and the cod and haddock swept area estimates within the covered area were raised by the “index ratio by age” observed for the same area in 2008-2011 (ICES 2012). The scaling factor (“index ratio”) for estimating adjusted total from <Total – area D’> was the average ratio by age for Total/(Total – area D’) in the years 2008-2011 (Aglen et al. 2012).

In 2017, the Norwegian vessel was not allowed to operate south of 70º 10’ N and west of 41º 00 º E, and no Russian vessel participated in the survey. Only a small part of strata 7 was covered, and strata 13, 15, 17 and 20 were not covered. The cod, haddock, Greenland halibut and beaked redfish swept area estimates and cod and haddock acoustic estimates within the covered area were raised following the same procedure as for 2012. The scaling factor for estimating adjusted total from <Total –strata 7 > was the average ratio by age for Total/(Total – (strata 7+13+15+17+20)) swept area indices in the years 2014-2016.

In 2020, coverage was incomplete in strata 17, 19, and 20, and the cod and haddock acoustic and swept area estimates were raised by the “index ratio by age” observed for these strata in 2018-2019. The scaling factor for estimating adjusted total from <Total – strata 17, 19 and 20> was the average ratio by age for Total/(Total – (strata 17+19+20)) in the years 2018-2019.

In 2021, coverage was incomplete in strata 16, 19, and 20. Indices in the partly covered stratum 19 were extrapolated to the entire strata. No trawling was done in stratum 20. As cod and haddock abundances generally are low there, the stratum was partly ice covered and did not have coverage in the last two years, this stratum was excluded from estimation. Only one trawl station was taken in stratum 16. Here the cod and haddock acoustic and swept area estimates were raised by the “index ratio by age” observed for these strata in 2019-2020. The scaling factor for estimating adjusted total from <Total – strata 16> was the average ratio by age for Total/(Total – strata 16) in the years 2019-2020.

4 - Total echo abundance of cod and haddock

Table 4.1 presents the time series of total echo abundance (mean sA multiplied by strata area and summed over all strata) of cod and haddock in the investigated areas.

  StoX
Year Cod Haddock Sum
1994 5282 3898 9180
1995 3671 2948 6619
1996 2789 1248 4037
19971 1355 832 2187
19981 2254 543 2797
1999 1517 771 2288
2000 2833 1534 4367
2001 2158 1488 3646
2002 1976 2247 4223
2003 3717 3570 7287
2004 1174 2087 3261
2005 1370 2519 3889
2006 1116 2541 3657
20071 675 2311 2986
2008 3510 6195 9705
2009 2452 5300 7752
2010 3526 5939 9465
2011 2967 3715 6682
2012 3478 4182 7660
2013 5026 3604 9656
2014 4847 2915 7762
2015 5245 2161 7406
2016 2879 1587 4466
20171 2139 2588 4732
2018 3537 2851 6388
2019 3282 3039 6321
20201 2676 2199 4875
20211 1128 983 2111
2022 1437 1624 3061
Table 4.1. Cod and haddock. Total echo abundance in the Barents Sea winter 1994-2022 (m2 reflecting surface · 103) estimated by StoX. Observations outside main areas A-S are not included.

1 not scaled for uncovered areas

Since 1993 the acoustic values have been split between the two species during the scrutinizing. The values for cod have shown an increasing trend since the late 2000s, with a peak in 2013-2015. Total echo abundance was 40% lower in 2016 compared to 2015 and decreased further from 2016 to 2017, while there was an increase of more than 50% from 2017 to 2018-2019 and then a decrease in 2020 to a level similar to that in 2017. The 2021 echo abundance is the third lowest in the time series, and the lowest observed since 2006 (the lower value in 2007 likely reflects the lack of coverage of the Russian zone and is not directly comparable). The echo abundance increased slightly in 2022, but it is still among the lowest values in the time series.

The values for haddock increased gradually from the end of the 1990s to 2008, decreased gradually to less than one third of the 2008-value in 2016 but increased considerably in 2017 and further in 2018 and 2019, before decreasing in 2020. The 2021 echo abundance is the fourth lowest in the time series, and the lowest observed since 1999. In 2022 the echo abundance increased again, but is still the fourth lowest since 1999.

5 - Distribution and abundance of cod

5.1 - Acoustic estimation

Surveys in the Barents Sea at this time of the year mainly cover the immature part of the cod stock. Most of the mature cod (age 7 and older) have started on their spawning migration southwards out of the investigated area and are therefore to a lesser extent covered. There are indications that a higher proportion than normal spawned along Finnmark in some years, e.g., 2004-2006. Thereby, a higher proportion of spawners might have been covered by the survey in those years. Figure 5.1 shows the spatial distribution of acoustic registrations assigned to cod in 2022. The registrations reflect the general distribution of cod in the central and southwestern Barents Sea. The NASC values in 2022 were low, reflecting the overall low echo abundance.

 

Distribution of acoustic backscatter (m2/nmi2) assigned to cod in 2022. The black lines without yellow circles represent parts of the cruise track where the acoustic backscatter was scrutinized but not assigned to cod. NASC values < 5 was set to zero for this illustration. Circles with red outline represent NASC > 500.
Figure 5.1. COD NASC. Distribution of acoustic backscatter (m2/nmi2 ) assigned to cod in 2022. The black lines without yellow circles represent parts of the cruise track where the acoustic backscatter was scrutinized but not assigned to cod. NASC values < 5 was set to zero for this illustration. Circles with red outline represent NASC > 500.

 

Table 5.1 shows the acoustic indices for each age group by main areas in 2022. 26 % of the 1-year-olds were found in the extended area (N) in 2022 compared to 7 % in 2021. Age 3 cod had the highest percentage of total abundance in area N with 35 %. The time series of total abundance at age (1994-2022) is presented in Table 5.2.

The acoustic estimates have been variable and increasing in later years, with a peak in biomass in 2013, and this may partly be explained by variable and not complete coverage of the distribution area towards north and east in several years. As cod grow older it gets a more south-westerly distribution during winter, so that it “grows into” the covered area with increasing age. This is especially evident for the strong 2004 and 2005 year-classes, which as 6-11-year-olds stand out as the strongest in the time series. The 2019-2020 year-classes were among the lowest in the time series both at age 1 and 2 while the 2021 year-class was moderate at age 1. Table 5.3 shows time series for strata 24-26 (area N) in 2014-2022, which are included in the main time series.

Table 5.4 presents estimated coefficients of variation (CV) for cod age groups 1-14 in 1994-2022. These estimates were obtained by using StoX with a stratified bootstrap routine treating each transect as the primary sampling unit. In addition, a bootstrap routine for all trawl stations by strata was carried out within each run. The estimated CV (Standard Deviation ∙ 100/mean) is estimated from 500 iterations . A CV of 20% or less could be viewed as acceptable in a traditional stock assessment approach if the indices are unbiased (conditional on a catchability model). In 2022 the age groups 1 and 3-7 fall into this category. Values above this indicate higher uncertainty of the estimated index, with reduced information regarding year-class strength. In all years, CVs for age groups older than 10 years are above what could be considered as acceptable. This is to a large degree related to low catch rates resulting in fewer age samples for these age groups (Table 2.2).

Age group Total Biomass (‘000 t)
Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
A 24.8 1.13 0.89 2.09 4.47 7.07 8.58 6.08 0.73 0.57 0.82 0.58 0.00 0.00 0.02 57.9 90.8
B 4.27 0.16 1.83 1.41 6.24 6.95 17.5 11.6 4.70 1.13 0.34 0.18 0.08 0.00 0.15 56.5 172.8
C 16.4 0.59 0.71 1.00 1.34 2.10 2.49 2.13 0.50 0.02 0.00 0.05 0.00 0.00 0.06 27.4 27.5
D 178.2 6.28 8.58 17.2 18.7 14.5 5.47 4.15 1.26 0.41 0.20 0.06 0.08 0.00 0.00 255.1 101.2
D'1 9.37 1.46 0.97 2.00 2.44 1.95 1.50 0.70 0.21 0.07 0.04 0.06 0.00 0.00 0.04 20.8 17.6
E 85.7 7.39 1.94 2.45 1.69 2.47 1.46 0.74 0.05 0.03 0.00 0.00 0.00 0.00 0.00 103.9 16.9
S 70.2 12.4 4.10 14.7 12.6 7.86 3.45 1.22 0.20 0.13 0.06 0.01 0.01 0.00 0.00 127.0 51.9
N 135.8 14.0 10.4 12.1 9.16 4.19 2.53 1.13 0.21 0.08 0.04 0.00 0.01 0.00 0.01 189.6 40.6
ABCD 223.7 8.20 12.0 21.7 30.8 30.6 34.0 24.0 7.19 2.13 1.37 0.88 0.16 0.00 0.23 396.9 392.4
AN 524.7 43.4 29.4 53.0 56.7 47.1 42.9 27.8 7.85 2.44 1.51 0.94 0.18 0.00 0.28 838.2 519.4
Table 5.1. COD. Abundance indices (numbers in millions) for the main areas of the Barents Sea from acoustic survey winter 2022 estimated by StoX software. Bootstrap mean estimates.
Age group Total Biomass (‘000 t)4
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
1994 902.64 624.38 323.88 374.47 205.53 70.24 13.00 3.59 2.60 0.71 1.15 0.11 0.13 0.00 0.00 2522.43 1060.26
1995 2175.25 212.29 137.74 139.49 197.08 66.38 15.73 2.43 0.91 0.32 0.48 0.17 0.00 0.00 0.00 2948.27 665.14
1996 1826.33 271.71 99.40 89.62 111.34 82.96 22.17 2.22 0.30 0.10 0.07 0.05 0.10 0.01 0.00 2506.38 504.47
19971 1698.49 565.31 158.57 44.22 49.91 40.91 23.48 5.02 0.84 0.27 0.09 0.00 0.00 0.01 0.00 2587.12 346.39
19981 2523.56 475.15 391.16 189.79 44.87 41.22 27.85 16.06 1.81 0.50 0.04 0.00 0.00 0.00 0.06 3712.07 563.03
1999 364.84 231.51 147.62 130.29 52.03 11.93 6.94 4.13 1.47 0.24 0.01 0.03 0.01 0.00 0.00 951.05 262.81
2000 153.42 262.81 294.83 167.25 145.55 50.75 11.33 4.70 2.75 0.85 0.18 0.11 0.03 0.00 0.00 1094.56 545.52
2001 363.55 51.45 177.44 160.63 80.80 44.47 11.10 1.73 0.46 0.19 0.08 0.00 0.00 0.00 0.01 891.91 435.40
2002 19.22 209.10 61.37 106.23 98.78 52.18 20.07 2.90 0.32 0.52 0.09 0.00 0.00 0.00 0.02 570.8 428.50
2003 1505.00 52.53 306.71 116.80 124.62 116.52 37.69 10.05 1.93 0.31 0.07 0.00 0.08 0.07 0.00 2272.38 755.03
2004 161.20 117.19 33.41 85.21 32.96 28.03 18.14 5.33 1.16 0.31 0.08 0.00 0.01 0.00 0.00 483.03 244.57
2005 499.71 138.66 125.03 33.28 65.94 21.21 15.02 4.95 1.01 0.25 0.05 0.07 0.05 0.03 0.00 905.26 259.70
20062 411.21 157.95 64.77 53.82 18.35 29.52 9.50 4.90 1.28 0.20 0.13 0.30 0.00 0.00 0.00 751.93 227.27
20071 85.13 47.09 58.49 30.40 29.35 9.04 18.07 6.41 2.67 0.53 0.24 0.07 0.00 0.00 0.00 287.49 213.63
2008 50.87 94.20 199.85 288.71 116.17 72.91 21.82 14.43 2.80 0.81 0.04 0.01 0.01 0.00 0.00 862.63 822.87
2009 204.90 25.46 107.83 182.54 138.08 41.48 13.87 4.69 4.32 0.50 0.14 0.02 0.01 0.00 0.00 723.84 536.93
2010 620.25 43.56 22.82 87.98 160.16 154.39 44.56 14.57 3.90 2.89 0.94 0.11 0.12 0.09 0.01 1156.35 885.82
2011 266.00 91.00 40.36 28.32 65.20 106.97 101.80 19.76 6.11 1.70 0.92 0.25 0.15 0.09 0.02 728.65 787.82
20123 496.49 40.23 82.79 49.38 33.77 72.53 132.31 65.59 8.37 4.39 1.21 0.66 0.47 0.04 0.10 988.33 969.09
2013 313.11 89.17 60.55 84.49 72.18 47.75 98.41 130.54 55.32 5.41 4.02 1.30 0.73 0.20 0.07 963.25 1494.33
2014 1758.58 211.04 286.89 124.18 111.14 74.47 39.41 89.89 61.31 22.64 2.56 1.31 0.16 0.05 0.19 2783.82 1437.38
2015 1903.54 211.41 138.71 235.58 128.80 140.36 80.55 35.07 53.80 24.38 7.91 0.80 0.13 0.05 0.01 2961.1 1469.58
2016 240.80 201.89 56.29 76.91 119.38 64.84 50.17 25.80 13.49 17.83 7.35 2.15 0.72 0.22 0.10 877.94 873.17
20173 439.40 73.30 111.54 42.35 44.25 65.30 35.75 24.31 11.97 4.00 2.88 3.15 0.67 0.19 0.11 859.17 680.62
2018 2057.60 280.29 109.03 149.94 53.40 54.93 66.09 34.35 10.78 6.27 1.73 2.25 1.50 0.15 0.23 2828.54 883.80
2019 1437.21 362.38 203.63 125.42 144.06 60.98 34.99 37.86 9.64 3.47 0.55 0.32 0.18 0.28 0.24 2421.21 842.03
20203 92.68 157.92 117.32 117.32 81.36 90.60 42.35 26.57 21.41 6.23 1.75 0.67 0.66 0.51 0.89 758.24 809.18
20213 45.92 28.51 64.86 59.08 55.48 38.54 30.80 12.41 6.32 4.67 2.17 0.29 0.18 0.00 0.21 349.45 400.67
2022 524.71 43.42 29.42 52.98 56.69 47.05 42.94 27.77 7.85 2.44 1.51 0.94 0.18 0.00 0.28 838.17 519.4
Table 5.2. COD. Abundance indices (numbers in millions) from acoustic surveys in the Barents Sea standard area winter 1994-2022 estimated by StoX software. Area N included from 2014 onwards. Bootstrap mean estimates.

1 Indices raised to also represent the Russian EEZ.

2 Not complete coverage in southeast due to restrictions, strata 7 area set to default and strata 13 as in 2005.

3 Indices raised to also represent uncovered parts of the Russian EEZ.

4 1994-2020: bootstrap mean biomass estimated based on relationship between (unraised) numbers-at-age and biomass-at-age from StoX baseline run. From 2021: bootstrap mean biomass estimated directly in StoX; in years with adjustments for lack of coverage it is estimated based on relationship between unraised bootstrap mean numbers-at-age and unraised bootstrap mean biomass-at-age.

Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
2014 1112.50 53.97 54.53 11.67 14.62 7.31 2.26 4.73 2.98 0.27 0.02 0.00 0.00 0.00 0.00 1264.87 103.44
2015 589.67 88.32 25.22 49.00 12.68 11.24 5.34 1.08 3.40 1.16 0.77 0.05 0.00 0.00 0.00 787.93 122.36
2016 104.90 84.60 17.95 14.58 16.83 2.47 2.94 1.86 0.30 0.67 0.17 0.02 0.01 0.00 0.00 247.30 60.15
2017 31.09 28.70 26.54 5.44 5.68 4.13 1.54 0.65 0.24 0.05 0.28 0.04 0.00 0.00 0.00 104.37 40.15
2018 514.18 50.59 16.17 16.74 6.96 4.35 8.64 0.99 0.76 0.25 0.08 0.12 0.01 0.00 0.00 619.85 76.08
2019 371.39 75.30 20.87 27.74 20.56 7.98 3.63 5.27 0.42 0.44 0.14 0.04 0.01 0.03 0.00 533.82 112.10
2020 12.66 13.01 16.05 11.60 12.75 7.53 3.10 1.87 2.67 0.44 0.25 0.09 0.06 0.00 0.08 82.15 71.84
2021 3.35 1.85 4.11 6.72 4.13 3.70 1.61 0.45 0.20 0.21 0.01 0.01 0.00 0.00 0.01 26.36 24.23
2022 135.8 14.0 10.4 12.1 9.16 4.19 2.53 1.13 0.21 0.08 0.04 0.00 0.01 0.00 0.01 189.6 40.6
Table 5.3. COD. Abundance indices (numbers in millions) for new strata 24-26 from acoustic surveys in the Barents Sea winter 2014-2022 estimated by StoX software. 2014-2020: baseline estimates, from 2021: bootstrap mean estimates.
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 30 41 29 12 7 10 13 19 20 29 29 69 89 -
1995 14 24 15 9 7 8 12 23 26 35 54 50 - -
1996 11 15 14 10 10 11 14 16 29 43 58 54 100 110
19971 33 29 14 11 10 10 8 13 22 54 63 - - 129
19981 23 18 11 9 10 8 8 11 22 36 45 - 101 -
1999 22 23 17 15 10 11 11 13 25 58 114 121 107 -
2000 31 26 17 10 7 10 17 21 22 42 72 68 110 -
2001 13 15 11 9 10 9 13 22 32 36 78 - - -
2002 18 16 10 6 7 10 15 17 32 78 73 - - -
2003 26 31 15 13 8 8 13 17 20 40 59 - 99 94
2004 18 16 13 10 10 10 9 13 16 45 58 95 125 -
2005 26 49 19 14 14 14 12 20 26 24 62 90 49 91
20062 24 14 11 8 8 10 16 18 19 37 61 66 - -
20071 27 24 14 14 11 17 21 24 27 36 42 44 92 -
2008 18 24 15 16 13 10 16 14 20 44 75 65 100 -
2009 21 20 26 22 18 17 13 14 19 32 45 71 112 -
2010 36 17 19 25 17 12 11 13 17 22 28 86 74 70
2011 13 27 12 11 11 10 9 15 28 29 35 39 66 86
20122 36 14 53 11 19 19 17 13 19 35 33 55 52 81
2013 15 21 13 9 11 11 14 11 18 35 44 55 66 108
2014 15 10 11 10 13 8 11 11 14 21 30 53 59 96
2015 27 22 15 15 10 14 18 21 19 29 48 55 63 70
2016 36 20 13 13 11 15 17 16 23 23 32 46 55 87
20172 15 19 12 11 10 8 11 14 21 22 19 25 31 58
2018 11 9 9 9 9 8 8 13 15 24 24 33 53 51
2019 12 12 8 7 6 11 12 10 14 23 32 55 49 60
20202 15 15 10 7 10 11 15 16 18 23 29 38 31 38
20212 32 42 34 21 13 13 17 16 20 20 29 44 69 175
2022 20 25 20 17 11 11 19 21 31 36 48 52 74 -
Table 5.4 . COD. Estimates of coefficients of variation (%) for acoustic abundance indices. Barents Sea standard area winter 1994-2022.

1 Russian EEZ not covered

2 Russian EEZ partly covered

5.2 - Swept area estimation

Figures 5.2 - 5.5 show the geographic distribution of bottom trawl catch rates (number of fish per NM2 ), for cod size groups < 20 cm, 20-34 cm, 35-49 cm and ≥ 50 cm. Usually, a high proportion of the smallest cod (less than 35 cm) are found in the eastern part of the survey area within the Russian EEZ and near the northern borders of the standard strata system (strata 1-23). While this general pattern was still there in 2022, the 20-34 cm cod was nearly absent from the southern and south-eastern areas (Fig. 5.3). Catch rates of medium and large sized cod (35-50+ cm) were particularly low in the central Barents Sea (Figs 5.4-5.5). The highest catch rates of large cod are usually found along the Norwegian coast and around Svalbard and the ice edge in the north, but in 2022 there were relatively lower catch rates in the south (Fig. 5.5).

 

COD < 20 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 5.2. COD < 20 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge. Data source for the ice cover: https://cryo.met.no/archive/ice-service/icecharts/quicklooks/2022/

 

 

COD 20-34 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 5.3. COD 20-34 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

 

COD 35-49 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 5.4. COD 35-49 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm 2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

 

COD ≥ 50 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 5.5. COD ≥ 50 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm 2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

Table 5.5 presents abundance indices by main areas and age, and the full time series 1994-2022 is shown in Table 5.6. The bottom trawl indices have fluctuated somewhat for the same reasons as the acoustic indices, and the 2004 and 2005 year-classes stand out as the strongest in the time series. The 2009, 2011 and 2014 year-classes seemed to be strong as 1-year olds but have later been reduced to average level or below. The year-classes 2017 and 2018 also seemed strong at age one but are more average as 2- and 3-year-olds. The 2019-2020 year-classes were among the lowest in the time series both at age 1 and 2 while the 2021 year-class was moderate at age 1. A considerable number of cod was found in the extended survey area N (Table 5.7), which from 2021 was included in the official indices used for stock assessment. Looking at total estimates, about 23% of cod by numbers and about 16% by biomass were found in this area in 2022. Tables 5.7 present swept area abundance indices by age for area N in 2014-2022. As in the previous years, fair amounts of cod were also observed northeast of the extended area, i.e., north of Svalbard outside of the survey stratification.

Table 5.8 presents estimated coefficients of variation (CV) for cod age groups 1-15 in 1994-2021. In 2022, age groups 1-2 and 5-9 have CVs below or equal to 20 %. Values above this indicate higher uncertainty of the estimated index, with reduced information regarding year-class strength. In all years, CVs for age groups older than 10 years are above what could be considered as acceptable. This is to a large degree related to low catch rates resulting in fewer age samples for these age groups (Table 2.2).

Age group Total Biomass (‘000 t)
Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
A 20.5 0.98 0.75 1.70 3.24 5.38 3.54 4.29 0.55 0.46 0.37 0.20 0.00 0.00 0.02 41.9 53.2
B 0.92 0.06 0.42 0.30 2.05 1.44 6.89 3.62 0.92 0.21 0.05 0.05 0.01 0.00 0.05 17.0 52.0
C 6.15 0.22 0.28 0.31 0.57 0.63 0.84 0.80 0.18 0.00 0.00 0.02 0.00 0.00 0.02 10.0 9.74
D 218.1 9.59 11.2 21.8 25.6 20.7 7.58 6.26 1.79 0.52 0.24 0.10 0.12 0.00 0.00 323.7 140.9
D'1 42.8 8.13 4.46 7.38 8.40 10.6 13.6 3.91 1.21 0.69 1.20 1.11 0.00 0.00 0.77 104.1 147.1
E 128.7 12.5 2.67 4.15 2.20 5.14 0.67 5.75 0.04 0.04 0.00 0.00 0.00 0.00 0.00 161.8 40.8
S 91.8 16.1 16.3 30.8 23.0 12.75 5.20 1.84 0.42 0.13 0.07 0.02 0.01 0.00 0.00 198.6 90.7
N 158.9 18.1 15.8 22.2 21.5 9.86 6.33 3.96 0.58 0.26 0.15 0.00 0.02 0.00 0.03 257.8 99.7
ABCD 245.6 10.8 12.7 24.1 31.5 28.2 18.9 15.0 3.4 1.2 0.7 0.4 0.1 0.00 0.10 392.6 255.7
AN 667.8 65.6 52.0 88.7 86.6 66.5 44.6 30.4 5.7 2.3 2.1 1.5 0.2 0.00 0.90 1114.9 634.0
Table 5.5. COD. Abundance indices from bottom trawl hauls for main areas of the Barents Sea winter 2022 (numbers in millions). Bootstrap mean estimates.
Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
1994 1043.78 556.68 293.92 307.04 153.33 45.72 7.95 2.61 1.48 0.55 0.55 0.08 0.05 0 0 2413.74 763.41
1995 5356.43 541.25 282.84 242.36 251.01 76.42 17.98 2.42 1.07 0.50 0.61 0.19 0 0 0 6773.08 937.79
1996 5899.23 791.62 163.08 117.43 138.59 108.88 24.43 2.64 0.37 0.17 0.12 0.07 0.07 0.02 0 7246.72 718.00
19971 5044.09 1422.92 317.99 68.44 74.26 59.99 26.67 4.85 0.64 0.91 0.08 0 0 0 0 7020.84 558.85
19981 2490.54 496.48 355.10 166.94 31.67 26.15 17.52 8.16 0.79 0.52 0.04 0 0 0 0.04 3593.95 432.77
1999 473.04 350.21 188.48 180.75 61.39 12.71 6.81 5.14 1.01 0.26 0.02 0.04 0.02 0 0 1279.88 322.68
2000 128.57 242.33 245.81 130.03 111.73 26.75 4.56 1.84 1.21 0.33 0.10 0.03 0.02 0 0 893.31 363.23
2001 712.77 78.03 182.79 195.11 82.90 37.96 9.45 1.17 0.44 0.19 0.04 0 0 0 0.01 1300.86 436.57
2002 34.11 418.73 118.36 137.56 108.95 45.79 14.40 2.20 0.32 0.18 0.05 0 0 0 0.02 880.67 447.43
2003 3022.23 65.78 376.70 126.31 93.93 66.88 17.50 4.67 1.02 0.17 0.04 0 0.02 0.02 0 3775.27 546.13
2004 322.87 242.94 63.88 184.62 53.46 43.24 30.59 6.85 1.65 0.28 0.07 0.01 0.01 0 0 950.47 415.07
2005 853.43 216.67 248.88 55.06 102.97 22.38 16.36 3.81 0.92 0.30 0.04 0.02 0.04 0.04 0 1520.92 359.76
20062 674.21 289.39 116.49 115.38 28.32 43.42 13.72 5.24 1.36 0.24 0.18 0.18 0 0 0 1288.13 334.94
20071 594.69 369.74 361.13 127.73 68.51 13.65 23.60 6.82 2.30 0.41 0.11 0.10 0 0 0 1568.79 444.84
2008 68.83 101.96 194.37 300.59 111.90 40.24 17.34 8.11 1.79 0.36 0.03 0.02 0.01 0 0 845.55 686.98
2009 389.48 35.59 126.28 196.70 220.23 60.69 17.90 9.02 5.24 0.51 0.17 0.03 0.04 0 0 1061.88 757.32
2010 1027.59 95.14 36.81 114.25 154.80 144.50 39.56 11.24 3.67 1.60 0.58 0.04 0.02 0.04 0.02 1629.86 827.36
2011 617.18 225.81 85.40 50.37 129.70 138.66 103.51 16.37 4.36 1.20 0.82 0.19 0.14 0.04 0.02 1373.77 891.44
20123 702.97 100.30 75.72 64.59 33.71 90.69 132.58 48.61 9.02 2.26 0.88 0.55 0.44 0.07 0.05 1262.44 879.93
2013 435.72 142.96 68.84 114.09 63.18 40.43 64.54 76.38 33.52 2.22 2.87 0.40 0.35 0.06 0.03 1045.59 951.73
2014 1245.71 191.48 226.85 93.79 88.59 56.39 32.74 53.05 36.19 9.81 1.01 0.95 0.15 0.02 0.08 2036.81 897.87
2015 1642.00 342.76 144.07 228.25 147.29 113.53 74.43 29.22 53.51 18.08 3.38 0.75 0.12 0.07 0.04 2797.50 1338.73
2016 312.16 305.57 99.37 135.48 188.31 113.47 72.33 28.56 13.17 16.06 6.77 0.97 0.52 0.17 0.14 1293.05 1085.06
20173 644.51 128.92 179.25 62.15 84.54 90.16 37.82 26.33 8.18 3.26 2.61 3.70 0.58 0.17 0.06 1272.24 753.67
2018 2714.35 500.69 139.41 184.78 61.81 64.17 73.88 25.88 9.28 5.87 1.29 2.46 1.23 0.13 0.37 3785.60 908.45
2019 1790.57 559.44 281.57 179.15 221.90 79.65 32.96 38.31 8.15 2.62 0.54 0.24 0.16 0.18 0.12 3195.56 974.96
20203 164.75 273.82 237.73 160.24 131.56 114.88 49.83 24.26 20.44 4.53 1.66 0.93 0.51 0.26 0.73 1186.13 857.96
20213 80.88 34.87 111.50 119.35 112.31 54.28 37.98 13.57 7.27 3.53 1.25 0.42 0.25 0.04 0.32 577.83 528.35
2022 667.8 65.6 52.0 88.7 86.6 66.5 44.6 30.4 5.70 2.29 2.08 1.49 0.16 0.00 0.90 1114.9 634.0
Table 5.6. COD. Abundance indices (numbers in millions) from bottom trawl surveys in the Barents Sea winter 1994-2022. Area N included from 2014 onwards. Bootstrap mean estimates.

1 Indices raised to also represent the Russian EEZ. 2 Not complete coverage in southeast due to restrictions, strata 7 area set to default and strata 13 as in 2005

3 Indices raised to also represent uncovered parts of the Russian EEZ.

4 1994-2020: bootstrap mean biomass estimated based on relationship between (unraised) numbers-at-age and biomass-at-age from StoX baseline run. From 2021: bootstrap mean biomass estimated directly in StoX; in years with adjustments for lack of coverage it is estimated based on relationship between unraised bootstrap mean numbers-at-age and unraised bootstrap mean biomass-at-age

Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
2014 713.08 77.53 42.89 18.72 15.38 9.93 2.90 5.31 3.65 0.55 0.06 0.01 0.00 0.00 0.00 890.00 117.15
2015 403.27 85.44 26.44 46.50 20.73 11.77 5.27 1.82 2.47 1.44 0.45 0.06 0.00 0.00 0.00 605.64 129.79
2016 101.28 92.79 27.21 24.25 28.17 9.40 5.58 2.52 0.61 0.96 0.35 0.05 0.02 0.00 0.00 293.19 109.39
2017 182.91 49.50 60.34 27.67 28.94 31.41 10.26 3.29 0.60 0.26 0.33 0.08 0.00 0.00 1.72 397.32 187.18
2018 1010.90 115.27 29.03 42.62 13.37 11.59 14.39 4.05 1.55 0.40 0.19 0.24 0.03 0.00 0.00 1243.61 170.48
2019 493.52 119.15 40.37 33.55 42.75 12.63 6.88 8.39 1.43 0.61 0.14 0.08 0.02 0.06 0.00 759.60 190.84
2020 25.44 30.50 36.58 33.77 22.46 21.42 8.16 4.32 3.99 0.85 0.44 0.06 0.11 0.00 0.09 188.20 162.34
2021 31.98 12.50 22.74 32.50 26.64 14.80 7.51 1.66 1.13 0.86 0.04 0.08 0.00 0.00 0.02 152.45 115.76
2022 158.91 18.08 15.83 22.22 21.53 9.86 6.33 3.96 0.58 0.26 0.15 0.00 0.02 NA 0.03 257.76 99.69
Table 5.7. COD. Abundance indices (numbers in millions) for new strata 24-26 from bottom trawl surveys in the Barents Sea winter 2014-2022. Bootstrap mean estimates.
Age group
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1994 7 15 10 10 10 9 13 24 23 25 18 72 69 - -
1995 8 14 11 12 10 10 12 23 33 27 42 39 - - -
1996 7 12 19 10 12 9 13 13 25 40 50 39 48 92 -
19971 27 29 17 14 13 10 9 15 21 56 70 - - - -
19981 8 12 15 11 11 11 8 10 17 48 61 - 95 - 68
1999 18 28 17 14 9 10 14 29 22 62 106 95 91 - -
2000 12 18 15 8 9 10 12 11 15 32 55 65 84 - -
2001 11 15 17 14 10 11 16 23 28 36 57 - - - 96
2002 13 23 24 7 9 13 9 14 26 40 63 - - - 93
2003 25 33 26 19 8 7 10 12 17 40 55 - 71 69 -
2004 12 13 19 14 10 12 14 12 14 36 40 106 101 - -
2005 9 18 27 20 18 14 11 10 16 23 61 66 49 94 -
20062 12 13 14 27 17 13 21 12 17 27 55 63 - - -
20071 25 21 16 25 7 10 10 14 19 19 34 47 84 - -
2008 9 16 16 23 31 9 37 14 25 24 70 83 99 - -
2009 10 10 16 11 19 13 16 23 22 31 33 61 91 - -
2010 33 10 13 19 13 10 21 11 22 21 25 71 57 60 -
2011 6 24 11 15 16 10 9 10 26 19 48 36 58 64 99
20122 9 14 13 12 15 20 20 12 24 19 23 39 52 76 100
2013 10 19 14 17 12 10 12 10 17 21 55 34 43 102 94
2014 11 9 10 11 11 7 16 12 11 19 26 33 61 117 68
2015 7 19 12 13 15 16 27 21 40 16 21 28 74 71 82
2016 9 11 15 11 8 17 19 11 15 25 20 33 31 53 52
20172 10 11 12 14 26 15 19 23 11 18 20 26 43 37 96
2018 6 14 7 9 8 12 8 12 12 29 20 34 48 46 48
2019 8 8 9 9 16 16 12 8 14 15 24 35 40 35 82
20202 14 10 13 16 11 11 12 10 12 14 21 52 29 39 30
20212 15 10 16 11 10 12 10 16 15 13 24 38 68 91 46
2022 7 12 22 21 15 10 16 18 15 27 58 72 41 - 91
Table 5.8. COD. Estimates of coefficients of variation (%) for swept area abundance indices. Barents Sea standard area winter 1994-2022.

