-----------
"
;
,.
.'
ICES
1995
1
C.M. 1995/J:18
Baltic Fish Committee
POLISII HYDROACOUSTIC ASSESSMENT SURVEY 01' IIERRING. SPRAT AND COD
STOCKS IN ICES SUBDIVISIONS 25 AND 26 01' TIIE BALTIC
CONDUCTED IN OCTOBER 1994
by
Ryszard Grzebielec. Andrzej Paciorkowski
Miroslaw Wyszynski. Wlodzimierz Grygiel
Sea Fisheries Institute
Department of ßiology and Conservation
of Fish Resources
ul. Koll~taja 1. 81-332 Gdynia. Poland
.
Abstract
Within an international program of the ßaltic clupeoid fish
assessment coordinated by the ICES Planning Group. the Polistl
research vessel "Baitica" carried out a hydroacousticsurvey.
devoted to llerring and sprat in the ICES Subdivisions 25 and 26.
The survey covered the area of 14774 NH 2 . Echosignals were
integrated over 1204 one mile distances. Twenty nine control
hauls with pelagic herring trawl were conducted. 9263 specimens
of herring. 4612 of sprat and 73 of cod were measured. Otoliths
from 1459 herring.
709 sprat and 73 cod for ageing were
co 11 ected.
The estimated biomass density expressed in ton ries per 1 NH 2
eQualled 30.1 tonnes for herring. 44.2 tonnes for sprat and 3.7
tonnes for cod. The results compared to data from October 1990
survey conducted from on board r.v.
"Profesor Siedlecki".
(Orlowski 1993)
indicate a slight increase of the herring
biomass density (by 1.9 tonnes). a significant increase of the
sprat biomass density (by 26.7 tonnes) and also a large increase
of' the cod biomass density (by 2.3 tonnes). Distribution of the
herring and sprat biomass has also exhibited some changes.
Herring was less numerous in the Slupsk Furrow but was present
in
greater
numbers in the Bornholm Decp.
October sprat
aggregations shifted northeastward.
Cod cauBht with pelagic
trawl appeared only in trace Quantities in thc Gdansk Deep area.
The estimated herring and sprat biomass was recalculated into
numbers at age using age-length key and mean weights for each
ICES rectangle.
Introduction
During 3 - 20 of October 1994 r.v. "Baitica" carried out its
maiden hydroacoustic cruise.
The survey was apart of an
international program of the Baltic clupeoid fish assessment
prepared by the ICES Planning Group for Hydroacoustic Surveys in
the Baltic (Anon.
1994).
The main task of the cruise was
assessment of herring and sprat stocks in terms of biomass and
numbers in the ICES Subdivisions 25 and' 26. The r.v. "BaItica"
survey
continued the series of r.v.
"Profesor Siedlecki"
hydroacoustic surveys conducted during 1982-1990.
Equipment and survey method
Echosounding and echo integration were conducted during day
and night continuously. using hydroacoustic system consisted of
echosounder EK400.
echo integrator QD and a PC. Echointegrator
values referring to time periods equivalent to 1 NM distances
covered by the vessel along the acoustic transect were recorded
both as echodeflection and volume backscattering strength by
recommended depth layers. The data together with mean depth of
integrated layers were transferred from QD to PC and recorded on
the hard disco
The vessel speed during echointegration was
maintained within 8-10 knots depending on the sea state and wind
speed.
The hydroacoustic system was calibrated using a standard
copper sphere.
The calibration was carried out next to the
Swedish Island of Högön in the vicinity of Västervik harbour
with
assistance of dr Hakansson from Institute of Marine
Research in Lysekil.
Control fishing
Control hauls were conducted only during daytime using
midwater herring trawl WP 53/64 provided with 11 mm mesh bar
length in the codend.
Vertical opening of the trawl equalled
17-36 m (mean 26 m). Trawling speed was maintained at 3.5 knots.
Standard trawling time of 30 minutes was followed. Two hauls per
unit of survey area (ICES rectangle) was planned as a minimum
required sampling density.
Area stratification and estimation of fish abundance in number
In accordance with the ICES Planning Group rccommendations
all survey results were recorded by ICES statistical rectangles.
The parallel transect design was used. with equidistant spacing
of approximately 15 NM. similar to that followed during the r.v.
2
"Profesor Siedleeki" eruises sinee 1952.
Fish abundanee
in numbers was ealculated based on a total
biomass estimate and me an individual weight of fish. The total
biomass was estimated using Orlowski's method (1993). Target
strength of 1 kg of herring and sprat was calculated applying
the following formula:
where:
- mean length in a reetangle (ern)
w - mean weight in a reetangle (grams)
The results of the caleulations has been collated in the
standard format reeommended by the ICES Planning Group (Anon.
1994) and forwarded to the Group Chairman.
•
•
Results
The survey track along which the echo was integrated and
positions of the control hauls are presented in Fig. 1. The area
of reetangles included in the echointegration amounted to 14774
NM 2 .
