Shellfish Committee
ICES CM 1995/K:S
REPORT OF THE
STUDY GROUP ON LIFE HISTORIES AND ASSESSMENT OFPANDALUS STOCKS IN
THE NORTH ATLANTIC
This report is not to be quoted without prior consultation with the
General Secretary. The document is a report of a study group under
the auspices of the International Council for the Exploration of the
Sea and does not necessarily represent the views of the Council.
International Council for the Exploration of the Sea
Conseil International pour l'Exploration de la Mer
Palægade 2-4
DK-1261 Copenhagen K
Denmark
l. TERMS OF REFERENCE
The Study Group on Life Histories and Assessment Methods of Panda/us Stocks in the North Atlantic, has by
correspondence worked according to the ICES Council Resolution 1994 2:45 in order to report to the 1995 Annual Science
Conference, to:
a) assess the status of stocks of Panda/us borealis in the North Sea, Skagerrak and Kattegat;
b) determine the predation mortality of Panda/us stocks;
c) report to ACFM for its meeting in October/November 1995.
2. MEMBERS OF THE STUDY GROUP
M. Aschan
N. Bailey
B. Bergstrom
E.M. Nilssen
D.G. Parson
S. Munch-Petersen
F. Redant
A. Richards
D. Roddick
L. Savard
B. Sjostrand
K. Sunnanå
S. Tveite (chairman)
Norway
UK Scotland
Sweden
Norway
Canada
Denmark
Belgium
USA
Canada
Canada
Sweden
Norway
Norway
3. INTRODUCTION
In 1994 the North Sea Panda/us stocks were treated during the meeting of the joint Working group on Nephrops and
Panda/us stocks in Lisbon , 1-9 March (Anon 1994). The WG recommended that in preparation for the next meeting a
useful exercise would be to go through the ageing of shrimps in order to have a uniform method applied for the whole
period. A subgroup (S. Munch-Petersen, B. Sjostrand and S. Tveite) met for the purpose in January 1995 at Flødevigen
Norway.
During the annual science conference in 1994 it was decided that Panda/us stocks should be treated by the Study Group by
correspondence.
The Danish, Swedish and Norwegian input for stock assessment for IIIa/IVa E and landings and effort figures from UK.
(England and Scotland) are the only information received.
The study group was notable to bring forward any information on predation mortality.
4. PANDALUS STOCKS IN SUB-AREA IV AND DIVISION HIA
A detailed overview of the various stocks is given in Anon. (1990). The working Group
assessments units:
l. Skagerrak and Norwegian Deeps combined
2. Fladen Ground
3. Fam Deeps
grouped them into three
Nominallandings for Division Hia and Sub-area IV are shown in Table 4.1
4.1 SKAGERRAK AND THE NORWEGIAN DEEPS
4.1.1 Natural mortality
The level of natura! mortality for Panda/us have been discussed at several occasions. The value used in earlier assessments
i.e. 0,75 for Div.IIIa, IVaE is not well founded.
Work is initiated to elucidate predation mortality, however, no changes were made in the values ofnatural mortality used in
this years assessments.
l
4.1.2 Landings
Landings from the Skagerrak (Division IIIa) and Sub-area IV are shown separately in Table 4.1 Table 4.1.1 gives the
landings since 1970 and discards since 1985 from the Skagerrak and Norwegian Deeps combined. For Denmark the splitting
between Fladen and Norwegian Deeps are arrived at using the log book recordings. The landings have remained above 10
000 tonnes, since 1985. The total landings in 1994 amounted to 11650 tonnes, a small decrease since 1993. Norwegian
landings are restricted by weekly quotas according to market situation.
4.1.3 Discards
The discards in the Norwegian and Swedish fisheries were estimated by the methods described in the 1993 report (Anon
1993) to 426 tonnes in 1994.
4.1.4 Effort
Annua! figures for landings per unit of effort (LPUE) and effort are given in Table 4.1.2 Total effort values have been
estimated from LPUE data based on log-book records. The proportion of landings included in logbook data varied from high
(ca 95%) for Denmark and Sweden to low (ca 30%) for the Norwegian landings in 1994.
Both fishing effort and catch decreased in the Danish and Norwegian fisheries, whereas the Swedish catch increased by
18% in spite of 12% effort reduction.
4.1.5 Assessment
4.1.5.1 Age distributions
Numbers at age have been estimated by splitting length frequency distributions into normal distributions, using different
method for collating the quarterly length frequencies and different software analysing the data.) It was felt that the
assessment could be improved by reanalysing the data in an uniform way. The Pandalus working group in 1989 (Anon
1989) recomended that individual samples should be analysed before pooling. At the meeting in Flødevigen different
solutions were discussed. It was decided to pool the length frequencies obtained from Danish, Norwegian and Swedish
samples to one quarterly length frequency, because in many cases adding "impossible" length frequencies resulted in
analysable ones .. The Bhattacharya method as implemented in ELEFAN ( Pauly 1987 ) was believed to be the best program
to determine number of components and MIX ( MacDonald and Pitcher 1979 ) to calculate proportions. However, MIX
would not accept some of the small proportions and the mean lengths at age given in Figure. 4.1.1. show more consistent
growth curves than when the MIX results are plotted the same way. The ELEFAN results have therefore been used for all
years.