1Russian EEZ not covered

2Russian EEZ partly covered

5.3 - Survey mortalities

Table 5.9 gives the time series of survey-based mortalities (natural log ratios between survey indices of the same year-class in two successive years) for the acoustic and swept area indices since 1994. These mortalities are influenced by natural and fishing mortality, age reading errors, and the catchability and availability (coverage) at age for the survey. In the period 1994-1999 there was an increasing trend in the survey mortalities. Most later surveys show lower mortalities, but there are some fluctuations for the same reasons as mentioned for the acoustic and swept area indices. Presumably the mortality of the youngest age groups (ages 1-3) is mainly caused by predation, while for the older age groups the fishery is the main cause. Although the survey mortalities are noisy, the mortalities for age 4 and older correspond well with the strong decrease in fishing mortality around 2007 in the stock assessment. The low survey mortalities in the 2010s, even with “impossible” negative values, could partly be caused by fish gradually “growing into” the covered area at increasing age. 2019-2020 and 2020-2021 estimates suggest higher survey mortalities than in previous years, while mortality decreased for most age groups in 2021-2022.

  Age
Year 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9
  Acoustic investigations
1994-95 1.45 1.51 0.84 0.64 1.13 1.50 1.68 1.37
1995-96 2.08 0.76 0.43 0.23 0.87 1.10 1.96 2.09
1996-97 1.17 0.54 0.81 0.59 1.00 1.26 1.49 0.97
1997-98 1.27 0.37 -0.18 -0.01 0.19 0.38 0.38 1.02
1998-99 2.39 1.17 1.10 1.29 1.32 1.78 1.91 2.39
1999-00 0.33 -0.24 -0.12 -0.11 0.02 0.05 0.39 0.41
2000-01 1.09 0.39 0.61 0.73 1.19 1.52 1.88 2.32
2001-02 0.55 -0.18 0.51 0.49 0.44 0.80 1.34 1.69
2002-03 -1.01 -0.38 -0.64 -0.16 -0.17 0.33 0.69 0.41
2003-04 2.55 0.45 1.28 1.27 1.49 1.86 1.96 2.16
2004-05 0.15 -0.06 0.00 0.26 0.44 0.62 1.30 1.66
2005-06 1.15 0.76 0.84 0.60 0.80 0.80 1.12 1.35
2006-07 2.17 0.99 0.76 0.61 0.71 0.49 0.39 0.61
2007-08 -0.10 -1.45 -1.60 -1.34 -0.91 -0.88 0.22 0.83
2008-09 0.69 -0.14 0.09 0.74 1.03 1.66 1.54 1.21
2009-10 1.55 0.11 0.20 0.13 -0.11 -0.07 -0.05 0.18
2010-11 1.92 0.08 -0.22 0.30 0.40 0.42 0.81 0.87
2011-12 1.89 0.09 -0.20 -0.18 -0.11 -0.21 0.44 0.86
2012-13 1.72 -0.41 -0.02 -0.38 -0.35 -0.31 0.01 0.17
2013-14 0.39 -1.17 -0.72 -0.27 -0.03 0.19 0.09 0.76
2014-15 2.12 0.42 0.20 -0.04 -0.23 -0.08 0.12 0.51
2015-16 2.24 1.32 0.59 0.68 0.69 1.03 1.14 0.96
2016-17 1.19 0.59 0.28 0.55 0.60 0.60 0.72 0.77
2017-18 0.45 -0.40 -0.30 -0.23 -0.22 -0.01 0.04 0.81
2018-19 1.74 0.32 -0.14 0.04 -0.13 0.45 0.56 1.27
2019-20 2.21 1.13 0.55 0.43 0.46 0.36 0.28 0.57
2020-21 1.41 0.93 0.73 0.79 0.77 1.11 1.26 1.54
2021-22 0.06 -0.03 0.20 0.04 0.16 -0.11 0.10 0.46
  Bottom trawl investigations
1994-95 0.66 0.68 0.19 0.20 0.70 0.93 1.19 0.89
1995-96 1.91 1.20 0.88 0.56 0.84 1.14 1.92 1.88
1996-97 1.42 0.91 0.87 0.46 0.84 1.41 1.62 1.42
1997-98 2.32 1.39 0.64 0.77 1.04 1.23 1.18 1.81
1998-99 1.96 0.97 0.68 1.00 0.91 1.35 1.23 2.09
1999-00 0.67 0.35 0.37 0.48 0.83 1.03 1.31 1.45
2000-01 0.50 0.28 0.23 0.45 1.08 1.04 1.36 1.43
2001-02 0.53 -0.42 0.28 0.58 0.59 0.97 1.46 1.30
2002-03 -0.66 0.11 -0.07 0.38 0.49 0.96 1.13 0.77
2003-04 2.52 0.03 0.71 0.86 0.78 0.78 0.94 1.04
2004-05 0.40 -0.02 0.15 0.58 0.87 0.97 2.08 2.01
2005-06 1.08 0.62 0.77 0.66 0.86 0.49 1.14 1.03
2006-07 0.60 -0.22 -0.09 0.52 0.73 0.61 0.70 0.82
2007-08 1.76 0.64 0.18 0.13 0.53 -0.24 1.07 1.34
2008-09 0.66 -0.21 -0.01 0.31 0.61 0.81 0.65 0.44
2009-10 1.41 -0.03 0.10 0.24 0.42 0.43 0.47 0.90
2010-11 1.52 0.11 -0.31 -0.13 0.11 0.33 0.88 0.95
2011-12 1.82 1.09 0.28 0.40 0.36 0.04 0.76 0.60
2012-13 1.59 0.38 -0.41 0.02 -0.18 0.34 0.55 0.37
2013-14 0.82 -0.46 -0.31 0.25 0.11 0.21 0.20 0.75
2014-15 1.29 0.28 -0.01 -0.45 -0.25 -0.28 0.11 -0.01
2015-16 1.68 1.24 0.06 0.19 0.26 0.45 0.96 0.80
2016-17 0.88 0.53 0.47 0.47 0.74 1.10 1.01 1.25
2017-18 0.25 -0.08 -0.03 0.01 0.28 0.20 0.38 1.04
2018-19 1.58 0.58 -0.25 -0.18 -0.25 0.67 0.66 1.16
2019-20 1.88 0.86 0.56 0.31 0.66 0.47 0.31 0.63
2020-21 1.55 0.90 0.69 0.36 0.89 1.11 1.30 1.21
2021-22 0.21 -0.40 0.23 0.32 0.52 0.20 0.22 0.87
Table 5.9. COD. Survey mortality from surveys in the Barents Sea standard area winter 1994-2022.

5.4 - Growth and maturity

Tables 5.10 and 5.11 present the time series for mean length and mean weight at age for the standard area. There have previously only been moderate fluctuations, but with a decreasing trend for older fish (8+) in later years. However, in 2020-2021, both length and weight at age was considerably reduced for several age groups, with length at age 4 and 5 and weight at age 4, 5, 6 and 8 in 2021 being the lowest observed in the time series. Growth improved somewhat in 2022, but for age groups 1 and 4-9, weight at age is below average in 2022. The reduced weights in the latest years are reflected in the annual weight increments, which for ages 1-5 in from 2019-2002 and 2020-2021 were at or near the lowest observed while growth between 2021 and 2022 was around average for most ages (Table 5.12).

The proportion mature at age is presented in Table 5.13. Since 2010, the proportion mature at ages 6-8 has declined but has in recent years stabilized. Low values were, however, observed for ages 6 and 9 in 2022.

The degree of coverage of the Russian EEZ may also influence the biological parameters, as body size tends to decrease towards the northeast in the survey area. In addition, length, weight, and maturity at age of older ages has higher uncertainty due to fewer samples (c.f. table 2.2).

Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 11.3 17.9 30.2 44.6 55.2 65.7 73.9 78.9 87.4 97.2 97.6 104.7 + -
1995 12.2 18.1 29.0 42.2 53.9 63.9 75.4 80.4 85.9 99.1 90.1 109.0 - -
1996 12.1 18.8 28.8 40.5 49.4 60.9 71.8 85.1 92.4 94.9 96.1 104.2 103.9 +
19971 10.8 16.9 29.7 41.0 50.6 59.4 69.6 81.2 92.3 80.4 + - - -
19981 10.5 17.8 30.8 40.9 50.9 58.5 67.7 76.7 87.2 103.0 111.4 - + -
1999 12.0 18.4 29.0 40.0 50.4 59.4 70.4 78.4 88.5 87.6 + + + -
2000 12.8 20.7 28.4 39.7 51.5 61.4 70.4 76.3 84.9 84.3 100.0 + + -
2001 11.6 22.6 33.0 41.2 52.2 63.3 70.4 78.3 86.0 95.7 104.7 - - -
2002 12.0 19.6 28.9 43.6 52.1 61.9 71.4 79.5 91.2 89.7 103.7 - - -
2003 11.4 18.1 29.1 39.7 53.4 61.7 70.6 80.8 89.1 90.1 105.4 - + +
2004 10.6 18.4 31.7 40.6 51.7 61.6 68.6 79.7 90.9 90.4 92.2 + + -
2005 11.2 18.3 29.5 43.4 51.1 60.4 71.0 79.6 89.0 96.4 109.3 + 129.6 +
20062 12.0 19.4 30.9 42.1 53.8 60.3 66.7 76.7 84.9 98.9 95.4 84.9 - -
20071 13.2 20.7 29.6 41.1 52.8 62.5 70.4 78.2 87.5 92.7 101.8 121.6 + -
2008 12.1 22.3 33.0 43.2 51.8 64.0 69.9 81.3 88.7 95.3 + + + -
2009 11.2 21.1 32.1 42.6 53.2 61.9 76.6 81.8 89.5 97.8 99.5 + + -
2010 11.2 18.4 31.4 42.7 52.4 60.7 70.5 80.4 88.8 96.3 102.2 + + 126.0
2011 11.9 19.5 29.4 41.9 51.0 60.7 68.1 78.3 86.1 95.4 102.2 110.4 114.3 +
20122 10.6 18.4 29.7 41.0 52.4 58.1 66.5 75.6 86.0 91.8 105.9 114.0 119.0 +
2013 11.2 19.3 31.1 41.1 51.7 62.0 69.7 76.5 81.2 95.3 93.7 110.7 110.8 +
2014 9.7 17.1 29.5 40.5 52.0 59.6 70.2 76.8 81.8 87.1 97.4 98.9 107.8 +
2015 10.5 15.9 30.0 40.3 51.1 60.2 68.8 77.5 81.2 88.7 94.0 101.9 127.5 +
2016 12.2 18.3 27.7 40.6 49.8 60.5 68.3 76.6 85.5 86.5 90.5 94.1 112.0 122.5
20172 12.3 22.2 31.2 42.5 51.2 60.5 69.6 75.5 85.2 90.9 96.0 92.6 108.6 108.7
2018 11.2 19.1 32.7 42.4 51.2 61.6 69.0 77.5 83.4 87.6 97.0 99.3 101.8 106.8
2019 11.7 17.5 31.2 42.4 51.0 59.6 69.7 77.0 84.1 87.1 99.3 103.4 104.6 109.8
20202 12.0 17.5 25.5 39.5 50.2 58.6 66.7 74.8 83.0 90.0 93.9 92.4 111.2 113.9
20212 11.6 19.9 26.5 37.4 48.0 58.5 66.7 74.9 84.0 91.7 97.7 102.1 105.8 +
2022 10.8 20.4 32.4 39.1 49.3 58.4 68.7 75.3 84.1 92.5 98.2 102.6 113.2 -
Table 5.10 COD. Mean length (cm) at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates. “+” indicates few samples (< 3), while “–“ indicates no samples. Lengths are not adjusted for incomplete coverage.

1 Russian EEZ not covered

2 Russian EEZ partly covered

Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 13 56 262 796 1470 2386 3481 4603 6777 8195 8516 13972 + -
1995 15 54 240 658 1336 2207 3570 4715 5712 8816 6817 12331 - -
1996 15 62 232 627 1084 1980 3343 5514 7722 8873 9613 12865 12556 +
19971 13 52 230 638 1175 1797 2931 4875 7529 5739 + - - -
19981 11 52 280 635 1182 1728 2588 4026 6076 11257 14391 - + -
1999 14 59 231 592 1178 1829 2991 4128 6321 7342 + + + -
2000 16 74 210 558 1210 1963 3036 3867 5401 6154 10023 + + -
2001 14 106 336 646 1288 2233 3088 4439 5732 8442 11429 - - -
2002 14 67 238 747 1229 2063 3199 4578 7525 6598 12292 - - -
2003 13 61 234 597 1316 2014 2989 4715 6517 7500 12812 - + +
2004 11 59 275 608 1143 1947 2623 4137 6673 7368 8109 + + -
2005 13 61 246 723 1146 1866 2949 4226 6436 8646 12537 + 24221 -
20062 13 69 280 669 1420 1970 2641 4260 5914 10179 9439 8328 - -
20071 19 73 235 639 1302 2190 3039 4411 6394 8056 10826 20104 + -
2008 15 90 335 798 1399 2442 3235 5210 6981 9641 + + + -
2009 13 83 294 704 1302 2065 4067 5087 6874 9460 9511 + + -
2010 12 64 304 700 1296 2033 3162 4743 6562 8984 10315 + + 22766
2011 15 66 246 668 1131 1940 2726 4013 5969 8275 10309 13159 14868 +
20122 13 62 252 609 1276 1681 2489 3764 5920 7809 12199 15006 17582 +
2013 11 65 269 602 1208 2055 2809 3843 4822 8447 9101 15108 14743 +
2014 8 50 246 603 1226 1780 2866 3930 4927 6203 8570 9566 12239 +
2015 10 44 242 602 1221 1929 2741 4043 4804 6817 7759 11544 21652 +
2016 13 53 200 593 1049 1928 2674 3830 5540 6129 7110 8272 15256 21945
20172 15 102 292 720 1178 1972 3056 3962 5901 7429 9301 8599 12958 14894
2018 12 69 320 688 1228 2062 2803 4154 5409 6632 9156 10510 11810 12443
2019 12 48 273 685 1164 1870 2916 3974 5394 6068 9637 11507 12371 13993
20202 14 44 153 548 1077 1692 2476 3625 5074 6758 8040 8107 14892 15793
20212 14 68 164 462 910 1682 2484 3620 5379 7160 9313 10923 12410 +
2022 11 77 311 535 1052 1716 2885 3855 5321 7751 9538 11432 14940 -
Table 5.11. COD. Mean weight (g) at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates. “+” indicates few samples (< 3), while “–“ indicates no samples. Weights are not adjusted for incomplete coverage.