Length of the vessel traek eovered with eehointegration
totalled 1365 NM but only 1204 NM were accepted for final
analysis as elementary sampling distance units (ESDU).
In total
29 hauls were carried out of which 3 were rejected
as not representative
(Table 1).
The
index of rectangles
coverage with control
hauls equalled 1.7 (less than planned
index of 2).
The
index of area coverage with representative
acoustic transects amounted to 12.3 NH 2 per 1 ESDU (in 1990 9.26 NM 2 ).
The greatest biomass of 653.522 tonnes constituted sprat
(Tab.
2.
Fig.
2 and 3 - created using SURFER Golden Software
Inc.),
one third of which was concentrated in reetangles 4064
and 4065. Herring biomass was estimated at 444.284 tonnes. Near
half of its biomass was eonfined to 3 rectangles in the northern
part of the survey area. Cod biomass was estimated at 54.579
tonnes;
almost all of
it was found to be distributed in the
Bornholm Deep.
The total
length 6f sprat caught (Fig.4) varied within the
range from 6.5 cm to 16.5 cm. The Subdivision 25 apart from
rectangles 3760 and 4062 was dominated by sprat of 12.5 - 15.0
cm in
length.
In the two latter rectangles sprat of 7 - 9 cm
were predominant while within the remaining rectangles sprat
belonging
to those
length-classes were not numerous.
The
Subdivision 26 was dominated by sprat of 11 - 14 cm.
Examination of the sprat age distribution
(Fig. 5) also
indicates differences between Subdivisions 25 and 26. In the
3
..
Subdivision 25 mainly sprat from age groups 2 - 4 were taken
except for rectangles 3760 and 4062 where sprat of the age group
o were prevailing. In the Subdivision 26 younger (age groups 1 3) sprat were caught.
Only in one rectangle (3764) a greater
share of juvenile sprat (407. constituted age group 0) was found.
The total length of herring taken (Fig. 6 and 7) ranged from
7.5_ cm to 29.0 cm. Fish ·from 16.5 cm to 22.5 cm in length were
predominant.
A considerable number of juvenile herring from
length classes 8 - 12 cm was found in rectangles 3760 and 3764.
Results of age readings (Fig. 8 and 9) indicated that they were
herring from 1994 year-class (age group 0). Catches in the
remaining rectangles were dominated by 3, 4 and 5 years old
herring. An exception was age distribution in the rectangle 3863
where also age group 1 was Quite abundant.
The estimated biomass of herring and sprat has been converted
into numbers by successive age groups (Tab. 3 and 5). For each
rectangle age-length keys and mean weights by age-groups were
calculated (Tab.
4 and 5). That kind of presentation of the
Baltic fish biomass hydroacoustic assessment survey results has
been prepared in the SFI (Gdynia) for the first time.
In 1994~ the percentage share of herring, sprat and cod in
catches changed compared to 1990 (Fig. 10). A nearly stable
distribution of the herring share in control hauls observed in
1990,
changed towards a considerable increase of the herring
proportion within rectangles of the Subdivision 25. In case of
sprat an opposite trend took place i.e.
their share has
increased within rectangles of the Subdivision 26. On the other
hand,
cod taken in the pelagic layers of the Subdivision 25
occurred in a greater share than during 1990 survey.
Following the change of the percentage share of herring.
sprat and cod in catches from control hauls conducted in 1994,
the pattern of biomass distribution in the Polish EEZ has also
changed (Fig.
11).
Compared to 1990. the sprat biomass in the
Subdivisions 26 and 25 increased considerably. Large quantities
of herring appeared in rectangles 4060. 4061 and 4062 outside of
the Polish zone.
However, within the zone the.herring biomass
dropped by about 6.500 tonnes. mainly within the central part of
the zone.
A considerable increase of the cod biomass was no ted
in the western part of the EEZ. An insignificant Quantity of cod
biomass occured in the Gdansk Deep (rectangle 3863).
In the Polish EEZ changes were also observed in the biomass
distribution with regard to north-south (N-S) and west-east
(W-E) direction (Fig.
12). The biomass distribution in the
diFection N-S was analysed by summing up the estimated fish
biomass, originated from rectangles having identical two initial
numbers in the rectangle code.
The distribution in the W-E
direction was estimated taking into account two last numbers in
4
the code.
Compared to 1990. the presence of herring was much
more distinctly marked in the western part of the surveyed area
(e.g.
rectangles 3700.
3800. 3900. 4000 - were conventionally
depicted by --50) and to a lesser extent in the eastern part
(rectangles --53.
--04).
With regard to N-S distribution a
considerableincrease of the herring biomass in the southern
part
(--38)
was
noted.
Sprat biomass shifted northward
(rectangle 39--) and eastward (--02. --03). Cod shifted to a
large ext~nt to the southern part of N-S direction and to the
western part of the W-E direction.