The new analysis resulted in a decreasing trend for the proportion of 1-group and increasing trend for 2-4 group in relation
to the distribution used in last years report. (Figure 4.1.2)
4.1.5.2 Mean weight and maturity at age
Weight at age have been obtained by applying quarterly length-weight relationships to the mean lengths at age. For the
Danish and Swedish data it were former ly used summing of mean weight per length group for the length frequencies of each
yearclass. This change in procedure led to some changes both positive and negative in SOP (Table 4.1.3). The mean weight
at age in the stock were assumed to be equal to the mean weight in the catch.
The 0- and 1-group are assumed to be immature, and the 3-group and older groups fully mature. The mature part of the 2group or potential spawners is taken as the sum ofintersexes and females in the first quarter of the year. This proportions has
been:
1994
1988
1989
1991
1992
1993
1990
1987
1985
1986
0.30
0.73
0.68
0.70
0.64
0.73
0.20
0.68
0.62
0.09
4.1.5.3 Natural mortality
M has been set at 0.75 for all ages. The proportion of the annual M occurring before spawning is taken to be 0.25 on all ages
in all years and proportion ofF before spawning was set at 0.2.
2
4.1.5.4 VPA
Comparison new vs. old dataset:
Extended Survivor Analysis (XSA) was run for the new set of age distributions and weight at age, with exact same settings
as in the 1994 report (Anon 1994). The tuning converged after 26 iterations, versus 90 for the old dataset. The majority of
standard errors figures decreased and R-squares increased. In summary the fishing mortalities and spawning stock biomass
levelled off. The F' s became high er during the first years and lower during the last. (Fig. 4.1.3 ). The SSB show ed the
opposite development.
Standard error of the weighted Log(VPA populations):
age
l
2
.25
old
85-93
.30
.23
new 85-93
.26
.24
.26
1985- 1994
3
.36
.30
.28
4
.50
.44
.41
5
.80
.60
.69
1985-1994:
XSA was also used for the 1985-1994 dataset to estimate stock sizes and exploitation levels from data on catches, effort and
catch per unit of effort data (three fleets) and the results from the yearly shrimp surveys. Table 4.1.4 gives the tuning input
file with catch at age and efforts for the four "fleets" used.
In most instances default values were used for the various input variables in the XSA (Table 4.1.5 ). Age groups O and l
were assumed to have catchabilities changing with stock size. Catchabilities were assumed independent of age for shrimps of
age 2 and older.
The standard errors (logarithmic) surrounding the estimates ofpopulation abundance at l Jan. 1995 varied from .24 for the
1-group to .69 for the oldest shrimps (see table above).
Fishing mortalities, expressed as unweighted mean over age-groups 1-3, (see Table 4.1.6) seem to have decreased from
1992. This decrease is mainly due to a major drop in the value for the 3-group, which for the last 4 years has appeared as
very high. Stock size in terms of number at age are given in Tab le 4.1. 7. Both with and without sum of products corrections
spawning stock increased from 1993 to 1994 due to the rich 1992 yearclass, whereas the total stock biomass decreased.
4.1.5.5 Recruitment
The abundance indices of young shrimps obtained by the Norwegian survey in October are given in Table 4.1.9. A
description of the survey methods was given in Anon. (1991).
The 1992 index is a record high mainly because the catches in western Skagerrak were 6 times higher than obtained before,
but also because the yearclass ranked very high in other areas. The 1993 year-class was estimated by the survey in 1993 and
as 1-group in 1994 as about average size. The 1994 yearclass was below average in the 1994 survey.
4.1.5.6. Catch prediction
Comparison new vs. old dataset:
The new data for the 1985-1993 period gave 30% higher status quo prediction for landings in 1994 than the old dataset. The
stock biomass predictions increased by 10-14% for 1994-1996.
1985-1994:
Input data for the prediction are shown in Tab le 4 .1.1 O. The fishing pattem used is the 1992-1994 average scaled to the 1994
level (mean of ages 1-3). Mean weights are averages for the period 1985-94, and recruitment in 1995 and 1996 is the
average for the period 1985-1993.
.
The average proportions of O - and 1-group catches that have been landed are 71 % and 85% respectively. These proportions
were applied on the predicted catches in 1995 and 1996.
The status quo landings for 1995 was predicted to 14 630 tonnes. whereas the agreed TAC is 16 000 tonnes. Predicted status
quo catches in 1996 and 1997 are l O O16 and 11 611 respectively (Tab le 4.1.11 ).
4.1.5.7 Management consideration
The landing figures for 1995 so far do not indicate that TAC will be reached. The 1993 and 1994 yearclasses are both below
average, it would therefore be necessary to increase the effort in order to maintain the catch level for the next years. At
least for Norway the market situation has been the effort goveming factor and the capacity of fleet have not been utilised
during the last years.
3
The high discard figures indicate that the selection properties of the trawl are not very good. The development of sorting
grids and other means of facilitating the escape of small shrimps should be encouraged.
4.1.5.8 Assessment quality
The ageing of shrimps has been revised in this years assessment, resulting in slight improvements in performance of the
XSA. The SOP factor could possibly be improved by utilising the Swedish and Danish measured weight per mm group, this
year only length - weight relationships have been used.
4.2 FLADEN GROUND
Table 4.2.1 shows the landings from the Fladen Ground since 1972. In spite of relatively good CPUE (Table 4.2.2) the
landings were low during 1994, only 16% of the maximum catch in 1983. No data for assessment purpose were available.
4.3 FARN DEEPS
In recent years Panda/us in the Fam Deeps have been fished by UK vessels only. Totallandings fell from 500 tonnes in
1988 to none in 1993. In 1994 there was a small fishery of 4 tonnes.
