Abramova: Composition. Abundnnce and Population Structure of Spring-Time Zooplankton
163
Table I: Temperature, salinity, depth and ice cover distribution in the Laptev Sea during the Transdrift IV
expedition in May 1996
Sta- Date
Latitude
Longitude
Depth Temperature (0C)
Salinity
Ice
tion
ON
°E
m
surface I bottom surface I bottom
sm
18.05
73° 15.60
130°00.40
21.5
-0.45 1 -1.46
13.53 129.23
143
2
18.05
73°00.50
130°30.50
22.0
-0.73/-1.43
13.84 1 27.62
153
3
18.05
74°44.80
130°29.50
17.5
-0.69 1 -1.32
12.97/26.81
177
4
20.05
72°14.15
130°29.77
13.0
-0.55 1 -1.20
10.73 124.65
182
5
20.05
72°29.78
130°34.08
14.0
-0.38 1 -1.21
7.20/26.29
120
6
20.05
72°00.30
130°29.10
15.0
-0.46 1 -1.31
9.04/24.87
164
8
20.05
72°30.93
130°05.49
6.0
-0.09 1 -0.80
2.12/20.48
170
9
22.05
72°37.40
130°29.47
15.0
-0.42 1 -1.35
8.15/26.63
145
10
22.05
72°22.61
130°29.62
12.0
-0.37 1 -1.24
5.88 / 24.63
175
11
22.05
71°53.04
129°51.60
7.0
-0.25 1 -0.75
5.28/21.31
196
12
23.05
74°30.52
130°29.42
25.0
-1.62 I -1.53
29.13/30.11
159
13
23.05
74° 14.82
130°30.70
25.0
-1.56 / -1.59
29.33 / 29.56
170
14
23.05
74°00.08
130°30.11
25.0
-1.43 / -1.48
26.47/30.79
162
15
23.05
73°45.02
130°30.36
24.0
-1.34 / -1.46
19.48/29.79
167
16
25.05
73°30.35
130°30.41
19.0
-1.13/-1.46
21.11/27.74
140
17
25.05
72°24.44
129°29.08
20.0
-1.59/-1.51
29.26/30.73
148
18
25.05
74°07.02
128°28.57
26.0
-1.67/-1.32
30.89 / 32.15
207
19
25.05
74°01.74
127°30.10
28.0
-1.58/-1.48
29.28 / 32.42
123
20
27.05
73°44.95
126°30.64
13.0
-1.52 I -1.60
27.16/28.79
144
21
27.05
73°45.00
125°29.66
6.0
-1.95 / -1.89
35.52 / 36.32
204
22
29.05
74°32.72
126°26.58
33.0
-1.68 / -1.63
31.07 / 32.63
134
23
29.05
73°45.03
127°30.68
9.0
-1.20 / -1.34
24.48 / 25.16
145
24
29.05
73°44.69
128°32.30
22.0
-1.24/-1.61
23.13/31.95
159
25
29.05
74°51.54
125°29.73
33.0
-1.69 1 -1.68
31.90 / 32.63
143
generation appear in February. Conventionally two well-distinguished reproduction peaks are
observed in Buorkhaya Bay, accompanied by increased abundance of mature males in the
population and mass outcome of nauplii in March-April and September. Depending on
particular conditions of different years, spawning peaks may be shifted to earlier or later
periods. In May-June 1996, mainly mature females, individual males and copepodits of 5th
stage were recorded in A. longiremis population, some of females having spermatophores. The
content of this species in the samples was varying between 0.5 and 18.5% of the total density
of organisms. The available material has permitted to outline the following dynamic pattern of
the species development: copepodits of 2-5 stages were recorded in the samples from
Buorkhaya Bay in February and March, copepodits of 4-5 stages predominated in April, scarce
mature male and female were recorded in May-June. Evidently, part of population starts
163
Table I: Temperature, salinity, depth and ice cover distribution in the Laptev Sea during the Transdrift IV
expedition in May 1996
Sta- Date
Latitude
Longitude
Depth Temperature (0C)
Salinity
Ice
tion
ON
°E
m
surface I bottom surface I bottom
sm
18.05
73° 15.60
130°00.40
21.5
-0.45 1 -1.46
13.53 129.23
143
2
18.05
73°00.50
130°30.50
22.0
-0.73/-1.43
13.84 1 27.62
153
3
18.05
74°44.80
130°29.50
17.5
-0.69 1 -1.32
12.97/26.81
177
4
20.05
72°14.15
130°29.77
13.0
-0.55 1 -1.20
10.73 124.65
182
5
20.05
72°29.78
130°34.08
14.0
-0.38 1 -1.21
7.20/26.29
120
6
20.05
72°00.30
130°29.10
15.0
-0.46 1 -1.31
9.04/24.87
164
8
20.05
72°30.93
130°05.49
6.0
-0.09 1 -0.80
2.12/20.48
170
9
22.05
72°37.40
130°29.47
15.0
-0.42 1 -1.35
8.15/26.63
145
10
22.05
72°22.61
130°29.62
12.0
-0.37 1 -1.24
5.88 / 24.63
175
11
22.05
71°53.04
129°51.60
7.0
-0.25 1 -0.75
5.28/21.31
196
12
23.05
74°30.52
130°29.42
25.0
-1.62 I -1.53
29.13/30.11
159
13
23.05
74° 14.82
130°30.70
25.0
-1.56 / -1.59
29.33 / 29.56
170
14
23.05
74°00.08
130°30.11
25.0
-1.43 / -1.48
26.47/30.79
162
15
23.05
73°45.02
130°30.36
24.0
-1.34 / -1.46
19.48/29.79
167
16
25.05
73°30.35
130°30.41
19.0
-1.13/-1.46
21.11/27.74
140
17
25.05
72°24.44
129°29.08
20.0
-1.59/-1.51
29.26/30.73
148
18
25.05
74°07.02
128°28.57
26.0
-1.67/-1.32
30.89 / 32.15
207
19
25.05
74°01.74
127°30.10
28.0
-1.58/-1.48
29.28 / 32.42
123
20
27.05
73°44.95
126°30.64
13.0
-1.52 I -1.60
27.16/28.79
144
21
27.05
73°45.00
125°29.66
6.0
-1.95 / -1.89
35.52 / 36.32
204
22
29.05
74°32.72
126°26.58
33.0
-1.68 / -1.63
31.07 / 32.63
134
23
29.05
73°45.03
127°30.68
9.0
-1.20 / -1.34
24.48 / 25.16
145
24
29.05
73°44.69
128°32.30
22.0
-1.24/-1.61
23.13/31.95
159
25
29.05
74°51.54
125°29.73
33.0
-1.69 1 -1.68
31.90 / 32.63
143
generation appear in February. Conventionally two well-distinguished reproduction peaks are
observed in Buorkhaya Bay, accompanied by increased abundance of mature males in the
population and mass outcome of nauplii in March-April and September. Depending on
particular conditions of different years, spawning peaks may be shifted to earlier or later
periods. In May-June 1996, mainly mature females, individual males and copepodits of 5th
stage were recorded in A. longiremis population, some of females having spermatophores. The
content of this species in the samples was varying between 0.5 and 18.5% of the total density
of organisms. The available material has permitted to outline the following dynamic pattern of
the species development: copepodits of 2-5 stages were recorded in the samples from
Buorkhaya Bay in February and March, copepodits of 4-5 stages predominated in April, scarce
mature male and female were recorded in May-June. Evidently, part of population starts