Acknowledgments
Authors
extend their thanks to dr N. Hakansson from the
Institute
of
Marine
Research
in
Lysekil
for
consultations as weil for his participation in the calibration
of the r/v "Baitica" acoustic system. and to dr A. Orlowski from
SFI in Gdynia for his advice on the biomass calculation method.
S~edish
•
•
Summary
During 3 - 20 of October 1994 r.v. "Daltica" carried out
its maiden hydroacoustic survey. The investigations were part of
an international pro gram of the Baltic clupeoid fish assessment
prepared by the ICES Planning Group for Hydroacoustic Surveys.
The main task of the cruise was assessment of herring and sprat
stocks in terms of biomass and numbers in the ICES Subdivisions
25 and 25 (the southern Baltic).
The
r.v."Baltica" survey continued the series of r.v.
"Profesor Siedlecki" hydroacoustic cruises conducted during
1982-1990.
The survey covered the area of 14774 NM 2 . Echosignals were
integrated over 1204 one mile distances (ESDU). Twenty nine
control hauls with midwater trawl were conducted. 9203 specimens
of herring. 4512 of sprat and 73 of cod were measured. Otoliths
from 1459 herring.
709 sprat and 73 cod were collected for
ageing.
An insignificant increase of the herring biomass density from
the
level of 28.2 t/NM 2 in 1990 to the level of 30.1 t/NM 2 in
1994 was noted;
moreover a considerable increase of the sprat
biomass density from 17.5 t/NM 2 to 44.2 t/NM 2 as weil as also
marked au~mentation of the cod biomass from 1.5 to 3.7 t/NM 2 •
respectively. was observed.
Certain changes in the distribution of herring and sprat
biomass compared· to 1990 in the Polish EEZ has also occured.
Relatively smaller quantities of herring were found in the
Slupsk Furrow and greater in the southern part of the Bornholm
5
..
Deep.
The
October
1994
aggregations
of sprat shifted
northeastward.
Pelagic biomass of cod moved to the western part
of the W-E direction and to the southern part of the N-S
direction.
Catches from control hauls conducted in the Subdivision 25
were dominated with sprat of age groups 2 - 4 while in the
Subdivision 26 predominated fish by one year younger. The
juvenile sprat occurred in trace Quantities in almost all
rectangles of both Subdivisions but the southern part of the
Bornholm Deep.
Gulf of Gdansk and the southern part of Middle
Bank where they prevailed. In the above mentioned areas juvenile
herring was also present whereas in the remaining rectangles 3.
4 and 5 years old herring dominated the control catches.
The estimated biomass of herring and sprat has been
converted into numbers by succesive age groups.
For each
rectangle age-length keys and mean weights by age-groups were
calculated. That kind of presentation of the Baltic fish biomass
hydroacoustic assessment survey results has been prepared in the
SFI for the first time.
References .
ANON .• 1994. Report of the Planning Group for Hydroacoustic
Surveys in the Baltic. ICES C.M.1994/J:4
Orlowski A.• 1993. Distribution of fish stocks vs environmental
factors in the polishfishery zone; Determined by the acoustic
method (cruise of R.V. Profesor Siedlecki. Oct. 2-24.1990)
Bulletin of the Sea Fisheries Institute. 1(128)/1993
••
6
Table 1. Calch data
r. v. "BaItica" , 3-20.10.1994, hydroacouslic survey
No.
ofhaul
Date
Time
start
UTC
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
94-10-05
94-10-05
94-10-06
94-10-09
94-10-09
94-10-09
94-10-11
94-10-11
94-10-11
94-10-11
94-10-12
94-10-12
94-10-13
94-10-13
94-10-13
94-10-15
94-10-15
94-10-15
94-10-15
94-10-16
94-10-16
94-10-16
94-10-17
94-10-18
94-10-19
94-10-19
94-10-19
94-10-19
94-10-19
07:50
16:00
07:30
09:00
11:00
17:00
07:30
12:05
15:40
17:55
13:00
15:55
12: 15
15:30
17:50
07:25
09:55
12:05
15:50
09: 15
14:55
16:45
09:35
15:55
07:10
09:50
13: 10
15: 15
07:05
Latitude
start
DD
55
55
55
55
55
55
54
54
54
54
55
55
55
55
55
55
55
55
55
55
55
55
55
54
54
55
54
54
54
MM
22.9
21.1
32.7
35.6
26
3.2
31.8
53.6
55.7
57.9
25.4
15
44.1
25.8
20.5
35.4
36.5
25.7
16.2
59.8
49.9
52.6
40.8
29.8
55
2.5
45.3
35.7
29.4
Longitudc
start
MM
DD
15
15
15
15
15
15
15
15
16
16
16
16
17
17
17
18
18
18
18
19
19
19
20
18
18
19
19
19
19
20
27.3
52.8
56.1
54.9
35.7
50.4
37.7
11.6
2.1
49.1
49.5
46.5
50.9
40.1
27.8
55.2
56.8
46.8
13.5
28.9
37.1
6.1
54.8
49.7
11.6
22.3
23.8
33
Duration
Speed
ffiJn.