5. REFERENCES
Anon (1989) Report on the Working group on the assessment of Pandalus Stocks ICES
doc.C.M. 1989/Assess:9
Anon. (1990) Report on the Working group on the assessment of Pandalus Stocks ICES
doc.C.M.1990/Assess:9
An on. (1991) Report on the Working gro up on the assessment of Pandalus Sto eks ICES
doc.C.M.1991/ Assess:8
Anon. (1993) Report on the Working group on the assessment of Nephrops and Pandalus Stocks
ICES doc.C.M.1993/ As sess: 11
An on. (1994) Report on the Working group on the assessment of N ephrops Pan dal us Sto eks ICES
doc.C.M.1994/Assess: 12
MacDonald,P .D.M. 1979. Age groups from size-frequency data: a versatile and efficient
method of analysing distribution mixtures. J .Fish.Res. Bo ard Can. 36:987 -l 00 l.
Pauly, D. 1987. A review of the ELEFAN system for analysis of length-frequency data in fish
and
aquatic invertebrates. ICLARM Conf. Proc. 13: 7-34.
4
Table 4.1 Nominallandings (tonnes) of Panda/us borealis in ICES
Division llla and subarea IV as officially reported to ICES.
Year
Division llla
Den mark
Norway
757
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
834
773
716
475
743
865
763
757
973
1679
2593
2920
1571
1717
4105
4686
4140
2278
2527
2277
3256
3296
2490
1987
Sweden t
2740
2906
2524
2130
2003
1740
2212
1895
1529
1752
2121
2210
1421
982
1392
1123
1415
1186
1.463
2541
2167
1841
2489
3498
3753
3877
3722
3509
4772
4811
5198
3047
3156
3006
3441
4250
4081
4389
988
933
1474
1357
1085
1075
1304
1471
1747
2057
2133
2526
Tolal
Sub-area IV
Denmark Norway
4479
5132
4420
4261
3664
3946
5618
4825
4127
5214
7298
8556
8218
6281
6159
10351
10854
10423
6400
6987
6754
8444
9603
8704
8902
3460
3572
2448
196
337
1392
1861
782
1592
962
1273
719
1069
5752
4638
4582
3896
9223
2647
3298
2079
750
1881
1985
1337
s-Weden
1107
1265
1216
U<
U<
(Enql.)•
(Sec~.)·
14
692
1021
931
767
5J
261
136
124
604
1051
960
692
594
1140
1435
1545
1657
1274
1785
1681
3145
4614
3418
3146
2715
2891
3421
2425
i8
34
:15
31
92
112
120
128
157
252
220
122
137
161
147
167
194
186
265
sa
238
203
1
100
438
187
163
432
525
2006
1723
2044
309
406
341
354
65
277
415
458
526
489
353
304
64
u:;
'19
:Il
1836
25
1347
358
774
109
590
365
54
116
516
35
Total
4681
5275
4543
2311
1586
2782
5240
3854
4504
2137
3060
2527
3060
9422
6334
8257
6550
13920
8098
7802
6031
3744
5104
6118
4028
• lndudes small amounts of other Pandalid shrimp
t 1970 to 1974 indudes subarea IV.
Total1988 and 1989 indudes 19 and 21 t. by the Netherlands
1994 figures are preliminary.
Table 4.1.1 Panda/us borealis landings from divisions Ille lSkagerrak) and IVa.
(eastern part, Norwegian Deeps) as estimated by the Wor ing Group
Year
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Den mark
1102
1190
1017
755
5~
817
1204
1120
1459
1062
1678
2593
3766
1567
1747
3827
4834
.4599
3068
3150
2479
3583
3725
2915
2118
Norw
1729
2486
2477
2333
1809
2339
3348
3004
2440
3040
4562
5183
5042
5361
4783
6646
6490
8343
7661
6411
6139
6106
7136
7504
6813
Sweden
2742
2906
2524
2130
2003
2003
2529
2019
1609
1787
2159
2241
1450
1136
1022
1571
1463
1321
1278
1.433
1540
1908
2154
2300
2719
Total
landin s
5573
6582
6018
5218
4342
5159
7081
6143
5508
5889
8399
10017
10258
8064
7552
12044
12787
14263
12007
1099.4
10158
11597
13015
12719
11650
Estimated
discards
584
477
808
830
1548
1723
765
713
1188
426
5
Table 4.1.2
Year
National CPUE and effort as estimated by the Study Group ,
Pandalus borealis. Div. llla - lYa E
Denmark
CPUE
k /d
452
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
719
556
499
432
421
585
653
634
571
677
Table 4 .l .3
effort
3869
5326
8700
9212
7104
7477
4236
5487
5875
5015
3120
Norway
CPUE
k /hr
no ata
no data
36
36
31
23
26
30
35
32
31
effort
Khrs
179
230
251
273
232
206
204
237
218
Sweden
CPUE
k /hr
25
32
30
23
22
23
26
31
27
25
33
effort
Khrs
40
49
49
57
57
63
58
61
00
91
82
combined
effort index
rei. to 1986
0,00
0,00
1,00
1,20
1,22
1,30
1,08
1,01
1,09
1,25
l, 16
Yirtual Population Analysis. Catch number at age. Panda lus in Div. Ill a
lYa east
and
Run Iitie : Pandalus llla + IVb As.sessment
1995WG
At 15/09/1995 18:39
Table 1
YEAR
Catch numbers at age Numbers"1 o••-3
1987
1986
1985
1988
1989
1990
1991
1992
1993
1994
42707
1227845
872517
440173
13896
591
15713
581274
1242004
