ICES CM 1998/D:6
Ref.G
Resource Management Committee
REPORT OF THE
INTERNATIONAL BOTTOM TRAWL SURVEY IN THE NORTH
SEA, SKAGERRAK AND KATTEGAT IN 1997: QUARTER 1
by
The International Bottom Trawl Survey Working Group
This report is not to be quoted without prior consultation with the
General Secretary. The document is areport of an expert 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
Palregade 2-4 DK-1261 Copenhagen K Denmark
Table of Contents
Section
I INTRODUCTION
I
2 SURVEY METHODS AND PARTICIPATION
1
3 DATAAVAILABLE
1
4 STANDARD OUTPUT FROM THE ICES IBTS DATA BASE
1
5 REVISION OF THE AUTUMN SPAWNER HERRING INDEX
1
6 RESULTS GOV-TRAWL FOR 1997
6.1 North Sea
6.2 Skagerrak-Kattegat (Division lIla)
2
2
3
7 RESULTS OF THE SAMPLING FOR HERRING AND SPRAT LARVAE IN 1997
e
•
Page
.4
8 HYDROGRAPHIC DATA
8.1 Hydro-chemistry Survey
4
4
9 REFERENCES
5
Tables 3.1-8.1
6
Figures 5.1-8.3
14
·1
INTRODUCTION
This report presents the final results for the International Bottom Trawl Survey (IBTS) in the first quarter of
1997. The survey was formerly called the International Young Fish Survey (IYFS).
In 1990 it was decided to combine the effort of the International Young Fish Survey with a number of national
surveys such as the English and Scottish Groundfish Surveys into a quarterly coordinated bottom trawl survey, to
be held for aperiod of 5 years. These quarterly surveys started in 1991. During a meeting of this Working Group
in November 1995 (leES 1996a) early analyses of the data indicated the potential usefulness of quarterly surveys
and it was decided to encourage their continuation.
The results for quarters 2-4 will be published elsewhere.
The data in this report comprise the bottom trawl catches of the 8 standard species (herring Clupea Izarengus,
sprat Sprattus sprattus, mackerel Scomber scombrus, cod Gadus morhua, haddock Melanogrammus aeglejinus,
whiting Merlangius merlangus, saithe Pollachius virens and Norway pout Trisopterus esmarkt), as weil as the
catches of herring larvae. Also summarized results of temperature and salinity sampling are presented.
SURVEY METHODS AND PARTICIPATION
2
For all maUers on survey methodology, the reader is referred to the Manual (ICES, 1996b). Details on the
participation in the 1997 survey are given below. The whole survey area has been covered as planned.
Country
Denmark
France
Germany, F.R.
Netherlands
Norway
Sweden
UK Scotland
Vessel
"Dana"
"Thalassa"
"W. Herwig III"
"Tridens"
"l\tichael Sars"
"Argos"
"Scotia"
Total
•
3
Number of Hauls
Period
1-19/2
4-24/2
1811-07/2
3/2-27/2
2311-15/2
2711-1312
3111-18/2
GOV
MIK
48
65
70
51
40
46
45
94
20
365
289
20
53
40
62
DATA AVAILAULE
In Table 3.1 is shown for which years data are presently available in the ICES IBTS data base for the quarter I
surveys.
At the time of the analysis of the 1997 data presented in this report all final data were available in the database.
4
STANDARD OUTPUT FROl\l THE ICES mTS DATA UASE
For details on the standard analysis of the data the reader is referred to adescription by Pedersen (1989). At
request, copies of this paper are available at the ICES Secretariat.
5
REVISION OF THE AUTUMN SPAWNER HERRING INDEX
In 1994 the Herring Assessment Working Group for the Area South of 62°N has adopted a new index for 1ringer abundance of North Sea autumn spawners. The new index is based on daytime catches in all statistical
rectangles sampled during the quarter 1 survey, both in the North Sea and in the Skagerrak/Kattegat. In the
-.
calculation of this index, catches made in rectangles shaBower than 10m, or deeper than 200 m (250 m in
Skagerrak), have been given less weight. The weighting factors are given in Figure 5.1.
It is implieitly assumed that all I-ringer herring in thc North Sea, Skagerrak, and Kattegat are autumn spawners.
Unsampled reetangles are allocated the mean catch rate estimated within "roundfish areas" and the index is
expressed as the mean eateh ratc (number per hour) for the entire survey area. The indices for 2+-ringers have
been rcvised in the same way, with the exception that the catches in Skagerrak amJ Kattegat are assumed to be O.
This implicitly assumed that all 2+-ringers in Skagerrak and Kattegat are loeal or Baltic spring spawners. The use
of "zero" catches instead of "missing" catches of 2+-ringers in this area is convenient because it brings the
indices of all age groups on a similar scale so that for instance mortalities can be caIculated directly from the
indices.
The IBTS Working Group decided at the meeting in November 1995 (ICES 19961H:I) that saithe should be
added to the list of standard species. The indices of saithe for each age group are calculated in a similar way as
for I-ringer herring (see above) with the exception that also night-time hauls are used for saithe.
6
RESULTS GOV-TRAWL FOR 1997
6.1
North Sea
Preliminary indices based on certain size classes are compared with the final indices in Table 6.1. With the
exception of herring and sprat, the preliminary indices are very close to the final ones. Final indices of 1- and 2group fish of the eighth standard species are given in Table 6.2. Table 6.3 gives the mean age composition of the
standard species within the relevant standard areas.
•
In the analysis only day-light hauls are used for herring, whereas for the other species aB valid hauls are used.
The number of hauls used for herring and for the other species is shown in Figures 6.1 and 6.2.
Per species a set of figures gives the distributions of the 1-, 2-, and 3+ group and the mean length of I-group fish
per rectangle. In the analysis a specific standard area for each species is used to calculate the index of year class
strength. This area is indicated in the figures.
lIerring
Indices for 1- and 2-ringed herring are presented in Table 6.2 and mean numbers per rectangle are given in
Figures 6.3 to 6.6. It should be noted that the term "age group" in herring refers to number of winter rings and not
to years. All juvenile herring in the North Sea are assumed to be autumn spawners, and this means that for
instance age group I herring in February 1997 represent year class 1995.
The index for the 1995 year dass is the largest value since 1986, a value more than twice the series average.
Sprat
Sprat indices of 1- and 2-group are given in Table 6.2. The distribution of the same age groups and the 3+ group,
as weIl as the mean length of I-group per rectangle, are shown in Figures 6.7-6.10.
The Herring Assessment Working Group has also for sprat adopted a new index series (ICES I993/Assess: 15) in
which only hauls between 10 and 150 m dcpth are included. The standard area has rcmained the same: Division
IVb only.
The index value for the 1996 year class, at a little below the series average and only 20% of the record 1988 year
class, is still three times higher than that for the preceding year class.
l\Iackerei
Indices for mackercl are given in Table 6.2, the distributions of 1-, 2- and 3+ groups, and thc mean length of 1group fish are given in Figures 6.11-6.14.
2
•
-
-
--------
The index value of I-group is very high, more than 20 times the second highest, due to the high abundance in the
northern and north-western part ofthe survey area.
Cod
Abundance indices are given in Table 6.2, the distributions of 1-, 2-, and 3+ group, and the mean length of 1group fish are given in Figures 6.15-6.18.
The index. value for one-year-old cod (1996 year dass) is the third highest recorded and more than twice the
long-term average.
Haddock
Abundance indices are given in Table 6.2, the distributions of 1-, 2-, and 3+ group, and the mean length of 1group fish are given in Figures 6.19-6.22.
The index value at 860 is 25% above the long-term average and more than three times that of the weak 1995 year
dass.
•
Whiting
Abundance indices are given in Table 6.2, the distributions of 1-, 2-, and 3+ group, and the mean length of 1group fish are given in Figures 6.23-6.26.
The decreasing trend in whiting abundance continued in 1997 and the index value is the lowest produced since
1982.
Saithe
Abundance indices are given in Table 6.2, the distributions of 1-, 2-, and 3+ group, and the mean length of 1group fish are given in Figures 6.27-6.30.
As usual only very few 1- and 2-group saithe were found in the North Sea in 1997.
Norway Pout
Abundance indices are given in Table 6.2, the distributions of 1-, 2-, and 3+ group, and the mean length of 1group fish are giyen in Figures 6.31-6.34.
•
High catch rates of the 1996 year class of Norway pout in the northern North Sea in particular produced the
largest index value for one-year-olds in the whole 23 year series, a value more than three times the series average
and ten times that far the 1995 year class.