kn
00:50
00:30
00:30
00:30
00:30
00:30
01:00
00:30
00:30
00:30
00:45
00:30
00:35
00:30
00:30
00:30
00:30
00:35
01:00
00:35
00:30
00:30
00:30
00:30
00:30
00:30
01:00
00:35
00:30
3.5
3.5
3.5
3.6
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.9
3.5
3.5
3.7
3.6
3.5
3.5
3.5
3.4
3.7
3,4
35
3.9
3.5
3.6
Water
depth
m
91
93
80
78
88
78
52
76
54
Headrop
depth
m
43
46
40
50
12
12
34
72
48
78
61
73
83
100
89
94
88
97
62
62
74
62
97
103
101
78
48
19
34
22
32
30
68
60
64
30
54
30
20
42
25
57
55
41
45
18
Nel
opening
m
0
17
26
26
28
28
24
26
0
0
26
26
26
25
25
24
25
25
22
36
24
25
28
24
28
28
26
25
26
Validity
invalid
invalid
invalid
Total
catch
kglh
0
50.7
101.6
155.3
505.7
57.9
6.9
55.1
0
5.9
37.2
60.6
11
875.6
3":.7
201.2
192
670.6
43.2
325.4
207.6
615
231.8
79.5
54.7
151.6
334.5
661.7
14.9
__ ~ __Table 2. Fish density and biomass estimates by lCES squares
r.v. "Baltica", 3-20.10.1994, hydroacouslic survey
•
leES
rectangle
Area
[NW'2]
3760
3764
3860
3863
3864
3960
3961
3962
3963
3964
4060
4061
4062
4063
4064
4065
685.0
162.7
1043.8
706.4
946.1
985.0
1032.2
1032.2
1032.2
1032.2
1019.3
1019.3
1019.3
1019.3
1019.3
1019.3
14773.6
<I >
<Svc>
[mm]
[dB]
-46.58
62.40
-46.14
69.23
-48.47
40.39
78.15
-45.61
59.37
-46.80
23.75
-50.78
39.81
-48.54
-47.69
48.36
-48.02
44.84
74.38
-45.82
56.44
-47.02
-47.50
50.54
-54.05
11.18
46.60 . -47.85
107.75
-44.21
-44.44
102.24
Biomass area density
[t/NM"2]
Herring
Sprat
Cod
Biomass
[tl
Herring
Sprat
Cod
6.25
1.89
41.36
40.42
52.86
18.47
23.77
17.77
3.85
9.50
59.08
65.59
19.93
21.37
72.24
0.31
25.89
71.25
8.70
51.37
36.36
17.37
36.13
51.56
54.36
86.69
18.16
16.21
0.95
41.33
81.98
127.06
25.02
0.00
12.19
1.03
0.30
2.55
1.51
0.00
0.00
0.00
13.16
6.09
0.00
0.00
0.00
0.00
4279.4 17736.3
307.0 11592.7
43167.0
9076.5
28555.4 36285.1
50011.2 34402.3
18190.4 17112.5
24538.4 37292.5
18341.2 53220.3
3978.1 56114.3
9802.7 89485.7
60221.5 18513.4
66851.5 16518.0
20318.7
964.1
21780.2 42132.2
73630.8 83560.5
310.9 129515.3
17141.2
0.0
12727.9
726.1
288.0
2511.1
1559.4
0.0
0.0
0.0
13417.4
6207.7
0.0
0.0
0.0
0.0
30.07
44.24
3.69
8
444284
653522
54579
Table 3. Estimated number (in milIions) of herring
r.v. "BaItica". 3-20.10.1994. hydroacoustic survey
Strata
SD
25
26
Total
AgeO
Age 1
3760
3860
3960
3961
3962
4060
4061
4062
420
927
353
584
512
1180
1559
456
391
25
7
77
48
3764
3863
3864
. 3963
3964
4063
4064
4065
27
1334
1225
116
238
585
1998
7
21
152
33
0
2
1
11
201
7
0
0
Age3
Age2
Age4
Age6
Age5
Age7
Age8
6
167
58
19
4
103
48
29
0
106
29
42
35
107
143
73
0
259
89
192
100
228
483
91
6
221
109
171
176
284
458
111
6
133
49
44
114
293
109
63
0
4
2
29
25
68
86
35
6
12
7
9
6
66
22
21
5
386
126
9
12
40
24
3
0
180
162
14
28
85
0
331
207
34
66
223
453
2
2
109
260
42
76
150
753
0
0
108
290
14
27
32
370
0
0
23
127
2
14
26
134
1
0
0
20
2
1
6
16
112
0
16
17
72
0
Agel0+
Age9
6
0
0
1
3
15
3
12
0
6
4
72
0
0
0
0
1
1
2
3
101
0
01
0
0
1
0
01
31
0
9
0
0
0
7
4
01
01
01
01
01
