0 200 400 600 800 1000 1200
Year
1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998
Overl ap fract ion
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
(a)
(b)
Fig. 1.1.12. Time series of (a) habitat volumes of Baltic cod (
-
), herring (-
) and sprat (-), and (b) the fractions of the herring and sprat habitats where Baltic cod occurred.S u b-divisio n
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
T o tal le n g th (cm )
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
T o tal le n g th (cm )
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
T o tal le n g th (cm )
.
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
Total length (cm)
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
Total length (cm)
% N
N= 780.603 (N-measured = 6312) N = 95.325 (N-measured = 1698)
Sub-division
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
Total length(cm)
% N
N = 200.123 (N-measured = 1870)
Sub-division
4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25 12.75 13.25 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75
Total length (cm)
% N
N = 91.604 (N-measured = 1482)
Fig. 1.1.14. Length distribution of sprat in Sub-divisions 24, 25, 26, and 27/28 (Cruise No. 228b RV "W.Herwig
0 1 2 3 4
1 2 3 4 5 age group n (billion)
legend:
+
G2 G3 G4 G5 G6 G7 G8
42
41
40
39
38
37
b)
0 1 2 3 4
1 2 3 4 5 age group n (billion)
legend:
+
G2 G3 G4 G5 G6 G7 G8
42
41
40
39
38
37
Fig. 1.1.15. Sprat number per age group (billion), (a) May/June 1999; b) May/June 2001)
a)
0 2 4 6
Sprat
Herring
biomass ( t x 104 ) legend:
G2 G3 G4 G5 G6 G7 G8
42
41
40
39
38
37
b)
0 2 4 6
Sprat
Herring
biomass ( t x 104 ) legend:
G2 G3 G4 G5 G6 G7 G8
42
41
40
39
38
37
Fig 1.1.16. Herring and sprat biomass (‘0000 t) per rectangle (a) May/June 1999; b) May/June 2001)
0 50 100
Fig. 1.1.17. Vertical distribution of the mean Sa-values per Sub-division in May/June 1999.
Fig. 1.1.18. Vertical distribution of Sprat on a transsect along 15.7°E from south to north across the Bornholm Basin in May/June 1999.
Fig. 1.1.19. Mean Sa-values in the water layers 8 – 30m, >30 – 60m and > 60 – 90m in relation to bottom depth per Sub-division in May/June 1999.
legend :
water layer 8-30 m wate r layer 30-60 m water layer 60-90 m Sa - value in:
Fig. 1.1.20. Vertical contour plots of temperature and salinity from stations on a transect across the investigated area (RV
„Walther Herwig III“ in May/June 1999).
4 8 12 8 12 16
Temperatur (°C) Salinity (psu)
20
60
100 20
60
100 20
60
100 20
60
100 57° N
55° N
57° N
55° N
57° N
55° N
57° N
55° N
14° E 18° E
D e p t h (m)
Fig.1.1.21. Scatter plots of temperature and salinity on selected stations in the Arkona- and Bornholm Basin as well as in the s. w. Gotland and Aland Sea (RV „Walther Herwig III“ in May/June 1999).
Oxygen [ml/l]
Fig. 1.1.22. Cumulative frequency distribution plots describing the hydrographic factors influencing the vertical distribution of sprat in May/June 1999
waterdepth [m]
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
NASC per nm-intervall (sum over all depth) [m²/nm²]
1
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
a) b)
Fig. 1.1.23. Charactarization of patchiness of fish-distribution in 1999 and 2001 at a basin-wide, horizontal scale. The overall backscaterring values of every 1nm-transect unit was plotted against waterdepth.
local time (UTC+2hours)
0 2 4 6 8 10 12 14 16 18 20 22 24
depth of center gravity [m]
0
elevation of the sun [°]
0
Fig. 1.1.24. Vertical distribution of pelagic and daily vertical migration in reation to hydrographic parameters and elevation of the sun in June 2001. Data were derived from hydroacoustic data used for calculation of the center depth of gravity of echostrength.
15 16 17
0,0
Fig. 1.1.26. Cumulative frequency distributions of cod CPUE in relation to oxygen saturation (A), salinity (B) and temperature (C) in the Bornholm Basin in 1998/99. The plot of f(x) for each habitat variable is in bold and indicated as ‘habitat’.
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
Cod CPUE
0 100 200 300 400 500 600
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
Herring CPUE
0 2000 4000 6000 8000 10000
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
Sprat CPUE
0 5000 10000 15000 20000 25000 30000 35000
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
Oxygen saturation in %
0 10 20 30 40 50 60 70 80 90 100
A
E F C D
B
Fig.1.1.27. CPUE in relation to oxygen saturation. Bornholm cod (A), Gotland cod (B), Bornholm herring (C), Gotland Herring (D), Bornholm sprat (E) and Gotalnd sprat (F).