6.2
Skagerrak-Kattegat (Division lIla)
The number of hauls per rectangle for herring and gadoids is shown in Figures 6.1 and 6.2.
The final indices for 1- and 2-group herring and 1- and 2+ group sprat are given in Table 6.4. The herring indices
are calculated as the mean catches in four depth strata, covering the depth range of 10-150 m, and weighted by
the surface area of each stratum.
Agellength keys for eod are available from the 1981 IBTS and onwards. The stocks of cod in Skagerrak and
Kattegat are assessed separately and indices are given for each area. Final and preliminary indices for cod and
preliminary indices for whiting and haddock are given in Table 6.5.
Updates ofthe indices for the 1997 survey are not available.
3
7
RESULTS OF THE SAMPLING FOR HERRING AND SPRAT LARVAE IN 1997
During the IBTS fish larvae were sampled by a small meshed ring net (MIK). This gear was towed in oblique
hauls during night. The eatehes were used for estimation of larval densitics and total abundanee, in the estimation
a 100% effieieney of the gear for eatching clupeid larvae at night was assumed.
Larval density is estimated from:
2
Density (no. m- ) = (no. Caught I [distance towcd (m) * net-opening (m2)] * water depth (m».
The number of larvae within a given rectangle is estimated by multiplying the estimated density of larvae by the
surface area of the rectangle. The total abundance of larvae in the North Sea (the MIK index) is the sum of
estimates from all statistical reetangles.
Herring
In total 289 hauls were earried out. This sampling intensity gave a reasonable coverage of the sampling area.
In February 1997 the herring larvae were distributed with major eoneentrations off the Seottish coast (Figure
7.1). The distribution pattern resembles last year's westerly distribution of the larvae. However, in 1997 the
distribution extended further to the south than obscrved in 1996. The total abundanee is estimated to 148.1 *109
which is an increase compared to last years (Table 7.1, Figure 7.2).
•
Sprat larvae
Sprat larvae were sampled in small quantities in the eentrallsouthcrn sections of the sampling area. Because of
the limited numbers, no ealculation was earricd out.
8
HYDROGRAPHIC DATA
8.1
1I)'dro-chemistry Surny
Six ships eontributed hydrographie data to the 1997 data set. These consist of 415 stations worked between 18
January and 27 February. Nutrient data were supplied for 70 stations, contributions being received from only two
ships. Data quality was good, and as a result, no stations were rejected by the data eentre. Many of the data sets were
submitted very late preventing the early completion of this report.
Charts of the distribution of bottom temperature and salinity are given in Figures 8.1 and 8.2. An updated table,
giving the time series of temperature and salinity at 10 locations in the North Sea during IYFSIIBTS (I) surveys
from 1970 to 1997 is provided as Table 8.1. The Figures and Table show that temperatures throughout most of the
North Sea were some 1°C warmer than average in the Northern North Sea, but were up to 2°C eolder than average in
the south (but much warmer than in 1996). Salinity was very close to the long-term mean throughout the North Sea.
During the 28 years of this time series, there are no significant trends in salinity and temperature in most areas of the
North Sea. Howevcr, in the northcm North Sca, where inter-annual variability is least, there is some evidence of a
rising trend of some 0.1 in salinity and 0.8°C in temperature over this period. Figure 8.3 illustrates the salinity time
series, along v..ith the time series of the index of the North Atlantic (atmospheric) Oscillation (NAO) during thc same
period.
9
REFERENCES
ICES 1993. Rcport of the I1crring Asscssmcnt Working Group for the Area South of 62°N.
leES Doe. C1\I
1993/Assess: 15.
ICES 1995. Report of the Hcrring Asscssmcnt Working Group for the Area South of 62°N. ICES Doc. CM
1995/Assess: 13.
4
•
lCES 1996a. Report ofthe International Bottom Trawl Survey Working Group. lCES Doc. CM 19961H:I.
lCES 1996b. Manual for the International Bottom Trawl Surveys. Rev. V. Addendum to ICES CM 19961H:1.
Pedersen, L. 1989. International Young Fish Survey, computation of aggregated standard tables and charts. lCES
Secretariat, section computer management. Table.
•
•
5
Table 3.1 Data available in the ICES IBTS data base as at February 1998.
First Quarter.
-/
x
Country
Denmark
France
Germany
Netherlands
Norway
Sweden
UK England
UK Scotland
USSR
Country
Denmark
France
Germany
Netherlands
Norway
Sweden
UKEngland
UK Scotland
USSR
Country
=
=
=
Data available
No data available
No survey made
1972
1973
1974
1975
1976
1977
1978
1979
1980
./
./
-/
./
./
./
./
x
x
./
./
./
x
x
x
x
x
-/
./
./
-/
./
-/
-/
-/
-/
-/
x
x
x
x
-/
-/
-/
./
-/
-/
-/
-/
x
-/
-/
-/
-/
1981
1982
1983
1984
1985
1986
1987
1988
1989
x
x
./
-/
./
-/
-/
./
./
./
-/
-/
-/
-/
./
-/
./
-/
-/
-/
-/
./
-/
-/
-/
./
-/
-/
./
-/
-/
-/
-/
-/
-/
-/
-/
-/
./
-/
./
-/
-/
-/
x
-/
-/
-/
./
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
./
-/
-/
-/
./
-/
-/
-/
x
x
x
x
x
x
1990
1991
1992
1993
1994
1995
1996
1997
./
./
-/
./
./
./
-/
./
./
-/
-/
./
-/
-/
-/
-/
-/
-/
-/
./
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
-/
Denmark
France
Germany
Netherlands
Norway
Sweden
UKEngland
UKScotland
./
-/
USSR
x
-/
-/
-/
./
./
-/
x
x
x
x
x
x
x
-/
x
-/
x
v'
x
-/
x
-/
x
-/
x
-/
x
6
x
•
•
Table 6.1
Preliminary indices for l-group fish based on a split of the length distribution,
and final indices for the North Sea from the first quarter IBTS in 1997.
For herring the "old" standard area is used.
Herring
Sprat
Mackerel
ead
•
Preliminary
Final
4,318
4,068.8
1172
853.7
725.6
718.8
40.5
40.0
Haddock
862
860.2
Whiting
295
287.7
0
Saithe
Norway pout
10,409
7
9,751.6
Table 6.2
lETS indices far 1- and 2-ycar-old fish of various species. Indices in mean number per hour within the relevant standard
area in the North Sea.
Year class
HERRING
SPRAT
MACKEREL
I-ring 2-ring age I age 2 agc I
00
1969
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
1995
1996
COD
age 2
90
123
481
16.5
172*
312*
431*
772*
109
1,260
161
1,443 716
2,083
661
2,542 838
3,684 4,103
4,530 775
2,313 580
1,016 794
1,159 377
1,162 762
2,943 1,094
1,667 1,285
1,186
194
1,735 437
4,069
1,186
136
1,474
248
1,402
941
296
210
382
660
71
803
148
4,246
177
1,121
1,561
1,755
4,003
1,138
233
854
004
104
2.3
0.2
1,380
502
754
387
298
103
74
1,437
442
557
116
340
422
1,368
2,716
558
409
+
0.1
0.1
1.9
0.1
0.7
0.5
8.9
1.2
l.l
35.0
6.9
16.0
1.0
2.2
+
1004
718.8
0.1
0.2
+
+
+
+
+
0.1
5.2
004
0.0
2.1
+
0.1
1.8
1.2
0.2
004
0.8
0.1
+
0.7
3.6
age I agc 2
- 25.9
98.3 34.5
4.1 10.6
38.0
9.5
14.7
6.2
40.3 19.9
7.9
3.2
36.7 29.3
12.9
9.3
9.9 14.8
16.9 25.5
2.9
6.7
9.2 16.6
8.0
3.9
15.2 17.6
0.9
3.6
17.0 28.8
8.8
6.1
3.6
6.3
13.1 15.2
304
4.1
4.5
204
13.0 19.9
404
12.7
14.8 22.1
9.7
8.0
6.9
3.5
40.0
HADDOCK
age I
855
740
187
1,092
1,168
177
162
385
480
896
268
526
307
1,057
229
579
885
92
210
219
679
1,115
1,242
229
1,375
267
860
age 2
32
299
971
110
385
670
84
108
240
402
675
252
400
219
828
244
326
688
97
114
131
371
543
504
205
813
366
WHITING
SAITHE
age lage 2 age lage 2
31
274 190
332 763
1,156 496
322 153
893 535
679 219
418 293
513 183
457 391
692 485
227 232
126
161
128 179
436 359
341 261
456 544
669 862
394 542
1,465 887
509 675
1,014 748
916 524
1,087 637
721 457
l.l
679 486
0
0
502 342
288
0
NORWAYPOUT
age I
4,242
4.599
4,813
1,913
2,690
4,081
1,375
4,315
2,33 I
3,925
2,109
2,043
3,023
127
2,079
1,320
2,497
5,121
2,681
1,868
5,941
923
9,752
age 2
2,412
385
334
1,215
240
611
557
403
663
802
1,423
384
469
760
260
773
677
902
2,644
375
785
2,631
1,474
* Revised according to new proccdures by the Herring Assessment Working Group for the Area South of 62°N (l995/Assess: 13), but not
based on retrieval from databasc.