01
11
01
01
I
Table 4. Estimated mean weight (in gramms) of herring
r.v. "Baitica", 3·20.10.1994, hydroacoustic survey
SD
Strata
AgeO
Total
Age 1
Age2
Age4
Age3
Age5
Age6
Age7
Age8
Age9
Age 10+
25
3760
3860
3960
3961
3962
4060
4061
4062
10.2
46.6
51.5
42.0
35.8
51.0
42.9
44.6
7.6
20.9
19.3
6.3
5.6
5.1
6.2
5.0
5.5
39.0
39.6
38.2
20.4
39.0
34.4
24.9
0.0
49.6
49.1
41.7
33.2
39.1
40.5
31.5
0.0
49.1
53.7
45.7
38.9
48.6
45.6
37.3
70.0
48.6
54.7
46.7
37.2
50.8
47.7
41.3
40.0
46.6
56.5
53.4
40.2
56.4
57.1
50.8
0.0
112.5
80.6
57.5
45.1
61.6
64.1
56.8
75.0
66.7
56.8
76.7
66.6
61.6
82.1
77.6
40.0
0.0
0.0
83.8
65.2
76.8
121.0
83.1
0.0
0.0
0.0
80.0
105.0
112.8
98.3
107.8
0.0
0.0
0.0
0.0
68.8
0.0
0.0
97.5
26
3764
3863
3864
3963
3964
4063
4064
4065
11.3
21.4
40.8
34.2
41.2
37.2
36.9
47.5
5.9
5.7
6.4
0.0
10.3
10.0
0.0
0.0
27.5
12.7
23.3
34.3
35.8
25.1
20.7
36.7
0.0
20.5
35.0
29.6
36.3
30.5
29.3
0.0
0.0
24.3
44.2
32.9
39.7
34.2
34.8
40.0
32.5
31.9
44.0
31.0
37.2
34.6
31.3
0.0
0.0
27.3
46.5
43.0
44.3
55.8
40.6
0.0
0.0
73.4
44.1
64.3
53.8
55.2
42.3
95.0
0.0
64.9
77.7
80.5
76.5
72.0
57.3
0.0
0.0
66.2
76.1
83.8
68.2
101.6
55.4
0.0
0.0
68.8
0.0
0.0
0.0
75.8
111.7
0.0
0.0
0.0
0.0
0.0
115.0
90.0
0.0
0.0
Table 5. Estimated Dumber (in millions) of sprat
T.V.
"Baitica", 3-20.10.1994, hydroacoustic survey
SD
Strata
AgeO
Total
Age 1
Age2
Age3
Age4
Age5
Age6
25
3760
3860
3960
3961
3962
4060
4061
4062
4295
663
1211
2394
3698
1051
988
213
4088
204
315
156
0
68
48
180
69
25
40
7
126
28
0
0
90
145
285
318
828
188
112
0
47
159
344
807
1513
306
288
7
0
92
138
594
754
251
296
7
0
27
521
280
215
203
161
10
0
2
21
211
122
5
78
7
26
37641
38631
3864
39631
39641
4063
40641
40651
1803
3136
3433
4185
7228
3459
7124
11533
7901
72
137
100
361
62
781
0
435
834
1243
126
380
1251
1284
1670
3448
1785
3733
4809
162
646
697
16821
1944
854
1026
11071
16
210
45
360
405
367
93
265
131
441
171
2341
2961
111
21
1381
0
34
10
13,
221
142
21
0
I
1077
138
2137
5213
Age8+
Age7
0
11
15
19
0
0
4
3
71
0
0
01
01
01
0
01
1
0
0
2
0
0
0
0
0
0
44
0
0
0
01
0
0
Table 6. Estimated mean weight (in gramms) of sprat
T.V.
"Baltica", 3-20.10.1994, hydroacoustic survey
Strata
SD
AgeO
Total
Age2
Age 1
Age3
Age4
Age5
Age6
Age7
Age8+
25
3760
3860
3960
3961
3962
4060
4061
4062
4.1
13.7
14.1
15.6
14.4
17.6
16.7
4.5
3.6
4.2
4.0
4.5
0.0
4.0
4.5
2.5
11.7
13.9
13.3
10.0
12.6
12.2
0.0
0.0
16.3
16.8
16.6
14.5
13.2
15.6
15.6
0.0
15.0
18.1
17.9
15.4
15.0
17.7
16.2
12.51
0.0
19.1
19.1
17.2
15.9
18.4
18.1
16.7
0.0
20.2
19.9
19.6
18.2
19.7
19.5
17.2
0.0
21.7
19.8
15.8
16.4
21.8
16.6
15.0
0.0
20.8
21.0
20.0
0.0
0.0
20.7
15.0
0.0
0.0
21.5
0.0
0.0
0.0
0.0
0.0
26
3764
3863
3864
3963
3964
4063
4064
4065
6.4
11.6
10.0
13.4
12.4
12.2
11.7
11.2
2.9
4.4
3.2
3.4
4.5
2.8
4.2
0.0
8.1
9.5
9.1
10.9
9.9
9.9
10.5
9.9
9.6
11.4
10.4
12.7
11.9
11.6
11.9
11.2
10.21
13.71
11.5
13.81
13.6
13.1
12.71
14.9
11.4
13.3
18.1
16.1
14.3
13.9
16.5
20.5
16.0
18.1
14.0
17.4
16.5
15.2 .