288130
17674
o
AGE
o
1
2
3
4
+gp
TOTAI.NUM
TONSLAND
SOPCOF%
SOP 1994
6
36461
1027292
1260871
191514
47929
14935
975704
11110
55226
109572
46434
13460
1252658
1557376
1333574
816547
1045879
1173137
474785
1094654
108487
436766
1477651
579407
2564067
2568956
19039
o
2621350
13728
92
2144795
13234
100
30660
o
2264440
12323
102
2597729
12628
92
75088
712
2987490
15072
100
158695
38431
319
2672107
11852
295515
22332
1444
681884
338637
43328
816
2731613
12542
1108258
508662
613709
971146
429783
164479
4104
2238447
12857
105
13907
12076
106
98
96
101
104
104
99
101
o
91
91
so
99
w
Table 4.1 .4
Virtual Pop u la ti on Analysis. Tuning input file. Panda lus in Div. Ille and
east
Denmark
l
l
5326
8700
9212
7105
7477
4236
5487
5875
5015
3120
Norway
1
1
179
230
251
273
232
206
204
237
218
Sweden
1
l
.li
49.2
57.1
56.9
62.8
58.3
61
80.3
90.8
81.8
Norwegian Surveys
85
l
Sl4
o
5
276485583
326611687
340689967
142836988
410334845
271383830
195430088
120202880
263225692
97470046
339351114
350102566
319062162
226028144
179661620
222763369
265247147
406666023
187050350
208263515
86
Sl4
1
5
463152872
670513635
390658044
1003745988
820255904
356160180
244702376
745684975
327720895
85
1
5
120833122
104423689
105315499
65074167
219731053
205786106
120557947
78094762
229436995
130529143
o
100
100
100
100
100
100
100
100
100
100
51544154
170271875
129128971
100029250
89223659
32294578
70727586
159459280
94364469
48314692
12899660
7475389
20421873
38281428
11416082
7820680
7338002
5239699
2978960
2963602
241454641
254139376
273579216
218255629
97610156
128896988
324618385
267322564
162447181
10600502
40192390
104699406
27925599
23637954
13373090
10666689
8439016
9964439
22526459
54439011
39916884
45571670
4m8561
24488472
43630807
103599303
82251471
64701676
94
5637568
2390018
6312894
17440385
6113221
5930299
4526706
3404187
2596569
3968773
o
483300
193607
955148
214880
65011
o
o
126699
o
o
496464196
627947843
618185205
439481640
673300868
483397786
827868200
529889898
700238771
~
685345
381040
2612321
525632
196496
o
o
358922
o
o
148307388
111934149
98629822
102974680
96207372
168917972
163627064
264207367
163039822
278900638
as
1 0.833
4
2221
1476
766
2332
9830
4594
2015
20517
5030
2425
l
IV a
o
154520
59849
435149
115067
49297
o
o
110435
o
0.917
32650
10485
24061
3878
19714
17692
23950
17628
30574
16899
1687
398
912
5785
2873
7525
2584
534
1202
2747
4882
1979
4096
13028
7047
11015
4500
5518
9639
9222
11123
9492
11260
o
o
164
450
277
o
423
Table4.1.6 Vi rtua l Pop u la ti on Analysis. Fishing mor ta li ty at age. Panda lus in Div. Ill a and
IVa east
1995WG
Run title : Pandalus IlJa + IVb Assessmenl
At 16/09/1995 16:47
Terminal Fs derived using XSA (With F shrinkage)
Table 8 Fishing mortality (F) at age
1985
1986
1987
YEAR
AGE
o
l
2
3
4
+gp
FBAR 1-3
.0028
.1346
.5385
.9946
.4829
.4829
.5559
.0012
.1704
.3717
.9398
.5456
.5456
.4940
.0015
.2498
.6404
.5668
.6681
.6681
.4857
1988
.0046
.1983
.6268
1.1905
.8193
.8193
.6718
1989
.0079
.3255
.7252
1.0312
.6703
.6703
.6940
1990
.0035
.2274
.8499
.7439
.5683
.5683
.6071
1991
.0015
.1378
.5966
1.4504
.6008
.6008
.7283
199~
.0070
.1126
.8346
2.3332
.5893
.5893
1.0934
1993
.0042
.1843
.7009
1.7277
.6400
.6400
.8710
1994
.0017
.1278
.5682
1.2379
.4999
.4999
.6446
FBAR
92-94
.0043
.1416
.7012
1.7662
.5764
7
Table 4.1.5 Virtual Population Analysis. XSA tuning output. Pandalus in Div. llla and lYa east.
Lowestoft VPA Version 3.1
16/09/1995 16:45
Extended Survivors Analysis
1995WG
Pandai!J$ llla + IVb Assessment
CPUE data from file C:\vpa\vpaiiia\nyiiiaef.dat
Catch data for 1O years. 1985 to 1994. Ages O to 5.
Fleet
Last
year
1994
1994
1994
1994
First
year
1985
1986
1985
1985
Denmark
Norway
Sweden
Norw. Surveys
First
age
1
1
1
last
age
4
4
4
4
o
Alpha
Beta
.000
.000
.000
.833
1.000
1.000
1.000
.917
Time series weights :
Tapered timeweighting applied
Power • 3 over 20 years
Catchability analysis :
Catchability dependent on stock size for ages < 2
Regression type • C
Minimum of 5 points U$ed for regression
Survivor estimates shrunk to the population mean for ages < 2
Catchability independent of age for ages >- 2
Terminal population estimation:
Survivor estimates shrunk towards the mean F
of the final 5 years or the 4 oldest ages.