•
Table 6.3
Age composition of the standard species in 1997 for the relevant standard areas in the North Sea.
2
3
4
5
4,068.8
436.6
180.6
34
14.4'
Sprat
853.7
409.1
50.7
4.6
0.0'
Mackerel
718.8
3.6
0.4
1.4
0.4
0.6
40.0
6.9
2.3
l.l
0.4
0.4
Haddock
860.2
366.4
470.6
24.8
15.1
3.4
Whiting
287.7
342.2
162.5
60.4
18.0
9.2
0.0
0.0
0.0
1.5
2.4
0.5
9,751.6
1,474.1
669.9
2.9
0.0
0.0
Age group
Herring
eod
•
Saithe
Norway pout
'Plus-group.
9
6+
-
Table 6.4
--
---
---
---
IBTS indices for herring and sprat in Skagerrak-Kattegat. The herring indices are weighted by the
area of four depth strata and the sprat indices are the mean by hour within the total area (n.a. = not
avai1able).
Sprat
Herring
Year
Total
I-ring
2-ring
Autumn-spawners
2-ring
I-ring
Spring-spawners
I-ring
2-ring
I-group
2+group
Total
1974
1,325
1975
5,339
1976
2,069
1977
5,713
984
6,697
1978
5,119
2,117
7,236
1979
3,338
1,482
4,820
1980
2,311
387
1,607
307
704
80
4,960
3,592
8,558
1981
3,246
1,393
966
1,318
2,250
75
2,809
3,068
5,877
1982
2,560
549
1,408
445
1,152
104
1,577
4,695
6,272
1983
5,419
1,063
1,522
946
3,897
117
1,173
1,685
2,858
1984
6,035
1,947
2,793
1,419
3,242
528
5,818**
861
7,034
1985
7,994
2,473
1,867
-*
606
2,404
2,426
5,388
1986
21,489
2,738
1,562
-*
1,176
670
1,934
4,545
1987
11,733
3,671
2,921
-*
949
2,234
2,219
8,048
1988
67,753
10,095
-*
-*
-*
-*
7,834
-*
2,161
950
5,527
10,634
1989
17,451
4,976
-*
0
-*
4,976
435
1,012
3,310
1990
3,544
3,876
0
3,192
3,544
684
510
243
944
1991
3,588
3,749
-*
480
-*
3,269
659
468
1,945
1992
5,057
1,934
0
771
5,057
1,163
5,897
634
7,122
1993
26,738
3,165
0
203
26,738
2,962
1,593
4,237
7,186
1994
8,777
2,333
0
0
8,777
2,333
1,494
586
3,361
1995
7,114
535
0
0
7,114
535
2,006
1,726
3,802
1996
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
255
5,099
5,312
1997
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a
n.a.
n.a.
* Separation not valid.
** From 1984 onwards only hau1s taken in depths between 10 and 150 m are inc1uded in the estimates
10
•
•
Table 6.5
Year Class
•
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
Indices of 1- and 2-group cod and l-group whiting and haddock in Skagerrak-Kattegat.
The preliminary indices are the mean number per hour for cod < 25 cm,
whiting and haddock < 2Ocm.
Cod l-group
Skagerrak
Prel. Final
79
18
36
32
24
18
82
15
81
62
25
42
119
171
77
111
37
n.a.
15
36
28
23
14
78
5
77
56
31
9
96
110
82
97
36
n.a.
Cod l-group
Kattegat
Prel.
Final
386
42
126
113
49
18
229
48
76
131
39
26
104
96
39
9
213
11
68
3
153
19
64
64
40
22
390
172
n.a.
31
19
300
52
n.a.
6
Cod 2-group
Skagerrak Kattegat
93
31
30
19
52
lO
113
18
24
8
25
5
16
7
47
35
n.a.
•
11
171
63
258
143
106
72
372
28
48
16
112
20
38
13
114
272
n.a.
Whiting
l-group
Prel.
Haddock
l-group
Prel.
499
236
99
392
561
722
968
690
262
500
940
1379
2178
2978
478
2255
1636
1796
1359
525
1105
883
n.a.
40
4
48
34
72
161
57
251
125
20
8
74
288
405
180
233
490
n.a.
--
Table 7.1
-
-_.-
- -l
-
Density and abundance of herring larvae caught in February during the IBTS. Values for year classes by areas are
density estimates in number per square metre. Total abundance is found by multiplying density by surface area and
summing up.
Area
North
west
North
east
Central
west
Central
east
South
west
South
east
Division
lIla
Southern
Bight
O-ringers
abundance
Area m2 x 109
83
34
86
102
37
93
31
31
N 109
1976
0.054
0.014
0.122
0.005
0.008
0.002
0.002
0.016
17.1
1977
0.024
0.024
0.050
0.015
0.056
0.013
0.006
0.034
13.1
1978
0.176
0.031
0.061
0.020
0.010
0.005
0.074
0.000
52.1
1979
0.061
0.195
0.262
0.408
0.226
0.143
0.099
0.053
101.1
1980
0.052
0.001
0.145
0.115
0.089
0.339
0.248
0.187
76.7
1981
0.197
0.000
0.289
0.199
0.215
0.645
0.109
0.036
133.9
1982
0.025
0.011
0.068
0.248
0.290
0.309
0.470
0.140
91.8
1983
0.019
0.007
0.114
0.268
0.271
0.473
0.339
0.377
115.0
1984
0.083
0.019
0.303
0.259
0.996
0.718
0.277
0.298
181..
