es

(01)

Relative Biomass / 5m depth interval

0.02 .04 06 .08

100

Depth (m)

200 |-

230

Figure 15.

August 1972

002 04 06 .08

TTT 1

November [972

Relative biomass (%) per 5 m interval versus depth (m)
for 21 + 25 August 1972, 30 October - 3 November 1972,

and 12 - 16 June 1973

d%o2 04 06 .08
TT

June 1973

__\



1972 NOV STATION 35 DEPTH 28 M SCAN 35M

igre

gra

MEAN VALUE OF PROFILES OVEK 54 INTERVALS

22222

1-16
17-32
33+ 48
49-64
65-80

120-80
120-80
120-80
120-80
120-80

20245
- +0494
=60744
-.0997
= +3085

200-120
200-120
200-120
200-120
200-120

+5270
1.0532
1.5787
2.1035
es6112

NOV STATION 36 PA 10®#4 AVE 5 DEFIH 2&8 M SWEEF
MEAN VALUE OF PROFILES OVER 5M INTERVALS

CH
CH
CH
CH
CH

1-16
17-32
33 4B
49-4
65-60

120-80
120-80
120-60
120-80
120-80

~eO11!
2084)
20359
63657

25835

€00-120
200-120
200-120
200-120
200-120

+ SE50
9106
Be E753
3+ 6360
Be S516

500-€00
500-200
$00-200
500-200
500-200

35M

$00- 200
500-200
500-200
500-266
500-260

NOV STATION 38 PA 10#*4 AVE 5S DEPTH 120 M SWEEF 155 M
MEAN VALUE OF PEGFILES OVER SM INTERVALS

222

22

Seergggegcageaggaagar

1- 3
4- 6
1-9
10-12
13-15
16-18
19-2)
Be 24
25-27
28-30
31-33
34-36
37-39
40-42
43-45
AG 48
49-51
5a- 54
55+ 57
58-60
€1-63
64-66
67-9
70-72

120-80
120-80
120-80
120-80
120-80
120-80
120-80
$20-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80

120-80

= 00264
20219
720195
20143
-.00928
+0135
«0366
70518
20764
© 11BE
+1665
«2296
62962
©3867
+ 4466
»5855
» €000
26753
«TAB
©8150
+8761
29418
1.0156
1.0844

17

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
€00-120
200-120
200-120
200-120
200-120

+2464
+4197
+7245
+8916
1.0605
162219
1.38698
1.5879
1.6567
1. 7886
1.9102
2.0181
261314
262165
2.3379
264507
2.5581
2.6915
268459
3.0015
3.1642
3+3387
365156
3.7152

500-£00
500-260
500-260
500-200
500-600
$00-200
500-200
900-200
s00-£00
800-200
500-200
500-200
500-200
500-200
500-200
500* 200
500-200
500-200
500-200
500-200
00-200
S$00-200
500+ 200
500-200

we SEIS
-.4092
+3063
722013
2-060

=24199
7+ 4008
03473
~ 62813
-° 0467

+0410
21159
+2162
+3318
+4535
+SB6
+ 6603
+ 7304
+ B07
+640
+9072
+9 562
140143
1.005
1.1251
1.18.43
16236
1.3001
1.3551
1.4131
164734
165276
16895
1+ 6437

Mt
10M
1M
20M
em

Ev
1oM
134
20M
eM

vi
10M
154
20M
2M
30M
3a
40M
AM
SOM
5a
60M
6o4
70M
734
60M
bar
90M
om
100M
10
110M
J1a4
120M


6T

Figure 4.

Density (no. /m3) of oligotrophic Bosmina coregoni on 21 - 25
August 1972 in surface waters (0 - 5 m) of Lake Ontario at
60 stations of IFYGL Biology Program


1973 JUN STAT

1973

1973

MEAN VAL

CH 1- 6
cH Tle
CH «(13-18
CH «19-24
CH 25-30
CH 31-36
CH «37-42
CH 43-48
CH 49-54
CH «55-60
CH E1-66
CH «€7-72
CH 73-78
CH 79-84
CH 85-90
CH 91-96

JUN STATION 30 DEPTH 28 MSWEFF
MEAN VALUE GF PROFILIS OVER SM

CH
CH
CH
CH
cr

1-16
17-32
33-48
49-64
€5-60

1QN 26 DEPTH 150
UE OF PROFILES 0

129-680
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
160-60
120-80
120-80
120-80
120-80
120-80

120-60
10-80
120-60
120-60
120-80

JUN STATIGN 31 DEPTH
MEAN VALUE GF PLOFILES OVER

CH
CH
cH
CH
CH
CH
CH

a-t1
12-22
23-33
34-44
45-55
56- CE
67-77

= 21699
163€70
264373
30 Al es
4.1056
4. 6301
4.7887
467360
4.6541
4. 5€55
4s 4600
4 AT
Ae 3109
46 2256
4.1430
4.0599

1.5484
1.7614
31028
29679
167152

120-60 -1-3670

120-80 -2

6160

120-80 -3-4127
120-80 -3-.7807
120-80 -2-1054

120-80
120-80

0 6194
+3050

M SWEEP 60 M
VER SM INTERVALS

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-180
200-120
200-120
200-120
200-120
200-120
200-160
200-120

34M

INTESVALS

5e 125E
5e 7049
6. BBE
6.8 589

200-120 -1. 5676
200-120 -3.1f€5
200-120 -2-6317
200-120 - 43425
200-120 - 5.7465

36M SWEEP 44M
SM INTERVALS

200-120
200-120
200-120
200-120
200-120
200-120
200-120

148

+9092
1686419
2.5003
269365
163575

+0030
-.9270

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-€00
500-200
500-200

500-200
500-200
500-200
500-200
500-200
500-200
500-200

= 2 BD
6518
T16€
1196
650
gala
~ 1.0173
-1.61004
-1. 1624
-1.2662
=163477
- 1.4304
-1.518)
-1. €072
“1.057
<1. HAS

2 14ee
+ 3E0E€
+ SOR6
© OTE
+6199

we 15S
26157
21876
+3609
5351
+ 1097
+8843

MM
10M
1M
20M
em

10%
1a
20M
aot
30M
3&4


1913-FEB STA 69 PA 10®*4 AVG S DEPTH 76M DEPTH77 M SCAN 80 M
MEAN VALUE GF PHOFILES OVER SM INTERVALS

CH 1- 6 120-80 ©7308 200-120 500-200
CH 712 120-80 1.4288 200-120 500-200
CH «13-18 120-80 1.5022 200-120 500-200
CH 19-24 120-S$0 1.4920 200-120 -144435 500-200
CH «25-30 120-80 164869 200-120 -1.4026 500-200
CH «31-36 120-60 1.4941 200-120 -1- 4086 500-200
CH 37-42 120-80 1.5038 200-120 -144183 500-200
CH 43-48 120-80 1.4808 200-120 -1-4012 500-200
CH 49854 120-60 164638 200-1280 -1-4036 500-200
CH S5-60 120-80 1.4932 200-120 -144117 500-260
CH 61-66 120-80 1.4891 200-120 -1.4207 500-200
CH «67-72 120-60 144408 200-120 -164317 500-200
CH 73-78 120-60 1.4345 200-120 -1-4453 S00-200
CH «79-84 120-80 164277 200-120 -1.4556 500-200
cH «85-90 120-80 3.24351 200-120 -1-4@5 500-200

1973 FEB STA 90 PA 10%*4 AVG 5 DEPTH L3 DEPTH (SOUNDER) £0 SCAN 25
MEAN VALUE OF PROFILES GVER SM INTERVALS

CR 1-20 120-80 =.«6544 200-120 146677 500-200 +1194 at
CH £1-40 120-80 -1-4540 200-120 1.6052 500-260 «0292 10M
CH 41-60 120-80 -1.6804 200-120 144637 500-200 --0634 154
CH «61-80 180-80 -).4496 200-120 = 7% 40 500-200 --1611 20M

1973 FEB STA 92 PRE AMP 10*4 AVG 5 DEPTH 67 M@DEPTH 66M SCAN 100 M
MEAN VALUE OF PROFILES @VER SM INTEKVALS

CH 1- 5 120-80 1.0658 200-120 1.5550 500-200 --+ 6730 M
CH 6-10 120-60 2.0924 200-120 1.0485 500-200 -+ B16 10M
CH 11-15 120-80 28.6162 200-120 + 6486 500-200 --8944 15%
CH 16-20 120-60 44266 200-120 -1.0404 500-200 -1-00€9 20M
CH 21-25 120-80 5.4838 200-120 -1-.9 746 500-200 -1-1173 2m4
CH 26-30 220-80 567512 200-120 -2.1232 500-200 -1.2286 30M
CH 31-35 120-80 568356 200-120 -2.0902 500-200 -145405 3&4
CH 36-40 120-80 5.9163 200-120 -&.0524 500-200 =144528 40M
CH 41-45 120-80 5.9479 200-120 -1.9641 500-200 -1.5674 45M
CH 46-50 120-80 5.9550 200-120 -148513 S00-£U0 -1.6793 50M
CH 51-55 120-80 5.9536 200-120 -14 7304 500-200 -1. 22 SoM
CH 5660 120-80 Se9E11 200-120 -1. 6160 500-200 ~1.906 6OM
CH €1-65 120-S$0 5.9678 200-120 -1.5021 500-200 -2.0234 654
CH «66-70 120-80 569766 200-120 -1-39284 900-200 -2-13% 704
CH 71-75 120-80 5.9901 200-120 -1-28 60 500-200 -2-2525 72
CH 76-80 120-80 5.9998 200-120 -31461779 500-200 -2.3666 80M
CH «81-85 120-80 6.0088 200-120 -1-0712 500-200 -2-4801 8&4

143


RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development,

U.S. Environmental Protection Agency, have been grouped into
five series, These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:

Environmental Health Effects Research
Environmental Protection Technology
Ecological Research

. Environmental Monitoring

5. Socioeconomic Environmental Studies

Pon

This report has been assigned to the ECOLOGICAL RESEARCH STUDIES
series. This series describes research on the effects of pollution

on humans, plant and animal species, and materials. Problems are
assessed for their long- and short-term influences. Investigations
include formation, transport, and pathway studies to determine the
fate of pollutants and their effects. This work provides the technical
basis for setting standards to minimize undesirable changes in living
organisms in the aquatic, terrestrial and atmospheric environments.

EPA REVIEW NOTICE

This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.


19f2 NOV STATION 12 PA 10**4 AVG 5 DEPTH 27m SCAN 34M

ig72

igT2

MEAN VALUE OF PROFILES OVER SM INTERVALS

cH 1-15 120-80 209284 200-120 -.2057
CH =1€-30 120-80 ~-.0860 200-120 i beac
CH 31-45 120-60 -1.0826 200-120 2.4418
CH AG-60 120-80 -.4519 200-120 144596
CH 61-75 120-80 ~1.3085 200-120 +8104

500-200
500-200
500-200
500-200
$00-200

NOV STATION 14 PA 10##4 AVG 5 DEPTH 15M SCAN 19 M

MEAN VALUE OF PROFILES GVER 54 INTERVALS

CH 1-26 120-80 -.2593 200-120 «1621
CH 87-52 120-80 -. 6B 200-120 ~.2926
CH 53-78 120-680 -.3162 200-120 + 6333

NOV STATIGN 15 PA 10##4 AVG 5 DEPTH 102 M SCAN
MEAN VALUE OF PROFILES GVER SM INTERVALS

CH i- 3 120-80 =025) 200-120 --.2582
CH 4- 6 120-80 + 6095 200-120 -.9864
CH 1-9 120-80 11-0050 200-120 -1466701
CH «10-12 120-80 242499 200-120 ~3.0962
CH 13-15 120-80 2463311 200-120 -361674
CH 16-18 120-60 2.2227 200-120 -3-0844
CH 19-21 120-60 2.1322 200-120 -3-0011
CH 22-24 120-60 2.0160 200-120 -2.9185
CH 25-27 120-60 149191 200-120 -2+68695
CH = 26-30 120-80 149030 200-120 -2.7739
CH 31-33 120-50 1.9099 200-120 -&. 7247
CH «34-36 120-60 1-8906 200-120 -2+6521
CH = 37-39 120-80 168806 206-120 -2.5719
CH 40-42 120-80 1.6661 200-120 -2.4916
CH 43-45 120-80 1.8517 200-120 -264163
CH 46-48 120-80 148420 200-126 -243383
cH 49-51 120-80 1468315 200-160 -8462599
CH Se-54 120-60 1468223 200-120 -201773
CH 55-57 120-60 148069 200-120 -241050
CH 56-60 120-80 147968 200-120 -2-0371

113

500-200
500-200
500-200

150 M

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
s00-200
500-200
500-200

+057
© 2464
«4246
+600
+ 1% 62

723249
281287
20316

-.0411
198
23447
 SE94
TAS
+6967

1.0839

1.269

1.4573

1. 6442

1.8321

2.0196

2. 2039

2.3945

be SBT

2e 7643

229502

2120

3.3110

3- 49 48

at
10M
1M
20M
em

M
10M
to


29

Figure 18. column biomass (g dry wt/m?) during June 1973


1973 JUN STATION 7 DEPTH 23 M SWFEF 45 M
MEAN VALUE OF PRGFILFS OVEE 5M INTERVALS

CH 1-12 170-40 Onee 200-120 1.5001 500-200 0000

* 2 . - . Ed
CH 13-24 120-80 OL1e7 200-120 28.9902 500-200 +0000 10M
cH 25-36 120-80 0061 200-120 4.4763 500-200 -0000 1m
CH 37-48 120-80 +0908 200-120 5.9475 ‘500-260 +0000 com