17.61
15.0
0.0
17.1
22.0
20.0
20.0
13.7
17.6
0.0
11.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
17.41
0.01
0.01
0.01
0.01
0.0
0.0
.....
N
i.
Fig. 1. Location of acoustic sample"s and control hauls
T.V.
59
"Baltica", 3-20.10.1994, hydroacoustic survey
62
61
60
63
20
56.00
.
L-.---,.c..kL-+------+-----+-....:.....------t----:::---r::-=.:::;;,--=-~.
~~'"IF:::----I
. . . '
.: ..
.:'"
.....
. ..
...-
-
.
.•.~.
..'
.....'
.•..
..,
.
1~
~:::".:
.
2 w.-: ..
- -.-. : ..-
.
)_
23\
..
\
.. ..•..
'i
........--
2
~.
•..
55_00
'
::
104-.00
.:'
......
....
M.oo
65
64
15.00
.... ::-
-...-
........
~
.... ::::::;-...•......
.
-
.
21.00
Fig. 2. Distribution ofherring biomass (t/NM2)
T.V.
"Baltica", 3-20.10. I 99-t, hydroacoustic survey
60
59
62
61
63
65
"-
56.0
55.0
54.0
14.0
64
15.0
16.0
17.0
18.0
.
Fig. 3. Distribution of sprat biomass (tINM 2 )
r.v. "Baltica", 3-20.10.1994, hydroacoustic survey
59
60
62
61
63
64
65
56.0
0
~
.....
U'1
Q)
C"J
55.0
CI)
C"J
54.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
SubdIvIsion 25
Subdhlsion 26
3764
3760
i~Lh
18
30
Lfllt.-D
6.5
7.5 8.5
~L.
;g .1..--.•111.
_
3860
3863
SOL
~L.__1.1••._
I •.
40
30
fg
30
•• 1 _
&5
~5
8.5 a5
• •1_1_•.
10511.51~51351~51~51a5
5°L
65 7.5 8.5 95 10511512.5135145155165
3864
~gL
40
30
..llL__ ~~
•.•.•
-llIIJl__~
6.5 7.5 65 9.5 10.5 11.5 12.5 13.5 14.5 15.5165
3961
3963
11_
._11.11 __
01
------_-----
6.5 7.5 6.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 165
~o _
_1.111_1.__
1,
__
6.5 7.5 85 95 10.5 115 12.5 13.5 145 155 165
3962
__
3964
___
.I.lh..
lo!g 1...
-_
6.5 7.5 8.5 9.5 10.5 11.5 12.5 135 14.5 15.5 16.5
ro~IL.
•.1111.....,_ _
~
_
6.5 7.5 8.5 95 105 11.5 12.5 13.5 14.5 155 165
4060
4063
~og1---------..-.....dlLAI'''._ ro~I.
.
.llu.. _
1U
• • 1
6.5 7.5 8.5 95 10.5 11.5 12.5 13.5 14.515.5 16.5
6.5 7.5 8.5 9.5 10.511.512513514.5 155 165
4061
4064
___.dIJh__ ~g~L
. du.. I.U.
90
111_
0
_
6.5 7.5 6.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5
0
•
.
__ 20Ig
3960
ig
_
6.5 7.5 8.5 9.5 105 11.5 12.5 13.5 145 15.5 165
9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5
6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5
4062
~lm.
&5
~5
8.5 a5
_
6.5 7.5 8.5 9.5 10.511.512.513.514.515.516.5
4065
. u __
~o l
_~ I
1-.-..
1Q511.51~51351~51~51&5
--_.-----------_._-------- --------------- ------
bI. __
6.5 7.5 8.5 9.5 10.5 11.5 12.5 135 145 15.5 165
---------
length (an)
length(an)
--------------------------------- --Fig. 4. Length distribution of sprat by redangles
16
Subdivision 25
Subdivisioll 26
3760
3764
'~I~
o
_2gl•• _
1~1
2
3
4
5
6
7
o
8
1
234
40
2g
o
1~L..
60
40
2g
_ ••• _
1
234
5
6
7
o
8
1:
3960
1~l..
2g
..
40
o
1
2
3
40
2g
_
4
5
6
7
8
1
u.__..
2
3
4
5
6
7
8
Lu
1
2
456
7
8
567
8
.........
_
3
3963
100
80
60
40
-.l.-..JI • • -
o.
o
2
3
4
5
6
20
7
o
8
'rogl_~_
. ....1.2
3
4
5
2
3
3964
6
7
-'.~
o
8
1
_.
234
_
5
6
7
100L.