1985
0.116
0.057
0.421
0.344
0.464
0.777
0.085
0.084
177.4
1986
0.317
0.029
0.730
0.557
0.830
0.933
0.048
0.244
270.9
1987
0.078
0.031
0.417
0.314
0.159
0.618
0.483
0.495
168.9
1988
0.036
0.020
0.095
0.096
0.151
0.411
0.181
0.016
71.4
1989
0.083
0.030
0.040
0.094
0.013
0.035
0.041
0.000
25.9
1990
0.075
0.053
0.202
0.158
0.121
0.198
0.086
0.196
69.9
1991
0.255
0.390
0.431
0.539
1.500
0.369
0.298
0.395
200.7
1992
0.168
0.039
0.672
0.444
0.734
0.268
0.345
0.285
190.1
1993
0.358
0.212
0.260
0.187
0.120
0.119
0.223
0.028
101.7
1994
0.148
0.024
0.417
0.381
0.332
0.148
0.252
0.169
126.9
1995
0.260
0.086
0.699
0.092
0.266
0.018
0.001
0.020
106.2
1996
0.003
0.004
0.935
0.135
0.436
0.379
0.039
0.032
148.1
Year class
12
•
---
Table 8.1
Time series data of bottom temperatureand salinity during IYFS/IBTS(I) 1970-1997
2
3
4
5
6
7
8
9
10
60° O'N
2°E
57° 30'N
57° 30'N
2°E
57° 30'N
4°E
55° D'N
55° O'N
2°E
SSO O'N
4°E
55° O'N
8°E
54° O'N
3°E
52° 30'N
3°E
I
I
Location
Position
---------------
I
Year
tOe
1970
\971
1972
OOE
Sal
I
I
OOE
Sal
tOe
5.9
34.75
7.0
34.82
6.5
Sal
tOe
I
tOe
4.5
34.82
6.2
34.88
34.9\
4.8
7.0
35.05
6.5
34.90
34.95
5.3
35.0U
4.7
34.92
6.9
35.15
6.0
35.10
5.9
35.20
4.5
34.78
35.02
7.2
35.20
6.7
35.10
35.\\
6.5
35.08
6.3
35.04
35.05
6.6
35.15
6.4
35.13
6.6
35.00
6.5
35.15
5.6
35.\2
6.1
34.8\
34.92
6.0
34.98
5.5
35.08
5.8
34.95
7.\
35.\5
7.0
35.05
5.8
35.22
6.9
35.08
7.4
1974
6.9
35.28
6.5
1975
7.3
35.20
6.6
\976
6.7
35.20
6.5
I
Sal
Sal
ee
\973
tOe
tOe
Sal
I
Sal
tOe
4.0
34.72
5.5
34.80
34.86
5.2
34.80
6.\
35.00
6.0
34.86
6.0
34.90
5.6
34.90
6.4
34.90
6.1
34.85
4.9
34.95
4.9
4.9
34.85
5.0
I
Sal
tOe
0.5
33.00
3.5
33.00
2.5
I
I
Sal
tOe
Sal
4.0
34.72
4.0
5.9
34.55
7.0
34.95
33.80
5.2
34.70
6.9
35.\0
5.0
33.00
6.4
34.80
6.5
35.05
4.7
33.00
6.\
34.78
8.0
35.20
5.2
33.50
5.9
34.62
6.9
34.62
34.85
2.2
31.00
5.1
34.78
5.\
34.80
34.80
3.\
33.60
5.6
34.78
7.1
35.22
34.90
34.62
\977
6.0
35.\8
6.2
35.02
5.1
35.00
4.8
1978
6.4
34.88
6.6
35.00
6.0
34.90
4.7
34.88
5.6
34.78
4.9
34.88
4.2
34.80
2.2
32.50
4.6
34.68
5.5
\979
6.4
35.\5
6.0
34.80
4.\
34.88
4.0
34.98
4.5
34.64
2.8
34.62
2.8
34.62
-1.5
32.00
3.0
34.62
4.2
34.95
1980
5.9
35.12
6.6
35.00
5.5
35.00
4.5
34.70
6.\
34.60
3.8
34.65
4.5
34.50
3.\
33.50
5.\
34.70
6.\
35.1\
\981
6.9
35.22
6.6
34.90
6.2
35.05
5.8
35.15
6.5
34.80
5.8
34.82
5.1
34.82
3.4
32.50
\982
6.6
35.28
6.1
35.02
5.9
35.05
5.5
35.\0
5.5
34.72
4.8
34.82
4.5
34.62
2.8
32.50
4.7
34.30
6.0
34.65
6.9
35.22
6.5
35.00
6.4
35.10
6.2
35.\5
5.6
34.62
6.1
34.95
5.2
34.90
3.0
33.00
5.2
34.80
6.4
34.70
34.80
5.0
34.84
4.9
34.90
3.5
33.00
4.9
34.65
7.4
34.95
4.7
34.91
5.0
34.90
1.0
32.50
4.0
34.70
6.0
34.80
\983
\984
6.3
35.\8
6.4
35.10
6.4
35.\0
5.2
35.12
5.9
1985
6.9
35.17
6.8
35.10
6.5
35.18
5.9
35.05
6.5
34.70
1986
6.6
35.25
5.8
35.05
5.4
35.08
5.2
35.05
5.2
34.65
3.9
34.72
3.6
34.60
0.0
32.50
4.0
34.60
4.0
34.65
1987
6.5
35.28
6.1
34.90
5.9
35.08
4.9
35.00
5.0
34.75
4.2
34.80
4.3
34.60
0.8
30.00
4.9
34.60
4.8
34.90
1988
7.6
35.18
7.6
34.95
7.4
35.03
7.0
34.96
7.1
34.70
6.6
34.80
6.5
34.50
5.9
33.50
6.9
34.60
7.7
34.90
1989
8.5
35.29
8.0
34.85
7.8
34.89
7.6
35.05
7.5
34.76
7.\
34.8\
6.8
34.80
6.0
34.\0
6.5
34.68
7.5
34.62
1990
8.5
35.29
7.6
35.00
7.6
35.\2
7.6
35.\5
7.5
34.70
7.5
34.85
7.5
34.80
6.5
34.10
7.4
34.70
7.4
34.60
6.1
34.97
6.6
34.65
5.8
34.85
5.5
34.80
3.0
34.00
5.8
34.60
6.\
35.30
1991
7.9
35.30
6.7
35.10
7.1
35.22
1992
8.\
35.29
7.6
35.10
7.\
35.16
7.\
35.19
7.4
34.80
6.6
34.80
6.5
34.80
6.6
32.00
4.5
34.80
6.0
35.20
1993
7.4
35.31
6.5
34.92
6.4
35.18
6.5
35.30
6.5
35.05
6.2
35.00
5.4
34.95
4.3
33.50
5.6
34.80
6.0
35.00
\994
6.2
35.20
6.5
35.05
5.5
34.93
4.3
34.80
6.3
34.90
5.4
34.90
5.2
34.80
4.0
32.00
5.5
34.70
7.0
35.00
1995
7.5
35.23
7.0
34.92
7.\
35.00
6.7
35.09
6.7
34.7\
6.0
34.87
5.6
34.8\
4.0
30.03
6.0
34.65
7.9
34.5\
\996
7.\
35.24
6.5
34.9\
5.0
34.94
4.7
34.87
6.0
34.59
4.6
34.7\
3.0
34.44
-0.2
32.12
3.4
34.71
3.8
34.83
1997
7.6
35.21
7.3
34.92
6.2
34.92
6.4
35.09
6.5
34.72
5.8
34.80
4.9
34.72
2.9
32.93
5.2
34.67
5.2
34.96
ES
E6
E7
E8
E9
0.0 0.0
_.--_.
0.1
I
0.0
I
FO
Fl
F2
F4
F3
F5
F6
F7
F8
F9
GO
G1
G2
52
0.2 0.5 0.1
-_.-_ ... - - 0.0
I
0.0
51
0.1
0.2
50
0.8
0.5
0.0
61"
60'
0.0 0.5
'-'--
.0.5
I
49
---------- ._-- --!0.9
48
. 0.5
--
------47
10.6
---
59'
46
4.
45
58'
43
si
41
40
39
38
37
36
35
3e
33
32
31
30
29
28
4
.
Figure 5.1
27
2'
0'
>
2
0
4
~:
8'
10'
12
Weighting factors used in the revised IBTS herring index. Numbers denote the relative weight of a
given rectangle. Only weighting factors less than I are shown.
14
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
I
6t
1
- .
11-_ _ _
I
60
~~.cf 1
~ b
59°
\J111
1
,
2,
51
1
2 .
2
1
1
50
U
I
•
1
i
2
1
2
I
2
1
49
------+-
2,
1
1
1
--,--1
---
48
1
47
2:
1
-- ---
-
I
2
1
46
1
--,--1
1
0
1
__ L __ 1
~4
__
0
•
2
1
2
1 :
21
1 I
45
1
I
.58
44
--+-
I
2
1
0
2
1
57
2
I
1
2
5l
1
55·
e
I
2
I
2
,
I
43
I
1
1
2
1
I
2 I
2
I
1
!
2
1
1
2
2
2
2
2
2
3
3
2
,
i
1
2
42
21
!
41
1
40
'
21
2
39
2
38
37
36
35
0
53
34
33
0
52
32
.
31
51
30
29
50H---+---+--t----J--t--+7'"
28
Date of Product1on: SEP 05
o'
Herring.
.
1997
12
CLUP HAR
Number of Hauls.
Figure 6.1 Number of hauls used in the analysis of herring 1997 data.
15
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
ES
E9
Fa
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
--- - .
,
1
6t
----i,
---,
"
__
1
-
0
59
p
51
2
--2
2
2
2
I
0-
1
2
2
2
2
2
1
2
2
2
2
..... ----
et
2'
2'
50
49
(7
o
60
1
---
I
~_2_._-=-_
~~ 2
2
2
2
2
2
-
48
-,
2
-
,-
47
2
-
i
2
I
46
2
45
43
57
42
41
40
39
38
37
36
33
32
31
o
51
30
29
50 ft---.....L----+---+----j--+--+7"
28
Date of Production:
SEP 07,
1997
27
o
10
Saithe,
POll VIR
Number of Hauls.
Figure 6.2 Number of hauls used in the analysis of 1997 data on sprat, mackerei, cod, haddock, saithe, whiting and Norway Pout.
16
International Sottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
0
0
6t
01
0
•
0
51
---
·1~
0
60
0
0
0
0
50
0
....