S.E. of the mean to which the estimates are shrunk •
Minimum standard error for population
estimates derived from each Aeet • .300
Priorweighting not applied
.500
Tuning converged after 29 iterations
Regression weights
.877
.820
.751
Fishing mortalities
Age
o
1
2
3
4
.954
.921
.976
AGE
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1.000
1986
1987
1988
1989
1990
1991
1992
1993
1994
0,00
0,14
0,54
1,00
0,48
0,00
0,17
0,37
0,94
0,00
0,25
0,64
0,67
0,00
0,18
0,70
1,73
0,64
0,00
0,13
0,55
0,01
0,33
0,73
1,03
0,67
0,00
0,23
0,57
0,01
0,20
0,63
1,19
0,82
o
1.92E+07
1.75E+07
1.05E+07
1.73E+07
2.04E+07
1.96E+07
1.27E+07
2.26E+07
1.50E+07
1.36E+07
2
1.19E+07
9.06E+06
8.25E+06
4.97E+06
8.15E+06
9.54E+06
9.23E+06
5.97E+06
1.06E+07
7.05E+06
3
4
4.41E+06
4.90E+06
3.61E+06
3.03E+06
1.92E+06
2.78E+06
3.59E+06
3.80E+06
2.52E+06
4.17E+06
4.42E+05
1.21 E+06
1.60E+06
8.99E+05
7.66E+05
4.40E+05
5.62E+05
9.34E+05
7.79E+05
5.90E+05
1.82E+05
7.73E+04
2.24E+05
4.28E+05
1.29E+05
1.29E+05
9.88E+04
6.22E+04
4.28E+04
6.54E+04
2.93E+06
1.12E+06
8.09E+04
3.32E+06
7.55E+05
1.12E+05
.2833
.4107
.6933
Estimated population abundance at 1sl Jan 1995
O.OOE+OO
6.43E+06
Taper weighted geometric mean of the VPA populations:
1.64E+07
8
1.000
1985
XSA population numbers (Thousands)
YEAR
.997
.990
8.16E+06
Standard error of the weighted Log(VPA populations) :
.2420
.2620
0,85
0,00
0,14
0,60
0,74
1,45
0,01
0,11
0,84
2,33
0,57
0,60
0,59
0,57
1,24
0,50
Table 4.1.5 Continued
Log catchability residuals.
Fleet : Denmark
1986
-0,11
-0,60
0,29
-0,23
1985
-0,15
0,03
0,62
-0,07
Age
1
2
3
4
1987
0,00
-0,34
-0,.46
-0,30
1990
0,25
0,42
0,29
0,03
1989
0,33
-0,04
0,29
-0,12
1988
0,03
-0,25
0,35
0,00
1991
-0,18
-0,02
0,82
-0,01
1992
-0,17
0,38
1,33
0,04
1993
-0,02
0,12
0,96
0,03
1994
-0,01
0,15
0,89
0,02
Mean log catchability and standard error of ages with catchability
independent of year dass strength and ccnstant w.r.l. time
3
-3.6930
.7745
2
-3.6930
.3123
Age
Mean Log q
S.E(Log q)
4
-3.6930
.1305
Regression statistics :
Ages with q dependent on year dass slrength
t-va lue
1.019
Slope
.75
Age
lntercept
7.71
RSquare
.69
No Pts
RSquare
.31
.18
.97
No Pts
10
Reg s.e
.19
Mean log q
-4.95
lO
lO
lO
Reg s.e
.45
.94
.13
MeanQ
-3.69
-3.13
-3.75
Ages with q independent of year dass strength and constant w.r.t. time.
Age
2
3
.4
t-va lue
-.723
-1.163
-.904
Slope
1.40
1.93
1.06
lntercept
-.83
-6.52
3.29
Fleet : Norway
1986
-0,03
-0,.48
0,42
-0,1
Age
1
2
3
4
1987
0,19
-0,08
-0,2
-0,04
1988
0,18
-0,01
0,59
0,24
1989
0,41
0,05
0,39
-0,02
1990
0,19
0,32
0,19
-0,06
1991
-0,38
-0,24
0,6
-0,24
1992
-0,24
0,34
1,29
0,01
1993
-0,03
0,1
0,95
0,02
1994
-0,22
-0,09
0,65
-0,21
Mean log catchability and standard error of ages with catchability
independent of year dass strength and ccnstant w.r.t. time
3
.4168
.7300
2
.4168
.2544
Age
Mean Log q
S.E(Log q)
4
.4168
.1501
Regression statistics :
Ages with q dependent on year dass strength
t-value
.505
Slope
.79
Age
lntercept
3.95
RSquare
.48
No Pts
9
Reg s.e
.28
Mean log q
-.83
Ages with q independent of year dass strength and constant w.r.l. time.