~
u.__..
_
80
o .----o
234
----
567
o 1 234 5 6 7 8
8
4064
4061 .
'~IO----..-. ....u.--..-----o
234
5
6
7
8
'~I
_
oW....-------o
1
2
3
80
100~
60
..
~--..
o
2
3
4
4
5
6
7
8
4065
4062
40
,.2g
8
4063
4060
'~I
4
40
2g
u
o
o
1:L.
3962
•
_
3864
o
3961
'~I
8
3863
3860
1~~
567
5
6
_
7
'~Lu
o o
8
age
1
2
L.J.
-
3
-
-
4
-
-
5
-
age
Fig. 5. Age distribution of sprat by redangles
17
-
-
-
-
678
3760
40LJ
3962
30
20
10
o
.-J.IIJ.u.'___ _~_JI.'__.................
t
7.5
10.'
U
U.S
1.5
1'.'
••
19.5
2l
115
~_ _
US
.z4
27
21.'
1ll
0
UUAl..
.-JI....
IIJI.-
..h
7.'
9
10.'
U
l~U
n
u
I'.'
.1
3860
io~l, . ~__ ....
_
7.'
•
t
10.5
11
13.5
1S
16.5
11
20t
22.S
15.5
11
18.'
i'o~I, __~
.
.
7.S
,
10.'
U
U
.6.' .1
1'.'
t
10.'
11
13.,
U
16.'
11
lLS
ioll. .••.
........
14
25.5
21
Je.'
7.'
,
10.'
12
40
••I.Wlh.....
_·..-.IJ.IJ.IJ..............
,
10.'
U
U
U
16.5
.1
I'."
11
21.'
14
io~ 1~. . __~. .
-
-.l1,UJ
u.,
1'.'
)T
la.'
19.'
ns
21
1-4
aB
J"
D.S
lf.'
.1
."
11
21.'
z.4
"t
27
11..'
4062
30
7.'
I1
-"......
..111111••••••
13.'
3961
~o~ 1.
_
M
4061
.....1I.
..111111.1•••••.
U.J
12.'
-"......
..111111111....
_
7.'
3960
io~I_~
<-21
4060
ldlJl..h.
.1
JIH
••. ,
US
27
2:1.5
Ic;ngth (an)
7.'
I .I.IJIJU...............
10.'
11
13.'
15
16.'
.1 .,.,
Jt
11.,
Ic;ngth (an)
Fig. 6. Length distribution of herring by rectangles in Subdivision. 25
18
"__~
lI.-J'_......
••11.1111.........
_.
9
J4
U,
J7
'U
3964
3764
~lku.
7.5
,
IO.J
U
u.. . .
U.5
U
16.5
11
19.'
_
11
n.s
14
215
11
11.5
i:o~
...........................JI.JIJ............_
-
I;
1.'
9
lOS
11
13.,
.111111111111•••••
U
16.'
11
19.'
11
21.5
24
1.5.5
14
ns
4063
3863
40
30
20
1l , -__.•.•. . __...1111.1111111••••
..
0
~
1.'
c a.JIUl.lLaA......................
,
10.'
U
n.s
15
14.'
tS
1'.'
21
12.'
_
14
U5
27
UJlIJl
1111.. 1......
1_
'Oll ,
7.'
11.5
,
10.'
12
11.'
U
1'.'
.1
19.'
21
n.s
4064
3864
40
30
20
10
o 1---_ _~__JU
Jll.JIJhul....
III.JIJ
.......
_
.........
1.'
,
10.S
1Z
U.S
U
16.'
.1
19.'
21
12.'
24
2.5.5
27
2a.S
ioll,_
. ..11111111111••••••
. . I.I.IJ
1.'
,
10.'
12
13.'
U
16.'
11
19.'
21
12.S
4065
3963
40
30
1lo1_
7.S
20
10
o
1111tttJ1•••••••
--JUJIJ
,
10.S
12
11.,
U
16.5
.1
.,.,
21
ns
24
US
length (cm)
.- ..
27
lI-S
.....-JL-__-JL_ _......_
~
1.'
,
10.S
U
11.'
U
16.'
.1
19.'
U
length (cm)
_----------
Fig.7. Length distaibution of herling by rectangles in Subdivision 26
19
ll.S
J..
nJ
3962
3760
'~~
0
'OOl
80
60
~~
1
2
3
456
7
8
9
10
o
..d....
1
2
3
4
I
2~
_
o
UW.. . .~-~~~~
••
1 2 3
456
7
8
9
10
'~I
o
8
9 10
_
12345678910
4061
100
80
60
100
80
40
40
60
20
0
0
1
2
d.
3
4
5
6
7
8
9
10
2~ .........-......IJ..-~-....o
I
•
o
4062
.
__
1
2
Ul,J-......-__-_~~
3
4
5
_
2345678910
1
3961
2~
7
- • . 0..--..--.