_ _ _ _ .....l...-. __
3
49
0
---0
48
0
0
3
3
47
./
3
46
----,
~~~S3
0
59
\)111
1
0
38'
1
31
0
0
2'
--- - -----,
2lle
0
I
0
!le
45
0
-I
.58
83
0
44
1
:5
57
2
!lO.
,
33
!l81
1
01
01
0
43
98 1
O!
3
SII
SO!! I
S2
g
1121 I
42
90S
41
2.'
,i
113
40
~
I
39
lil81 '
38
37
36
35
34
33
32
31
30
29
o
50 H---+--l-----+----+--l------t-7'
28
Date of Production:
4
o
0°
Herr ing,
o
2
4
o
CLUP HAR
Number per Hour .
Age Group 1.
Figure 6.3 Herring: number per hour, I-ringers.
17
SEP 05.
o
10
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
0
61"
0
--.-
-t
60
,
.
0
0
50
0
0
49
105
1
1
3
:
-1---~008
,
1
39~0
22
283
47
46
o I,
2~8
61
45
29
I
-~------t
65
48
37
5
- - - - , - -,
23
318
0
0
--....- -
!5~0 116~: ~ 1
215
58"
I
0
~~-~\JI\1
51
0
C7
" _ ' _,_
0
,I
5,
--
"
59
0
I
o!
589
~~
I
o1
57
68
510
~1
I
156
392
I
o
I
I
I
293!i
76
I
23
43
i
I
01
0
~
~2
-
69
~58
:
42
277
I
0
1236 I
51
10
!
821
391
41
I
40
I
39
38
208
37
36
33
32
31
30
29
50 H----+--f-----I---+---if.----I---,./
28
Date
0 f
Product ion:
o
0°
Herr ing.
SEP 05,
10
CLUP HAR
Number per Hour ,
Age Group 2.
Figure 6.4 Herring: number per hour, 2-ringers.
18
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
30
2.
20
10
I
I
293
21
2
6
51
o
I
50
2
49
48
173
H----f-----+-------t
.
59H-----f--4.,
28
I
~----
47
21
159
-----
.3
- ,-- 1.5
I
46
19 I
--,--j
272
3
290
23
o
45
I
------'---- I
I
1-----..--------o
62
o
365
oI
oI
---r-
o
193
I
I
44
o
43
10
42
57
.5
61
I
oI
131
427 I
100
129
2
286
I
o
I
3
o
41
o
40
o
39
138
o
38
o
o
37
36
35
34
33
32
31
o
51
30
29
50H----+-----+--f--+---+--+--r'
28
Date of Production:
Herring,
CLUP HAR
Number per Hour ,
Age Group 3+.
Figure 6.5 Herring: number per ho ur, 3+ ringers_
19
SEP 05
1997
27
International Sottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
1 + - - - j J - - - - _.
o
o
6t 1+---1---- - -
0:
51
0
-
o
118
o
148
o
50
o
49
o
o
48
143
138
47
146
46
0
i
60
o
o
o
o
o
59°H--'-f- ----4..., ~----
164
--- -
-
--,
150
173
143
----,-
,
148
o
o
137
148
o
154
150
155
I 152
137
o
o
145
162
I
-I
r
.
45
147 i 128
I
oI
144 i 154
! 158
o
150
I
157
156
I
144
I
: 162 1158 : 151 I 154 : 149
I
I
57
I
181
159
! 159
43
112
I
I
42
145 I
I
124
41
113
40
I 145 I 155
39
38
37
36
33
32
.
31
51
30
29
501+---+----+--1---+---l--_+_.,./
28
.
0'
Herring.
Date of Product ion:
s'
4
CLUP HAR
Mean Length.
Age Group
Figure 6.6 Herring: mean iength, age I.
20
1.
SEP 05
o
10
.
1997
12
27
International Sottom Trawl Survey 1997Q1
E5
E6
E7
FO
E9
E8
F2
F1
F4
F3
F6
F5
F7
F8
F9
GO
G1
G2
52
r--- ._.
,
-
-
o;
o;
----
'-
-
-
o!
---
o,
oi
0
0
o,
0,
48
I
,
I
50
0
49
- - - .....
I
0
0
0
0,
8
0
0'
o
48
I
3
86
0
----
0
!
51
01
I
I
o I'
o
I
11:
3
---+--I
o
-
-
7 '
0
13
0
1015
4
o
1
0
0
0
I
o
I
46
0
-I
o
I
I
01
44
43
,
I
o
I
o '
0
2
17
0
0
1809
10
805
4
8132
42
0
o
9
45
0
1
57
o
--
.---,--
-~----
47
!
I
0
41
46
40
17
39
38
37
342
36
35
4
34
33
32
31
30
29
50 H-----+--t---+---+------'f----t-/
28
Date of Product1on:
4
o
0'
Sprat,
SPRA SPR
Number per Hour .
Age Group
Figure 6.7 Sprat: number per hour, age group 1.
21
1.
SEP 05,
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
50
49
48
47
46
45
43
o
57
42
41
40
39
38
37
36
o
53
33
32
31
o
51
30
29
50H----I---l---+----+---~-.../.__./
28
Date of Product1on:
o
0'
Sprat.
SEP 05,
10
SPRA SPR
Number per Hour .
Age Group 2.
Figure 6.8 Spral: number per hour, age group 2.
22
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E7
E6
E8
Fa
E9
F2
F1
F4
F3
F5
F7
F6
F8
F9
GO
G2
G1
52
-
0
~
--
I
51
0
0
o
0
0
0
0
0
0
0,
o.
49
0
0
0
o:
48
0
---
61"
50
0
---.
60°
1 ; 378
-
~~IJ·
0
59
u
10
0
--~---
'\JJ~
33'I
3
I
_ _ _ _
0
0
0'
0
0_
47
--"---j- -
I
0
46
---~-I
•
,
7.
0
I
2
o
0
45
I
I
58°
57"
o
44
0
169
273
26
0
0
20
15
0
o
I
o
0
o I
0
I
oI
I
3
5
I
43
0
0
o
I
0
42
0
1
i
0
41
0
40
I
I
oI
•
76
2
161
139
5
376
35.
17.
I
3\
1
1.
27
6
39
i
38
37
.7
36
•
35
34
33
32
31
30
29
28
Date of Production:
SEP 05,
1997
o
12
Sprat,
SPRA SPR
Number per Hour ,
Age Group 3+.
Figure 6.9 Sprat: number per hour, age group 3+.
23
27
International Bottom Trawl Survey
E5
E7
E6
E8
F1
FO
E9
F2
F4
F3
F6
F5
F7
F8
1997Q1
GO
F9
G2
G1
52
0
0
---
61°
---
71
•
60
0
0
59
~~f4
\)1\1 92
I,
I
0
0
0
50
01
~
0
0
0
0
0
0
96 i
----,
93 ' 100
0
----_.-.
0
--_
0
-
--
-
1-!
73
86 , 90
84
0
0
79
93
0
I
47
0
0
97
48
0
.. -
89
88
49
o!
I .: __
----,--
81
-+---
---_.-
0-
51
0
I
0
0
I
i
17
o
0
o
0
-------,
0
I
46
45
58
0
57
88
87
0
0
----
o,
o
0
!
0
0
0
o
0
I
o
~ ~
I
43
I
I
I
42
97
91
oI o
85
95
0
0
86
93
0
93
84
0
91
38
82
82
37
0
0
0
0
0
0
oI
0
71
41
0
0
81
69
40
81 ' 70
62
93 I
I
39
66
36
52
32
31
o
51
30
29
50f+---!---+---+----+--f----h-"
28
Date of Product1on:
SEP 05,
o
10
Sprat.
SPRA SPR
Mean Length.
Age Group 1.
Figure 6.10 Sprat: mean length, age group I.
24
i997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
,
~373 ,
.
t--
I
15
.38
--- .--
I
I
51
136. '37333
I
i
~,
0
5048
.1
o
50
I
50
1963
-
_ _ ....1---- _.
49
0
31
359
212
535
0
0
82
29
604047
48
5
0
0
.61
047
47
I
oI
--1--
------- -
59"H------L
2 I
5
I
oi
0
16 :
46
21
- - - - --'-------,,
0
•
0
0
0
o
0
04
0
2
o II
0
0
0
o
I
01
o!
o
I
0
0'
1
58
o
45
i
2
0
0
0
0
o
,
o,
0
0
0
0
0
1 I
o
0
0
o'
o
0
0
o
0
0
'
38361
5
44
0
43
I
1
57
o
0
I
1
I
85
I
I
0
42
I
41
40
'
I
I
I
39
0
38
I
37
0
36
01
35
o'
34
0
33
o
52
32
31
o
51
30
29
o
50 f+---+--+---j---+--f-----t:::>-"
28
Date of Production:
4
o
0
0'
Mackere 1,
8
SeOM seo
Number per Hour .