1 Russian EEZ not covered

2 Russian EEZ partly covered

Year\Age 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10
1994-95 41 184 396 540 737 1184 1234 1109 2039
1995-96 47 178 387 426 644 1136 1944 3007 3161
1996-97 37 168 406 548 713 951 1532 2015 -1983
1997-98 39 228 405 544 553 791 1095 1201 3728
1998-99 48 179 312 543 647 1263 1540 2295 1266
1999-00 60 151 327 618 785 1207 876 1273 -167
2000-01 90 262 436 730 1023 1125 1403 1865 3041
2001-02 53 132 411 583 775 966 1490 3086 866
2002-03 47 167 359 569 785 926 1516 1939 -25
2003-04 46 214 374 546 631 609 1148 1958 851
2004-05 50 187 448 538 723 1002 1603 2299 1973
2005-06 56 219 423 697 824 775 1311 1688 3743
2006-07 60 166 359 633 770 1069 1770 2134 2142
2007-08 71 262 563 760 1140 1045 2171 2570 3247
2008-09 68 204 369 504 666 1625 1852 1664 2479
2009-10 51 221 406 592 731 1097 676 1475 2110
2010-11 54 182 364 431 644 693 851 1226 1713
2011-12 47 186 363 608 550 549 1038 1907 1840
2012-13 52 207 350 599 779 1128 1354 1058 2527
2013-14 39 181 334 624 572 811 1121 1084 1381
2014-15 36 192 356 618 703 961 1177 874 1890
2015-16 43 156 351 447 707 745 1089 1497 1325
2016-17 89 239 520 585 923 1128 1288 2071 1889
2017-18 54 218 396 508 884 831 1098 1447 731
2018-19 36 204 365 476 642 854 1171 1240 659
2019-20 32 105 275 392 528 606 709 1100 1364
2020-21 54 120 309 362 605 792 1144 1754 2086
2021-22 63 243 371 590 806 1203 1371 1701 2372
Table 5.12. COD. Yearly weight increment (g) from bottom trawl surveys in the Barents Sea standard area winter 1994-2022.
Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 0.00 0.00 0.00 0.00 0.06 0.14 0.31 0.71 0.92 1.00 0.83 1.00 + -
1995 0.00 0.00 0.00 0.01 0.05 0.26 0.32 0.51 0.85 0.91 1.00 1.00 - -
1996 0.00 0.00 0.00 0.00 0.01 0.16 0.33 0.51 1.00 1.00 1.00 1.00 1.00 +
1997 0.00 0.00 0.00 0.00 0.01 0.08 0.38 0.80 1.00 0.83 + - - -
1998 0.00 0.00 0.00 0.01 0.04 0.18 0.33 0.64 0.84 1.00 - + - -
1999 - 0.00 0.00 0.00 0.01 0.12 0.37 0.70 0.88 + + + - +
2000 0.00 0.00 0.00 0.00 0.05 0.28 0.85 0.86 1.00 1.00 + + - +
2001 0.00 0.00 0.00 0.01 0.05 0.27 0.43 0.70 0.91 1.00 - - - -
2002 - 0.00 0.00 0.01 0.04 0.29 0.47 0.56 0.87 1.00 - - - -
2003 - 0.00 0.00 0.00 0.05 0.21 0.40 0.69 0.94 1.00 - + + -
2004 - 0.00 0.00 0.01 0.05 0.25 0.53 0.72 0.87 0.88 + + - +
2005 0.00 0.00 0.00 0.00 0.04 0.18 0.49 0.80 0.92 1.00 1.00 + 1.00 -
2006 0.00 0.00 0.00 0.03 0.05 0.20 0.39 0.74 0.72 1.00 1.00 1.00 - -
2007 0.00 0.00 0.00 0.01 0.05 0.33 0.57 0.84 0.98 1.00 1.00 1.00 + -
2008 0.00 0.00 0.01 0.01 0.12 0.32 0.54 0.74 0.82 1.00 1.00 + + -
2009 0.00 0.00 0.00 0.00 0.08 0.25 0.49 0.64 0.91 0.96 0.86 + + -
2010 - 0.00 0.01 0.01 0.10 0.37 0.50 0.79 0.89 0.95 0.93 + + 1.00
2011 0.00 0.00 0.00 0.00 0.03 0.22 0.43 0.54 0.84 0.88 1.00 1.00 1.00 +
2012 0.00 0.00 0.00 0.00 0.09 0.21 0.42 0.67 0.85 0.93 1.00 1.00 1.00 +
2013 0.00 0.00 0.00 0.00 0.01 0.11 0.40 0.69 0.79 0.98 0.95 1.00 1.00 +
2014 0.00 0.00 0.00 0.00 0.03 0.10 0.41 0.76 0.87 0.97 0.98 0.96 1.00 +
2015 0.00 0.00 0.00 0.00 0.00 0.06 0.16 0.65 0.91 0.97 0.95 1.00 1.00 +
2016 0.00 0.00 0.00 0.00 0.00 0.04 0.16 0.54 0.78 0.95 0.95 1.00 1.00 1.00
2017 0.00 0.00 0.00 0.02 0.00 0.09 0.34 0.65 0.89 1.00 1.00 0.97 1.00 1.00
2018 0.00 0.00 0.00 0.00 0.02 0.13 0.32 0.56 0.84 0.96 1.00 0.97 0.97 1.00
2019 0.00 0.00 0.00 0.00 0.01 0.12 0.34 0.76 0.89 0.86 0.95 1.00 1.00 1.00
2020 0.00 0.00 0.00 0.00 0.01 0.11 0.29 0.63 0.82 0.89 1.00 1.00 1.00 1.00
2021 0.00 0.01* 0.00 0.00 0.00 0.14 0.33 0.58 0.84 0.95 0.96 1.00 1.00 +
2022 0.00 0.00 0.02 0.00 0.00 0.06 0.39 0.63 0.66 0.96 1.00 0.96 1.00 -
Table 5.13. COD. Proportion mature at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimate. The proportion mature is the number of fish classified as maturity category 2 and 3, divided by the total number of fish assigned categories 1-3.

* Based on one sample only.

5.5 - Stomach sampling

Since 1984, cod stomachs have been sampled regularly during the winter survey. The sampling strategy has generally been the same as that for sampling otoliths. Stomach have been frozen on board and analysed in the laboratory, except for the period 1994-2000, when some of the stomachs were analysed on board and only the main prey categories were identified. For details about the sampling methodology and the Norwegian-Russian cooperation on diet investigations in the Barents Sea, see Mehl and Yaragina (1992) and Dolgov et al . (2007).

The number of stations and stomachs sampled as well as the proportion of empty stomachs and the mean stomach fullness index (SFI, see below) for each of four size groups (≤ 19 cm, 20-34 cm, 35-49 cm, ≥ 50 cm) is given in Table 5.14. Tables 5.15 - 5.18 show the mean diet composition by prey species/groups by year for each size group. Note that in the years 1994-2000, blue whiting, long rough dab and Norway pout were included in the category ‘other fish’ when stomachs were analysed on board.

The stomach fullness index is calculated as SFIi=100*ΣWSi/Wi, where WSi is the weight (g) of the stomach of fish i, and Wi is the weight (g) of fish i . For 1987 SFI has not been calculated, because very few fish were weighed that year due to technical problems. The distribution on prey groups has been adjusted by distributing the unidentified component of the diet proportionally among the various components, taking into account the level of identification.

The proportion of empty stomachs is largest for the smallest fish (Table 5.14), a pattern seen for all years. The stomach fullness in 2021 was lower than in 2020 for all length groups except cod ≤ 19 cm. Capelin is the dominating prey for cod ≥ 20 cm, followed by shrimp (Tables 5.16-5.18), while krill dominates for the smallest cod (Table 5.15). However, in many years capelin is also an important prey for the smallest cod. The proportion of capelin in the diet decreased from 2020 to 2021 for cod ≥ 30 cm while it increased for smaller cod. Cod cannibalism as proportion of the diet has shown a decreasing trend in recent years.