Age
2
3
4
Slope
1.78
1.24
.90
t-va lue
-1.420
-.458
1.607
lntercept
-12.44
-4.42
.78
RSquare
.34
.36
.98
No Pts
9
9
9
Reg s.e
.43
.56
.12
MeanQ
.42
.97
.37
Fleet : Sweden
1985
-0,23
-0,08
0,51
-0,18
Age
1
2
3
4
1986
-0,06
-0,54
0,36
-0,16
1987
-0,05
-0,4
-0,52
-0,36
1988
0,06
-0,18
0,43
0,07
1989
0,48
0,14
0,48
0,07
1990
0,3
0,46
0,33
0,07
1991
-0,15
0,03
0,87
0,04
1992
-0,27
0,27
1,22
-0,06
1993
-0,08
0,02
0,87
-0,06
Mean log catchability and standard error of ages with catchability
independent of year dass strength and ccnstant w.r.t. time
Age
Mean Log q
S.E(log q)
2
.2773
.2949
3
.2773
.7559
4
.2773
.1487
t-va lue
.651
lntercept
4.24
Regression slatistics :
Ages with q dependent on year dass strength
Age
Slope
.78
RSquare
.55
No Pts
lO
Reg s.e
.25
Mean log q
-.98
9
1994
-0,05
0,11
0,85
-0,01
Table 4.1.5 Continued
Ages with q independent of year dass slrength and constanl w.r.l. time.
Age
t-va lue
-1.290
·1.269
-.081
Slepe
1.81
1.95
1.01
2
3
4
lntercept
-12.74
·14.48
-.30
RSquare
.26
.20
.96
No Pts
10
lO
10
Reg s.e
.52
.88
.15
MeanQ
.28
.84
.22
Fleet : Norwegian Surveys
Age
1986
·0,34
·0,39
-0,85
0,14
0,58
1985
-0,30
-0,05
0,02
1,90
o
1
2
3
4
l, 11
1987
·0,05
0,20
0,14
0,51
0,45
1988
-0,18
·0,33
·0,60
0,56
1989
0,14
0,14
0,15
-1,00
1991
0,09
0,03
-0,07
1,32
0,50
1990
·0,08
-0,12
0,45
0,12
·0,80
Mean log catchability and standard error of ages with catchability
independent of year dass strength and c:cnslant w.r.l. time
Age
Mean log q
S.E(log q)
3
2
·9.3173
1.2787
·9.3173
.4100
4
·9.3173
.7514
Regression slalistics :
Ages with 9 dependent on year dass strength
Age
Slepe
.33
1
.56
o
t-va lue
2.136
1.439
lntercept
15.24
12.59
RSquare
.58
.59
No Pts
RSquare
.06
.06
.35
No Pts
10
10
Reg s.e
.22
.23
Mean log q
-12.43
·9.94
Ages with q independent of year dass strength and conslanl w.r.t. time.
Age
2
3
4
Slepe
3.17
1.80
1.15
t-va lue
-1.449
-.529
·.228
lntercept
-3.05
4.48
8.51
Reg s.e
1.22
10
1.79
.76
7
lO
MeanQ
-9.32
-8.51
-8.90
Terminal year survivor and F summaries:
Age O Catchability dependent on age and year dass slrength
Year dass • 1994
Fleet
Estimated
Survivors
1.
1.
lnt
s.e
Ext
s.e
.000
.000
.000
N
Var
Ratio
.00
.00
.00
.00
o
o
o
Sea led
Weights
.000
Estimated
F
.000
.000
.000
.000
Denmark
Norway
Sweden
Norwegian Surveys
6926155.
.000
.000
.300
P shrinkage mean
8157589.
.26
.001
F shrinkage mean
2190113.
.50
.005
l.
.000
.000
.000
.000
1 .374
Weighted predidion :
Survivors
at end of year
6426498.
In l
s.e
.18
Ext
s.e
.31
N
3
Var
Ratio
1.688
F
.002
Age 1 Catchability dependent on age and year dass strength
Year dass • 1993
Fleet
Sea led
Weights
l .151
1 .143
1 .151
2 .301
Den mark
Norway
Sweden
Norwegian Surveys
lnt
s.e
.300
.308
.300
.212
P shrinkage mean
3317297.
.28
.114
F shrinkage mean
1765468.
.50
.204
Weighted predidion :
Survivors
al end of year
2930165.
lO
N
Estimated
Survivors
2893238.
2342649.
2790752.
3444916.
In l
s.e
.12
Ext
s.e
.08
Ext
s.e
Var
Ratio
.00
.00
.00
.27
.000
.000
.000
.058
N
7
Var
Ratio
.648
F
.128
Estimated
F
.129
.157
.134
.110
1992
0,27'
0,29
0,26
2,15
0,47
1993
0,22
0,05
0,40
0,90
1994
0,07
0,10
·0,05
1,48
0,76
Table 4.1.5 continued
Age 2 Calchability conslanl w.r.t. time and dependent on age
Year dass
= 1992
Fleel
Den mark
Norway
Sweden
Norwegian Surveys
F shrinkage mean
lnt
s.e
Estimaled
Survivors
1191082.
1048380.
1138533.
1249572.
.223
.214
.217
.191
725524.
.50
Ext
s.e
.081
.031
.094
.092
N
Var
Ratio
.36
.14
2
2
2
3
.44
.48
Sea led
Weights
.208
.227
.220
.267
Eslimated
F
.540
.596
.559
.521
.778
Weighled predidion :
Survivors
at end of year
1115741.
lnt
s.e
.10
Ext
s.e
.06
N
Var
Ratio
10
F
.547
.568
Age 3 Calchability conslanl w.r.t. time and age (~xed al the value for age) 2
Year dass • 1991
Fleet
Den mark
Norway
Sweden
Norwegian Surveys
F shrinkage mean
Estimaled
Survivors
89046.
85800.
81919.
107645.
lnt
s.e
.222
.221
.217
.192
53940.