Relative Salinity
0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-100 0 100 200 300 400
Temperature [° C]
0 2 4 6 8 10
Relative Salinity
0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-2000 -1000 0 1000 2000 3000 4000 5000
Temperature [° C]
0 2 4 6 8 10
Relative Salinity
0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-15000 -10000 -5000 0 5000 10000 15000 20000
Temperature [° C]
0 2 4 6 8 10
A
E F C D
B
Fig. 1.1.28. Bornholm Basin. Residuals from the regression of CPUE versus oxygen saturation in relation to relative salinity and temperature for cod (A and B), herring(C and D) and sprat (E and F).
Temperature [° C]
1 2 3 4 5 6 7 8
Relative Salinity
0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-200 -100 0 100 200 300 400 500
Relative Salinity
0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-4000 -2000 0 2000 4000 6000 8000
Temperature [° C]
4 5 6 7 8 9 10
Relative Salinity
0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05
Residuals
-10000 -5000 0 5000 10000 15000 20000 25000
Temperature [° C]
1 2 3 4 5 6 7 8
A
E F C D
B
Fig. 1.1.29. Gotland Basin. Residuals from the regression of CPUE versus oxygen saturation in relation to relative salinity and temperature for cod (A and B), herring(C and D) and sprat (E and F).
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5
54.0
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5
Longitude E
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5
54.0
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5
Longitude E
Fig. 1.1.30. Cod CPUE in the Bornholm Basin during the study period. The CPUE has been scaled, for each year the smallest dot symbolizes the lowest CPUE and the largest doth the highest CPUE, respectively. Hence, trends in absolute density are not shown on this graph. The basin’s bottom topography is documented by inserting the 50m, 60m, 70m, 80m and 90 m depth contour lines (from outside towards the center of the basin).
15.0 15.2 15.4 15.6 15.8 16.0 16.2 16.4 16.6 16.8 17.0
17.0 17.2 17.4 17.6 17.8 18.0
18.0 18.2 18.418.6 18.8 19.0 19.219.4 19.6 19.820.0 20.2 20.4 20.620.8 21.0 21.221.4 21.6 21.8 22.0 55.6
15.0 15.2 15.4 15.6 15.8 16.0 16.2 16.4 16.6 16.8 17.0
54.5
17.0 17.2 17.4 17.6 17.8 18.0
18.0 18.2 18.4 18.618.8 19.0 19.219.4 19.6 19.8 20.020.2 20.4 20.6 20.821.0 21.2 21.421.6 21.8 22.0 55.6
Fig. 1.1.32. Sprat biomass re-distribution between SD 26 and 28 in 1992 – 2000; Hydroacoustic surveys R/V Monocrystall, Atlantniro.
Fig. 1.1.35. Age composition of sprat (%) at peak spawning time in 1995 by statistical rectangle according to deep water and shallow water rectangles.
Fig. 1.1.37. Age composition of sprat (%) at peak spawning time in 2000 by statistical rectangle according to deep water and shallow water rectangles.
Fig. 1.1.39. Water temperature (°C) and salinity (PSU) by depth strata and statistical rectangle during peak spawning time in 1995.
Fig. 1.1.40. Water temperature (°C) and salinity (PSU) by depth strata and statistical rectangle during peak
Fig. 1.1.41. Water temperature (°C) and salinity (PSU) by depth strata and statistical rectangle during peak spawning time in 2000.
1 8 .0 ° 1 9 .0 ° 2 0 .0 ° 2 1 .0 ° 2 2 .0 °
Fig.1.1.42. Distribution of sprat density in the Baltic Sea, May 1987.
54 .5°
5 4 .5 °
Figure 1.1.44. Distribution of sprat density in the Baltic Sea, October 2000
10 1 5 2 0 25 30 35 40
0 1 2 5 10 15
S p rat d en sity, m ln /n m ^ 2
T ick n ess of su rface layer, m
Figure 1.1.45. Distribution of sprat density in surface layer in the Baltic Sea, October 1998
1 0 1 5 2 0 2 5 3 0 3 5 4 0
0 1 2 5 1 0 1 5
S p rat d en sity, m ln /n m ^ 2
T ick n ess of su rface layer, m
Figure 1.1.46. Distribution of sprat density in surface layer in the Baltic Sea, October 2001
0 1 2 5 10 15
10 15 20 2 5 30 35 40
S p rat d en sity, m ln /n m ^ 2
T ick n ess of b ottom layer, m
Figure 1.1.47. Distribution of sprat density in bottom layer in the Baltic Sea, October 1998
10 1 5 2 0 25 30 35 4 0
0 1 2 5 1 0 1 5
S p rat d en sity, m ln /n m ^ 2
T ick n ess of b ottom layer, m
Figure 1.1.48. Distribution of sprat density in bottom layer in the Baltic Sea, October 2001.
5 4 .5 °
Figure 1.1.49. (a) Distribution of sprat density at age 1 in the Baltic Sea, October 1987.
5 4 .5 °
Figure 1.1.49. (b) Distribution of sprat density at age 2 and older in the Baltic Sea, October 1987.