1973 JUN STATION & DEPTH 75 M SWEEP 77 M

MEAN VALUE GF PROFILES OVE SM INTERVALS

CH l- 6 120-80 1.4686 200-120 -1.606h 500-200 +1467 ot
CH q-1e 120-60 f4259e 200-120 -2.5997 900-260 +3355 10M
CH 13-168 120-80 3.0620 200-120 =3. 2899 500-200 +5250 1
CH 19-84 120-806 3.6796 £00-120 -3.98601 500-200 «7164 €0M
CH 25-30 120-80 467051 200-120 -4. 6675 500-200 +9094 e254
TH 31-36 120-80 5. S224 200-120 - 5.3547 s00-200 141084 30M
CH 37-42 JVE0-80 64 335€ 200-120 - 6.0414 s00-200 1.2962 35%
CH 43-46 120-80 741514 200-120 - 6. 7287 800-200 1.4950 40M
CH 49-54 120-60 7.49677 200-120 - 7.41865 500-200 1.31 454
CH 55-60 120-86 8.7856 200-120 -&.1093 500-200 levee SOM
CH 61-66 160-80 9.6028 200-120 -6- 7996 500-200 2.09! Siw
CH 67-78 120-80 10.4195 200-160 -9.4914 SOU-£060 &429E5 60M
CH 73-76 120-80 1146377 200-120-10-1641 500-200 2.4942 ESM
CH 79-84 120-80 12.0472 200-120- 10.8679 s00-200 £662 70M
CH 65-90 120-80 12.8663 200- 120-11. 5620 500-200 26989 75M

1973 JUN STATION 10 DEPTH 117 M SWEEF 200 M
MEAN VALUE OF PROFILES OVER SM INTERVALS

CH 120-80 +0019 200-120 +1065 +1662 mM
CH 120-60 0083 200-120 © BLES +3773 10M
CH 120-60 200-120 +3207 500-200 «S71 14
CH 120-80 008 200-120 24077 500-200 +7353) OM
CH 120-80 o0z0 200-120 +5343 $00- 260 +9065 5
cH ~.0013 200-120 ©6344 800-200 14-0963 30M
cH 120-60 -.0024 200-120 £7643 500-200 1.2461 SSM
cH 120-40 -.0024 200-120 .89€0 S00- 144510 40M
CH 120-60 +0000 200-120 1.6164 500- 26€573° 454
CH 120-860 +0083 f00-120 1.14€4 S00-F00 146635 50M
cH 120-80 +0046 200-120 1.42509 500-£00 20706 Sm&4
CH £3-24 120-80 0092 200-120 143542 £623 C06
CH SRE 120-60 0124 200-120 144576 Ee 4s 56 COM
CH 87-88 20164 200-180 146517 500-200 &.€943 70M
CH £9-30 20200 200-126 1.7417 S00-200 £.90F4 7M
CH 31-32 2 OEAK 200-120 148388 560-200 361119 &OM
CH 33-34 +0298 200-120 1.9F86 500-800 363210 &&
CH 35-36 +0350 200-120 28.0169 3.5975 90M
CH 37-38 120-80 20597 200-12Q 2.1041 368049 9&M
CH «39-40 120-60 +0449 €00-120 241934 500-200 40119 100M
CH «41-42 120-80 20496 200-120 2.f618 S00-£00 4-£200 104
CH 43-44 120-80 6 053€ 200-120 &-3709 500-200 4.428 110M
CH 45-4€ 120-80 +0593 200-120 2.4604 500-200 4.6373 11%M

146


Table 16. GROWTH CHARACTERISTICS AND A GRAZING ESTIMATE FOR HYPOTHETICAL POPULATIONS
OF ZOOPLANKTON IN AN OLIGOLROPHIC VERSUS A MESOTROPHIC LAKE, ACTUAL
(PARENTHESES ) AND RELATIVE VALUES FOR FEEDING.

eh

Oligotrophic Mesotrophic
(L. Superior ) (L. Ontario)
Diaptomus Daphnia Bosmina |/Diaptomus Daphnia Bosmina
I. Organismic Characteristics
Feeding related q
Filtering rate (ml/en/aay) | (.42) (042), (415) (.42) (042) (35)
!} = 100 100 36 100 100 36
Ingestion rate with cell |
density (cells/an/day) | (1800) (400) (400) (5000) (1300) (1300)
I 100 22 22 100 26 26
Ingestion efficiency with
cell size (%) F = (016) (.065) (.065) (.010) (.065) (065)
ake 100 100 10 100 100
Growth related
Size at maturity (mm) (1.6) (0.7) (0.3) (1/1.6) (2/07) (1/0.3)
(reciprocal) ° fo) ° 19 2 100
(no predation)
Birth rate (byay) (.14) (.23) (.22) (.20) (.33) (.31)
70 100 aL 70 100 91
Organismic Subtotal 29u 322 re) 305 308 353
II. Rroduction and Grazing
Factors
Relative grazing per (6.21) (5.55) (1.98) (5.46) (18.45) (6.59)
individual 100 89 31 30 100 36
Relative net production (4.2) (10. ) (9.0) (1.6) (10.) (13.4)
in ten days an 100 90 12 Th 100
Production-Grazing Subtotal, on (4100) (8900) (2790) (373) (7400) (3600)
Relative Grezing 46 1.00 31 5 100 48
jtII. Adaptation value 481 611 YOL 3u6 (sr 537



(0 - 25 m tow) than nets fished in deeper, less productive waters
(0 - 100m). In any case, without such a device, it obviously is
impossible to predict the efficiency of a net at the moment it
encounters a layer of plankton.

Recommendations

Devices are currently available, such as high-frequency sonar,

which graphically delimit layers of zooplankton (see Part VI).
Combined with such graphic devices, a net equipped with the device
described herein is a logical companion, permitting precise estimates
of net efficiency at any level during a vertical tow.


AMZNOV STATION 52 PA 10#*4 AVE 5 DEPTH 65M SWEEP 77M
MEAN VALUE OF PROFILES OVER SM INTERVALS

CH

I- 6
Tele
13-18
19-84
25-30
31-36
37-428
A3- 46
49-54

120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-680
120-60
120-60
120-80
120-80
120-80

20951
«1902
+ 2849
63797
2 ATAe
= SEG9
© 6633
24465
20798
1.1490
21034
+ 7TZ06
036

200-120 1.43956
200-120 143932
200-120 «8149
200-120 -.0473
200-120 -.8396
200-120 -1- 6616
200-120
200-120
200-120 -3-4153
200-120 -3.3653
200-120 -46 85
200-120 - 5.2441
200-120 - 5+ 2349

500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-200
500-200

192 soy STATION 56 PA 10°*4 AVG 5 DEPTH 154 M SWEEP 200 M
MEAN VALUE GF PROFILES OVER 54 INTERVALS

CH
CH.
CH
CH
CH

CH
cE
CH
CH

2
=

QeVQgggeggegeageeeae2

1- 2
4
5 6
1- 8
9-10
vi-1e
13-14
15-16
17-18
19-20
21-22
23-84
25-26
27-28
29-30
31-32
33-34
35-36
37-38
39-40
Ain ae
43-44
45-46
AT~ 43
49-50
91-52
53-54
55-5
51-58
59-60

120-60
120-80
120-80
120-80
120-80
120-60
120*80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-86
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80

+0939
164171
261985
166340
1.6300
1. 6087
1.5879
1.5708
1.5245
1.5017
1.4753
1.4489
164180
163629
163589
163353
1.3048
1.2302
1.2529
1.2219
1618
1.1693
1.1906
161653
1.1476
1.0948
1.0678
1.0545
1.0160

©9767

200-120 2048
200-120 -1e404
200-120 -2.5869
200-180 -2.5169
200-120 -£.4452
200-120 -263709
200-120 -2e3101
200-120 -2.2492
200-120 -2.1775
200-120 -2.12833
200-120 -2.0672
200-120 -2-60093
200-120 -1.9496
200-120 -1-8825
200-180 -1.8273
200-120 -1. 7768
200-180 -1+7153
200-120 -1.6495
200-120 -1. 5858
200-120 1.5291
200-120 -144731
200-180 -1.4350
200-120 -1. 4488
200-120 -1.3957
200-120 -103467
200-120 -162837
200-120 -1.2339
200-120 -141755
200-120 -161256
200-120 -1.0552

122

S00- 200
500-200
500-200
500-200
500-00
500-200
500-200

500- 200-

500-200
500-200
500-260
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500- £00
$00-200
500- £00
500-200
500-200
500-200
500-200
500-200

-23514
28014
«0329
#1343
«2981
+4623
© 6243
Pile
°9570
1.1202
1.280
164498
166135

72235
+0152
350
+ 1043
1.0469
1639 &
1. 7409
2408 65
264315

€e 7733
361225

Be 446
308147
Ae 1586
464993
468424
S- 18 73
5. 5315
Se 8 736
6 E181
Ce SEB EB
669133
EDO
Te DBE
169423

8628 56
6.6321
8.9 760
963195
9+ 6630

MM
10M
1o%
20M
eM
30M
sot
40M
ASM
50m
Sot
604
6st

10M
1%
20M
Et
30M
34
404
454
SOM
5a
60M
om
70M
TM
60M
84
9014
oot
1004
1054
110M
11M
1204
1254
13014
ASeM
1404
1454
150M


1972 NOV STATION 63 PA 10#*4 AVG 5 DEPTH 120 M SUFEF 140 M
MEAN VALUE OF PRORILFS OVER Sad INTEAVALS

CH
CH
CH
cH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
cH
CH
CH
CH
CH
cH

1- 3

te &

In 9
10-12
13-15
16-16
19-21
€e- 84
25-27
26-30
31-33
34-36
37-39
AQ~ 42
Ag 45
4G> AB
49-51
Sé- 54
55-57
58-60
61-63
€4- 66
61-69
70-72

120-80
120-80
120-80
120-80
120-80
120-80

120-80
120-80
120-86
120-80
120-60

20-60
120-80
120-80
120-60
120-80
120-60
170-80
120-80
120-80
120-80
120-80
120-60

22449
+4570
237i
oe 4727
2 6TBE
BTEC
1.1005
2.3667
1.5700
1.7407
1.9580
2.1657
&e VSL
@.6025
be 16E
3.0210
3.8894
3. 453e
3. 6557
3.8 OBE
4e1133
43425
4.5583
Ae7723

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
€60- 160
200-120
200-120
€00- 120
200-120
200-120
£00-120
200-120
200-120
200-120

128

= +1820
723430
=e 51S
~ 2 7128
= 69139
-161670
-1651862
- 145398
-167721
-1.9694

264303
26603
2686940
+3164

-3.5532
~ 3+ 7709
- 3.9775
- 4.1828
=e 4133
~ 4s 6260
whe BHA
- 500272

S500- £00
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500~£00
500-200
506-200
500-200
500-260
500-206
500-200
500-200
500-200
506-200
500-200
500-200
500- £00
500+ £00
500-200

+08 SE
«lgod
#3110
°G4E5
+5760
+75
+8103
+9201
140273
121357
166413
163476
1.4543
1.5604
2. €6E8
1. 7657
1.8 G2
1.9730
260777
2-16 56
€.e906
203965
&- 5083
Be 6084

MM
10M
1st
20M
em
30M
Kev
40M
4c
50M
SSM
Ort
6a
70M
7M
BOM
6a
90M
OM
100M
105%
1104
114
120M


Utilizing al, as a’ weighted version of A » 4 second diversity index, qa,
can be torned in a way analogous to equation (11).

We now have four community measures. a depends on niche structures and
is essentially independent of population densities. 4d, on the other
hand, is a measure of population densities and does not depend on niche
structure. ‘Q! end a! ere both mixed measures, including information
on niche structure and population densities.