.50
Ex l
s.e
.242
.207
.255
.161
N
Var
Ratio
1.09
.94
1.18
.84
3
3
3
4
Scaled
Weights
.182
.186
.190
.214
Eslimaled
F
1.171
1.196
1.229
1.044
1.541
Weighted predidion :
Survivors
at end of year
80881.
lnt
Ext
s.e
.14
.11
s.e
N
14
Var
Ratio
.767
F
1.238
Age 4 Calchability constant w.r.t. lime and age (~xed al the value for age) 2
Year dass == 1990
Fleel
Den mark
Norway
Sweden
Norwegian Surveys
F shrinkage mean
Estimaled
Survivors
19689.
15957.
19001.
27419.
18512.
lnt
s.e
.262
.258
.260
.369
Ex l
s.e
.095
.129
.086
.189
Var
Ratio
.36
.50
.33
.51
N
4
4
4
5
.50
Sea led
Weights
.263
.266
Estimated
F
.481
.265
.566
.494
.072
.367
.505
Weighled predidion :
Survivors
al end of year
18731.
lnt
s.e
.14
Ext
s.e
.06
N
18
Var
Ratio
.406
F
.500
11
Table 4.1.7 Yirtual Population Analysis. Stock number at age. Pandalus in Div. Ula and lYa east
Run Iitie : PandaiUJ llla + Nb Asses.smenl
At 16/09/1995 16:47
Terminal Fs derived using XSA (With F shrinkage)
Table 1O Stock number at age (start of year)
1985
1986
1987
1988
Numbers•10••-4
1989
1990
1991
1992
1993
1960760 1265663
953803
923006
278177
358889
44002
56167
12899
9878
101
o
3249742 2613603
2262466
596932
379877
93358
6221
1498471
1061257
251952
77884
4277
171
2894012
1994
YEAR
AGE
o
1
2
3
4
+gp
TOTAL
1923348
1187205
440607
44222
18207
1747849
906019
490191
121470
m7
3613590
3273729
o
472
1052772
824599
360914
159668
22418
199
2420571
1734442
496531
303419
89855
42790
993
2668030
2035143
815497
192365
76579
12906
228
3132718
o
3338854
1995 GMST 8592
1362784
o
704892 642650
416914 293017
59047 111574
6537
8088
o 1873
2550174 1E+06
Table 4.1.8 Virtul Population Analysis. VPA summary tables with and without SOP corrections.
Pa nda lus in Div. Ill a and lva east.
Run title : Pandalus llla + Nb Asses.smenl
1995WG
At 16/09/1995 16:47
Table 16
Summary
(without SOP corredion)
Terminal Fs derived using XSA (With F shrinkage)
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Arith.
M.ean
OUnits
RECRUITS
Age O
19233480
17478494
1o52mo
17344416
20351430
19607602
12656627
22624662
14984710
13627836
16843698
(Thousands)
Table 17
Summary
TOTALBIO
TOTSPBIO
93.455
92997
71974
65975
77666
83694
75500
83278
80424
64657
16763
9208
1.4939
11676
11697
12475
14383
14495
12090
14525
78962
13225
(Tonnes)
(Tonnes)
LANDINGS
YIELO/SSB
FBAR 1- 3
12628
13234
15072
12857
12542
11852
12323
13728
13907
12076
.7533
1.4372
1.0089
1.1011
1.0723
.9500
.8568
.9471
1.1503
.8314
.5559
.4940
.4857
.6718
.6940
.6071
.7283
1.0934
.8710
.6446
13022
1.0108
.6846
(Tonnes)
(with SOP corredion)
Terminal Fs derived using XSA (With F shrinkage)
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Arith.
M.ean
Unib
12
RECRUITS
Age O
19233480
17478494
1o52mo
17344416
20351430
19607602
12656627
22624662
14984710
13627836
16843698
(Thousands)
TOTAlBIO
(Tonnes)
TOTSPBIO
86058
92988
72239
69005
70657
74946
m18
76209
79906
68256
15436
9207
14994
12213
10641
11171
14710
13264
12012
15334
76748
12898
(Tonnes)
LANDINGS
(Tonnes)
YIELO/SSB
12628
13234
15072
12857
12542
11852
12323
13728
13907
12076
.8181
1.4373
1.0052
1.0528
1.1786
1.0609
.8377
1.0350
1.1577
.7875
13022
1.0371
SOPCOFAC
FBAR 1-3
.9208
.9999
1.0037
1.0459
.9098
.8955
1.0227
.9151 .