Age Group 1.
Figure 6.11 MackereI: number per hour, age 1.
25
SEP 05.
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
I
-
-
17
- .
11
9',
9
I
397
4
2',
19
51
I
0
50
3
_ _ _ _ ..L--_
~
j
2
1
0
7
1
0
0
0
0
7
10
,
0
0
2
0
0
0
0
0
0
---_.
-
I
2
------r
,
--
0
49
48
47
1--
0
46
2
0
0
0
-,
o,
0
4
0
0
o
0
0
6
0
0
2
0
0
oI
0
0
17
0
0
0
0
01
0
0
0
0 i
0
0
0
0
0
0
0
0
0
0
0
---,--
I
45
I
0
I
0
I
0
I
0
01
I
0
I
0
1
o
43
i
I
42
I
I
I
I
0 :
I
:
41
40
0
39
;
0
o
0
0
0
o!
38
I
37
36
33
32
31
30
29
50H---+---t---+--f--!---.J..:,,/
28
Date of Product1on:
SEP 05
o
10
Mackere 1.
SCOM SCO
Number per Hour .
Age Group 2.
Figure 6.12 MackereI: number per hour, age 2.
26
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
50
49
48
47
46
45
44
o
57
38
54
o
o
o
I
o
o
I
35
o;
I
34
33
32
31
30
29
28
Date of Production:
4
o
o
2
0°
Mackerel.
o
2
4
o
SCOM SCO
Number per Hour .
Age Group 3+.
Figure 6.13 Mackerei: number per hour, age 3+.
27
SEP 05.
o
10
1997
27
International Bottom Trawl Survey 1997Q1
ES
E6
E7
E8
E9
Fa
F1
F2
F3
F4
FS
F6
F7
F8
F9
GO
G1
G2
52
,181
178
~f.;
60
~
-l-------c±=c=--d'
I
168
193
204
189
179
192
188
175
177
181
188
58
.
o
48
o
o
o
179
183
196
o
I 193
o
o
181
188
o
0
181
0
0
195 I 184
160
-
0
0
L/---'-----
188
275
0
o
0
__- t l f , - - - - - - - -
o
o
1175
46
45
----;'-~b==r-~~"..",r.=l---+-.-..,----~}
---l-_
o
47
- _. -- 1- -
182 , 185
172
57
49
'_. __ 0
183
o
50
0
59'1+--_-----1-, f!';..---r--- --~ -
o
51
195
0:
o
o
I 175
180
0
0 I
43
O! 225 :
.
;.-1_
4~
__~---/
I
42
0
o
o
o
o
o
o
175!
o
o
40
0
o
39
o
o
I
0 I
41
o
o
o
o
38
o
37
I
36
33
32
31
30
29
28
Date of Product1on:
0'
MackereI,
4
Age
Group
Figure 6.14 Mackerei: mean length, age 1.
28
1997
o
o
12
SCOM SCO
Mean Length.
SEP 05
1.
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
Fa
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
0'
-
61"
51
0
---50
3
2
0
17
9
1
3
1
10
48
1
2
2
9
4
47
0
5'
61
7
46
0
2'
0
1
49
0
60
0
0
-- j-
0
59
0
---~-I
I
e
1
1
0
0
0
14
0
2
45
61 ;
7
44
16 i
14 '
43
5: 167
58
23
. -+-
0
69
1
0
3
oi
o i,
4
I
42
3
2
0
0
o
:2067
293
105
1
3
45
i 287
5
37
174
23
39
23
4
38
57
--
,
13 I
42
6,
41
I
40
69 ! 64 '
37
19
36
35
34
33
32
31
o
51
30
29
50 t+---:-----l---\---+---+--------+:-/
28
Date of Production:
4
o
o'
Co d.
GADU MOR
Number per Hour .
Age Group 1.
Figure 6.15 Cod, number per hour, age group I.
29
SEP 05.
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
Gl
G2
52
51
1
o
o
f+-----+------±==..d- -
50
1,
5
o
6
3
5
11
9
4
6
o
1
17
7
8
5
12
34
2
5
6
11
2
2
2
o
77
o
o
86
o
12
5
4
3
14
49
48
, -
o
I
47
I
3
---
i
46
99
45
i
0'
43
4'
j'j------ ----- - - .
o
12
1
1
1
11,
10:
7
15
0,
42
18
41
1
8
4
I
2
5 i
o
o
40
13!
2
1
o
o
39
I
4
I
38
37
36
33
32
31
o
51
30
29
50 f+----l---+--f-----+---+---l--/
28
Date of Production:
SEP 05
o
10
Cod.
GADU MOR
Number per Hour .
Age Group 2.
Figure 6.16 Cod: number per hour, age group 2.
30
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
ES
E9
FO
F1
F2
F3
F4
F5
F6
F7
FS
F9
GO
Gl
G2
52
51
5 i
12!
36
12 ,
6'
i
6
4
32
4
4
10
0
o
o
19
8
2
B
1
10
11
47
4
46
61" H--+--'--1
2
o
i
,- r
4
2,
1.
6
_ _1 - - - - - , - - - - - --~-----,
57
2
7
6
0:
1
2
18
21
1
0
1
2·
1
I
I
2
2
1
49
48
45
17
I
I
9
50
I
2
I
I
44
4
3 I
8:
I
- - - - - - - j-
1
9
1
5
21
7
I
43
2 I
. _ - -.......L...4'\....v~-I--------;
21
42
I
41
I
40
0'
39
15
I
o
2
5
4
38
o
5
37
3
1
I
I
36
35
34
33
32
31
o
51
30
29
50H---+---+---+---+--~--h./
28
Date of Product1on:
o
0'
Cod,
10
GADU MOR
Number per Hour .
SEP 05,
Age Group 3+.
Figure 6.17 Cod: number per hour. age group 3+.
31
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
Fa
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
o
51
o
o
o
180
148
120
o
o
149
126
oI
145
222
138
145
123
oI
123
152
172
156
119
__
~--.
176
-
0
o
o
48
47
46
I
o
135
-,- - - -
49
-- l-
~------
o
50
164
I
167
- ----1- - .
I
:
o
185
215
101
o
0
167' 129
245
o
128
145
I
I
166
190
188
166
97 ; 155
45
!I
198
j
146
57
I
i
I
I
o
151
I 117
106
75
245
118
116
117!
! 206 I 149
i 134
I
o
205
o
o
170
!
47
155
43
---==L--4'
42
123 I 153 I
41
40
108! 117 '
39
126
38
37
36
35
3"
33
32
31
o
51
30
29
50H-----I----.--+---t---+-----t--/
28
Date of Production:
0°
Cod,
GADU MOR
Mean Length.
Age Group 1.
Figure 6.18 eod, mean length, age group I.
32
SEP 05.
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
620
51
776 i 1627
671
1563 12953 11917
50
800
C7
49
742 1698 4046 1006 1407
48
138 3193 I 993 1208 2789 3293 ,5239
-.
I
47
2567 1 467 1973 1526 7027 ,1135
-----
-~
-
-
46
543 1 541 1815 4771 !3702
1670
--~---
1760 , 427
-,
----
26
108
751
i
45
425 1076
44
3 :1377 1057
-
41
-
1
I
i
,
109
891
35 I
28
i
701
208
428 ,
7
!
!
58
o'
7 :
91
I 198 i 166 I 115 I
13
1
76
I
39 15850
I
I
i
43
42
19 I
o'
41
. 487
130 : 319
439
55
3!
I
I
I
118 I 152 i 306
0
oI
40
0
o
39
, 165
4
I
0
!
I
8
0
0
38
0
0
1
37
I
o
I
0
o
36
!
35
34
33
32
31
30
o
50
29
H---+-----t--t---+---+---t7'"
28
Date of Production:
o
o'
Haddock.
SEP 05
10
MELA AEG
Number per Hour .
Age Group 1.
Figure 6.19 Haddock, number per hour, age group 1.