System Matrix

If we are interested in the dynamics of a community in a near equilibrim
state and particularly in its local stability, analysis of the system
matrix is required. To determine this matrix the system is linearized
around its equilibrium point. The linearized system is

m
. = “
ny = gett (a, - 45)s 1 = 1,2,- (12)
where the Os 5 are defined as
a i m
ii-se -
J on, t = (k, zo ot 9% JB, 3 | . (13)
4 gel na.
ia
The resultant value of re] is
P, fh,
ett, aoe (4)

The tid form the elements of A, the system matrix. A and dy are
related by a simple matrix transformation. If D isa diagonal matrix
(all zeros except along the main diagonal) and the diagonal elements
are d,, = - PiML , then A = DA.

ky

Equation (12) cen be re-written in matrix form as

A= A(n - 8) (15)

68


92

Figure 10. Density (no./m3) of Cyclops vernalis on 21 - 25 August 1972
in surfece weters (0 ~ 5m) of Lake Ontario at 60 stations
of IFYGL Biology Program


iste AUG STATION 34 DEPTH 85 M PA 10##4 AVG 5 DEPTH 150 M
MEAN VALUE OF PROFILES OVER

CH
CH
CH
CH
CH
CH
CH
CH
CH
CH

1972 pug STATION 35 DEPTH
VFAN VALUE @F PROFILES AUER

CH
CH
CH
CH
CH

1-16
17-32.
33-48
49> 64
65-80

120-60 -.1697
120-80 -.3403
120-60 «4103
120-80 ~-4469
120-80 ~04720
120-80 24968
120-60° -.5re9
120-80 -+ 5434
120-80 -.5719
120-80 ~. S948
120-60 -+ 6266
120-80 ~.6650
120-80 -.7031
120-60 -.7352
120-60 -. 7564
120-80 =-.7818
120-60 -.6093

160-66 CELE
120-60 1.0086
160-60 1.8079
120-86 146170
160-60 166077

€9 MELFRS
SM INTERVALS

SM INTERVALS

200-120 -=.3552
200-120 8320
200-120 -.0387
200-160 «1495
200-120 3239
200-120 +5007
200-120 + EO
200-120 +8689
200-120 2140500
200-120 1.28837
200-120 1.4017
200-126 145862
200-120 te 7659
200-120 1469466
200-120 2.162)
200-160 22995
200-120 24758
PRE 10##4

200-120
200-160
£00-166
200-120
200-120

1972 AUG STATION 36 DEPTH 30 METERS PREAMP
MEAN VALUE GF PROFILES SVER

CH

1-14
15-28
e942
A3~-56
57-70
71-84

120-80 -.1437
120-80 -.0319
120-80 -.3956
120-80 ~.8767
120-80 -1.0429
120-80 -.8993

Est

200~120
200-120
200-120
200~120
200-120
200~120

97

6437
1eE381
1.6278
4.3684
6. 1€8)

10%#4 AVE
INTERVALS

« 7650
162734
Be 2566
363557
4elll7
367747

500-200
500-£00
SG0-800
500-200
500-260
506-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500-200
500-200
900-200
500-200

ANF S LEFIH

500-200
506-200
500-200
900-200
00-200

55 DEPTH

500-200
500-200
500-200
500-200
500-200
500-200

6 SEE
=21735
60110
«065
+4085

35

721 GE)
+1898
+ 55282
«9815
162887
1. 6411

10M
tow
60M
eo

M
10M
1st
20M
eat
30M


Table 4. COMPARATIVE MEAN DENSITIES (#/m3) OF CRUSTACEAN ZOOPLANKTON
FROM 0 - 5 m DEPTH, CONTRASTING URBAN INSHORE VERSUS
OFFSHORE COMMUNITY COMPOSITION.

June 1972 duly 1972 August 1972
Big Big Big
Species Cities Offshore Cities Offshore Cities Offshore
Cladocerans
Leptodora kindtii + + + + + +
Bosmina coregoni L 31 82 389 402 1,453
Bosmina longirostris 179 288 7,060 13,206 174,580 63,691
Daphnia galeata - 22 108 3,07 1,873 99
Daphnia retrocurva 5 16 164 W9 6,028 11,965
Daphnia longiremis - - - 29h - -
Ceriodaphnia lacustris - T - 103. 2,399 4,203
Chydorus sphaericus - 16 - 640 30 100
Holopedium gibberun - - - 54 43, 7
Polyphemus pediculus - ° - + pas 7
Diaphanosoma - - - - - 3
Cyclopoida
Copepodites 1,160 323 816 2,201 27,58 29,143
Cyclops bicuspidatus 650 1,42h 17,555 12,478 4,158 12,113
Cyclops vernalis 76 28 43 190 1,012 643
Tropocyclops prasinus 25 11 11 66 1,874 1,676
Mesocyclops spp. - + - + + +
Calanoida
Copepodites 35 60 97 12h 203 116
Diaptomus minutus 67 225 23 91 39 Th
Diaptomus oregonensis 10 yen - 6 ok 108
Diaptomus sicilis 18 18h 17 ng 58 17
Limnocalanus macrurus 68 183 AT 139 2k 6
Eurytemora affinis 28 + - 11 60 117

33


Table 13. ACOUSTICAL REFLECTIVITY (D,C. vours/m3), ESTIMATED
COLUMN BIOMASS (g dry wt/m), COLUMN VopUME (m?)
AND BIOMASS PER UNIT VOLUME (g dry wt/m?) FOR ALL
STATIONS, LAKE ONTARIO, FEBRUARY 1973.

Total
€olumn
Biomass Volume (m3) Unit Volume
Acoustic Biomass (g ary wt/m?) depth m Biomass
Field St. (120-200-500) | (from regression) (xl m?) —g ary wt/md
1 5.07 69.27 30 2.31
3 57 8.39 20 whe
5 +20 3.39 95 -O4
8 °. 0. oO.
ws 1.62 15.21 10 1.52
15 5.43 96.06 100 -%
20 9.35 127.19 ib 8.47
2h 0. 0. lo
26 oO. 0. 0.
30 11.85 161.01 20 8.05
31 7.83 106.62 25 4.26
32 76.31 1,033.15 170 6.07
3h 12,22 166.01 85 1.95
35 “57 8.39 25 23h
42 10.02 136.25 15 9.08
dh 0. oO. 0.
46 10.05 136.65 210 1.13
48 9.21 125.29 25 5.01
60 1.81 25.16 10 2.51
62 50.22 680.15 165 412
6h 23.68 321.07 85 3.77
66 6.19 84.43 25 3.37
3 7-31 99.58 15 6.63
17 221 3.52 117 +03
DB oO. om 230 0.
78 4.16 56.96 50 1.13
19 82 11.77 20 59
83 11.74 159.52 95 1.68
85 O. 0. 0.
89 oO. oO oO.
90 16.52 22h.19 10 22.4
92 3.23 438 65 68
95 Oo QO. om
105 0. co Oo.
52
96.52
= 2,
ay

58


1973 STATION 83 FEB PA 10** 4 AVE 5 DEPTH 99 M DEPTH 96M SWEEP 130 M

MEAN VALUE OF PROFILES OVER 5M INTERVALS

Buy gegggggggoasge2g2ee92

PRA22Qgggegggggegggegaggg99R 899999999

In 3
4a- 6
T- 9
10-12
13-15
16-16
19-21
22-24
25-27
28-30
31-33
34-36
37-39
40-42
43-45,
46-48
49-51
5e-54
55-57

120-80

120-80

120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-50
120-80
120-80
120-60
120-80
120-20
120-60
120-80
120-80
120-80
120-80

+7863
1.1546
1.3321
163190
1.3024
162793
1.2572
162397
1.2218
1.1975
161851
161667
161580
1.1983
1.1770
161614
1.1442
161230
1.1025

760046
-.022)
-+0379
0504
-20702
- +089)
-21045
1240
14186
1544
1695
01828
21972
722126
ee B27T4
62415
28543
722670
722846
=23014
73142
~+3250
703451
=+3625
703749
-+3909
= +4033
24188
04346
24491
=e M647
~eATTE
“24912
25043
=e 5179
765343,
- 25485

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200120
200-120
200-120
200-120
200-120
200-120
200-120

aye

~ 3639
+2903
21645
+2255
+2902
+3573
+4256
+4897
+ 5549
+ 6244
+ 93
+ 1578
+8128
+8145
+8600
+9425
1.0062
1.0664
1.1501

-.0275
=20455
= +0602
~ 60752
- +0870
= +0998
well91
-21358
=21537
701735
-21937

500- 20u
500-200
500-200
500-200
500-200
500-200
500-200
500-200

=. 5240 a
25934 10M
=. 6616 1M
<2 7316 20M
“DN eoM
+6633 30M
--920 354

29933 40M

500-200 -1.0573 494
500-200 -141230 SOM
500-200 -1-1867 S&
500-200 -1.-247% 60M
500-200 -143096 6&4
500-200 -1-3724 70M
500-200 -164346 75M
500-200 -1-4963 60M
50C-200 -1-5577 654
500-200 -1- C804 90M
500-260 -1. 634 954

S00-200
500-200
500-200
500-200
S00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
S$00- 260
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-00
500-200
500-200
500-200
500-200
500-200
500-200

ATION &5 FEB PA 10%#4 AVE 5 DEPTH 188 M DEPTH 186M SWEEP 225 M
EAN VALUE OF PROFILES OVER SM INTERVALS

--0033 ul
-20100 10M
-20167 154
=.0202 20M
-.0226 em
-.0240 30M
-20243° 354
-.020 404
--0290 4M

-20314 SOM
~20319 SSM
--0292 60M
--0265 6
-.0263 70M
00246 754
--0235 80M
-.0228 6&1
-20221 90M
--0216 954
-.0207 100M
--0200 105%
-+0201 110%
20192 1154

~.017 120M
-20174 125M
“00159 130M
--0162 135M
=20154 140M
-20126 1454
-e01k3 150M
-e0114 15m4
-+0118 160M
00143 16
-<016S5 170M
00185 17M
~20161 180M
--0180 18m


Table 3. COMPARISON OF AREAS UNDER STRESS WITH OLIGOTROPHIC
AREAS ON BASIS OF RELATIVE DENSITIES OF DIAPTOMUS
SICILIS + MINUTUS AND BOSMINA LONGIROSTRIS (no./m3).

Density of Organisms at Maximum

Diaptomus Bosmina
sicilis + minutus longirostris

Areas under stress;

Metropolitan Toronto 100 200,000
Oswego Area 150 300,000
Mexico Bay 500 50,000
Popham's and Weller's Bays 500 50,000
312.5 150,000

MEAN Bosmina :Diaptonus ratio 48031

Oligotrophic Areas

Station 17 (mid-western) 1 ce)
Station 77 (mid-eastern) Tho 0
Station 83 (mid-eastern) al 3,000
255 1,000

MEAN Bosmina :Diaptomus ratio 3.921

29


Table 14 (continued), ACOUSTICAL REFLECTIVITY ney vouts/m3), =
COLUMN BIOMASS (g dry wt/m*), COLUMN You

AND BIOMASS PER UNIT VOLUME ue ary wt/m) ro aot
STATIONS, JUNE 1973.
Biomass Volume of Unit Volume
Acoustic Biomass mg dry wt depth Biomass
Field st. (120-200-500) (from regression) (x1 m°=m3) g dry wt/m?
97 2.80 38.57 15 2.57
77 7.84 106.76 121 88
5 9.76 2132.73 25 5.30
27.19
127.19
qe
mean = 3.02

61


1g72 AUG STATION 38 DEPTH 125 METERS AVE § PRE 10##4 DEFIH 145
MEAN VALUE OF PROFILES OVER 5S INTERULS

1972

CH

CH

AUG

QALQgeIgeIgeggggggggaggceggqgesgageeee

1- 3
a 6
I- 9
10-12
13-15
16-18
19-81
2b- 24
25-27
28-30
31-33
34-36
37-39
40-42
43-45
46~ 48
49-51
S@-54
SS= 57
5-60
61-63
GA- 6G
67-69
70-78
T3-75

120-80
120-80
120-80
120-60
120-60
120-80
126+80
120-80
120-80
120-80
120-80
120-60
120-60
126-80
120-80
120-80
120-80
120-80
120-80
120-40
120-6
120-80
120-80
120-80
120-60

STATION 40 DEPTH

120-80
120-86
120-80
120-80
120-80
120-80
120-60
12p-80
120-80
120-80
120-80
120-60
120-80
120-' 60

120-80

© 8018
721410
“21561

21971

33645

07728
120756
161440
1.2287
1e32le
1.3361
143089
1.3014
163204
163158
1.320€

3378

41,3202
1.4819
1.5665
1.5865
1.6064
1.6069
1.6178
1.6350

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
00-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-180
200-120
200-120
200-120
200-120
200-180
200-120

©2373
+8072
+5588
+32
+5391
2 ABR
+3730
+5520
+7029
BETS
1.0594
1.2224
164648
165682
167722
169516
2.1395
263525
2.4030
Ge S418
26 159%
269661
362215
36453 E
3-57

175 METEKS FRE 10 ##4 AVE
MEAN VALUE OF PROFILES OVER 54 INTERVALS

+2E74
+ 2E06
22664
22716
22779
42829
©2837
22651
«2847
+ 2888
2 29.46
- 2946
02931
+8863
«2910
© 28 ES
+2603
62729
«2672
32669
#2679
+2639
*2ell
+2610
+2627
+2609
2259
+2490
+2420
+2444
#2379
© B387
+2366
©2315
2270

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
€00- 120
£00-120
200-120

98

+ 6029
8427
1.0325
1.2035
1463541
164982
1. €472
1.7904
1.93€7
2.0998
262747
Be 4634
2.6535
ee64al
3.0400
3.2290
3.4249
3.6205
3.6189
4.0143
462120
44076
4.6087
4.963
49884
Se 1626
S398
50 S744
be 7725
509 643,
Ge 1636
63570
6. S526
e745)
6.9406

500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00-<G0
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
900-200
S60-200
500-200
500-260
500-200
500-400
500-200
500-200

DEFTH 250

500-200
500-200
500-200
500-200
500-200
500-200
$00-£00
500-200
500-200
500-€00
500-200
500-206
500-200
500-200
500-<00
500-200
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LV7ANGV STATION 46 PA 10##4 AVE 5 DEPTH 150 M DEPTH 200 M
MEAN VALUE OF PROFILES OVEX SM INTERVALS