0 100 200 300 400 500 600 700 800 900
1964 1968 1972 1976 1980 1984 1988 1992 1996
Year km3 and millions
Total Reproduction Volume Recruitment at age 2
Fig. 1.1.51a.Total reproduction volume and corresponding recruitment at age 2 in the eastern Baltic cod stock in 1964-1998 (recruitment at age 2 shifted two years back to correspond year of birth (ICES 1999a). (RVs courtesy of M. Plikshs, March 2000, R from ICES 1999a).
0 100 200 300 400 500 600 700 800 900
1964 1968 1972 1976 1980 1984 1988 1992 1996
Year
km3
Bornholm Basin Slupsk Furrow Gdansk Deep Southern Gotland Basin Central Gotland Basin
Fig.1.1.51b. Total reproduction volume and contribution of various spawning grounds to total reproduction volume in 1964-1998.
Fig. 3.1.52a. Distribution of SSB of Baltic cod in February-March in 1982-1990.
Fig. 3.1.52b. Distribution of SSB of Baltic cod in February-March in 1991-1999.
a)
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
1982 1984 1986 1988 1990 1992 1994 1996 1998 Year
Fig. 1.1.53a-f. Least squares/h of SSB and recruitment at age 1 [R] of cod in different areas of the Central Baltic for the time period 1982-1999.
Fig. 1.1.54. Abundance indices for cod age 1, 2 and 3+ in the Central Baltic per Sub-division (SD).
age 1
0 2000 4000 6000 8000
SD 25 SD 26 north SD 26 south SD 28
age 2
abundance index (* hour-1) 0 5000 10000 15000 35000 40000
age 3+
year
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 0
10000 20000 30000 40000 50000
Fig. 1.1.55. Stock size of sprat age 1+ derived from autumn hydroacoustic survey:Sub-divisions (SD) 22-29 south compared to combined SD 25, 26 ad 28.
Fig. 1.1.56. Stock size of sprat age 1+ :Sub-divisions (SD) 22-32 derived from combined western & central MSVPA compared to combined SD 25, 26 ad 28 from area dis-aggregated MSVPA.
Sprat 1+
year
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000
Stock size from hydroacoustics (millions)
0 50x103 100x103 150x103 200x103 250x103 300x103
SD 22 - 29 south SD 25, 26 & 28
Sprat 1+
year
1975 1980 1985 1990 1995 2000
Stock size (millions)
0 50x103 100x103 150x103 200x103 250x103
300x103 SD 22-32 (western + central MSVPA) SD 25, 26 & 28 (dis-aggregated MSVPA)
Fig. 1.1.57. Relative spatial distribution of sprat stock sizes (age 0+) from hydroacoustic surveys in September/October in the Baltic Sea.
Sprat age 3+
year
1980 1985 1990 1995 2000
Proportion of total stock in SD
0 20 40 60 80 100
SD 24 SD 25 SD26 SD 27 SD 28 SD 29 south
Fig. 1.1.58. Relative spatial distribution of sprat stock sizes (age 3+) from hydroacoustic surveys in September/October in the Baltic Sea.
Sprat age 0+
year
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
Proportion of total stock in SD
0 20 40 60 80 100
SD 22 SD 23 SD 24 SD 25 SD 26 SD 27 SD 28 SD 29 south
Sprat age 1
year
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000
Proprotion in SD
0.0 0.2 0.4 0.6 0.8 1.0
SD 25 SD 26 SD 28
Fi Fig. 1.1.59. Relative spatial distribution of sprat stock sizes (age 1) from hydroacoustic surveys in September/October in the Baltic Sea.
Sprat age 1
year
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
Proportion of total stock in SD
0.0 0.2 0.4 0.6 0.8 1.0
SD 22 SD 23 SD 24 SD 25 SD 26 SD 27 SD 28 SD 29 south
Fig. 1.1.60. Relative spatial distribution of sprat stock sizes (age 1) from hydroacoustic surveys in September/October in Sub-divisions (SD) 25, 26 and 28.
Fig. 1.1.61. Catch rates of adult cod in benthopelagic trawl surveys covering the Bornholm Basin in April, May and July 1995-1999.
Fig. 1.1.62. Relative CPUE of the eastern Baltic cod spawning stock (maturity stages III-VIII) according to spawning area in various months of 1996.
year
1995 1996 1997 1998 1999
Catch rate (kg * hour-1 )
0 100 200 300 400 500 600 700
April May July
month
February/March May June/July July/August
relative CPUE (n/trawling hour)
0.0 0.2 0.4 0.6 0.8 1.0
SD 25 SD 26 SD 28
Fig. 1.1.63. Horizontal distribution (stock sizes per ICES statistical rectangle) of sprat 1+ in October 1998, and cod 2+ in May/June and October 1999 from hydroacoustic surveys.
41G5 41G6 41G7 41G8 41G9 41G10
0 5000 10000 15000
0 5000 10000
October 1998 May/June 1999 October 1999
39G5 39G6 39G7 39G8 39G9 39G10
0 5000 10000 15000
40G5 40G6 40G7 40G8 40G9 40G10
Stock size (millions)
0 5000 10000 15000