.9936
1.0557
.5559
.4940
.4857
.6718
.6940
.6071
.7283
1.0934
.8710
.6446
.6846
1701167
811863
338543
77940
13884
Table 4.1. 9 lndices of Q- and 1-group shrimp from Norwegian
trawl surveys in October and VPA values. Panda lus in Div. llla and IVa east
VPA(new95)
o- r
Yecu-dass
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
3077
1813
1432
675
2002
9388
4052
1877
19967
4743
2371
7023
20902
6914
5988
2541
8714
10743
12116
10739
22294
9911
2- r
1- r
11872
9060
8246
4965
8155
9538
9230
5969
10613
7049
19233
17478
10528
17344
20351
19608
12657
22625
14985
13628
Table 4.1.10 Input value for pr ed i et i on. Panda lus in Div. Ille and IVa east
Most Recent Data year (enter)
1995
Recruits
1994 ~o
1996
Recruits
First Precl. Year
1995 ~o
1997
Recruits
1996 ~o
Seccnd "
1997
Third "
maturity
MeanWt
MeanWt
Prep F befare spawnin9:
M
ogive
catch 9
Prep M befare spawnin9:
slodc 9
~
0,75
0,00
1,19
1,19
o
0,00
0,75
3,57
3,57
1
0,70
0,75
5,65
5,65
2
0,75
1,00
8,54
3
8,54
0,75
1,00
11,54
11,54
4
1,00
0,75
14,68
14,68
5
~
o
l
2
3
4
5
Stoc:ksize
Jan 1
1994
(enter)
F
1994
(enter)
13627
7048
4169
590
65
o
Stocksize
Jan l
1995
(From vpa)
0,0017
0,1278
0,5682
1,2379
0,4999
0,4999
6427
2930
1116
81
19
Fishin9
paltem
Fishing
pattem
mean F
scaled lo
92-94
(enter)
1994
4406
4902
3609
3034
1924
2782
3589
3799
2520
4169
17011
17011
17011
(enter)
0,2
0,25
refF
0,004
0,142
0,701
1,766
0,576
0,576
0,003
0,143
0,7CB
1,787
0,583
0,583
Table 4.1.11 Prediction res ults. Panda lus in Div. Ille and IVa east
Stock size for prediction
Jan 1
Stock
Landed
1995
Biornass
æ3
pro p
Landed
average
Catch
1995
1995
1995
1995
1995
recruit.
20243
o
32
0,71
17011
45
1848
o
22944
6427
0,85
2174
16555
8336
6178
1
6178
2930
9531
5527
6182
1116
1
6182
935
690
301
81
301
1
206
19
279
90
1
90
14630 tonnes
70486
14758
sum:
14970
Prediction with management option table
1996
ÆFF
æ3
FACTOA
0,00
o
14611
14168
0,13
0,2
0,4
0,26
13741
0,6
0,39
13330
0,52
12935
0,8
0,64
12554
1
1,2
0,77
12186
0,90
1,4
11832
1,03
11491
1,6
1,8
1,16
11161
10844
1,29
2
CATCH
LAND
o
2506
4714
6676
8433
10016
11452
12763
13966
15075
16103
o
2440
4585
6484
8178
9700
11076
12328
13473
14526
15498
TSB
70921
70921
70921
70921
70921
70921
70921
70921
70921
70921
70921
1997
æ3
CATCH
24939
o
22345
3675
20145
6464
18266
8609
16650
10284
._1525_1____11§.1L
14032
12678
12963
13550
12021
14273
11184
14880
10437
15398
13
Table 4.2.1
Landings in tonnes of Pandalus borealis from the Fladen Ground
(Division IVa) as estimated by the Study Group
Year
Den mark
Norw
Sweden
Total
2204
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
199.4·
157
282
1 308
1 552
425
890
565
1122
187
163
434
525
1937
1692
2027
268
377
347
112
81
44
76
1
685
2 391
320
716
1 833
3489
2229
2998
877
1575
1 033
635
7564
4591
4990
3717
8012
1163
3010
2053
506
1564
2059
1 242
352
283
5729
8
13
4553
3649
3416
7326
1077
2438
1 681
422
1 448
1 521
1 207
1 827
75
1 341
301
686
4
2
84
75
547
3
365
31
S3
'E
116
5\B
35
o
• Provisiona
Table 4.2.2
Panda/us borealis, Fladen Ground. Reported CPUE
(shrimp frawlers), and estimated effort.
Danmark
UK (Scotland)
Total elfcrt
Year
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Total effort
lnde!)( 1
295
0,96
1,18
0,97
1,21
0,96
1,24
0,83
0,99
1,28
1,50
1,44
1,83
1,93
lndex 1
hours
4757
20528
676
15593
4239
8469
1909
8415
3493
429
1685
4855
4694
3016
3558
5908
1298
2463
1313
281
1006
831
621
5229
330
0,31
1,3
0,0
1,
0,2
0,5
0,1
0,5
0,2
0,0
0,11
0,3
0,0
Combined
index 2
0,21
1,54
1,55
1,00
1,11
1,84
0,41
0,77
0,.40
0,09
0,32
0,29
0,20
Table 4.3 Landings (t) of Pandalus from division lvb the Farn Deeps as estimated by the Study
Group
Year
l977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
14
UK (England)
UK (Scotlandl
Den mark
91
235
203
1
Total
NO data
til
2
34
17
65
:D
2
137
212
91
168
14.4
3
1
4
6
5'
106
300
86
92
384
72
390
500
248
145
3
1
75
8
+
1
o
4
35
---+-1994
-----1993
_._1992
--M--1991
-:*--1990
30
25
E 20
~1989
E 15
-:-1988
-1987
-1986
-+-1985
. 1984
1: t
11
o
85
l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l
86
87
88
89
90
91
92
93
94
year
Figure 4.1.1 Mean carapace length (mm) at age (quarters) in area Ille- IVa east for yeardasses 1984 to 1994
15
10
-o-lagp
--o-2-gp
--M--3-gp
5
o
~
-<>-4-gp
-5
-10
-15
-20
1985
1986
1987
1988
1989
1990
1991
1992
1993
Figure 4.1.2 Percentage difference "new" minus "old" of age groups 1-4, for the two datasats.
0,9~----------------------------------------~
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
-o-newF
-o-old F
0,0~--~----------~---------+----~----------
1985
1986
1987
1988
1989
1990
1991
1992
1993
Figure 4.1.3 Average Fishing mortality for 1-3 group 1985-1993 according to XSA using "old" and "new" dataset
15