CH ois 2 120-80 -.0263 200-120 -.5117 500-200
CH 3+ A 120-80 +2989 200-120 -141983 500-200
CH OS & 120-80 «3031 «© 200-120 -1.1829 500-200
CH o7- & 120-80 +3327 200-120 -.9278 500-200
CH 9-10 120-80 .3860 200-120 -.670 500-200
CH 11-12 120-80 4245 «200-120 -.4590 500-200
CH 13-14 120-60 64464 260-120 -- F248 500-200
CH 15-16 120-80 4743 200-120 -.0070 500-200
CH 17-18 120-60 5119 200-120 2043 500-200
CH 19-20 120-60 +5365 2P0-120 +4238 = 500-200
CH 21-22 120-80 «5691 200-180 «6263 500-200
CH 83424 120-80 6082 200-120- .8264 500-200
CH 25-26 120-80 46357 200-120 1.0392 00-200
CH 27-88 120-80 -€716 200-120 1.2770 500-200
CH 29-30 120-80 .€987 200-120 1.5282 500-200
cH 31-32 120-80 «7198 200-120 147870 500-200
CH 33-34 120-80 7333 200-120 20538 500-200
CH 35-36 120-80 «7560 200-120 2.3214 560-200
CH 37-38 120-60 £7793 200-120 2.6017 00-200
CH 39-40 120-80 +8136 200-120 2.8763 500-200
CH 41-42 120-80 «8322 200-120 3.1473 500-200
CH 43444 120-80 8488 200-120 3.4214 500-200
CH 45-46 120-80 «8639 200-120 360933 500-00
CH 47-48 120-80 +8889 = 200-120 369694 500-200
CH 49-50 120-80 «9304 200-120 4.2394 500-200
CH 51-52 120-80 «9684 «200-120 4.5132 500-200
CH 53-54 320-80 69924 200-120 4.722 500-200
CH 55-56 120-80 1.0241 200-120 5.0491 500-200
CH 57-86 120-80 1.0531 200-120 5.3236 500-200
CH 59-60 120-80 1.0832 200-120 5.5670 500-200

ISTAOV STATION 48 PA 10°*4 AVE 5 DEPTH 26 SWEEP 39 M
MEAN VALUE OF PEOFILES OVEK §4 INTERVALS
CH 1-13 120-80 -.0467 200-120 .5266 500-200
CH 14-26 120-80 -.0936 200-120 1.0524 500-200
CH 27-29 120-80 -.1411 200-120 1.5774 500-200
CH 40-52 120-80 -.1665 200-120 1.6722 00-200
CH 53-65 120-80 -.2362 200-120 1.4207 500-200

1 :

H2 soy STATION 49 PA 10944 AVE 5 DEPTH 30 4% SWEEF 40 M
MEAN VALUF GF PROFILES OVER SM INTHRVALS
CH I-12 120-80 -.8646 200-120. be -
CH 13-24 120-80 -1.7294 200-126 elines cooseoe
CH 25-36 120-60 -2.5943 €00-120 3.0383 500-200
CH 37-48 120-60 ~3.4593 © 200-120 364515 S0G-£00
CH 49-60 120-60 -463245 £00-120 3.2820 500-200
CH 61-72 120-60 ~5.18697 200-120 28.6471 500-200

120

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was not significant (p >.05) (Table 7). Thus the ratio of observed
to theoretical carrying capacity (n/K) does not confirm the other
evidence suggesting that dramatic changes are oceurring within water-
masses off larger cities along Lake Ontario's shores,

SIGNIFICANCE

Fewer species of crustacean zooplankters were found in urban inshore
areas of Lake Ontario than in adjacent inshore or offshore regions,
While the cladocerans Daphnia, Ceriodaphnia and Chydorus ere important

in rural inshore areas, they have given way to Bosmina longirostris
and Cyclops in urban inshore waters.

Ecologically it was significant that seasonal and geographical
differences in zooplankton distribution wherein the urban inshore
waters were presumed more eutrophic than offshore waters, paralleled
changes thet have occurred in the zooplankton communities of the
Great Lakes over much longer periods of time. These findings thus
suggest that in waters offshore of urban centers we find drifting,
planktonic communities which are highly modified, even though drifting
along shore rapidly at velocities of 10 km/day (Scott, 1973). The
causal effects of changes in zooplankton community composition off
large cities quite plausibly are included in the concepts of algal
resource availability, zooplankton selective feeding, and zooplankton
predator abundance. These mechanisms ere currently being investigated
in our laboratory.

Fron a management viewpoint, the indices of diversity and theoretical
community competition may be used to identify similar urban-influenced
watermasses. More importantly, such indices should be useful in the

conduct of surveys, especially as nutrient inputs to the Great Lakes
are reduced,

39


Poole, R. W. 1974. An Introduction to Quantitative Ecology.
McGraw Hill, New York. 532 pp.

Porter, K. 1973. Selective grazing and differential digestion of
algae by zooplankton. Nature 24:179-180.

Richman, 5. 1966. The effect of phytoplankton concentration on

the feeding rate of Diaptomus oregonensis. Verh. Internat.
Verein. Limnol. 16;392-398.

Robertson, A. A. 1966. The Distribution of calanoid copepods in the
Great Lakes. Univ. Michigan Great Lakes Res. Div. Publ. 15:129-139.

Roth, J. C. and J. A. Stewart. 1973. WNearshore zooplankton of
southeastern Lake Michigan, 1972. Proc. 16th Conf. Great Lakes
Res. 1973, 132-142,

Schelske, C. L., L. E. Feldt, M. A. Santiago and E. F. Stoermer, 1972.
Nutrient enrichment and its effects on phytoplankton production
and species composition in Lake Superior, Proc. 15th Conf.

Great Lakes Res. 1972, 149-165.

Schoener, T. W. 1974. Some methods for calculating competition
coefficients from resource-utilization spectra. The American
Naturalist 108

Sokal, R. R. and F. J. Rohlf, 1969, Biometry; The Principles and
Practice of Statistics in Biological Research. W. H. Freeman
and Co,, San Frencisco, 776 pp.

Stoermer, E, F. 1973. Analysis of phytoplankton composition and
abundance during IFYGL. Corvallis; U.S, Envir. Prot. Agency,
EPA 66013-73 021. pp. 89-109.

Vendermeer, J. H. 1972a. “On the covariance of the community matrix,"
Ecology Vol. 53, No. 1, pp. 187-189.

Vandermeer, J. He 19726. (Miche Theory. In; Annual Review of
Systematics and Ecology 1972, Palo Alto, pp. 107-130.

Volterra, V. 1926. Variations and fluctuations of the number of
individuals of animal species living together. In: Animal
Ecology (ik. N. Chapman, ed.) MeGraw Hill, New York. pp 409-448.

Watson, N. He 1974. Seasonal abundance of crustacean zooplenkton
and net plankton biomass of Lakes Huron, Erie and Ontario.
J. Fish. Bd. Can. 31;309-317.

Wells, L. 1960. Seasonel abundance and vertical movements of planktonic

erustacea in Leke Michigan. U.S. Fish and Wild. Serv., Fish.
Bull. 60;343-369.

81


Mathematical techniques have been developed to model zooplankton
communities, using new application of the community matrix. Eventual

uses will include the development of simple mathematical indices
for perturbed communities.


CONTENTS

Sections

I Conclusions and Recanmendations

It Introduction

Tit Methods

Iv Analysis of Zooplankton Populations

v Effects of Urban Centers on Zooplankton Biomass

VI Acoustical Estimates of Zooplankton Biomass

VII Comparative Mathematics Analysis of Zooplankton
Communities

VIII A Hypothesis on Calanoid Succession to Cladocerans
During Eutrophication

x References

x Appendices

aii

oul

10
30
ho
64

71

18
83


1973 FEB STA 95 PA 10##4 AVG 5 DEPTH 18 M DEPTH 25 M SCAN 30 M
MEAN VALUE OF PROFILES GVER SM INTERVALS

cH 1-16 120-80 «1014 200-120 -+.7959 s00-200 -- 5320 Ei
CH 17-32 120-80 «2023 200-120 -144956 500-200 --8000 10M
CH 33-48 120-80 #3033 200-120 -1-4673 500-200 -.7@8 154
CH 49-64 120-80 +4044 200-120 29192 500-200 -. 7344 20M
CH 65-80 120-80 +5053 200-120 =-.3733 500-200 --688 254

1973 FEB STA 105 PA 10®*4 AVG 5 DEPTH26 ] DEPTH 18 SWEEP 30

MEAN VALUE OF PROFILES OVER 5M INTERVALS

CH 1-20 120-80 1.1257 200-120 -- 7816 500-200 --0717 4
CH 21-40 120-80 29819 200-120 -1.6272 800-200 ~.0661 10M
CH 41-60 120-80 98454 200-120 -2.1278 500-200 --0630 1&4

Uhh


9€

Table 5b, INSHORE (LESS BIG CITIES) COMMUNITY STRUCTURE.

Community
Competition
Date pepe Soetiaceen Theor eas aa TCT 5 Seeeiee s| z Diversity —

lgT2
15-19 May 495 461.12 5,239.09 wy 5 1.47 4.83 1.28
12-16 June 2,288 330022 40,863.06 19 7 2.43 5.36 1.90
10-14 July 20,299 331 09 213,957.09 18 8 2.73 3.95 2.18
21-25 August 251,259 239-610: J1,303,347 9.19 Th al 9 2.92 3.70 2.21
30 Oct.-3 Nov. | 40,061 Oh 413 583,453.12 48 20 15 2.40 4,13 1.85
27 Nov.-3 Dec. | 13,833 46 415 179,9%8  .08 1.00 21 9 2.94 4.83 2.23
1973
5-9 Feb. 2,602 60 .12 35,364  .07 oh I ob 2.33 4.09 0.86
19-22 Mer. 1,830 | .52  .13 28,179 .07 88 18 8 2.17 5.83 1.73
24-28 April yjiak | 360 03 44,203.09 46 19 2B 2.43 4.97 1.9
12-16 June 26,132 | .35  .10 405,847 06 -B 19 8 2.575 4.08 2.0
MEAN 40,270 43 315,082 = 413 2.55 4.55 1.87
(sune 72-June 73)



1973 JUN STATION 89 DEPTH 72 M SWEEP 80 M.
MEAN VALUE OF PROFILES OVER SM INTERVAL S,,

CH le € 120-80 -.0724 200-120 +1673 500-200 +000)

CH Tle 120-80 1.1972 €00-120 -1.0258 500-200 Spoon los
CH 13-38 120-80 1.46808 200-120 -1. 6540 500-200 -0000 1M
CH «19-24 120-80 2.1632 200-120 -1.8865 500-200 «0005 20M
CH 85-30 120-60 2.2313 200-120 ~ 1.8886 500-200 +0000 294
CH 31-36 120-60 2.2476 200-120 -1.8376 506-200 +0000 SOM
CH 37-42 120-80 262577 200-180 -1.7774 500-206 20000 3m
CH 43-48 220-80 2.2718 200-120 -1. 7228 500-200 *0G00 40%
CH 49-54 120-80 2.2849 200-120 ~1. 6646 500- £00 -0C00 4a4
CH 55-60 120-60 2.2984 200-120 -1. 6084 500- £00 +0000 50M
CH 61-€6 120-80 83108 200-120 -1. 5486 500-206 -c000 «5m
CHE 67-72 120-60 2862220 200-120 -1.4633 500-200 »00CO 60M
CH «73-768 126-60 2.3358 200-166 -1,4191 S0G- £00 -ocog GM
CH 79-84 120-80 263474 200-120 -1.3588 506-200 +0000 70M

1973 JUN STATION 90 DEPTH 16M SWEEP 25 M
MEAN VALUE OF PHOFILES VER SM INTERVALS

cH 1-8) 120-80 -24795 200-120 20017 500-2600 +0000 MM
CH = be-42 120-80 -.7790 200-120 -.1091 500-200 +0000 10M
CH 43-63 180-60 -1.0059 200-120 -.2038 500-200 0000 1s

1973 YUN STATION 92 DEFIH 65 M SkERF ITO M
MEAN VALUE OF PRORILES OVFR 5M INTERVALS

CH 1- 4 120-60 +7034 200-120 1.0918 500-200 -.36€55 cv
CH S- 8 1£0-80 +9638 200-120 1.33286 500-200 -.1512 10m
CH 9-1k 120-80 3.0260 200-120 144306 S00- 200 20CES 1
CH 13-16 120-80 160235 200-120 1.49028 500-200 22781 20M
CH 17-20 120-80 1.0227 200-120 1.5461 500-200 +4936 ESM
CH 21-24 120-80 140241 200-120 1.6044 500-200 + 71@3 30M
CH 25-26 120-80 1.0266 200-120 1. 65€€ $00-£60 19682 3K
CH @-32 120-80 1.0899 200-120 1.7094 500-660 266661 40M
CH 33-36 120-60 140353 200-120 147614 900-£00 164778 aM
CH 37-40 120-60 140383 200-120 14-6136 500-200 1.7377 50M
CH 41-44 120-80 140398 €00-120 1.6697 500-200 1.9984 SoM
CH A548 120-40 1.0420 200-120 19215 500-200 eB S08 OM
CH 4-52 120-80 1.04€6 200-160 169781 500-260 & SefeR CoM
CH = 53-5Eé 120-80 1.0501 200-120 & 0212 500-200 2. B53 70M
CH 57-€0 120-80 200-120 2.0711 500-200 3.0467 7
CH 61-64 120-80 200-120 2.1202 500-600 343124 60M
CH 6S" 68 120-60 200-120 241705 500-200 3.5740 6M

155


and Pix is the proportion of the species utilizing the kth environment,
then _

x Pik (7)

is a measure of niche breadth (Levins, 198). For a two dimensional
niche such as is used in this study the relationship becomes

rE Pie (8)
Q

If the two dimensions are independent equation (8) can be written

1

ros
Ly (2) 2 (9)
Le

Properties of whole communities can be measured as well. Levins (1968)
suggested the average “ as & measure of niche separation in the community.
This parameter,

o, (10)

is a measure of,average species_co-occurrence in Levins’ originel
formuletion. @, analogous to o, is a community measure of competition
in the present formulation,

Diversity is another example of a community property_and is often
measured by the Shannon-Weaver information measure, d, community diver-
sity, is defined as

ac .
a4-1 im J (12)
ja Bon

67


@ rapid response to resource explosion. Our species have been calibrated
using field data for Daphnia galeata (Hall, 1964) and Diaptomus and
Bosmina longirostris McNaught, unpublished), The significantly lower
maximum birth rate for Diaptomus (Table16) will likely become a limiting
factor under eutrophic conditions,

Once the organismic factors had been described (Table 16, Section I),
we proceed to give them relative values. However, it must be noted that
individual feeding and growth factors have not been weighted. In
nature some are certainly more importent than others. In many cases,
specific values for high or low foods were available. Potentially
adaptive characteristics have been summarized (Table 16) by actual and
relative value.