    no. stomachs sampled % empty stomachs mean stomach fullness
Year Stations <20 cm 20-34 cm 35-49 cm >=50 cm <20 cm 20-34 cm 35-49 cm >=50 cm <20 cm 20-34 cm 35-49 cm >=50 cm
1984 31 176 288 242 381 18.8 14.9 5.0 4.5 1.59 2.05 1.80 1.46
1985 49 106 494 582 612 44.3 34.0 19.8 20.6 1.55 3.58 4.46 3.43
1986 73 231 309 398 427 43.3 32.4 26.9 19.0 0.73 2.48 2.90 2.94
1987 52 133 415 501 409 32.3 48.9 45.3 48.9        
1988 79 29 418 844 704 34.5 40.2 31.6 29.7 1.01 1.29 0.91 0.84
1989 82 82 378 890 1132 40.2 21.2 16.3 20.6 1.45 2.28 2.12 1.47
1990 60 177 300 450 870 39.0 22.7 18.4 16.4 1.84 2.18 2.01 1.60
1991 70 271 463 450 1107 40.6 25.5 11.3 9.5 0.95 2.28 3.73 4.27
1992 100 229 382 471 922 65.9 45.8 31.4 38.2 1.79 3.15 3.05 1.92
1993 117 139 393 570 1073 76.3 38.4 21.2 26.7 1.86 3.34 2.99 3.05
1994 138 296 370 580 1163 64.9 34.9 25.0 24.3 0.76 2.04 2.00 1.63
1995 161 452 517 638 1482 52.2 36.4 32.0 30.8 1.16 1.39 0.93 0.80
1996 254 483 507 540 1338 55.7 39.1 28.0 27.4 0.92 1.32 1.38 1.02
1997 149 305 337 358 1105 57.0 34.1 20.7 29.5 0.98 1.60 1.81 1.48
1998 197 496 492 564 1042 64.7 48.2 29.3 28.6 2.20 1.93 1.67 1.22
1999 211 310 471 554 849 61.3 38.6 27.4 25.9 2.11 1.90 2.06 1.76
2000 243 413 645 669 1069 53.8 28.7 21.2 21.1 1.36 1.98 2.41 1.74
2001 361 644 728 884 1485 72.4 42.3 29.3 32.2 2.32 2.98 3.33 2.79
2002 345 393 704 799 1423 69.2 42.8 30.9 30.9 1.57 2.78 2.36 1.88
2003 285 325 499 637 1468 61.5 39.5 22.6 24.4 5.55 2.78 2.55 2.28
2004 329 508 525 663 1522 51.8 37.9 24.1 27.6 1.94 2.02 1.76 1.55
2005 335 509 651 648 1423 43.6 34.7 26.5 25.4 2.29 2.22 1.79 1.65
2006 259 402 464 534 1059 59.2 42.5 21.9 24.5 1.80 1.88 2.56 1.80
2007 273 386 483 592 1341 60.6 45.3 30.7 30.1 1.68 1.87 1.83 1.50
2008 326 260 733 933 1655 61.9 38.5 26.0 23.0 1.94 2.42 2.93 2.19
2009 319 385 547 798 1657 56.1 35.1 22.3 23.9 1.57 1.89 2.02 1.58
2010 360 594 552 748 2079 51.5 38.6 23.0 25.5 1.83 2.19 2.72 2.49
2011 359 515 628 506 1821 56.7 37.7 17.2 23.9 2.08 2.06 2.47 2.49
2012 297 373 408 431 1626 42.6 27.5 13.9 21.0 1.80 2.45 2.28 1.67
2013 279 209 352 425 1435 44.0 28.4 12.7 17.2 1.49 2.25 2.36 1.93
2014 434 570 686 686 2004 42.8 26.7 18.4 19.8 1.59 2.17 2.11 1.33
2015 356 664 562 670 1735 45.8 29.9 20.1 23.1 1.53 2.09 1.96 1.59
2016 387 427 616 728 1971 52.5 32.0 25.4 24.2 1.51 1.92 2.03 1.56
2017 293 339 465 529 1416 46.0 35.5 28.5 28.2 1.90 1.99 1.66 1.50
2018 432 638 850 935 2086 44.8 28.1 19.4 17.5 1.50 2.07 2.29 1.74
2019 506 787 974 1095 2302 46.1 29.6 19.1 17.2 1.60 1.95 2.04 1.87
2020 458 633 952 992 2369 38.1 28.2 18.2 18.0 1.71 1.98 2.33 2.16
2021 447 385 824 899 1842 49.1 23.1 12.7 16.5 2.53 1.71 1.80 2.05
Table 5.14. Number of stations and stomachs sampled, % empty stomachs, and mean stomach fullness by length group in the Barents Sea winter 1984-2021.
Year Amphipods Krill Shrimp Other invertebrates Capelin Herring Polar cod Blue Cod Haddock Redfish Long rough dab Norway Other
whiting pout fish
1984 1.2 7.7 37.5 4.5 13.3           35.8      
1985 15.5 7.9 27.9 44.4                   4.3
1986 14.3 3.8 34.0 14.4 15.2                 18.3
1987 24.8 17.7 10.9 0.2 25.4   21.0              
1988 3.5 19.2   64.3             13.0      
1989 41.1 27.9   31.0                    
1990 5.5 14.2 38.4 3.7 3.8           3.2     31.2
1991 12.2 18.7 6.9 8.4 53.8                  
1992 3.7 3.8 6.9 54.3 17.7                 13.6
1993 35.3 59.0   5.7                    
1994 19.1 40.8 10.9 11.6                   17.6
1995 12.9 6.7 33.9 3.5 7.4   27.8   6.2         1.6
1996 16.3 25.4 15.0 27.4 9.4                 6.5
1997 23.3 35.9 26.5 0.3                   14.0
1998 20.9 30.3 17.2 12.4 16.9             2.3    
1999 9.9 18.4 34.0 6.5   18.0 13.2              
2000 3.3 57.1 17.8 0.0 17.3                 4.5
2001 7.0 31.2 10.1 10.7 26.8 8.6               5.6
2002 15.0 32.1 21.1 13.9 17.9                  
2003 1.6 80.0 10.4 1.4 6.6                  
2004 11.0 44.7 5.9 9.1 14.3 4.2 10.8              
2005 17.2 22.8 16.2 0.3 35.8                 7.7
2006 9.7 49.9 7.8 20.5 12.1                  
2007 6.0 74.6 6.1 0.5 11.6             1.2    
2008 7.3 47.6 31.3 8.7 0.7             0.3   4.1
2009 4.7 61.4 1.9 8.8 18.1                 5.1
2010 3.5 41.7 1.4 1.6 48.2           0.7     2.9
2011 1.5 24.8 14.6 4.0 29.6           8.2     17.3
2012 4.7 20.2 8.5 4.0 53.0                 9.6
2013 2.2 66.2   17.8                   13.8
2014 8.9 42.6 12.7 8.9 26.8                 0.1
2015 2.8 44.8 10.6 13.6 22.1                 6.1
2016 15.7 39.7 9.6 5.6 21.5                 7.9
2017 12.7 6.9 1.0 38.0 0.9           31.0     9.5
2018 9.0 43.9 11.2 9.6 19.0                 7.3
2019 7.5 34.9 13.9 9.8 27.7               2.2 4.0
2020 10.4 53.9 4.4 9.1 13.2       2.2     1.4   5.4
2021 6.0 45.2 8.4 2.5 31.7             2.1 4.1  
Table 5.15. Mean stomach content composition (% of total SFI) of cod ≤ 19 cm from the survey in the Barents Sea winter 1984-2021.
Year Amphipods Krill Shrimp Other invertebrates Capelin Herring Polar cod Blue Cod Haddock Redfish Long rough dab Norway Other
whiting pout fish
1984 0.1 0.1 21.0 2.7 40.2   8.1       26.3 0.2   1.3
1985 0.2 0.1 17.0 2.0 69.2 9.3       1.1 0.2     0.9
1986 2.0 1.1 5.9 2.8 56.2 7.0       0.8 23.3     0.9
1987 0.5 1.9 25.2 0.3 53.7       6.6   11.4     0.4
1988 0.9 0.2 20.7 7.0 52.9           18.3      
1989 11.9 7.1 9.0 5.6 33.2   5.4   1.6   25.4 0.5   0.3
1990 0.6 0.5 18.5 0.7 66.7           8.4     4.6
1991 0.1 0.2 4.3 0.2 92.5           2.0     0.7
1992 0.4 0.8 6.4 1.2 88.1       0.4   2.5     0.2
1993 0.1 0.6 8.1 0.3 78.4 5.9 3.8   0.9 1.1 0.1     0.7
1994 1.2 10.2 8.3 1.7 54.9 14.2 4.8   1.7   1.2     1.8
1995 1.4 1.5 9.4 1.8 45.8   10.8 0.6 13.3 3.4 9.3     2.7
1996 1.9 0.5 13.6 1.3 48.9   5.3   24.9   1.8 0.3 0.8 0.7
1997 1.1 3.4 17.6 1.6 42.6   1.2 5.4 10.0         17.1
1998 2.2 2.6 23.5 1.6 47.8 3.4     10.3     5.6   3.0
1999 2.3 4.0 24.5 3.4 45.6 13.5 0.8   3.2 2.7        
2000 0.7 8.0 14.2 0.3 59.4 4.2 5.3   3.6 2.1   0.1   2.1
2001 0.9 2.8 8.5 2.8 69.4 4.7 5.6   4.0         1.3
2002 0.5 1.6 12.2 2.9 71.2 0.7 7.0     1.9       2.0
2003 0.5 2.4 7.3 0.7 71.9 14.4     2.1     0.1 0.5 0.1
2004 2.1 5.2 9.7 1.9 60.6 5.9 6.4   1.9 4.2       2.1
2005 0.6 2.3 12.0 0.9 61.2 3.6 7.7   5.7       4.9 1.1
2006 1.4 1.5 11.8 3.2 66.6 1.6 2.8 2.1   3.4     4.9 0.7
2007 2.3 4.8 15.0 7.3 58.8 0.1       7.7 3.7     0.3
2008 0.5 3.8 11.1 4.7 63.3   3.5     2.4 4.2 1.0   5.5
2009 0.5 6.6 8.8 5.6 71.2   2.4   1.5   0.2     3.2
2010 0.7 5.2 7.4 1.8 74.2 1.0     6.4   2.2     1.1
2011 0.9 3.3 8.3 3.7 74.3       1.1   6.0 0.1 1.1 1.2
2012 0.4 2.6 7.2 2.3 77.1 0.4     7.7         2.3
2013 0.3 7.2 10.4 3.4 68.0   2.1   4.3   0.3 0.1   3.9
2014 2.6 3.5 6.3 5.8 74.7 1.7     1.5 0.1       3.8
2015 0.9 2.4 9.8 3.4 75.9       3.7 1.6   0.3   2.0
2016 2.7 5.8 9.1 6.0 65.2         3.7 0.7     6.8
2017 0.4 3.3 7.8 4.6 67.0 1.7       4.5 2.0 6.7   2.0
2018 1.2 6.5 4.9 6.5 64.6 3.0     7.8 1.7 0.1   2.0 1.7
2019 0.6 4.4 9.2 9.1 64.7 0.5     7.6 1.4       2.5
2020 2.8 12.4 7.4 7.0 64.5       1.4 0.5 0.7 0.4   2.9
2021 2.2 14.1 16.2 10.3 42.1   2.6       4.3 0.9   7.3
Table 5.16. Mean stomach content composition (% of total SFI) of cod 20-34 cm from the survey in the Barents Sea winter 1984-2022.
Year Amphipods Krill Shrimp Other invertebrates Capelin Herring Polar cod Blue Cod Haddock Redfish Long rough dab Norway Other
whiting pout fish
1984 0.5   18.2 1.3 41.5       0.7 2.6 34.5 0.1 0.6  
1985 0.5   4.7 0.2 88.7 4.2     0.5 0.2 0.9     0.1
1986 0.8 2.5 6.8 3.6 58.4 12.4         15.3     0.2
1987 0.5 0.2 22.9 1.7 47.9 9.2 1.8   4.4 2.0 5.5   3.8 0.1
1988 1.0 1.9 29.1 6.3 51.2     1.5     8.8     0.2
1989 4.1 1.8 11.3 3.3 50.2   7.9   0.2   18.6 0.8 0.2 1.6
1990 0.1 0.1 7.4 1.6 84.8 2.0       1.3 2.5   0.2  
1991 0.1 0.1 1.8 0.6 94.0         1.5 1.2 0.1   0.6
1992   0.1 3.3 3.7 79.7 9.1     0.3 0.3 1.2   1.7 0.6
1993 0.1 0.2 6.0 0.6 85.4 5.6 0.5   0.2 0.4   0.2 0.8  
1994 0.9 14.2 6.9 1.2 48.9 13.5 9.1   2.2 0.4 0.3     2.4
1995 0.9 0.6 12.8 2.2 44.7 6.2 1.2   17.9 8.6 4.7     0.2
1996 1.8 0.7 10.0 2.2 21.6 1.5 2.1 5.5 37.4 6.7 2.5   6.9 1.1
1997 0.9 0.3 14.8 4.3 40.3   5.2 3.6 17.1 3.7 0.5 0.1 1.2 8.0
1998 1.1 0.4 23.2 6.8 50.3 8.5 1.2 1.8 4.1 1.5 0.8     0.3
1999 0.3 0.4 28.0 1.8 44.9 12.0 2.4   1.9 5.7 0.5 0.1 0.4 1.6
2000 0.9 0.3 8.2 0.6 83.5 4.1 0.4   0.7 0.3       1.0
2001 0.4 0.2 6.3 3.3 73.6 5.2 7.3 1.4 1.1 0.5   0.3   0.4
2002 0.2 0.6 10.4 4.2 68.3 2.3 4.8 0.8 3.2 3.9   0.5 0.4 0.4
2003 0.3 1.1 8.2 1.6 68.4 11.1 1.2 0.2 2.7 4.9       0.3
2004 0.9 1.6 14.5 4.5 61.7 6.5 2.3 1.0 4.1 1.5     1.0 0.4
2005 0.7 0.7 13.7 2.1 58.3 3.1 3.6 1.9 0.2 13.2   0.3 1.4 0.8
2006 0.1 0.2 13.1 1.5 64.8 2.0 1.3 1.6 1.1 12.7   0.2 0.3 1.1
2007 3.5 0.8 18.7 2.4 47.6 7.8   0.2 1.1 13.1 0.4 0.4 3.3 0.7
2008 0.3 0.9 11.7 1.3 71.9 2.7 7.4     0.9 1.1 0.3 0.4 1.1
2009 0.8 1.7 6.9 6.9 75.9 1.8 2.4   1.7 0.4 0.6 0.1 0.8  
2010 1.0 1.2 6.3 1.3 81.2 0.4 0.3   2.2 3.6 1.4 0.1 0.6 0.4
2011 0.1 0.7 7.5 3.2 76.0 1.5   1.4 4.2 0.9 2.3 0.1 1.4 0.7
2012 0.5 0.9 7.7 4.3 71.2 0.5 0.8 0.3 4.2 4.4 0.8 0.3 2.6 1.5
2013 0.4 1.5 7.9 4.6 77.9   1.1   3.3 1.6 0.3 0.1 0.3 1.0
2014 0.3 0.6 10.5 3.9 74.4 1.8     1.6 4.3 0.6 0.1 0.9 1.0
2015 0.5 3.2 7.9 2.3 77.1 1.3 0.2 2.3 2.4 1.1 0.3 0.4   1.0
2016 3.3 1.0 8.8 5.7 68.2 1.3     2.2 5.7 1.1 0.7 0.7 1.3
2017 0.1 1.1 12.3 4.1 70.5       0.4 5.6 0.7   2.6 2.6
2018 0.2 2.0 6.5 2.4 70.0 5.9     7.0 5.0 0.3   0.2 0.5
2019 0.5 1.1 9.8 3.0 69.8 3.9     6.1 4.0 0.4 0.1   1.3
2020 1.6 2.5 7.5 3.1 81.1 2.0     1.5 0.1 0.2 0.2   0.2
2021 2.6 3.5 20.0 5.7 55.9 1.4 2.6 0.4 0.6 0.6 4.7 0.5   1.5
Table 5.17. Mean stomach content composition (% of total SFI) of cod 35-49 cm from the survey in the Barents Sea winter 1984-2021.
Year Amphipods Krill Shrimp Other invertebrates Capelin Herring Polar cod Blue Cod Haddock Redfish Long rough dab Norway Other
whiting pout fish
1984 0.4   16.3 1.3 48.1   0.6   3.5 2.4 26.4 0.3   0.7
1985 0.2   5.2 0.4 85.8 3.0   0.3 2.1 0.6 1.2 1.1 0.1  
1986 0.6 0.2 4.4 3.9 53.9 3.2   2.5 9.5 7.9 7.7 0.1 4.1 2.0
1987 1.9 0.1 7.4 6.5 2.2 3.6 3.1 3.3 15.6   35.3 0.3 18.9 1.8
1988 0.9 0.7 11.7 7.0 11.9     4.8 0.0   16.3 4.7   42.0
1989 0.8 1.0 10.1 7.2 50.9   1.1   0.0 0.5 25.1 1.2 0.8 1.3
1990 0.1 0.3 5.2 1.8 74.4 1.1   5.2 0.1 4.8 4.0 0.9 1.8 0.3
1991     1.2 0.5 94.1 0.4     0.6 0.9 1.0 0.1 0.4 0.8
1992 0.2 0.1 5.6 3.8 56.7 17.6 0.1   2.3 4.1 3.7 2.3 2.6 0.9
1993   0.3 2.2 11.4 54.9 16.0 0.3 0.6 5.2 4.3 0.9 0.0 3.8 0.1
1994 0.5 12.9 5.9 2.8 35.4 7.1 4.4 0.2 12.0 4.3 5.8 1.1   7.6
1995 0.5 0.3 5.0 2.2 8.4 8.0 0.7   18.3 20.4 18.8 2.2 0.2 15.0
1996 0.5 0.2 4.1 2.7 9.3 14.6 2.5 0.4 27.2 27.8 6.2 1.8 2.6 0.1
1997 0.2 0.2 10.1 0.8 45.8 5.0 1.1 3.4 5.3 8.2 4.3 0.8 0.6 14.2
1998 1.2 0.2 22.7 3.8 34.5 7.3 1.0 1.2 6.2 6.6 4.1 3.7 2.6 4.9
1999 0.2 0.1 25.8 6.3 26.5 9.8 2.5 0.7 10.3 5.0 0.4 1.4 0.5 10.5
2000 0.9 0.4 7.9 1.6 68.9 6.5 0.8 2.3 2.8 3.4 0.7 1.5   2.3
2001 0.7 0.2 4.4 4.6 71.7 4.4 1.6 2.5 3.3 2.6 0.3 1.9 0.4 1.4
2002 0.2 0.7 5.9 6.5 50.9 3.0 4.2 2.0 9.0 13.0 1.0 1.7 0.7 1.2
2003 0.1 0.2 5.5 4.9 59.1 10.6 1.5 1.1 4.3 9.1 0.5 1.4 0.4 1.3
2004 0.2 0.2 6.5 3.2 48.2 4.9 0.5 2.6 7.6 17.0 1.6 2.7 1.6 3.2
2005 0.3 0.3 5.8 4.2 33.2 2.9 0.8 5.6 7.9 31.2   1.5 2.5 3.8
2006 0.1 0.1 4.6 4.8 45.8 1.8 0.6 6.1 1.8 28.3 1.6 1.8 1.5 1.1
2007 0.5 0.2 8.3 5.0 29.2 18.4   1.9 7.8 20.8 2.0 2.3 2.7 0.9
2008 0.1 0.4 4.9 2.7 60.7 7.5 0.3 0.4 0.9 17.4 0.8 1.8 0.9 1.2
2009 0.2 0.3 5.5 4.2 53.0 8.6 0.8 0.4 4.1 12.9 1.5 2.9 3.9 1.7
2010 0.6 0.3 2.5 2.3 72.7 1.7 0.2 0.1 3.5 10.6 0.9 2.0 2.5 0.1
2011 0.1 0.3 3.1 2.9 82.0 0.4 0.6   2.6 5.2 0.9 0.5 1.1 0.3
2012 0.1 0.2 4.0 7.1 60.9   0.1 0.1 2.6 16.7 0.5 1.1 3.8 2.8
2013 0.3 0.7 4.1 7.6 67.9 0.2 0.4 0.6 5.1 8.3 0.9 1.4 1.8 0.7
2014 0.5 0.5 5.6 10.4 55.4 2.2   0.2 6.3 10.9 1.0 3.1 1.6 2.3
2015 0.2 0.1 4.1 6.7 69.9 1.1   1.1 2.9 6.8 2.1 1.3 2.4 1.3
2016 1.0 0.9 3.4 14.8 60.0 2.9 0.1 0.7 5.3 6.5 0.7 2.7 0.4 0.6
2017 0.1 0.6 2.9 4.2 74.2 1.4   1.5 0.6 10.7 1.3 1.2 1.0 0.3
2018 0.1 0.9 3.7 9.5 51.7 2.5 0.1 0.1 8.1 19.3 0.7 2.0 0.7 0.6
2019 0.4 0.5 3.8 6.6 68.4 2.8 0.1 0.2 5.5 7.4 1.0 0.5 1.9 0.9
2020 0.4 0.8 2.6 7.5 59.3 5.5 0.0 0.2 13.4 4.8 1.8 1.9 1.0 0.8
2021 0.4 1.1 5.2 9.3 51.0 10.6 3.9 0.1 3.6 8.1 2.3 2.8   1.6
Table 5.18. Mean stomach content composition (% of total SFI) of cod ≥ 50 cm from the survey in the Barents Sea winter 1984-2021.

6 - Distribution and abundance of haddock

6.1 - Acoustic estimation

As for cod, it is expected that the survey best covers the immature part of the haddock stock. At this time of the year a large proportion of the mature haddock (age 6 and older) is on its spawning migration south-westwards out of the investigated area. In some earlier years, e.g., 2004 and 2005, concentrations of mature haddock have been observed pelagically rather far above bottom along the shelf edge. The bottom trawl sampling poorly covers these concentrations. There are indications that the distribution of age groups 1 and 2 in some years are concentrated in coastal areas not well covered by the survey. This occurred in the late 1990s and will have strongest effect on poor year-classes. In the later surveys, small haddock have been widely distributed, and the strong year-classes have been found unusually far to the north. Favourably hydrographic conditions and/or density dependent mechanisms might cause this. However, it is difficult to separate the two factors.

Figure 6.1 shows the spatial distribution of acoustic registrations assigned to haddock in 2022. The registrations reflect the general distribution of haddock in the southern and eastern Barents Sea. The overall echo abundance in 2022 was higher than the very low registrations in 2021, with several coastal transects registering NASC-values above 500 (up to 700 m2/nmi2 ).

 

HADDOCK NASC. Distribution of acoustic backscatter (m2/nmi2) assigned to haddock in 2022. The black lines without yellow circles represent parts of the cruise track where the acoustic backscatter was scrutinized but not assigned to haddock. NASC values < 5 was set to zero for this illustration. Circles with red outline represent NASC > 500.
Figure 6.1. HADDOCK NASC. Distribution of acoustic backscatter (m2/nmi2 ) assigned to haddock in 2022. The black lines without yellow circles represent parts of the cruise track where the acoustic backscatter was scrutinized but not assigned to haddock. NASC values < 5 was set to zero for this illustration. Circles with red outline represent NASC > 500.

 

Table 6.1 shows the acoustic abundance indices by age within the main areas. As in most of the previous years the highest abundance was observed in main area D. The full time series is presented in Table 6.2. Abundance of age 1 in 2022 increased compared to 2020 and 2021 when it was very low. This is reflected in low abundances of ages 2 and 3 in 2022. Abundance of age 6 in 2022 was quite high, while abundance of older fish (age 8+) kept declining from the high in 2013-2014.