33
1997
27
,-----------~~~-
-
-
-
-
-
-
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F8
F7
F9
GO
G1
G2
52
109
51
114 :
110 . 102
43
23
597
13
56
192 1161
26
228
50
I
71
286 1955 i 344
5590 I 261
137
365
~-----
-
176
-
~
49
48
47
108
1---
I
203
104
46
444 2466
____ ._
46
563
-I
-~-~-
631 . 137
45
73
19
4_
45
320
----
200
864
324
394 4030 :
857
693
I 560
I 337
I 413
503 2149
850
, 834
I 116
3
I
13 I 221
157 1065
I
71
348
0
42
88 '
0,
9
01
0'!
01
40
0'
39
0
38
01
37
41
41
I
0
79
0
01
0
43
1
I
1
2
36
35
3'
33
32
31
30
29
28
Date of Production:
0'
Haddock.
8°
MELA AEG
Number per Hour .
Age Group 2.
Figure 6.20 Haddock, number per hour, age group 2.
34
SEP 05
,
10
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
o
51
30
29
50H----t-----+----+---l--+---b/
28
Date of Production:
0'
Haddock,
4
o
MELA AEG
Number per Hour ,
Age Group 3+.
Figure 6.21 Haddock, number per hour, age group 3+.
35
SEP 05.
o
10
1997
o
12
27
International Sottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
161 ' 162
61"
,
159
I
158 . 153
50
158
---160
153
154
156
150
147
147
154
49
60°
170
152
153
48
__ -0--- .
173 i 160
?
143
151
136
- - - - - - - -.
59
162
,
154
143
-'-r - -
149
-
58°
--
46
147
149
,
- - _ _ _- - - 1
I
160
47
150
1- -
155
147
151
180 ' 154
162
153
168
164
167
157
168
196
197
169
I 168
I 185 i 167
! 205
175
189
I
167
191
I 193
-I
I
I
159
45
i
155
43
196 !
57
oi
178
j
187
i
42
0
41
166
187
191 !
187
0
0'
40
0
39
i 178 I
0
0
o
I 178
0
0
0
,
I
I
I
38
01I
I
o!
37
0
36
33
32
31
51°
30
29
501-+---'---+---+---+--+----+-,./
28
Date of Production:
SEP 05
1997
o
12
Haddock.
MELA AEG
Mean Length.
Age Group
Figure 6.22 Haddock, mean length, age group I.
36
1.
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
o
:
-
2
~
J
71
~:~
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590
:
('
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57
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t
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151
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162:
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36
192
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101
I
)
r
602! 473
i
237 !10?5
\
i 107
i
41! 237
82 1181 1135
I
21
i 368
51 : 206
587
! 414 I
36!
11
I
59,
15
i
i
384
i
45
41
66
I
45
27
I
268
943
21 1 40:
\l~ 47 ~633
384
18
~
74
I
65
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1
38
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108
62
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144
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9
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a
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o
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28
~r="
o
o
Wh i ti ng.
Date of Production:
o
2
4
o
MERL MNG
Number per Hour .
Age Group 1.
Figure 6.23 Whiting: number per hüur, age group I.
37
0
8
SEP 05,
o
10
1997
o
12
27
International Bottom Trawl Survey 1997G1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
I
6 I
2
51
9 I
50
28
~292
42
92
324
16
I 475
373
161
49
1 171
295
112
143
49
78
I
48
288
47
99
59'f+-----L f - I t ' . . - - - -
556
.
----
,
------,-----,
108
187
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I
403
I
46
66
--------
,
38 '
28
-,,
1
I
!
122
47
-r---------'--
702 1100
77 i
o
230
80
I
107
I
_---'ar--5-9~,13-5-0-1-7-2 _ _7_ _3~ ~ _O~!_._9_1_ _6---r-i----Fh#::;4:::T''-f---------1
o
57
,
I 335
31
I 423 I
8
660 6014 ,: 507
~954 ! 912
I
I
0
I
10
10
0
0
42
I
3
21
41
O!
0
40
0
0
39
I
17
I
1
I
6 I
43
o
30
9
0
38
64
61
37
238
36
33
32
31
30
29
50H---l---+--f---t--+--+'/
28
Date of ProducUon:
4
o
Wh i ti ng,
SEP 05,
o
0'
10
MERL MNG
Number per Hour ,
Age Group 2.
Figure 6.24 Whiting: number per hour age group 2.
38
1997
o
12
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
I
101
104
479
967 I
21
154
1233 .
6
464
100
9
339
48
245
112
371
47
--
--
206
26
50
49
- - - .+
60° H------'-------1;
1518 :1720 11625 1017
1
;3905
314
860
-----, 578
232 ' 133
186
---
.58°
--
24
27
1
,
I
I
72
99
o ! 154
775
379
o I 15
497
252
14
23 I
103
555
23
309 3729 1297
541 ,1455
1
46
-------1
I
3 I
3
i
23
0
--
3
0
26
0
1
0
1
3
0
0
-
45
65
44
52
43
3 1
42
41
I
40
39
0
40
3
0
1
16
19
1
1
37
1
4
36
38
35
34
33
32
31
30
29
28
Date of Production:
10°
0'
Whiting,
SEP 05
MERL MNG
Number per Hour .
Age Group 3+.
Figure 6.25 Whiting: number per hour, age group 3+.
39
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
,
212 ; 180
0
61"
--
226
1 - -.--
--
227 , 217
I
226 ' 165
59?
I
240
I
228
51
I
181
217
-+---- -
160
~
-
164
211
204
176
185
192
185 . 207
191
I
49
-
198
-r--- -- -
50
182
215
--~-
167
207
. --------.
-_.
60°
I 206
.-
-~
164
48
47
--l---
46
175' 161
---,-
-4
I
I
45
I
•
143
159
145
164
226
199
169
205
157
143
1
159 I 212
140
123
! 139
140
I
199
203
132
129
122
207
145
141
113
154
121
149
105
125
96
146
138
166
133 ' 157
58°
5,0
220
I
I
134
,
~
I
181
1
43
100 I
I
124
I
42
149
I
135
126
!
41
110 i 125
117
!
40
!
I
I
100
112
39
121
38
37
36
I
53°
33
52
32
31
°
51
30
29
50H----+---+--1---+----l----l-.,/
28
Date of Production:
SEP 05.
o
10
Wh i t ing,
MERL MNG
Mean Length,
Age Group 1.
Figure 6.26 Whiting: mean length, age group I.
40
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
o
o
0 1
0
61 H - - - t - - - , - - -
~
i
H-+--• -_
600
C7
0
o
o
50
o
0
o
o
49
o
I
0
o I
0
o
o
0,
0
48
ct~,cI'O
0
~I::>----
o
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0'
0
0
47
o
o
0
46
I
o
o
.58
51
o
0
o
I
-
'r----,---~--
o
0
1
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59'H---t---t..
0
I
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,
---~-I
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0
0
0
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01
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0
I
0
41
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o
0
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o
40
o
o
0
1
I
1
I
0
57
o
o
I
I
o
o
o
o
o
o
0
o
o
o
0
o
o
o
o I
o
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1
43
1
I
I
42
I
39
1
38
I
37
36
35
34
33
32
31
30
29
501-+---1---..----+---+--1----+7'"
28
Date of Production:
4
o
o'
Sa i the,
0
8
POLL VIR
Number per Hour .
Age Group 1.
Figure 6.27 Saithe: number per hour, age group 1.
41
SEP 07.
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
Fa
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
o
0
0
1
0
51
o
1
I
H---t---
_ I _~__ 0
Cl
o
60
•_
,
o
l
.
0
1+-----+---1---
._.__
0
I
0
o
0'
0
0
o
0
0
0
o
0
0
o
0
I
I
50
49
48
0
-
o
47
o
46
- ., -- I
sl
o
o
o
o
o
0
o
o
o
o
o
o
o
o
o
o
o
o
45
I
o
43
o
I
0
0,
0'
0
o
oI
0
I
0'
0
1
o
42
I
41
0
40
39
38
37
36
35
3tt
33
32
31
30
29
28
Date of Production:
SEP 07,
o
10
Saithe,
POLL VIR
Number per Hour .
Age Group 2.
Figure 6.28 Saithe: number per hour, age group 2.
42
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
Fa
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
4,
0
4 i
15!
51
82
I
4
4
I
_.
•
59 f+----f--{..
o
01
1
2
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oI
o
o
~----
<:J1,\1
1
o
4
1
- -
~
3
I
0
~.