POPULATION GROWTH AND GRAZING

Determination of relative population growth and grazing in Lake Superior
served as the calibration for our oligotrophic lake. During August
three species of Cyclotella constituted 16h by density of the phyto-
plankton (Schelske, et al. 1972) and ranged in size fron 2.51 to lu

in diameter. The remaining algae were predominantly flagellates. Thus
the bulk of the phytoplankton was less than 154 and fell in the 1 - 2m
category (Stoermer,1973) while cell densities ranged fran 350 - 1500
cells/ml.

Lake Ontario is the mesotrophic example. In August, the time of maximm
phytoplankton standing crop, the plankton is evenly composed of chloro-
phytes (38%), cyanophytes (34%), cryptomonads (12%), dinoflagellates (12%)
and chrysomonads (4%) (ifunawar and Nauwerck, 1971). These forms ranged
in size from 2 - 1371 in diameter, with almost all between 2 - 65, ,

and the largest sub group of these between 2 - 22)

To determine grazing, on an individual basis for each species, we have
simply multiplied filtering rate (F) times the efficiencies for
ingestion with size (E,), times the ingestion rate (I) times the
standing crop of phytoplankton (Np), for Lake Superior within the 1 - 22y
size category (925 cells/ml) and Por Ontario (Stoermer, 1973) within

the 1 - 22u (1300 cells/ml) and 22 - 65u (1300 cells/ml) categories.
This calibration suggests more Bosmina when netplankton is abundant,

as Hrbé&ek et @l. (1961) have observed. Thus relative grazing (G)

is denoted;

G@=F+l Boh, (21)

To determine net production, we used the exponential growth equation:
= t

Ny = wer (22)

where N, = number at time t, Ny = number at the onset, and r = the
intrinste growth rate. Furthermore;

r=b-d

16


EPA=660/3=75=021
JUNE 1975

Ecological Research Series



1972 AUG STATION 5@ DEPTH 100 DEPTH 65 PA 1074 AVE 5
MEAN VALUE GF PROFILES OVFK SM INTER VAL'S

cH i- 5 120-30 ©0939 200-120 =.2483 500-200 -.0%7 a
CH 6-10 120-80 + 6248 200-120 -49743 500-200 +0898 10M
CH 41-15 120-60 «2512 200-120 -1-0091 500-200 +2550 1S
CH 1620 120-80 -.4655 200-120 -e9671 500-200 +4225 20M
CH «21-285 120-80 ~1.0870 200-120-9341 500-200 «61430 Em
CH 26-30 120-80 ~1-0877 200-120 -.8 664 500-200 +8507 301
CH 31-35 120-80, -2.2190 200-120 --8103 500-200 160517 354
CH 36-40 120-80 ~2.9990 200-120 ~-.7717 SG0-200 1.266 40M
CH 41-45 120-80 -3. 4892 200-120 ~.6 7367 500-200 1.4920 45%
CH 4650 120-60 -3.7771 200-160 ~~. 6996 500-200 147139 SOM
CH 51-55 120-80 -3.9503 200-120 -.6492 506-200 169361 SS4
CH 5é 60 120-80 -4.0104 200-120 -.5935 500-200 1616 60M
CH 61-65 120-60 -4.030i 200-120-4526 500-200 263849 654

agra AUG STATION 54 DEPTH 180 DEPTH 139 PA 10/4 AVEES
MEAN VALUE OF PROFILES OVEK Sa INTERVALS

CH 1- 2 120-60 ©2321 200-120 1.907% 500-200 -.9021 at
CH 3-4 120-80 eBTAT 200-120 22473 500-200 =. 7665 10M
CH 5- 6 120-80 +2934 200-120 243455 SOG-200 ~-e6143° ISM
CH T- & 120-80 ©3128 200-160 264114 500-200 -.4@3 204
CH 9-10 120-80 #3306 200-120 24708 500-200 -.3161 254
CH flele 120-60 +3449 200-120 &.se7e 500-200 -.+1676 30M
CH 13-14 120-80 +3609 200-120 25853 500-200 -.0151 354
CH 15-16 120-89 03727 200-120 2. 6462 500-200 +133 40M
CH 17-18 120-80 © 38.39 200-120 &- 7062 500-€00 +2867 454
CH 19-20 120-80 + SIE 200-120 2.7565 500-200 +4425 SOM
CH 21-22 120-80 +4097 200-120 266096 500-200 661 SoM
CH 23-84 120-80 +4240 200-120 28598 500-200 » 7403 60M
CH 25-26 120-80 «A347 200-120 29121 500-200 897 6m
CH 287-28 120-80 24469 200-120 269621 s00-200 140537 70M
CH 29-30 120-80 24582 200-120 3.0126 500-200 322116 754
CH 31-32 120-80 0 AI17 200-120 340630 500-200 1.3649 80M
CH 33-34 120-80 +4833 200-120 361143 $00-260 1.5879 8ot
CH 35-36 120-60 +4950 200-120 361674 500-200 1.676 90M
CH 37-38 120-80 +5054 200-120 3.2159 500-200 1.8497 9S
CH 39-40 120-80 +5170 200-120 32646 500-200 20171 100%
CH 41-42 120-60 +5256 200-120 3.63195 500-200 2.1842 1050
CH 43-44 120-80 +5353 200-120 3.3728 500-200 2.3464 110M
CH 45-46 120-80 + S459 200-120 3.4204 500-200 2.5203 1154
CH AT- 48 120-80 +5560 200-120 344702 500-200 2 644 120M
CH 49-50 120-80 5619 200-120 35206 500-200 26508 1254
CH 51-52 120-80 ©5716 200-120 3.5691 500-200 3.0208 130M
CH 53-54 120-80 +5810 200-120 3-6171 500-200 3.61683 135M

1972 AUG STATION 59 DEPTH 35 DEPTH 26 80 KC PALO // 4 AVE 5
MEAN VALUE OF PROFILES OVER SM INTEKVALS

CH 1-14 120-80 1462366 200-120 -1.1462 500-200 102 ot
CH 15-26 120-60 2.2606 200-120 -2-1760 500-200 23616 10M
CH 29-42 120-80 3.0619 200-120 -3.0922 500-200 +5583 1a
CH 43-56 120-60 3.5004 200-120 -3. S886 900-200 74% 20M
CH = =57-70 120-80 3.6884 200-120 -3- 7448 500-200 1.1%9 2M

102


1972

ig

NOV STATION 71 PA 10#*4 AVG 5 DEPTH 204M SWEEF 240 M
MEAN VALUE OF PROFILES OVER SM INTERVALS

RALLLLIAILRL

22222

CH
CH

CH

CH

QALKLARAGLIARVLAee

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200-1280
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260-120
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200-320
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200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
£00- 126
£60-120
£00- 126
200-120
200-120
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24444
+5052
+5655
+ 6346
+ 7028
+7700
18344
+6955
+9573
1.0138
leu7al
141332
1.1912
1.2460
163063
163677
144331
164957
165484
1.6111

NOV STATION 72 PA 10®*#4 AVE 5 DEPTH 31M SWEEP

MEAN VALUE OF FROFILES OVER SM INTERVALS

CH
CH
CH
CH
CH
CH

1-13
14-26
27-39
40-52
83-65
66-78

120-80
120-60
120-80
120-80
120-60
120-80

+6960
21918
©2675
-.2095
02941
= +4870

200-120
200-320

= 4659
=09813

200-120 - 1.4382
200-120 -&+0314
E00-120 - Ee 7568
200-120 - 344899

125

500-200
500-£00
$00- 200
500-200
500-200
500-200
506-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
s00- 200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
506-200
500- £00
500-200
500-200
500-200
500-200
500-200
500-200
500-200
506-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500- £00

M

500-200
500-200
500-200
500-200
500-200
500-200

+0989
+1909
68645
©5817
e A776
«5737
+603
© 1677
+8 753
+9 7118
1.003
16163
162676
1.3635
1.4624
1+ 5608
1. €610
1, 7613
1.8605
169 568
200575
ee1564
26 E548
63533,
Be A854
2. 5604
eo CERT
+ 7634
B08 CAT
209 CAE
320672
3-1 704
3.2730
3.3770
3. 4613
3. 5835
3. ES
Be BIA
3.8942
369949

72 G6ES
+0548
21S
+8688
«3646
+4735

5M
10m
1a
20m
2M
30M
35M
40%
454
50M
Sot
OM
65H
70M
734
om
Bs
90M
954
1004
1054
11034
1184
120M
1254
1304
13.54
14g
1484
180%
1554
1 60%
1654
170%
175%
1g 0M
16 54
190%
19 5%
2004

10M
1s
20m
5M
30M


21973. gun STATION 77 DEPTH 121 M SWEEP 80 M
MEAN VALUE OF PKOFILES OVEK SM INTERVALS

1973

QAQAgeggggeeegeee

1- 6
7-12
13-16
19-24
25-30
31-36
37-42
A3- 46
49-54
55-€0
G1- EG
€1-72
73-78
719-64
85-90

9149

120-80 €439
120-80 571
120-80 -1.0026
120-80 ~1-0083
120-60 ~1.0053
120-80 -1.0054
120-80 ~1-0054
120-60 ~1.0082
120-80 ~1-0695
120-80 -1-0114
120-60 ~1-0108
120-60 ~1.0112
120-60 -1-0106
120-60 -3.0187
120-60 -3.0131
120-80 1.20139

200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-1260
200-126.
200-120
200-120
200-120
200-120
200-120
200-120
200-120

JUN STATI@N 78 DEPTH 56 M SWEEP 65 4
MEAN VALUE GF PR@FILES OVER 5M INTEKVALS

QeaegQegegaeee

CH
CH
CH
cH

1- 7
B14
15-21
22» 26
29-35
36-42
43-49
50-56
57-63
64-70
TW1-77

120-80 ~.6326
120-80 -.9786
120-80 -1.1685
120-80 -1-1920
120-80 -1.1907
120-80 -1.1862
120-80 -1.1737
180-60 -1-1643
129-80 -1.1654
120-60 -161737
120-8D -1-1743

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

STATION 79 DEPTH 21 M SWEEF 25M

N VALUE OF PROFILES OVFA SM INTEEVALS

1-21
22-42
43- €3
64-84

120-80 --9098
120-60 -2.0332
120-60 -3.1336
120-80 -401114

200-120
200-120

renee

20010
+0701
01374
22051
«2705
+3340
+4007
+4655
+ SE9€
927
+ 6562
+7219
+ 761
+8495
«9141
29791

2973
22996
+2393
2 16EE
0888
20153
20493
21173
21978
*FB15
23599

22965
2118

200-120 -1-24€0
200-120 71-8193

153

500-200
500-200
500-200
S60-200
500-200
500-260
500-200
500-200
500-206
500-200
500-200
500-200
500-200
500-00
500-200
500-200

500-200
500-200
500-200
$00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-200
500-200

+0000
+0000
«0000
«0000
+0000
+6000
+0060
+0060
+0000
+0000
+0060
+6000
20000
+0000
+0000
©0000

+0000
+0000
+0600
+0000
+0000
0000
+0000
+0000
«0000
«0000
+0000

+1360
22917
47)
2 6042

Rvs
10M
i”
20M
eo
30M
am
40M
AR
SoM

com
esa
70M
7”
60M

10M
15
20M
em
30M
3m
40M
4a
Som
SM

10M
1
20M


ABSTRACT

The Crustacean zooplankton are excellent indicators of environmental
perturbation, especially if enough of their biology is known to explain
why certain species increase with nutrient enrichment of lakes. The dis-
tribution of zooplankton in Lake Ontario suggested that eutrophic indi-
cators were found in the vicinity of major urban centers. The ratio of
the number of Bosmina longirostris, the most successful eutrophic species,
to Diaptomus sicilis, the most oligotrophic form, supported this con-
clusion. Furthermore, mathematical indices, including diversity, the
community competition coefficient, and carrying capacity, separated urban
inshore from rural inshore waters, further evidence of perturbation.
Biomass estimates made with new acoustical techniques indicated that most
of the zooplankton biomass was in deep waters, thus the eutrophication
of Ontario's waters, both nearshore and in the vicinity of cities, is
still localized in nature. Mathematical techniques have been developed
to model such perturbations.