The strong 2004-2006 year-classes can be followed through the time series. In later years, the 2009, 2011, and 2013-2018 year-classes seem to be fairly strong. In particular the year-classes 2016 and 2017 have high indices at age 1-2. The year-class 2019 appears to be much weaker as the abundance of 1-year-olds observed in 2020 is the third lowest in the time series. The estimate of this year-class as 2-year-olds in 2021 are only half of the previously lowest estimate in the time series. Abundance of the 2020 year-class, while still on the low side, is nearly 60 % higher than the 2019 year-class, while the 2021 year-class is much stronger and above average in the time series.

The abundance of old fish (particularly age 14) was higher in 2020 than previously observed. This likely reflects the surviving individuals from the 2005-2006 year-classes. However, few of these fish appear to have survived and become part of the 15+ group in 2021 and 2022.

Table 6.3 shows indices for strata 24-26, which are also included in the full time series (Table 6.2). The contribution from main area N was rather low in all years, except in 2018 when 29% of age 1 haddock (by number) was found in the extended area, contributing 13 % of the total stock biomass index. The total abundance in area N in 2022 is comparable to the abundance in 2019 and much higher than in 2020-2021.

Table 6.4 presents estimated coefficients of variation (CV) for haddock age groups 1-14. In most years, CVs for age groups older than 7 years are above what could be considered as acceptable (approximately 20 %). In recent years, younger ages have also had relatively high CVs, which may indicate patchier distributions in a situation with low abundance.

Age group Total Biomass (‘000 t)
Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
A 250.1 10.2 0.87 3.46 8.20 9.06 2.92 0.05 0.02 0.18 0.63 0.00 0.00 0.00 0.00 285.7 33.3
B 170.0 11.9 4.30 2.07 10.0 6.29 0.98 0.09 0.05 0.00 0.00 0.00 0.00 0.00 0.00 205.8 128.5
C 398.6 15.4 2.25 11.1 12.4 21.1 2.95 0.18 0.00 0.00 0.00 0.00 0.00 0.05 0.00 464.0 11.4
D 609.6 27.1 3.60 41.8 50.1 52.2 3.15 0.24 0.07 0.03 0.00 0.00 0.00 0.01 0.00 787.8 1.31
D'1 35.3 0.34 0.24 3.60 5.44 5.09 0.17 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 50.2 18.3
E 73.4 0.18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 73.6 10.3
S 157.7 1.20 0.04 0.73 5.40 5.87 1.30 0.19 0.00 0.00 0.04 0.00 0.00 0.00 0.00 172.4 27.7
N 102.5 3.81 0.05 0.61 3.72 1.70 0.31 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112.7 51.8
ABCD 1428.3 64.6 11.0 58.5 80.7 88.6 10.0 0.6 0.1 0.2 0.6 0.00 0.00 0.1 0.00 1743.3 174.5
AN 1797.1 70.2 11.4 63.4 95.3 101.2 11.8 0.8 0.1 0.2 0.7 0.00 0.00 0.1 0.00 2152.2 282.6
Table 6.1. HADDOCK. Abundance indices (numbers in millions) for the main areas of the Barents Sea from acoustic survey winter 2022 estimated by StoX software.
Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
1994 887.82 187.96 348.73 626.65 121.38 8.55 0.70 0.33 0.61 0.48 1.46 0.16 0.00 0.00 0.00 2184.83 643.51
1995 1198.18 88.59 41.47 121.49 395.37 47.61 2.80 0.05 0.12 0.03 0.00 0.54 0.14 0.00 0.00 1896.39 508.78
1996 132.60 94.52 29.97 22.09 68.65 143.69 5.67 0.93 0.00 0.01 0.00 0.02 0.04 0.00 0.00 498.19 248.35
19971 508.87 26.51 57.27 22.22 15.47 56.13 62.77 4.68 0.07 0.00 0.00 0.01 0.05 0.06 0.00 754.11 201.67
19981 210.96 150.99 33.78 58.79 24.20 7.70 14.06 20.69 1.44 0.02 0.04 0.00 0.00 0.00 0.12 522.78 150.98
1999 653.40 30.11 83.67 21.64 22.10 6.17 1.55 3.88 2.72 0.03 0.00 0.02 0.00 0.00 0.00 825.29 107.86
2000 1063.01 404.77 36.39 75.53 14.01 12.61 1.57 0.53 2.01 0.69 0.17 0.13 0.02 0.00 0.00 1611.44 189.81
2001 753.01 266.12 233.45 40.20 41.38 2.20 1.61 0.15 0.09 0.14 0.28 0.09 0.09 0.00 0.02 1338.83 206.40
2002 1315.15 267.90 255.20 201.84 18.47 11.70 1.59 0.29 0.03 0.13 0.26 0.09 0.05 0.00 0.00 2072.70 298.25
2003 2743.74 362.35 203.68 184.57 136.04 12.26 6.01 0.26 0.14 0.26 0.34 0.09 0.07 0.00 0.00 3649.81 444.48
2004 528.97 466.54 151.01 101.85 107.82 57.68 7.61 1.15 0.29 0.04 0.05 0.05 0.04 0.08 0.00 1423.18 322.95
2005 2276.46 143.98 221.33 115.67 57.43 56.71 12.69 0.38 0.32 0.01 0.00 0.00 0.00 0.00 0.00 2884.98 305.99
20062 2091.11 624.78 56.32 123.84 47.37 19.26 13.64 3.23 0.08 0.15 0.00 0.03 0.00 0.00 0.09 2979.90 297.84
20071 2015.71 953.50 209.28 46.14 80.57 28.92 10.00 5.05 2.26 0.30 0.18 0.00 0.00 0.00 0.05 3351.97 401.72
2008 778.39 1753.54 812.41 303.04 90.02 74.12 7.41 12.77 1.63 0.14 0.16 0.18 0.00 0.00 0.00 3833.81 920.38
2009 443.93 209.05 883.68 629.98 266.65 38.87 14.57 1.26 0.34 0.66 0.00 0.05 0.00 0.00 0.00 2489.04 865.44
2010 1559.42 86.03 128.07 631.03 603.99 166.96 12.07 2.94 0.96 0.99 0.10 0.06 0.00 0.00 0.00 3192.62 1035.93
2011 428.46 288.27 54.16 84.23 313.02 292.21 54.91 1.71 0.96 0.23 0.00 0.20 0.07 0.00 0.00 1518.43 712.08
20123 1583.44 94.54 191.63 48.84 88.12 310.60 172.52 30.09 0.52 0.34 0.02 0.13 0.00 0.00 0.00 2520.79 814.60
2013 292.71 407.16 67.29 146.77 35.41 53.03 223.77 102.68 14.12 0.25 0.00 0.00 0.00 0.00 0.00 1343.19 759.62
2014 1838.71 109.92 334.82 39.12 108.72 23.18 34.77 86.36 36.63 1.66 0.52 0.00 0.00 0.01 0.00 2614.42 583.94
2015 1593.12 246.59 24.35 189.40 26.63 46.13 9.22 22.45 21.33 9.86 0.56 0.15 0.09 0.00 0.00 2189.88 387.71
2016 1276.00 107.18 71.81 12.08 59.62 12.52 17.28 7.48 17.21 12.74 2.76 0.48 0.00 0.03 0.02 1597.21 274.45
20173 3343.93 331.42 81.15 65.05 4.81 34.81 6.24 7.93 1.78 7.06 6.10 2.34 0.44 0.00 0.00 3893.06 338.87
2018 2925.90 810.16 171.03 62.74 64.40 6.77 15.57 2.75 2.57 1.56 5.56 2.99 1.87 0.14 0.00 4074.01 410.39
2019 1544.96 687.80 507.61 146.22 31.73 21.88 4.72 3.46 1.37 1.57 0.38 0.39 0.33 0.06 0.09 2952.57 396.54
20203 272.94 260.72 286.32 306.38 79.18 22.38 11.59 1.84 1.36 0.83 0.85 1.22 0.99 0.96 0.12 1247.68 381.58
20213 431.68 15.69 50.76 130.37 181.80 19.35 5.44 0.94 0.81 0.48 0.07 0.21 0.07 0.05 0.08 837.80 258.47
2022 1797.1 70.2 11.4 63.4 95.3 101.2 11.8 0.82 0.14 0.20 0.7 0.00 0.00 0.07 0.00 2152.2 282.60
Table 6.2. HADDOCK. Abundance indices (numbers in millions) from acoustic surveys in the Barents Sea winter 1994-2022 estimated by StoX software.

1 Indices raised to also represent the Russian EEZ.

2 Not complete coverage in southeast due to restrictions, strata 7 area set to default and strata 13 as in 2005

3 Indices raised to also represent uncovered parts of the Russian EEZ.

Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
2014 135.0 0.88 10.3 0.92 0.81 0.80 0.96 1.84 1.31 0.20 0.02 0 0 0 0 153.0 17.9
2015 71.2 22.2 0.71 17.9 1.10 6.77 0.90 1.31 4.01 3.03 0.14 0 0.09 0 0 129.4 48.2
2016 15.7 1.77 3.32 0.26 3.67 0.70 0.71 0.62 1.75 0.83 0.33 0 0 0 0 29.7 16.1
2017 80.1 8.20 1.23 2.28 0.40 2.60 0.40 0.92 0.29 0.64 0.61 0.33 0 0 0 98.0 18.1
2018 855.7 46.4 11.7 2.57 3.48 1.15 2.97 0.45 0.33 0.25 0.54 0.39 0.38 0 0 926.4 54.6
2019 67.68 25.50 16.12 5.59 1.07 1.01 0.13 0.11 0.05 0.03 0.03 0.09 0.03 0.05 0.00 118.11 17.84
2020 1.54 1.18 12.6 12.4 3.09 2.40 0.55 0.49 0.16 0.09 0.04 0.08 0.08 0.05 0 34.8 22.7
2021 5.47 0.44 0.23 4.87 7.44 0.73 0.28 0.14 0.08 0.01 0.05 0.02 0.05 0.00 0.00 19.8 13.4
2022 102.5 3.81 0.05 0.61 3.72 1.70 0.31 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112.7 51.8
Table 6.3. HADDOCK. Abundance indices (numbers in millions) for new strata 24-26 from acoustic surveys in the Barents Sea winter 2014-2022 estimated by StoX software. In 2020, the main index was revised to include these strata.
Age group
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 11 12 10 9 12 21 44 53 39 55 31 103 - -
1995 16 22 24 15 10 15 34 128 85 114 - 55 90 -
1996 20 27 31 23 16 15 22 44 - 120 - 98 108 -
19971 12 17 14 16 16 12 14 33 53 - - 121 63 74
19981 14 15 15 13 14 21 17 15 50 107 109 - - -
1999 19 24 21 28 22 23 32 34 26 118 - 123 - -
2000 9 9 21 12 18 17 28 45 30 39 72 102 104 -
2001 17 16 16 25 16 30 35 65 66 96 62 94 86 -
2002 8 10 12 10 16 16 29 51 111 69 60 53 71 -
2003 11 11 11 9 15 25 38 80 106 90 76 102 107 -
2004 37 23 23 30 33 17 21 26 45 65 65 86 64 66
2005 10 16 11 15 12 16 19 59 76 104 - - - -
20062 12 10 27 20 12 15 20 33 66 67 - 78 - -
20071 9 7 9 12 12 15 21 29 40 52 88 - - -
2008 13 10 10 10 21 24 29 62 94 263 84 137 - -
2009 14 13 9 11 14 19 19 43 79 48 - 107 - -
2010 15 17 10 10 9 13 27 34 49 49 108 92 - -
2011 15 13 16 12 11 10 15 40 58 94 - 84 115 -
20122 16 28 16 35 24 20 20 27 86 50 105 68 - -
2013 14 13 22 11 22 16 13 15 26 59 - - - -
2014 13 19 12 20 18 17 16 15 15 44 79 - - 109
2015 14 17 24 13 23 21 27 23 20 55 64 65 - -
2016 11 15 15 19 12 14 15 19 17 15 30 43 - 70
20172 6 9 15 13 22 16 22 23 34 29 24 36 67 -
2018 8 8 9 13 17 29 22 29 34 30 27 28 54 81
2019 9 8 8 8 13 14 29 26 48 35 64 35 72 115
20202 15 14 11 12 12 14 19 26 30 48 54 49 43 50
20212 15 25 19 34 45 21 37 48 78 94 61 121 57 87
2022 14 17 26 15 13 13 20 41 71 77 57 - - 86
Table 6.4. HADDOCK. Estimates of coefficients of variation (%) for acoustic abundance indices. Barents Sea standard area winter 1994-2022.

1Russian EEZ not covered 2Russian EEZ partly covered

6.2 - Swept area estimation

Figures 6.2 - 6.5 show the geographic distribution of bottom trawl catch rates (number of fish per NM 2 ) for haddock size groups < 20 cm, 20-34 cm, 35-49 cm and ≥ 50 cm. Like in previous years, the distribution extends further to the north and to the east than what was usual in the 1990s.

Table 6.5 presents the indices for each age group by main areas. The time series is shown in Table 6.6. The swept area estimates, too, are highest in the east in area D. The 2016-2018 year-classes currently dominate the bottom trawl indices. The weak 2019 year-class noted for the acoustic index is evident also in the swept area estimates, which is not surprising given that the same biological data used to calculate swept area indices are used to allocate acoustic backscatter to age groups. Overall, this survey tracks both strong and poor year-classes fairly well. Compared to cod a lower proportion of haddock is found in the extended survey area (Table 6.7). In 2022, the extended area contributed about 4 % of total abundance and about 2 % of total biomass.

 

HADDOCK < 20 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 6.2. HADDOCK < 20 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

 

HADDOCK 35-49 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 6.3. HADDOCK 20-34 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

 

HADDOCK 20-34 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 6.4. HADDOCK 35-49 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge

 

 

HADDOCK ≥ 50 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 6.5. HADDOCK ≥ 50 cm. Distribution in valid bottom trawl catches winter 2022 (number per nm2 ). Black crosses indicate zero catches and the stippled line the ice edge.

 

Table 6.8 presents estimated coefficients of variation (CV) for haddock age groups 1-14. In most years, CVs for age groups older than 7 years are above what could be considered as acceptable (approximately 20 %) .