2
50
40
-- o
- -t---:.,
33
49
14
48
23
47
-+---+-~
46
4
1
0
•
I
2
58
2 I
---1+---0
1
--.,-
21
!
o!
I
45
67
44
0
43
I
I
o
I
0
I
o·
0
42
41
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0
1.
01
oI
0
O!
0 I
0
o
o
0
o
o!
39
o
oI
o
o
38
I
0
i
i
40
I
37
36
35
34
33
32
31
30
29
50H---t----+--+--t-----:f---b/
28
Date of Production:
4
o
SEP 07.
o
10
Saithe.
POLL VIR
Number per Hour .
Age Group 3+.
Figure 6.29 Saithe: number per hour, age group 3+.
43
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
Fa
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
H---+---~
-;
o
l--t-_
61" 1+----1----' -
o
o
o
o
I
I
0:
o
o
o
o
50
o
o
o
49
o
o
o
48
o
0
o
47
o
0
o
46
51
-
o
601-+---+-----",
o
(7
,_.
0
__
0
o
o
o
0
0
0
o
o
0
I+----I---J.-- -.--
~~,cfo
59'1+----I--L %E:>
\]111
o
I
I,l--~-_,__- o
-
I
_
!
---~-,
i
45
o
0
o
o
o
0
o
o
o
o
o
o
o
0\
01
0
o
42
o
o
o
oI
41
o
o
o
o ~
0
40
o
o
0'
0
39
o
o
38
o
o
37
o
o :
o
58
o
o
oi
o
43
57
010/01
36
33
32
31
o
5\
30
29
50 rt--+-----+---+---f----If----b/
28
Date of Production:
1997
o
0'
Sa i the,
SEP 07,
12
POll VIR
Mean length,
Age Group 1.
Figure 6.30 Saithe: mean length. age group 1.
44
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
o
61
51
.3801
--j.-- . _ -
H---+-----j
7619
50
3274 12030
3892
49
9529 10~29 93350
3100
48
20729 -47375 ~1
47
~~520
46
17
~100
! 10-45
I
I 7979
---;
1
I
370
29215
---_.
- .
I 56-48 21~1
16078
I
5-495 12116
9095
-iI
---
i 9572
8418 10518
I
45
87 11-4306 139027
I
1760
122
4339 '
212008 113212
I -4385
44
I
106
570
288 99478
28
4
oi
43
704
203 r6381 po810
0
0
42
648 ,
25
16
!
2
o
25
2
o
I
0 1
0,
2
121
20-4 '
iI
0
I
0
6~
746
2
661
5
o
2
0
0
I
O.
0
I
I
41
I
40
I
0
39
0
38
37
36
35
34
o
33
32
31
30
29
28
Date of Product ion:
o'
Nar. Paut.
4
o
o
10
TRlS ESM
Number per Hour .
Age Group
Figure 6.31 Norway pout: number per hour, age group I.
45
SEP 05.
1.
1997
o
12
27
,-----------------
~
~
International Bottom Trawl Survey 1997Q1
ES
E6
E7
E8
E9
Fa
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
0
.6
667
.736
2080 ' 169.
2258
28.6
50
821
0
2738
49
632 , 9136
48
15.6
147
_._-_.711
48 : 226
-~
10
747
I
8284
3034
47
3-1~51---:
46
1463
-----87
371
~,
I
0[ 2779
34 .4978
115
1
45
1380
255 11252
I 1411
4'
I
48
18
I
I
0
o
0
42 16271
1024
I
686 , 751
35
I
5
14
96
0
o
12
0
0
38
0
0
0
37
o
64
I
43
5976
329
70
0'
0
I
2
I
0
42
21
41
oI
40
39
l
36
33
32
31
o
51
30
29
50H---+--r-----f---+--f----h/
28
Date of Production:
4
Nor. Pout,
o
TRIS ESM
Number per Hour .
Age Group 2.
Figure 6.32 Norway potit: number per hour, age group 2.
46
SEP 05.
o
10
1997
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
,
51
o!
7.... I
I
509 .
389
1102
o
776
306
1821
50
49
60 H------+--~--tl--{ ..
10..
819
I 3..80
2 ..5
-
47
--7 ~- 2~"": -..~31--:
46
186
100!
-b=d-----'-..
45
i
o
1.. 6
0
i
---------']f--- I
!57
104 248!58 I
0 i
41
5
o
190
--'--1
r--~r_~-_,--
9
---'-_...01
61!5
59°1-t--_ _~ f~--'---
48
148!
89
23
79
......r---==~=-J.==i_==f;===t-___1-v!
-r--~
i
44
156
504
o
o
oi
43
572
66
o
o
1
42
2
o
o
i
57
12
o
oI
0
o
0'
0 I
o
o
o
oI
o
o
o
1
01
o
0'I
o
o
41
I
40
I
I
0:
39
o
38
37
36
35
34
33
32
31
o
51
30
29
50 I-t---f---f--+---t-----I----b-"
28
Date of Production:
0'
Nor.
Pout.
4
o
TRlS ESM
Number per Hour .
Age Group 3+.
Figure 6.33 Narway paut: number per hour, age group 3+.
47
SEP 05.
1997
o
12
27
International Bottom Trawl Survey 1997Q1
E5
E6
E7
E8
E9
FO
F1
F2
F3
F4
F5
F6
F7
F8
F9
GO
G1
G2
52
51
105
106 '
97
105
110
110
95
102
113 i 109
108
107
99
105
115 I 114
110
107 ' 106
107
__ 1-_
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, 109 : 111
--
-
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108
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47
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46
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45
I
108
122 : 102 I
114
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89
O!
43
125 i 123
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I 109
0
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42
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1
40
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57
;
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132
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o
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49
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110 , 111
112
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50
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105
39
85
38
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37
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36
33
52
32
31
o
51
30
29
50H---+----+---+---l--t----h/
28
Date of Product1on:
Paut,
1997
o
0'
Nar.
SEP 05.
12
TRlS ESM
Mean Length.
Age
Group
Figure 6.34 Norway pout: mean length, age group I.
48
1.
27
0- ringers year dass 1995
0- ringers year class 1994
0- ringers year dass 1996
IU.l
~
1
~
I _
52t---11--t-+-+-+--+--+--+-+.<61
~ -- --HMI----t---t---t---t--f---I-P
49
60
46
61
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60
4 B,t--t-t-t-t--t--t--I--I--h"'",
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4 '1--t::~t--t--f-I--f-t--l--hN
59
4 6~!1--t--t--f-1--1--1--f-1--.I....
~(-r-r-t- "1--1--1--1-.+-+--+-+4--+-+--+=~
4 5f-r-~t-t-~t-f--HHL...::jF'--"1~---i---if-<lJ
44l../'-'~~d-~~+:-HH--l--+~X+:l
58
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41
41
40
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37
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l~
~
J4
JJ
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35
33
32
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30 rT--P+-+--H
19
4
Figure 7.1
10
11
~0
53
34
52
51
29L'----::--'---!---LA
4
Distribution of O-ringer herring, year dasses 1994-1996. Abundance estimales of O-ringers within each statistical reclangle based on MIK calches during IBTS
in February. Areas of filled circles illustralc densities in no m"2, the area of a cirde cXlending lo lhe border of a rectangle represents 1.5 m"2.
J
0
12
50
Time series of recruitment indices
0
300
x
•
4500
IBTS 1 ringer
MIK 0 ringer
4000
3500
250
3000
"'0
C
~
Q)
200
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C
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Q)
2500
0)
c
Ol
c
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x
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Q)
150
2000
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2
1500
100
1000
50
500
0
0
co
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<.D
(j)
(j)
(j)
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(j)
(j)
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co
co
co
co
co
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(j)
(j)
(j)
(j)
(j)
CD
(j)
(j)
~
~
~
~
~
co
(j)
(j)
Year class
Figure 7.2
Trend in MIK O-ringer and IBTS I-ringer indices für the year classes 1977-1996.
50
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I
57 1
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Figurc 8.1
51
7
9
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J
11
13
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-1
-5
1
357
9
11
13
61
61·
i
I
59
51
:
.... -~-..,,/
49·
-5
----''-----~----,----r--_____.\c,49
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5
Figurc 8.2
52
7
9
11
13
I
,
•
35.4 -IBTS- GON 2E
(5-Year Running Average)
- ....
35.2 ---~
/'
--- 4
....
)(
/'
-8
---
:5
0
~
!
NAO index
35.0
----
--- -4
34.8
1970
1990
1980
Year
Figure 8.3
53
2000
oE
~