The report was submitted in fulfillment of an EPA project, Grant No.
800536, by the State University of New York at Albany under the sponsor-

ship of the Environmental Protection Agency. Work was completed as of
15 August 1974.

di


1gj2 AUG STATION 60 DEPTH 12 TM Fa 10##4 AVG 5 DEPTH 25
MEAN VALUE OF PROFILES OVEK 5M INTERVALS

cH 12d
CH 25-48

1972 AUG STATION 62 DEPTH 169 METERS PREAMP 104 AVE

120-80 60992
120-80 1.0234

200-120
200-120

©5455
1.0463

MEAN VALUE OF PRGFILES OVEh SM INTERVALS

CH 1- 2
CH 3-4
CH 5 6
CH I 8
CH 9-10
CH 11-12
CH 13-14
CH «15-16
CH 17-18
CH 19-20
CH 21-22
CH eS-84
CH 25-26
CH 287-28
CH 29-30
CH 31-32
CH «33-34
CH 35-36
CH 37-38
CH 39-40
CH 41-42
CH 43-44
CH 45-46
CH 47-48
CH 49-50
CH 51-52
CH 53-54
CH 55-56
CH 57-58
CH 59-60
CH 61-62
CH 63-64
CH 65-66

1972 puG STATION 64 DEPTH 85 METERS
MEAN VALUE $F PROFILES OVER St

120-80 -.1066
120-80 =.1391
120-60 -.1622
120-80
10-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80 -.4095
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-0
120-80
120-80 -.8423
120-80 -.8794
120-80
120-80
120-80
120-80
120-80

¥20-80 -.8392
120-60 -.2752
180-80 143822
120-80 -166832
120-80 -1.8047
120-80 - 2.0649
120-80 -2. 2208
120-80 = 22619
120-80 -2-2746
120-80 +2.2744
120-80 -2.2767
120-86 -£6 2631
120-80 = 262671

120-80 -
120-80 -2.3373

200-120
200-120
200-120
200-120
200-120
260-120
200-120
200-120
200-180
00-320
200-120
200-120
200-120
266-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

1.000
1.0354
1.008
1.1064
1.14284
1.1626
1.220
1.2662
143033
1.3392
163754
1.4129

500-20C
500-200

S DEFTH

500-200
500-200
500-200
500- £00
500-260
506-200
500-200
500-200
500-200
50U- 200
500-200
500-200
500-200
500- £00
506-200
500-200
500- £00
500-200
560-606
506-200
S0G- 206
S00- 200
500-200
500-260
500-200
500-200
500-200
506-200
500-200
500-200
500-200
506-200
$00- 200

~ +3620
08651

210

elei

1.5614
1. 6754
1. DOS
1.9062
e014
2. 1308
2.e4e4
2. 3531
Be 4601
€. S724
e. Wes
be BAS
Be9CED
3.0101
3+1206
3.2292
363377
3. 4473
3.5582
3. E640
3-6 7704

PREA 10*#4 AVE 5 DEPTH 125

INTERVALS
200-120 +4728
200-120 -.3633
200-120 - +5458
200-120 ~+8314
200-120 -1+0135
200-120 -1.0911
200-120 -1.1473
200-120 - 141559
200-120 141409
200-120 1.0975
£00-120 -1-60655
200-120 - 140352
200-120 ~beO1E9
200-120 ~.9 GO
200-120 -.9203
200-120 - +8853
200-120 ~ 644%

103

500-200
500-200
5G0- 200
560-200
500-200
560-200
506-200
500-200
$00- 200
500-200
500-200
500-2600
560-200
Ss00- 200
500-200
500-200
500-200

22732
» ele
+9 708
1.3171
1. 6566
1.99 62
2633565
2. 10
3+ 0189
3.356}
3.34
4.0313
Ae 31
4. 75!
50427
S319
Se 718 6

oM
104

1004
10 £94
210M
1154
120M
1204
130M
134
140M
145M
150M
1ss4
160%
1650

M
10”
1s4
20m
eae
30”
3M
40M
4a
50M
Sot

60M
eat
70M
Tat
8oM
oot


he

Figure 8. Density (no./m3) of Cyclopoid copepodites on 21 - 25 August
1972 in surface waters (0 - 5 m) of Lake Onterio at 60 stations
of IFYGL Biology Program


SECTION X

APPENDIX A

TABLES OF MEAN ZOOPLANKTON
DENSITY BY SPECIES,
DATE AND DEPTH OF WATER
SAMPLED

83


SECTION IX
REFERENCES

78


PERFORMANCE OF ZOOPLANKTON NETS

Introduction

Our purpose was to design a meter to measure the efficiency of a
plankton net in a continuous fashion. Vertical net-hauls remain a
principal tool of many limnological investigators. In making such
hauls the nets encounter successive water layers containing varying
densities of organisms, With such encounters, a net becomes progres-
sively more clogged, Thus a simple measure of total flow tells
little, for the net could have an efficiency of 15 to 70% when a
distinct layer is encountered, But a continuous measure will enable
an investigator to tell precisely the efficiency at any point in the
water column.

These measures of efficiency which we have made will be of considerable
use. They suggest that standing crops of zooplankton in Lake Ontario
are 2 - 5 times larger than previously anticipated.

Construction and Operation

Two plastic rotor assemblies (Fig. 1), consists of a propeller 10cm
in length mounted upon a shaft, with a magnet mounted off-axis at
the opposite end. Each time the shaft rotates, a magnetic switch
is closed, thereby applying a signal to a magnetic tape recorder,

One rotor assembly was mounted 7.5 cm below the rim of a 3/4 m dia.
net and 17 cm from the rim. The other rotor was mounted 15 cm
outside the rim. The electronics were mounted in a sealed pipe 12 cm
in diameter, which served also as a weight. It was easily sealed

to withstand pressures to 150 m.

The electronics consisted of two free-running multi-vibrators operating
at widely different frequencies, The magnetic switch, closing at a
rate of once per revolution, is registered on a magnetic tape, The
information was stored on the magnetic tape. It was made by
transcribing the tape slowly (1/15 original) into a recording potentio-
meter. One may visibly separate the two frequencies and thus count
the number of times the magnetic switches closed.

Results of field-trial

A 3/4 m dia. net with mesh aperture of 64y was calibrated on Lake
Ontario. The net was lowered to 25, 50 and 100 m and raised to the
normal speed (slow) of a B,T. winch.

The results (Fig. 2) show a curvilinear decrease in filtering
efficiency. Whether the net was lowered to 25 or 100 m depth,
initially the efficiency was 65 - 70%. In each case the efficiency
had dropped to 15 ~ 30 % by the time it reached the surface. Nets
fished only in the trophogenic zone showed a steeper rate of deerease


9g =
TMm °
€
> 8h
2
wo °
3 °
— 7
°
D ° °
= 6b ° °
y °
fa} °
~ Sr
KR
+ °
w
oe 4
a
Cc
5 aL °
no}
o
8B
= aL Y= 0.68I + 13.53 X
[o}
° ° r= 80

1

io fe} °
oo fo
ol * ee 1 ! L \ !
e) A] 2 3 4 5 6
Acoustical reflectivity (D.C. Volts) /m?

Figure 14,

Regression of zooplankton biomass (g dry wt /m3 ) against
acoustical reflectivity (D.C. volts/m3), made from actual
samples and acoustical profiles collected simulteneously
on Lake Onterio

48


SECTION X
APPENDIX B

ACOUSTICAL DATA BY STATION
AND CRUISE FOR EACH

5 m DEPTH INTERVAL

90


The solution for n - A, valid only near A, is of the form

m ae
= ae 16
= Gs)

Ip
1
Ip>

=
ks
Where the m values \k, known as the eigenvalues of the system matrix Ay
are the roots of the equation

larz|= 0. (17)

I is the identity matrix and |A-Az|is the determinant of A-\I.

The stability of the equilibrium depends on the eigenvalues. If any
has a positive real part the equilibrium is unstable. Thus, if we
designate by on the eigenvalue with the largest real part, d seems
a good measure? community stability (May, 1973). We shall régirn to

this point later.

The Competition Coefficient

Basic to both the competition matrix and the system matrix is the
competition coefficient. Levins (1968) initially used as an approxima-
tion to competition the probability of co-occurrence, essentially a
niche overlap model of competition. Levins (Lane, 1971) and others
(MacArthur, 1972; May, 1973; Schoener, 1974; Vandermeer, 1972b) have
discussed other forms of niche overlap models. This study will utilize
a vather simple form.

Assume initially a one dimensional resource spectrum, Ri Bos R » where
Ry is the equilibrium density (or standing crop) of the kth resdurce
group. Let $., be the rate per unit density at which species i utilizes
resource k. ien P Ry 4.

z ik

kel
represents the resources utilized by species i at equilibriun. oo can
be expressed as sjp., where 5 Pie =l.

kel

Sioa magnitude term, is determined by filtering rates in this study.

. * tec 4 jis? Ro o.,
A simple measure of niche overlap for species i and j is z RE ak’ jk
kL

In order to equate niche overlap as competition coefficients with their

69


SECTION V
EFFECTS OF URBAN CENTERS ON ZOOPLANKTON POPULATIONS
INTRODUCTION

The zooplankton faunas of the Leurentian Great Lakes reflect water
quality, with seasonal population equilibria apparently achieved in

a short time between the quantity and quality of algal foods and the
density of grazers. Thus, to some degree, the variety and abundance

of the zooplankton is a reflection of the secondary influences of
nutrient loading. Ina similar fashion the population size structure,
and ultimately the species composition of the zooplankton, is influenced
by their fish predators (Wells, 1970).

As a working hypothesis, we suggest that urban development along the
shores of Lake Ontario influences the commumity structure of inshore
zooplankton populations during a growing season. A proposed mechanism
might involve the input of nutrients, in turn stimulating the production
of bluegreen algae, or the discharge of substances inhibitory or lethal
to zooplankton growth. However, we will not attempt to further define
this mechanism now. The purpose of this particular analysis of data
was to test this hypothesis. Basically three questions are important.
First, do differences in community structure occur lakewide on a
defined horizontal scale within a growing season? If so, are such
differences in community structure related to long-term changes
demonstrated for Lake Ontario? And most importantly, what do such
differences infer regarding the eutrophication of Lake Ontario's
ecosystem?

Definition of the time-scale of changes during community succession is
important to understanding eutrophication. This succession has been
partially answered. Over time, the zooplankton of the Great Lakes
probably have adapted to both changing foods and predators. During a
recent period of accelerated cultural eutrophication canmencing about
1900 (Beeton, 1969), major changes in zooplankton canmunity structure
probably were initiated. Diaptomus sicilis, the dominant form in

Lake Superior, seems the most oligotrophic form in the Great Lakes
(Patalas, 1972). Toward the eutrophic end of the spectrum, the summer
zooplankton community of Lake Ontario has shifted since 1939 fron
dominance by Diaptomus to an abundance of Bosmina longirostris (McNaught
and Buzzard, Tay Thus long-term shifts have been documented for
Lake Ontario and probably have occurred in all of the lower Great Lakes.

Lake Ontario is the seventeenth largest body of freshwater in the world
(Hutchinson, 1957), an international resource of tremendous value to
both the United States and Canada, Lake Erie, upstream to Lake Ontario,
is certainly responsible for important organic and inorganic inputs.
Thus it is also the purpose of this analysis of the Ontario ecosystem

30


eH

Table 8. CORRECTION FACTORS FOR ACOUSTICAL RETURNS NECESSARY TO EQUATE RETURNS TO
BIOMASS OF ZOOPLANKTON

Formula; intensity x normalization x attenuation = Correction Factor
beam correction

(step 1) (step 2) (Step 3)
Frequency Normalization Attenuation factor (x)
Bottom Corr. Equiv. Beam Correction
Corrections factor (x) Channel Depth (mM) factor (5° angle) (3)
80 kuz 1.056 4 1.44 1,08 la 1.00
2 1.7 1,12 2m 1.16
3m 1.33
120 kHz 1.161 6 2.0 1.17 Lm 1.51
7 24 12h 5m 1.71
8 2.7 1.29 6m 1.92
Tm 2.13
200 kHz 1.735 9 3.1 = 1.37 8m 2.37
10 3.4 Lhe 9m 2.61
lu 3.7 148 10m 2.8
500 kHz 3.282 BR KL 1.55


1972 NOV STATION 1

1972

gta

lgfe

PA 10##4 AVG 5 DEPTH 44M SCAN 50M

MEAN VALUE OF PROFILES QVEK SM INTERVALS

g22229

CH
CH

NOV STATION 2
MEAN VALUE OF

CH
CH
CH
CH

NOV STATION 3
MEAN VALUE OF

22QAQe

NOV STATION 5S
MEAN VALUE OF

gege2egeggg2e9aene9a

QLI222R

isl)
1e-22
23-33
34-44
45-55
56-66
6T-77
18-88

1-20
21-40
41-60
61-80

1-18
19-36
37-54
55-72

I- 3

4 &

7-9
10-12
13-15
16-18
19-21
Be BA
25-27
28-+30
31-33
34-36
37-39
40-42
A3- 45,
Ab= 48
49-51
52-54
55-57
58-60
1-63
64-66
6T- €9