Age group Total Biomass (‘000 t)
Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
A 312.8 31.0 0.56 4.26 5.54 6.72 2.50 0.05 0.02 0.11 0.24 0.00 0.00 0.00 0.00 363.9 28.9
B 148.3 9.80 3.39 0.78 5.15 3.04 0.39 0.07 0.01 0.00 0.00 0.00 0.00 0.00 0.00 171.0 17.2
C 129.2 7.27 0.80 3.38 3.19 5.39 0.93 0.06 0.00 0.00 0.00 0.00 0.00 0.02 0.00 150.2 15.1
D 801.2 57.6 4.41 64.1 85.9 87.6 4.67 0.30 0.08 0.04 0.00 0.00 0.00 0.02 0.00 1105.9 212.2
D'1 33.9 1.03 3.01 13.4 17.4 7.99 0.35 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00 77.0 28.5
E1 52.1 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 52.2 1.04
S 105.4 0.63 0.03 0.32 1.54 2.20 0.18 0.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 110.3 6.93
N 79.3 2.86 0.04 0.32 3.00 0.59 0.09 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86.2 6.81
ABCD 1391.5 105.7 9.15 72.5 99.8 102.8 8.48 0.47 0.11 0.16 0.24 0.00 0.00 0.04 0.00 1791.0 273.5
AN 1662.1 110.3 12.2 86.5 121.7 113.6 9.10 0.62 0.11 0.16 0.24 0.00 0.00 0.04 0.00 2116.7 316.7
Table 6.5. HADDOCK. Abundance indices from bottom trawl hauls for main areas of the Barents Sea winter 2022 (numbers in millions). Bootstrap mean estimates.
Age group Total Biomass (‘000 t)4
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+    
1994 604.20 224.79 314.53 436.25 46.18 3.54 0.16 0.13 0.20 0.15 0.47 0.03 0.00 0.00 0.00 0.00 403.7
1995 1429.04 199.52 54.86 167.10 343.38 29.62 1.44 0.03 0.04 0.02 0.00 0.29 0.09 0.00 0.00 0.00 443.9
1996 300.78 265.08 55.84 31.33 150.77 238.11 16.13 1.15 0.00 0.01 0.00 0.03 0.03 0.00 0.00 0.00 431.9
19971 1117.83 90.81 79.63 39.86 18.25 61.57 88.41 3.28 0.08 0.00 0.00 0.00 0.03 0.02 0.00 0.00 273.3
19981 248.27 196.70 21.68 36.75 11.84 1.29 9.20 7.21 0.65 0.02 0.02 0.00 0.00 0.00 0.03 0.03 91.7
1999 1207.98 83.20 56.92 15.87 9.42 2.83 0.81 1.28 0.77 0.02 0.00 0.02 0.00 0.00 0.00 0.00 86.7
2000 832.30 437.22 24.08 35.24 6.79 4.13 0.68 0.08 0.80 0.22 0.03 0.03 0.01 0.00 0.00 0.00 124.1
2001 1230.98 446.84 294.00 26.25 23.00 1.63 0.75 0.06 0.06 0.05 0.16 0.09 0.02 0.00 0.00 0.01 227.7
2002 1700.19 475.31 312.87 185.45 12.42 8.04 0.85 0.22 0.01 0.09 0.16 0.04 0.04 0.00 0.00 0.00 308.4
2003 3327.32 471.68 352.24 174.45 72.71 5.10 1.68 0.12 0.10 0.10 0.10 0.01 0.01 0.00 0.00 0.00 411.5
2004 700.86 706.61 173.13 100.52 77.02 51.28 7.41 0.91 0.13 0.04 0.05 0.04 0.04 0.07 0.00 0.00 307.6
2005 4473.16 386.39 317.89 141.06 50.66 61.19 10.08 0.25 0.08 0.01 0.00 0.00 0.00 0.00 0.00 0.00 431.0
20062 4944.60 1310.22 78.80 130.76 46.05 20.87 16.21 3.18 0.09 0.15 0.00 0.05 0.00 0.00 0.04 0.03 454.2
20071 3731.19 1684.83 443.27 81.78 84.67 26.28 5.41 2.20 1.38 0.80 0.07 0.00 0.00 0.00 0.03 0.00 594.8
2008 853.09 2042.01 1591.03 583.61 53.08 54.73 6.79 10.25 0.23 0.05 0.08 0.05 0.00 0.00 0.00 0.00 1100.5
2009 562.61 317.05 1230.43 751.01 368.33 25.41 12.44 0.85 0.09 0.35 0.00 0.01 0.00 0.00 0.00 0.00 976.7
2010 1634.82 79.89 102.45 510.45 443.76 139.32 7.99 1.02 0.39 0.47 0.05 0.05 0.00 0.00 0.00 0.00 759.4
2011 676.31 353.87 52.88 123.63 469.48 290.04 65.24 1.42 1.12 0.00 0.00 0.15 0.03 0.00 0.00 0.00 827.5
20123 1866.96 137.38 316.08 28.79 74.71 267.94 154.60 24.77 3.11 0.28 0.04 0.08 0.00 0.00 0.00 0.00 740.3
2013 344.58 490.28 57.44 143.98 22.02 33.62 191.14 69.38 6.11 0.08 0.00 0.00 0.00 0.00 0.00 0.00 600.9
2014 1281.40 123.95 381.17 32.73 104.40 23.26 50.04 97.54 38.69 1.82 0.59 0.00 0.00 0.02 0.00 0.00 656.0
2015 1133.97 342.02 30.61 187.04 43.60 39.44 14.67 18.73 30.74 9.70 0.33 0.14 0.02 0.00 0.00 0.00 404.4
2016 2299.37 561.96 163.38 34.34 115.60 22.41 41.95 12.44 32.40 27.64 4.34 0.98 0.00 0.14 0.05 0.02 569.4
20173 5065.43 770.04 134.94 105.48 7.55 55.34 9.69 15.60 2.53 10.33 8.74 4.06 0.73 0.00 0.00 0.00 566.0
2018 3823.29 1675.64 336.31 86.66 65.76 7.77 15.59 3.62 2.56 1.70 4.72 4.00 1.38 0.13 0.00 0.00 574.8
2019 1898.20 1125.27 1075.55 187.22 49.40 17.00 4.04 2.95 0.74 1.08 0.19 0.35 0.20 0.05 0.00 0.02 600.0
20203 110.62 267.79 424.22 586.99 99.12 22.08 6.06 2.61 1.04 0.67 0.23 0.71 0.70 0.49 0.02 0.00 537.8
20213 406.30 25.12 109.80 175.26 262.62 19.19 3.65 0.71 0.20 0.13 0.08 0.31 0.18 0.05 0.00 1003.6 342.0
2022 1662.1 110.3 12.2 86.5 121.7 113.6 9.10 0.62 0.11 0.16 0.24 0.00 0.00 0.04 0.00 2116.7 316.7
Table 6.6. HADDOCK. Abundance indices (numbers in millions) from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates.

1 Indices raised to also represent the Russian EEZ.

2 Not complete coverage in southeast due to restrictions, strata 7 area set to default and strata 13 as in 2005.

3 Indices raised to also represent uncovered parts of the Russian EEZ.

4 1994-2020: for years with raising, estimated based on relationship between unraised numbers-at-age and biomass-at-age from StoX baseline run. From 2021: estimated based on relationship between unraised numbers-at-age and biomass-at-age bootstrap mean estimates from StoX.

Age group Total Biomass (‘000 t)
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+
2014 128.7 1.26 12.3 0.65 2.22 0.12 3.38 1.16 0.74 0.07 0.0 0.0 0.0 0.0 0 150.6 20.9
2015 49.0 17.4 0.33 13.2 0.46 4.30 0.88 0.56 3.51 2.16 0.0 0.0 0.0 0.0 0 91.8 34.5
2016 42.6 4.50 10.2 0.51 9.69 2.45 1.43 2.41 4.80 3.13 0.36 0.0 0.0 0.0 0 82.0 45.7
2017 199.6 15.7 3.76 5.83 2.18 7.56 0.80 2.07 1.06 1.82 2.39 0.72 0.0 0.0 0 243.5 51.6
2018 1141.9 65.3 17.9 3.20 5.03 2.27 3.66 0.90 0.54 0.35 0.72 0.48 0.56 0.0 0 1242.8 77.9
2019 115.3 45.6 30.1 7.74 3.03 1.13 0.15 0.14 0.0 0.07 0.0 0.06 0.0 0.0 0.02 203.4 29.9
2020 3.61 3.93 35.1 33.1 8.11 7.89 1.93 1.05 0.54 0.28 0.13 0.25 0.27 0.11 0 96.3 63.2
2021 12.6 1.08 0.40 7.74 13.4 1.29 0.61 0.14 0.09 0.02 0.06 0.09 0.11 0.00 0.00 37.6 22.8
2022 79.3 2.86 0.04 0.32 3.00 0.59 0.09 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 86.2 6.81
Table 6.7. HADDOCK. Abundance indices (numbers in millions) for new strata 24-26 from bottom trawl surveys in the Barents Sea winter 2014-2022. 2014-2020: baseline estimates, from 2021: bootstrap mean estimates.
Age group
Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 11 13 15 13 15 29 52 45 33 52 38 97 - -
1995 12 19 28 29 16 21 38 180 75 97 - 58 97 -
1996 14 13 12 25 30 24 61 64 - 98 - 95 96 -
19971 13 35 13 15 17 21 18 57 54 - - - 64 92
19981 15 13 13 14 16 25 18 16 34 107 106 - - -
1999 15 37 14 24 21 24 25 31 22 89 - 97 - -
2000 9 9 18 9 16 14 34 51 31 34 63 91 105 -
2001 12 17 12 20 11 36 33 47 59 51 47 86 62 -
2002 9 11 10 10 22 17 27 39 81 60 48 51 75 -
2003 16 24 28 13 11 19 31 59 60 71 56 92 93 -
2004 9 12 15 16 10 13 28 24 43 56 58 93 60 54
2005 9 17 12 22 14 22 14 70 48 93 - - - -
20062 14 14 18 12 13 16 21 30 44 70 - 63 - -
20071 10 8 9 19 12 17 24 26 44 50 61 - - -
2008 12 17 15 13 19 30 27 81 42 81 68 88 - -
2009 13 20 15 21 24 18 32 27 91 68 - 94 - -
2010 10 17 18 22 18 18 25 29 42 55 144 167 - -
2011 10 10 14 25 18 13 20 38 73 - - 81 84 -
20122 19 28 17 16 15 13 15 33 73 48 83 61 - -
2013 12 12 13 14 27 24 27 14 26 50 - - - -
2014 7 26 12 22 16 22 20 14 24 40 55 - - 99
2015 7 13 26 14 44 11 25 18 21 28 40 51 97 -
2016 22 25 13 42 11 15 20 15 15 19 27 51 - 62
20172 5 13 15 12 20 14 21 27 25 18 21 36 77 -
2018 7 16 13 12 10 17 15 23 18 18 18 20 32 52
2019 9 11 15 12 27 12 40 20 30 30 35 29 35 46
20202 16 9 11 14 14 19 22 29 27 40 39 29 24 37
20212 12 22 17 16 22 13 21 25 47 46 47 66 42 69
2022 10 12 27 17 23 18 19 25 52 66 49 - - 65
Table 6.8. HADDOCK. Estimates of coefficients of variation (%) for swept area abundance indices. Barents Sea standard area winter 1994-2022.

1 Russian EEZ not covered

2Russian EEZ partly covered

6.3 - Survey mortalities

Survey mortalities based on the acoustic indices (Table 6.9) have varied between years, and for most age groups there are no obvious trends. However, there are signs of co-variability within years. Survey mortalities based on the bottom trawl indices increased considerably from 2016 to 2017 to among the highest in the ten last years and has since then remained high for some age groups. Survey mortalities from 2019-2020 and 2020-2021 stand out as some of the highest in the time series for several age groups.

Year 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9
      Acoustic investigations      
1994-95 2.30 1.51 1.05 0.46 0.94 1.12 2.64 1.01
1995-96 2.54 1.08 0.63 0.57 1.01 2.13 1.09 -
1996-97 1.61 0.50 0.30 0.35 0.20 0.83 0.19 2.60
1997-98 1.21 -0.24 -0.03 -0.09 0.70 1.38 1.11 1.18
1998-99 1.95 0.59 0.45 0.98 1.37 1.60 1.29 2.03
1999-00 0.48 -0.19 0.10 0.43 0.56 1.37 1.07 0.66
2000-01 1.38 0.55 -0.10 0.60 1.85 2.06 2.28 1.77
2001-02 1.03 0.04 0.15 0.78 1.26 0.32 1.71 1.67
2002-03 1.29 0.27 0.32 0.39 0.41 0.67 1.81 0.73
2003-04 1.77 0.88 0.69 0.54 0.86 0.48 1.65 -0.11
2004-05 1.30 0.75 0.27 0.57 0.64 1.51 3.00 1.28
2005-06 1.29 0.94 0.58 0.89 1.09 1.43 1.37 1.56
2006-07 0.79 1.09 0.20 0.43 0.49 0.66 0.99 0.36
2007-08 0.14 0.16 -0.37 -0.67 0.08 1.36 -0.25 1.13
2008-09 1.31 0.69 0.25 0.13 0.84 1.62 1.77 3.63
2009-10 1.64 0.49 0.34 0.04 0.47 1.17 1.60 0.27
2010-11 1.69 0.46 0.42 0.70 0.73 1.11 1.95 1.12
2011-12 1.51 0.41 0.10 -0.05 0.01 0.53 0.60 1.20
2012-13 1.36 0.34 0.27 0.32 0.51 0.33 0.52 0.76
2013-14 0.98 0.20 0.54 0.30 0.42 0.42 0.95 1.03
2014-15 2.01 1.51 0.57 0.39 0.86 0.92 0.44 1.40
2015-16 2.70 1.23 0.70 1.16 0.76 0.98 0.21 0.26
2016-17 1.35 0.28 0.10 0.92 0.54 0.69 0.78 1.43
2017-18 1.42 0.67 0.25 0.01 -0.36 0.79 0.82 1.13
2018-19 1.45 0.46 0.15 0.68 1.08 0.34 1.57 0.70
2019-20 1.78 0.88 0.50 0.61 0.35 0.64 0.98 0.88
2020-21 2.86 1.64 0.79 0.52 1.41 1.41 2.51 0.82
2021-22 1.82 0.32 -0.22 0.31 0.59 0.49 1.89 1.90
    Bottom trawl investigations    
1994-95 1.11 1.41 0.63 0.24 0.44 0.90 1.87 1.10
1995-96 1.68 1.27 0.56 0.10 0.37 0.61 0.23 -
1996-97 1.20 1.20 0.34 0.54 0.90 0.99 1.59 2.64
1997-98 1.74 1.43 0.77 1.21 2.65 1.90 2.51 1.62
1998-99 1.09 1.24 0.31 1.36 1.43 0.47 1.97 2.24
1999-00 1.02 1.24 0.48 0.85 0.82 1.42 2.27 0.47
2000-01 0.62 0.40 -0.09 0.43 1.42 1.70 2.47 0.33
2001-02 0.95 0.36 0.46 0.75 1.05 0.66 1.24 1.84
2002-03 1.28 0.30 0.58 0.94 0.89 1.56 1.96 0.74
2003-04 1.55 1.00 1.25 0.82 0.35 -0.37 0.61 -0.11
2004-05 0.60 0.80 0.20 0.69 0.23 1.63 3.39 2.43
2005-06 1.23 1.59 0.89 1.12 0.89 1.33 1.15 0.97
2006-07 1.08 1.08 -0.04 0.43 0.56 1.35 2.00 0.84
2007-08 0.60 0.06 -0.28 0.43 0.44 1.35 -0.64 2.25
2008-09 0.99 0.51 0.75 0.46 0.74 1.48 2.08 4.73
2009-10 1.95 1.13 0.88 0.53 0.97 1.16 2.50 0.79
2010-11 1.53 0.41 -0.19 0.08 0.43 0.76 1.73 -0.10
2011-12 1.59 0.11 0.61 0.50 0.56 0.63 0.97 -0.79
2012-13 1.34 0.87 0.79 0.27 0.80 0.34 0.80 1.40
2013-14 1.02 0.25 0.56 0.32 -0.05 -0.40 0.67 0.58
2014-15 1.32 1.40 0.71 -0.29 0.97 0.46 0.98 1.15
2015-16 0.70 0.74 -0.11 0.48 0.67 -0.06 0.17 -0.55
2016-17 1.09 1.43 0.44 1.51 0.74 0.84 0.99 1.59
2017-18 1.11 0.83 0.44 0.47 -0.03 1.27 0.98 1.81
2018-19 1.22 0.44 0.59 0.56 1.35 0.65 1.67 1.59
2019-20 1.96 0.98 0.61 0.64 0.81 1.03 0.44 1.04
2020-21 1.48 0.89 0.88 0.80 1.64 1.80 2.15 2.58
2021-22 1.30 0.72 0.24 0.36 0.84 0.75 1.77 1.86
Table 6.9. HADDOCK. Survey mortality from surveys in the Barents Sea standard area winter 1994-2022.

6.4 - Growth and maturity

Tables 6.10 and 6.11 present the time series for mean length and mean weight at age. Length and weight estimates have been variable with no specific trends in the latest years. Lengths in 2022 were below average for ages 1-2 and 5-7 but above average for older fish, while mean weights were below average for ages 1 and 4-7 and above average for older fish. Annual weight increments are shown in Table 6.12, these are highly variable and show no trends. The proportion mature at age also shows large variations between years (Table 6.13). The large variation is one of the reasons that length, weight and maturity at age are modelled from the empirical data in the haddock stock assessment to account for inconsistencies due to high sampling variance and to fill in missing age-year combinations. The assessment input data for these variables may therefore differ somewhat from tables 6.10, 6.11 and 6.13.