3960
80
100
60
40
6
4060
3860
80
100
60
40
5
6
7
8
9
'~j
10
o
..... _--
_
1
2
3
4
5
6
age
7
8
age
Fig. 8. Age distribution of herring by rectangles in Subdi\'ision 25
20
9
10
- ------ ---- - - - - - - - 1
3764-
,ooL
lEI
2~
80
60
40
•
0
1
2
3
4
.dL... __
2~
5
3964-
6
7
8
9
0
10
1
2
3
4
I~I
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
0
10
100
80
60
60
40
40
20
1
2
3
4
5
20
0
0
2
3
4
5
6
7
8
9 10
0
1
2
3
4
3963
I~I
0
-.d.
1
2
3
4
5
9
10
6
7
8
9
10
4064
100
80
1
8
-.11 ___
3864
0
7
4063
3863
0
6
5
._-5
6
7
8
9
10
4065
100
80
60
40
20
0
6
7
8
9
\-
0
10
1
2
3
4
5
6
age
7
8
9
age
Fig. 9. Age distribution of herring by rectangles in Subdhision 26
21
10
e
-
"Tl
ciQ'
.....
N~O\OOO
000000
0
o
CZl
:3
g-,
3760
0"0
"0
e;
(l)
~
o·
0..0
... :3
0"0
... 0
::r-tn
......
o
ll)
N
N
-,
01
::rc
Ei>
S'
.....
\0
\0
.+:0
3760~
~
N~O\OOO
;
-
000000
3760 JIi
3960
3961
3%1~
3961
3962
4060
4060~
4061
4061.
4060
4061
4062
~62b-
4062
e:
(')
()
3764
3764
~
3764
3863
3863
3864
3863
3864
3963
3964
3963
3964
4063
4064
4063
3963
3964
4063
4064t;=
4065 j
4064
4065
-I
I
\0 \C
\0 \C
O~
~
...
...
~
~.~
'"o
ll)
N~O\OOÖ
000000
3960
\0"'"
\00
0
0
e.
-
(')
83860
-otO
o...
_
;.>
::3
•
3860
0
....,::3
..... 0
......,
e
~
t:".
... ()
;.>_
3962
CI)
CS"
4065
3962
,
i
3860
3960
3864~
::c
0
::l
5'
0'Cl
.--------------~-
-
- - ---
..
Ilerring
250000
200000
150000
100000
50000
0
_.§iJ.mJ
0
'D
,...,
t'-
0
o
-
NON
~ ~ ~ ~ ~ ~
M
f""')
M
o
_
'D
M
~ ~ ~
N
'D
0\
0
'D
~
lt)
N
Cl
v.l
oBlllh.Il
_a-~
,..., "1" ,..., "1" ,...,
'D 'D 'D 'D 'D
t-e ,...,
00 00 0\
0
,...,
,..., ,..., 0\
,..., "1"
"1"
"1"
'D
0
"1"
lt)
~
lt)
'D
0
"1"
'D
N
Cl
v.l
~
!-<
Sprat
250000
200000
150000
100000
50000
0
0
'D
0
'D
00
,..., ,...,
t'-
~ ,...,
~
,...,
'D
N
'D
,..., ~ ~ ~
"1" ,..., "1" "'" "I:t
'D 'D 'D ~ ~
t'- ,...,
00 00
,...,
,..., ,..., ,...,
lt)
8
v.l
f"")
'D
'D
'D 0
~ ~ "1"
'D
8
v.l
~
!-<
Cod
25000
20000
15000
10000
5000
0
0
0
'D
00
,.,t-e ,.,
~
o
-
~ ~
,...,
,...,
N
....~
0
'D
0
"1"
'D
N
'D
~ ~
"1"
'D
lt)
,.,t'-
8
v.l
,...,
'D
00
,...,
"1"
'D
00
,.,
M
~
M
'7
~~'D'D
,...,
,..., ~ ~
lt)
'D
~
'D
N
Cl
v.l
~
!-<
- 1994, r.v. "Baitica"
c:=:J - 1990, r.v. "Profesor Siedlecki"
Fig. 11. Hydroacoustic estimates ofherring, sprat and cod biomass (t)
in the Polish EEZ by rectangles in 1994 compared to
those of 1990
23
Herring
250000
200000
150000
100000
50000
o
37"
38"
39"
40"
"60 "61
"62 "63 "64
Total
37"
38"
39" 40"
"60 "61
"62 "63
"64
Total
37"
38"
39"
"60 "61 "62 "63 "64
Total
Sprat
250000
200000
150000
100000
50000
o
Cod
25000
20000
15000
10000
5000
o
40"
Northward
(two initial numbers
ofthe rectangle code)
Eastward
(two last numbers
of the rectangle code)
~ - 1994, r.v. "Baltica" biomass estimate
c=J - 1990, r.v. "Profesor Siedlecki" biomass estimate
Fig. 12. Changes in the distribution ofthe herring, sprat and co
biomass in the Polish EEZ in 1990 and 1994 in N-S
and W-E directions
24