120-80 -.06977 200-120 -61475 500-200
120-80 ~.7373 200-120 =. 1488 500-200
120-80 -.7905 200-120 -.073 $00-200
120-80 ~.&207 200-120 ~-.0416 500-200
120-60 -.8121 200-120 +0027 500-200
120-80 27774 200-120 -.0149 500-200
120-80 -.7748 200-120 +0180 S00-200
120-80 -.7627 200-120 20546 500-200

PA 10**4 AVG 5 DEPTH 20 M SCAN 85M
PROFILES OVEHK SM INTERVALS

120-80 +0978 200-120 -.0274 500-200
120-80 -.2462 200-120 143897 500-200
120-60 =. 4903 200-120 1.64362 500-200
120-80 -.7626 200-120 164663 500-200

PA 10*#4 AVE 5S DEPTH 22M DEPTH 30 M
PROFILES OVER SM INTERVALS

120-80 -.9900 200-120 -.3102 500-200
120-60 -1.01€5 200-120 -.1315 500-200
120-66 -.9116 €00-120 20887 500-200
120-80 ~.6364 200-120 © be39 500-200

PA 10##4 AVG 5 DEPTH 115M SCAN 150 M
PRG@FILES OVER SM INTERVALS

120-80 -«3767 200-120 147085 500-200
120-80 -1.3035 200-120 147442 500-200
120-80 -14399% 200-12 1.4211 500-200
120-80 -1.5621 200-120 144854 500-200
120-80 -167383 200-120 11-6507 500-200
120-80 -1-68301 200-120 1.8086 $00- 200
120-60 ~1.8365 200~120 1.9572 500-200
120-80 -1-835! 200-120 2.1003 500~ 200
120-80 -1.86367 200-120 248351 500~200
120-80 -1-8 483 200-120 243779 500~200
120-80 -1.8625 200-120 2.5273 500~ 200
120-60 -1.8737 200-120 246705 500-200
120-60 -1-6879 200-120 88144 500-200
120-80 -168925 200-120 269553 500-200
120-80 -1.8957 200-120 3.0912 500-200
120-60 -1.9150 200-120 3.2329 500-2860
120-80 -1.9171 200-120 343712 500-200
120-80 -1.9216 200-120 365105 500- 200
120-80 -1.9267 200-120 3.6554 500- £00
120-80 -1.9433 200-120 368045 500-200
120-60 -1.9597 200-180 349545 500-200
120-60 -1.9767 200-120 461034 500-200
120-60 -1.9625 200-120 462409° 500-200

111

+ Ble
©6320
+9 730
41087
162418
163725
1. 5090
de 5619

+1870
+4249
+ G35
+6851

+ Tee6
0 KO
+0433
+0062

= AB 2B
6209
= 2 0448
+1946
24167
+ 6310
+8 5E9
1.069
1.2909
te 5113
1.7235
1.9617
2.19.48
Pe AAG
Be 6342
28 701
3.0823
3.3141
3. 549 6
3. 714
4.0065
4. 2293
4. A587

10
iM
204

vt
10%
1s
20M

aM
10M
1M
20M
en
30M
3M
40M
AY
50M
Soa
60M
6M
‘70M
74
60M
Bae
90M
oS
100%
1054
110M
115M


Table 9 (d). THREE PROFILES AT CONSTANT 5 m INTERVALS,
IN D.C, VOLTS/m>, LAKE ONATRIO, STATION 17,
AUGUST 1972.

PUNCHOUT CHANNEL DI FFEKENCES?

>NS

AUS STA 17 FA 10##4 AVG S DEeIH 130 SCAN 170
MEAN VALUE OF FnOrILES OVEH 54. INTERVALS

CH I- 2 120-66 09935 00-120 00049 500-200
Ci 3- 4 120-80 161259 £00-120 «1957 560-260
é

cH 120-66 1613577 200-160 239 & 500-760 «2051
cH 126-80 141366 £00-120 «C637 500-260 24377
CH 120-80 1.1348 200-120 D1 500-200 ©6777
CH 120-60 1.13523 200-126 2975 506-200 #9234
CH 1E0-60 1.1280 EO0-1EG 1a bass 500-600 168705
cH 2120-80) 161566 £00- 120 S00-200 1.4005
cH 120-60 161487 260-120 500-206 1.6077
CH 120-60 141404 €00-120

CH 120-80 161549 200-120 16 7565

ca TEG-E0  1e1EBE BC0-166 1.9083. 500+

ca 120-80) 1ebe1) 200-120 eeG514 500-60

CH 120-86 14.110 200-126 21974 500-200

CH 120-80 161171 260-126 263510 S6Ce

CH 1E0-80 161127 200-120 500-00 2.9605
CH 35-54 120-86 1.1095 200-120 SQU-2£60 3.61535
CH 35-36 120-0 1.0996 200-120 500-260 3.3455
CH S7-38 JHOrBO 14 G89 E 200-120 S6G-£00 3.5380
cH 592'40 1E0-60 1.0859 200-120 S00-2C0 3+ 7301
CH 41-42 1E0-80. 140806 200-120 500-200 3.9177
CH AGH AA 126-80 160687 f00-120 800-200 461074
CH 45-46 120-80 140637 260-120

CH AT- 48 120-60 1.0589 200-120 500-200.

CH 49-50 120-50 3.6516 #£00-120 500-200

CH 51-52 120-80 1.0456 200-120 464559 500-206" 4.5 0CG

47


1M2yoU STATION 103 PA 10®*4 AVE 5 [EPIH 27M SWELF 29
MFAN VALUE OF PELOFILFS OVFE

CH
CH
CH
CH
CH

1972 NOV STATION 105 PA 10##4 AVE 5
MEAN VALUF OF PROFILES OVER SM

cH
CH
CH
CH
CH

1-18
19-36

J-1€
17-38
33-46
9-64
€5-60

120-80
120-80
120-86
120-60
120-80

120-380
120-80
120-60
120-80
120-86

+0972
21941
22909
+ BBTE
+2619

0977
~ 6639S
EE

= + 1698
71.3465

SM INTERVALS

200-120
200-120
200-120
200-120
200-120

2u0- 120
200-126
206-120
200-120
200-120

132

2 AbED
99083
+5214
wet SOL
767775

~e8S51
--0104
--S077
98 ET
94

500-200
500-200
500-P00
SG0- 200
500-200

LHETH £6 M SbEHF 31M
INTERVALS

S00- 260
500- £00
S6G-200
500-200
500-200

elleo

©3166

+ 5468
© TBE
-9DE

slige
2E514
+39 70
+ £466
014

MM
10M
dia
£0M
eM

104
1SM
60M
Fao


Data Correction

In Table 9a we see an example of raw field data (first four sets at

80, 120, 200 and 500 kHz). These acoustical reflectivities have been
multiplied by the suggested correction factors (Table 8) to yield

four sets of "corrected profiles" (Table 9b). Then these corrected
profiles are subtracted (120 - 80 kHz, 200 - 120 kHz and 500 - 200 kHz)
to yield biomass estimates for particles of the three size ranges
previously indicated (Table 9c). Since the data are not useful in 1%
increments of the gated interval or scan depth, they are then converted
to acoustical reflectivity per 5 m interval, again for three size
ranges (last block) (Table 9d).

Calibration of Acoustical Technique

An empirically based calibration was made by comparing the sum of
differences in acoustical reflectivity, specifically between the

200 kHz and 120 kHz channels and the 500 kHz and 200 kHz channels,
with the product of numerical density of zooplankton and their mean
weight. This calibration utilized the data of the cruises of 21 - 25
August 1972 when animals were abundant and 30 October - 3 November
1972 when animals were relatively scarce. Because the 64: eperture
net used to collect animals was most efficient over a 5 m tow, and
because the sonar likewise was most sensitive fron 0 - 5m, all
calibration points were based upon 0 - 5 m data. A linear regression
was obtained for the relationship between acoustical reflectivity
(D.C, volts) and zooplankton biomass (g/m3 dry-wt), such that biomass
(g/m3) is related to corrected acoustical reflectivity (D.C. volts)
as follows:

(Corrected )
Biomass (g/m?) = 0,681 + 13.53 (Acoust. Ref)

Thus we observe (Figure 14) that the acoustical technique is insensitive
to biomass levels of less than 0.68 g ary-wt/m>. At very low acoustical
reflectivity, it appears that biomass is overestimated.

43


I. Evolutionary responses to variable phytoplankton foods.

A. evolution of generalists and specialists with regard to
selective algal grazing by zooplankton

B. evolution for increased filtering capacity

C. evolution for increased ingestion rate and efficiency,
both by size and density of algae

D. evolution toward increased efficiency of digestion

II. Evolutionary responses to fish predation.

A. evolution for small adult size at maturity

B. evolution of biotic potential (r-selection organisms with
high intrinsic birth rates (b, Pe) or low death rates)

Cc. evolution for reduced visibi dey, especially of larger
adults.

EVIDENCE FOR EVOLUTIONARY TRENDS

From studies of zooplankton feeding it has been evident that sone
oligotrophic forms are nannoplankton specialists, while many eutrophic
species are generalists. But little argument exists regarding whether
zooplankton are size-selective feeders. Calanoid copepods are special-
ists on nannoplankton, as confirmed by field studies. Eudiaptomus in
Lake Erken preferred nannoplanktonic chrysomonads (Nauwerck, 1963).
Similerly 70% of the diet of Diaptomus consisted of phytoplankton of
less than 64, diameter in one study (Lane, 1971), while in another
most was less than 22u (Bogdan and McNaught, 1974). In contrast,
Bosmina longirostris had a preferred range of particles in the nanno-
plankton category (1 - 15u) according to Gliwicz (1969), but has also
been observed to consume a sizeable percentage (50%) of cells above
64u (Lane, 1971). These differences in size will be used to calculate
grazing (Table 16).

Thus each organism has been given an adaptive value within the framework
of lake productivity. In actual application here, the relative values
for each of the 8 components to which the zooplankton show adaptation
are summed to determine the adaptive value. The 8 components had
relative values from 5 to 100 and the resulting adaptive values for
Diaptomus, Daphnia and Bosmina range from 346 to IE-Chebie Te).

The advantages of increased filtering capacity were discussed by Brooks
(1969), who found thet filtering capacity increased as the square of
body length (Brooks and Dodson, 1965). Indeed the larger Daphnia
filtered nannoplankton at the same rate as Diaptomus (Table 16), while
Bosmina longirostris lagged on all resources ‘Bogdan,1974 ). Dodson

7+) has suggested that the advantages of size and filtering capacity
alone were not enough to insure survival.

The efficiency of ingestion appears to be a dominant factor in contrasting
the evolution of feeding. studies by McMahon and Rigler (1963) on

72


Wells, L. 1970. Effects of alewife predation on zooplankton populations
in Lake Michigan. Limnol. Oceanogr. 15:556-565.

Wilson, D. s: 1973. Food size selection among copepods. Ecology 54:h,
909-914.

82


LE

Table 6. OFFSHORE COMMUNITY STRUCTURE.

Community
Canpetition Relationships with Number
Date Density |Coefficient Theor. Carrying-Capacity Species Diversity
N/m3 a vara K WE */ a7e Ss est. S|} H Rich Even

1972
15-19 May 670 | .48  .13 5,613.12 1.21 12 y 1.95 3.89 1.81
12-16 June 2,991 229 = 08 24,784 = 412 69 16 9 2.99 4.89 2.48
10-14 July 33,217 | .27 .10 383,233.09 -80 18 10 2.95 3.76 2.35
21-25 August [129,994 | «41 .10 [1,196,729 «12 5 19 9 3.31 3.52 2.59
30 Oct.-3 Nov. | 22,365 9 15 328,726 .07 +95 a. 6 3.23 5.60 2.45

27 Nov.-3 Dec. 9,816 4 418 134,737  .07 1.07 19 16 3.30 4.51 2.58
1973

5-9 Feb. 2,763 | 47.13 40,969 = .07 64 17 2.55 4.04 1.23
19-22 Mar. 2,291 | 58 .1L 20,42h JL Bon ew 1 2.76 3.27 2.55
2h-28 April 1,891 39 «18 18,540 10 89 15 18 2.9% 4.27 1.0
12-16 June 12,158 28 11 186,072.07 Ol 19 ua 2.69 4.41 2,10
MEAN 24,165 AL 259,357 «09. 1.01 3.19 4.25 2.15

(June 72-June 73


IMZ NOV STATION 59 PA 10®®4 AVG 5 CEFIH 40 M SKEEP 50 M
MEAN VALUE QF PHOFIJ.ES GVFK SM INTERVALS

CH
cH
CH
CH
CH
CH
CH
cH

1-10
11-20
1-30
31-40
41-50
51-60
61-70
71-80

160-80
1£0-60
120-66
120-80
120-60
120-80
120-60
120-60

20961
0 1D1G
©2874
+ 3629
©4783
©5737
© 6669
+7640

£00-120
200-120
200-120
200-120
200-120
200-120
200-120
£00-120

© Shaa
1.0492
+2109
167536
Be 107
3.0188
EeB647
2eA727

lg72NOV STATION 60 PA 10##4 AVE 5 DEPTH 20 M SVEFP
MEAN VALUE GF PROFILES OVER 5M INTERVALS

g222

92 NOV STATION 62 PA 10*#4 AVG 5
MEAN VALUE OF PROFILES OVEh SY

EQAggeggeggggggggegegggege2egeeeoosases

1-20
21-40
41-60
61-60

I~
3
5-
T-
9-10
M12
13-14
15-16
17-18
19-20
21-22
23-24
25-26
27-26
29-30
31-32
33-34
35-36
37-38
39-40
AL 42
A3- 44
Abe LG
AT- 48
49-50
51-52
53-54
55-56
57-58
59-60
€1- 62
63- 64
65> 6E
67-68
69-70
We72
13-74