The degree of coverage of the Russian EEZ may influence the biological parameters, as body size tends to decrease towards the northeast in the survey area. In addition, length, weight and maturity at age of older ages has higher uncertainty due to fewer samples (c.f. table 2.3).

Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 14.5 19.9 29.3 38.1 47.8 54.0 61.0 64.3 70.4 64.8 64.1 + - -
1995 15.1 18.2 28.6 34.0 42.8 51.3 58.9 + + + - + + -
1996 15.3 20.8 28.0 36.9 41.2 47.2 55.0 59.9 - + - + + -
1997 15.7 19.7 27.4 34.1 39.5 47.3 50.7 55.0 62.8 - - - + +
1998 14.5 22.5 29.3 37.3 43.1 48.4 52.1 53.3 58.2 + + - - -
1999 14.4 18.3 32.3 38.8 46.5 51.9 56.0 55.2 58.8 + - + - -
2000 15.5 21.6 29.9 42.0 47.0 51.1 53.4 59.1 59.3 62.0 + + + -
2001 14.6 22.1 32.1 37.6 48.0 50.4 59.1 56.2 64.6 66.5 68.2 + + -
2002 15.1 20.8 29.1 39.8 45.2 51.7 57.8 60.7 + + 64.6 68.0 + -
2003 15.8 23.9 26.4 36.6 45.8 49.7 54.8 60.9 63.9 61.6 67.3 + + -
2004 14.2 22.1 30.1 35.7 42.8 49.8 49.8 59.0 63.0 73.5 75.9 + + 74.1
2005 14.8 20.5 29.9 36.1 40.5 48.3 51.6 55.7 60.8 + - - - -
2006 14.5 22.0 30.7 37.9 43.3 47.3 50.7 56.7 60.4 + - + - -
2007 15.5 22.9 29.0 35.7 45.8 48.0 53.5 57.4 57.3 68.7 + - - -
2008 15.7 23.8 29.6 37.8 42.8 46.5 53.1 53.8 59.5 + + + - -
2009 14.3 22.3 29.7 35.5 41.7 48.1 49.7 56.5 + 62.8 - + - -
2010 14.4 19.9 30.8 36.9 41.1 45.3 49.7 58.9 59.4 62.0 + + - -
2011 13.6 23.2 28.5 39.4 42.9 46.1 48.3 62.5 53.8 - - + + -
2012 14.7 19.3 31.6 35.1 43.6 47.1 50.1 51.2 53.4 65.3 + 71.7 - -
2013 14.5 22.9 30.0 40.9 42.8 48.7 52.2 52.9 55.7 67.3 - - - -
2014 15.4 18.5 31.9 38.4 46.4 52.4 53.6 55.3 55.2 61.0 58.9 - - +
2015 14.5 20.4 26.2 39.8 45.7 52.5 53.6 57.5 57.0 59.9 59.9 67.3 + -
2016 14.9 18.4 30.9 36.8 47.8 53.1 56.0 58.6 61.1 60.4 60.1 63.6 - +
2017 15.8 20.5 30.5 40.0 49.6 52.9 56.1 60.6 61.2 63.2 62.5 64.7 67.3 -
2018 14.5 21.7 30.4 39.6 47.8 54.4 58.0 61.3 64.2 65.6 64.6 63.9 66.5 68.9
2019 14.8 21.5 29.7 37.1 46.1 52.5 53.6 60.5 64.3 65.7 67.5 67.3 69.5 69.3
2020 15.4 21.9 30.0 36.3 42.7 52.1 57.4 62.2 63.7 68.1 69.7 67.4 69.0 70.3
2021 14.4 19.5 29.1 36.2 42.7 49.2 55.0 60.5 66.7 69.4 73.0 71.6 71.7 +
2022 14.1 20.2 31.2 37.4 42.6 47.1 51.6 61.4 65.0 68.5 69.0 - - +
Table 6.10. HADDOCK. Mean length (cm) at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates. “+” indicates few samples (< 3), while “–“ indicates no samples. Lengths are not adjusted for incomplete coverage.
Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 25 85 244 539 1060 1599 2146 2719 3349 2722 2662 + - -
1995 30 69 219 382 775 1357 1954 + + + - 2537 + -
1996 32 92 218 473 669 1022 1627 1948 - + - + 3626 -
1997 35 82 193 381 616 1051 1300 1680 2476 - - - + +
1998 27 113 247 543 863 1166 1417 1583 2046 + + - - -
1999 28 77 334 580 1020 1445 1775 1730 2020 + - + - -
2000 33 109 275 736 1050 1367 1586 2093 2219 2575 + + + -
2001 28 106 337 582 1146 1422 2140 2029 2939 3139 3105 + + -
2002 30 85 244 621 923 1388 1927 2242 + + 2692 3280 + -
2003 36 128 192 492 959 1204 1534 1982 2580 2675 3179 + + -
2004 23 98 271 458 752 1162 1222 1978 2611 3875 4186 + + 4036
2005 29 97 263 471 669 1087 1376 1881 2120 + - - - -
2006 26 109 301 559 812 1086 1362 1925 2075 + - + - -
2007 32 109 253 519 1016 1193 1718 2043 2258 3443 + - - -
2008 32 114 247 551 835 1115 1573 1599 2167 + + + - -
2009 26 94 227 444 746 1147 1315 1732 + 2567 - + - -
2010 28 87 275 473 677 957 1261 1889 2204 2492 + + - -
2011 21 117 220 520 729 943 1171 2264 1641 - - + + -
2012 29 75 306 432 819 1015 1280 1313 1700 2693 + 3287 - -
2013 25 114 272 645 782 1138 1351 1502 1850 3117 - - - -
2014 32 68 352 589 1002 1428 1566 1674 1704 2212 2156 - - +
2015 23 88 200 590 885 1418 1501 1915 1848 2085 2298 3148 + -
2016 27 74 285 495 1058 1466 1754 2089 2290 2263 2402 2716 - +
2017 33 95 293 637 1247 1542 1822 2294 2420 2640 2633 2890 3241 -
2018 26 95 275 627 1051 1663 1967 2349 2699 2820 2681 2648 3011 3415
2019 25 90 242 510 968 1411 1618 2083 2722 2916 3072 3220 3475 3229
2020 27 89 244 458 806 1385 1863 2426 2658 2887 3334 3013 3366 3600
2021 27 86 208 447 735 1159 1591 2201 3156 3172 3835 3533 3771 +
2022 24 96 292 478 731 1027 1386 2316 2774 3052 3357 - - +
Table 6.11. HADDOCK. Mean weight (g) at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates. “+” indicates few samples (< 3), while “–“ indicates no samples. Weights are not adjusted for incomplete coverage.
Year\Age 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10
1994-95 44 134 137 235 297 355 - - -
1995-96 61 148 253 287 247 270 -5 - -
1996-97 50 101 164 143 382 278 53 528 -
1997-98 78 165 349 481 550 366 283 366 -
1998-99 50 221 333 478 582 609 313 437 -
1999-00 81 198 403 470 347 141 318 489 554
2000-01 74 227 308 409 372 773 444 846 920
2001-02 57 138 285 341 242 505 102 - -
2002-03 98 106 248 338 281 146 54 338 -
2003-04 62 143 267 261 203 18 444 629 1295
2004-05 74 165 200 210 335 214 660 142 -
2005-06 80 204 296 341 417 275 550 194 -
2006-07 84 144 218 457 381 632 681 333 1368
2007-08 82 138 298 316 99 380 -119 124 -
2008-09 62 113 197 196 311 199 160 - 400
2009-10 61 181 246 233 211 115 574 472 -
2010-11 89 133 245 256 266 214 1003 -248 -
2011-12 53 189 212 299 285 337 142 -565 1052
2012-13 85 197 339 349 319 336 221 537 1418
2013-14 43 238 317 357 646 428 323 202 362
2014-15 56 132 238 296 416 73 348 175 381
2015-16 51 197 295 468 580 337 588 375 414
2016-17 68 219 352 753 483 356 540 331 350
2017-18 61 180 334 414 416 426 527 405 400
2018-19 64 148 235 341 361 -45 116 373 217
2019-20 64 155 216 296 417 452 808 575 165
2020-21 58 120 202 278 350 199 337 733 519
2021-22 69 206 270 284 292 227 725 573 -104
Table 6.12. HADDOCK. Yearly weight increment (g) from bottom trawl surveys in the Barents Sea standard area winter 1994-2022.
Age/ Year 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1994 0.00 0.00 0.00 0.02 0.16 0.41 0.44 1.00 0.88 0.74 0.74 + - -
1995 0.00 0.00 0.01 0.04 0.18 0.38 0.41 + + + - 0.63 + -
1996 0.00 0.00 0.00 0.04 0.08 0.27 0.40 0.78 - + - + 0.00 -
1997 0.00 0.00 0.00 0.00 0.15 0.33 0.64 0.31 0.70 - - - + +
1998 0.02 0.00 0.00 0.04 0.15 0.54 0.50 0.79 0.95 + + - - -
1999 0.00 0.00 0.00 0.06 0.24 0.38 0.77 0.81 0.98 + - + - -
2000 0.00 0.00 0.00 0.24 0.54 0.66 0.82 1.00 0.90 0.86 + + + -
2001 0.00 0.00 0.00 0.22 0.54 0.49 0.89 1.00 1.00 0.70 1.00 + + -
2002 0.00 0.00 0.01 0.12 0.45 0.60 0.95 0.90 + + 0.79 1.00 + -
2003 0.00 0.00 0.00 0.04 0.40 0.59 0.73 0.60 0.64 0.68 1.00 + + -
2004 0.00 0.00 0.02 0.03 0.14 0.61 0.56 0.46 0.87 1.00 1.00 + + 1.00
2005 0.00 0.00 0.01 0.06 0.19 0.43 0.76 0.34 1.00 + - - - -
2006 0.00 0.00 0.00 0.12 0.41 0.59 0.84 0.86 0.50 + - + - -
2007 0.00 0.00 0.01 0.19 0.46 0.67 0.82 0.95 0.84 1.00 + - - -
2008 0.13 0.02 0.02 0.09 0.47 0.66 0.83 0.84 0.99 + + + - -
2009 0.00 0.00 0.00 0.04 0.16 0.29 0.64 0.65 + 0.41 - + - -
2010 0.00 0.00 0.05 0.08 0.20 0.41 0.60 0.75 0.91 0.89 + + - -
2011 - 0.00 0.00 0.07 0.14 0.41 0.38 0.38 0.79 - - + + -
2012 0.00 0.00 0.01 0.06 0.38 0.51 0.61 0.71 0.26 1.00 + 0.68 - -
2013 0.00 0.00 0.01 0.04 0.17 0.49 0.61 0.62 0.63 1.00 - - - -
2014 0.00 0.01 0.02 0.13 0.28 0.73 0.73 0.71 0.76 0.94 0.95 - - +
2015 0.00 0.00 0.03 0.05 0.15 0.44 0.64 0.67 0.39 0.54 1.00 0.68 + -
2016 0.00 0.00 0.00 0.02 0.32 0.70 0.83 0.82 0.89 0.83 0.94 1.00 - +
2017 0.00 0.00 0.01 0.15 0.32 0.63 0.74 0.95 0.93 0.97 0.98 1.00 1.00 -
2018 0.00 0.00 0.01 0.12 0.31 0.55 0.87 0.76 0.93 0.84 0.86 0.93 0.94 1.00
2019 0.00 0.00 0.02 0.08 0.18 0.59 0.66 0.83 0.92 0.97 1.00 1.00 1.00 1.00
2020 0.00 0.00 0.01 0.04 0.18 0.56 0.75 0.82 0.91 0.89 0.98 1.00 0.89 0.93
2021 0.00 0.00 0.00 0.06 0.14 0.47 0.64 0.73 0.81 1.00 1.00 0.79 0.88 +
2022 0.00 0.00 0.08 0.05 0.18 0.50 0.79 0.66 0.51 0.49 0.84 - - +
Table 6.13. HADDOCK. Proportion mature at age from bottom trawl surveys in the Barents Sea standard area winter 1994-2022. Bootstrap mean estimates. The proportion mature is the number of fish classified as maturity category 2 and 3, divided by the total number of fish assigned categories 1-5. “+” indicates few samples (< 3), while “–“ indicates no samples.

7 - Distribution and abundance of redfish

Earlier reports from this survey have presented distribution maps and abundance indices based on acoustic observations of redfish. In later years, blue whiting has dominated the acoustic records in some of the main redfish areas. Due to incomplete pelagic trawl sampling the splitting of acoustic records between blue whiting and redfish has been very uncertain. The uncertainty relates mainly to the redfish, since it only makes up a minor proportion of the total value. This has been the case since the 2003 survey, and the acoustic results for redfish are therefore not included in the reports.

7.1 - Golden redfish (Sebastes norvegicus)

Figure 7.1 shows the geographical distribution of golden redfish based on the catch rates in bottom trawl. In most years, the distribution is completely covered except towards the northwest. Table 7.1 presents the time series (1994-2022) of swept area indices by 5 cm length groups for the standard area (strata 1-23). The indices were low in many years since 1999 for all length groups. However, in 2016 and 2017 there was an increase in the indices of fish above 25 cm, and in 2018 the total index was at the same level as in 2017, while the total biomass was slightly lower. In 2019 the indices for fish between 35 and 50 cm increased further, and the total abundance and biomass were the highest since 1998. The index for most length groups declined in 2020 and further in 2021 when the abundance of fish < 20 cm was particularly low. In 2022 fish > 20 cm increased, but the total abundance and biomass had decreased. Table 7.2 present swept area abundance indices by length groups for area N in 2014-2022. Golden redfish was found in this extended survey area in 2014-2022, mainly west of Spitsbergen (strata 24). 16% of the total abundance and 5 % of total biomass was found in the extended area in 2022.

 

GOLDEN REDFISH (Sebastes norvegicus). Distribution in the trawl catches winter 2022 (number per nm2). Black crosses indicate zero catches and the stippled line the ice edge.
Figure 7.1. GOLDEN REDFISH ( Sebastes norvegicus) . Distribution in the trawl catches winter 2022 (number per nm 2 ). Black crosses indicate zero catches and the stippled line the ice edge.

Table 7.3 presents estimates of coefficients of variation (%) by length groups. In all years, CVs for most length groups are above what could be considered as acceptable in stock assessment (approximately 20 %).

 

  Length group (cm)         Biomass
Year 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60 Total (tons)
1994 675 7493 10100 12840 10914 17834 10065 4799 1645 937 202 121 77623 31841
1995 387 4658 13515 13118 10398 15429 16223 10587 3112 852 455 148 88883 42151
1996 40 715 3291 5983 8863 14089 15709 7502 2692 893 168 165 60010 35775
19971 0 500 1197 2809 6522 22751 28797 8235 1747 1092 239 97 73985 44977
19981 51 4525 2043 10795 73085 30862 14707 6984 1712 456 142 0 145363 49253
1999 181 928 2070 4002 4351 6275 6143 5474 2618 738 75 0 32854 20330
2000 533 1122 1506 4196 4895 5146 3611 1908 620 466 89 0 24092 10946
2001 55 411 398 2452 5802 5463 4509 3239 1154 343 96 37 23960 13896
2002 133 1053 2043 1854 3955 4204 3335 3654 1656 619 192 28 22726 13242
2003 0 478 1303 1538 4192 4081 2765 3204 1996 548 123 327 20554 13399
2004 700 195 420 973 2842 4365 5404 3858 2281 562 140 45 21786 15758
2005 0 119 203 362 1110 2090 3849 4664 2730 1276 299 128 16831 16389
20062 0 0 0 178 2495 5534 6307 4155 3179 950 124 12 22934 18790
20071 0 97 453 214 772 1526 2823 4275 2742 1194 197 58 14351 14553
2008 1736 2540 201 171 440 71