Bm so

120-60
120-80
120-80
120-80

120-80
120-80
120-80
120-60

120-86:

120-80
120-80
120-80
120-80
120-80
120-80
120-80
129-80
1EC-80
120-86
120-60
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80

20973
- 2 1488
+5700
75BE

01918
01874
el TD
~e1€1S
701455
wel3l2
= 1288

200-120
200-120
200-120
260-120

©5339
1.4328
+O
+3200

500-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200

eam

$00-200
500-200
500-200
500- £00

DEPTH 185 M SWEEP 210 M
INTERVALS

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200+120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

123

1
1.2599
163506
1.4288
1.5038
165712
1.6481
1.7650
1s 3
168615
169698
1299 6&9
220663
261453
2 239
2.6924
263563
20 4198
26 4943
Be 5738

500-200
500-£00
500-200
500-200
500-200
560-200
500-200

500-200
5800-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-260
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
560-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

-20071
-0R7
21656
©2545
«3429
24299

-20895
086
+0566
© 1398

+1263
-25e7
+3770
+5021
© 6264
+ 7502
«8 722
29965
161234
162473
1.3742
4. 49 53.
16616
1. 7325
1.6640
169654
2.08 54
2.2023
&. 3204
2.4406
Be SElL
2. OE
2.991
2.9166
3.0354
3.1550
3.8751
3+ 3939
3.510
3. 6367
3. 7589
368807
Ae 0647
Ae lZ97
406519
403721
Ae A952

104
1S4
204


1972 auG STATION 79 DEPTH 20 METERS AVE 5 PRE 108*4 DEPTH 30
MEAN. VALUE OF PROFILES OVEK 54 INTERVALS

1972

CH
CH
cH
CH

AUG STATIGN 83 DEPTH 99 METERS

1-16
17-32
33-48
49-64

120-80

= +5073

120-80 -1.0146
120-80 =-1.5217
120-80 -2.0290

MEAN VALUE OF PROFILES OVEK

QUAQgeggregeageeege2g

I- 3
4- 6
I 9
10-12
13-15,
16-18
19-21
BE CA
2527
28-30
31-33
34-36
37-39
40-42
AZ- AS
AC 48
49-51
5e- 54
55-57

120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80

1.9414
362773
2.7640
261784
3+ 3679
4.9012
b+ 4466
8.0397
9-5701
1121340
1267147
14.2706
1566255
1763766
18.9197
20-4662
22.0417
23.5701
25.4519

200-120
200-120
200-120
200-120

107

+5335
1.0658
165971
2612879

PRE 10##4 AVE 5
SM INTERVALS
200-120 -2.9074
200-120 -3-3017
200-120 -2.0621
260-120 -.3913
200-120 24644
200-120 -.43e4
200-120 ~.32e8
200-120 -.2156
200-120 -+.0897
200-120 -.0023
200-120 ©0754
200-120 +1709
200-120 22710
200-120 371
200-120 2 A899
200-120 «5879
200-120 + 6696
200-120 ©7657
200-120 +8677

500-200 +8295
500-200 1 6354
500-200 2.4333
500-200 3+ 2339

DEPTH 140

500-200 -1.0924
500-200 -&-+ 7439
500-200 -4. 4289
500-200 - 6 1054
$00-200 - 7. %37
S00-200 -9. 4569
500-200-11-1347
S00-200-.12.8102
500~ 200-14. 46 49
500-200-1641909
500-2£06-1766325
500-200-196 5047
500- 200-214-1776
500- 200~ 22.6 502
500 200~ 24. Se23
500- 200-26. 1928
500- 200-27.8 632
500~ 200= 29+ 5354
500- 200-31. 2061

5
10M
iM
20M


192 NOV STATION 32 PA 10#*4 AVG 5 DEPTH 171 M SWEEP 210 4
MEAN VALUE OF PHOFILFS OVER

lgtT2

CH

HQLLILLIAIggageaeee?

CH
CH
CH
CH
CH
CH
cH
cH
CH

NOV STATION 34 PA 10*#4 AVG 5 DFPTH

1- 2
3- 4
S- 6
7- 8
9-10
11-12
13-14
15-16
17-18
19-20
el-ee
23-24
25-26
27-26
29-30
31-32
33-34
35-36
37-38
39-40
Al- 48
43-44
45-46
47-48
49-50
51-528
53-54
55-56
S7- 56
3-60
61-62
63-64
65-66
67-68

120-60
120-60
120-60
120-60
1€0-66
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-60
120-60
120-86
120-80

+2045
22400
+ 333€
©3208
©3190
26991
+2863
eBT27
#2926
©3045
«3101
+ Sue8
+3999
+3940
+3987
24105
«4126
© 3847
+ STE6
9387
23528
+3365
©3437
©3378
+3260
+3206
+3182
+ S288
+3190
©3183
+2967
+ PBS
+ 2666
©2487

SM INTERVALS

200-120 ~1.0326
600-126 ~142940
200-120 ~1-3231
200-120 -1462558
200-120 ~1.19 68
200-120 ~1.1319
200-120 ~1-0660
200-120 -1.0036
200-120 -.9659
200-120 910
200-120 -.8 608
200-120 ~-80€7
200-120 -.8459
200-120 -+ 7673
200-120 ~. 7288
200-120 -.€973
€00-120 =. C449
200-120 -+5750
200-120 -+5308
200-120 -.4766
200-1820 -.419€
200-120 --3549
200-120 -.3009
200-120 -.2397
200-120 -+1760
200-120 -.1260
200-120 --0673
200-120 -.0064
200-120 +0310
£00- 120 +0833
200-120 +1459
200-126 +2009
200-120 +2613
200-120 +3240

MEAN VALUE OF PROFILES OVEK SM INTERVALS

CH
CH
CH
CH
CH
CH
cy
CH
CH
CH
CH
CH
CH
CH
cH
CH
cH
CH
CH
CH
CH
CH

1- 3
4- 6
7-9
10-12
13-15
16-18
19-21
2B- Ed)
25-27
£8~30
31-33
34-36
37-39
40-42
43-45
AGL
49-51
52-54
95-57
58-60
61-63
64-66

120-80
160-86
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-86
120-80
120-80
120-80
120-80
120-80
120-60
120-66
126-80
120-80
120-80
120-80

+0951

21897

+8193

ABET
-e1501
-1-0107
-1.6204
1.5758
“1.5675
1.5314
71.5321
-145099
71.5058
~1.4938
- 1.48 66
-1.4917
-1.4955
“465113
~1.5133
“1.5112
~1.5202
-1.5269

200-120 ~-. 5686
200-120 =1.4252
200-120 ~F68364
200-120 -3.270S
200-120 ~3.4019
260-120 ~3.3345
200-1280 -362531
200-120 ~3.1702
200-120 ~3.90952
e20C-120 ~3.0629
200-120 -2.9433
200-120 ~ 2.8 666
200-120 -2e 780
200-120 ~&. 70
200-160 ~2. 6544
200-120 -2.5575
200-120 ~2.4821
200-120 -2.4037
200-120 ~ee3259
200-120 -2.256
200-120 ~2-17%5
200-120 -2-1010

116

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
s00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00- 200
500-200
500-200
500-200
S00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-260
500-200
SOG-200
506-200
500-2U0

110 M SUEEF 135M

500-206
S00-£00
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500-200
500-200
500-200
500- £00
500-200
500-200
500-200
500-200
500-200
$00-200
500-200
500-200
500-200

-2765 Mt
+5358 10M
~VEE 1M

11-0625 80M
163664 254
1.90% 30M
166509) 354
261140 40m
Be37% As4
2.6501 50M
2.9163 55M
Be 1618 GOK
3.4502 654
3.7151 70M
369915 734
A,E642 80M
4.5320 6&4
4.6007 90M
56067) OSM
53332 1004
5S. 6000 1054
Se6 E52 110M
6 1347 1194
€-4075 120M
6 6606 125%
69556 130%
T2276 1391
7. 5013 140M
7.7763 L454
6.0509 1564
6.3267 1554
6. 6042 160M
88827 LES

9.159 '70M
+0076 Mt
e115) 10M
22057 14
+3011) 204
+3967 ec
+4942 30M
»912 354
«71 40%
+ %09 45M
+6740 SOM
3966 = =5aa

1.0617 60M

16156 654

122492 704

1.3402 754

1.4355 80M

1.5290 SM

1.6281 90%
1.7837 954
1.68223 100M
1.9162 1054
260164 110M


AJTROV STATION 45 PA 10®*4 AVG 5 DEPTH 183 M SWEEP 250 M
MEAN VALUE OF PROFILES OVER 54 INTERVALS

geggggagggegenees

Q22

1-
3+
5
7-
9-10
11-128
13-14
15-16
17-18
19-20
el-e2e
23-24
25-26
27-28
29-30
3i-32
35-54
35-36
37-38
39-40
41-42
43-44
AS- 46
AT- 28
49-50
51-52
53-54
55-56
ST 5é
59-60
61-62
63-64
65-66
67 ~ 68
69-70
7i-72

aqann

120-60
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-680
120-680
120-60
120-60
120-60
120-60
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-280
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
126-80
120-80

=20197
«6051
©7312
© 7988
#9454
1.0058
1.062
101677
1.2478
}.e9e5
1.3448
143983

167977
1.8402
1.6963
169452
1.9832
2.0360
260817
41207
Be 1506
Be E018
262465
2.63013
2s 3483
Ev 3845
2.4484
£44930
225308

221

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-1206
200-120
200-120
&00- 120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-169
ea00-120
200-120
600-120
200-120
200-120
206-120
2o0-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

- 23466
- +6068

1.4570
1.7649
260678
2.38 64
2.7072
3.0293
34349.2
32 6735
3.9978
4.3151
4s GSE
4e9541
52792
5.59 60
5.9097
662299
66 5492
6.8 C14
Tel 188
74908
768088
6.1205
Be 4ACT6
Be 14
9.0950

500-200 -.3163
500-200 -.3597
500-800 -.3716
500-200 -.3612

500-200 -.3676

500-200 -.4252
500-200 -.4999
500-200 -.507
500-200 6613
500-200 7468
500-200 -.8324
500-200 -.9158
$00-200 -.9977
500-200 -1.0837
500-200 -1.1645
560-200 -1.1384
500-200 -1.1770
500-200 -1.2591
SCO0=200 -1.3409
500-200 -1. 4262
§00-200 -1- 5133
so0-200 -1/ 6125
500-260 -1. 6371
500-200 <1. 7175
500-200 -1.8002
500-200 -1-8 %1
500-2600 -1-9563
500-200 -2-0360
$00-£00 -.1153
SO0-£00 ~2- 1918
500-200 -2.2666
500-200 3494
500-200 ~2.4245
500-200 -2- S007
500-200 -2-571
500-200 -2. 67

M
10M
im
20M
254
304
35M
40M
ASM
50H
Sha
60%
634
704
754
BOM
oo
90M
9 Se

100”
1054
110M
MSH
120M
1294
130M
13 54
146M
145%
1s0%
1554
16064
1694
170%
174
180M


1973

1973

JUN STATION 1 DEPTH 31 M SWEEP
MEAN VALUF OF PEOFILES OVLE 5M

2222992

JUN STATION 2
MEAN VALUE OF

CH
cH
CH

CH

JW STATION 3
MEAN VALUE OF

CH

CH
GH

JUN STATION 5
MEAN VALUE OF

CH
CH
CH
CH
CH

ggessgeaa

CH

1-14
15-28
e9-4e
43-56
57-70
71-64

1-19
£0- 38
39~ 57
56-76

1-20
21-40
41-60

1- 6
Tle
13-18
19-24
25-30
31-36
37-42
A3- 48
49-54
55- €0
61-66
67-72
73-78
79-34
85-90
91-96

120-80 +0661
120-80 +2090
120-80 9 288
120-80 +2456
120-80 21463
120-80 21245

DEPTH 20-M SWEFP
PROFILES OVE

120-680 +0047
120-80 -. 5464
120-80 -1- 5664
120-60 -2.6411

DEPTH 15 M SWEEP
PROFILES 6VEI

120-80 «6524
120-80 1.5677
120-60 2.5696

DEPTH 92 M SWEEF
PREFILES OVER Of

120-80 -1-3735
120-80 -2.7449
120-80 -3663518
120-80 ~4.5961
120-80 - 466751
120-80 -4-8 662
120-80 -4.6622
VE0-60 - 466 603°
120-80 -4.8591
120-S0 -4.66593
120-80 - 468590
120-80 - 468566
120-80 -4-8553
80-408 527
2 0-4-8525
120-80 -4+8510

36M
INTERVALS

200-120 -.0614
200-120 -.1546
200-120 -.22@
200-120 -.28657
200-120 -.2867
260-126 -.2703

26M
INTERVALS

200-180 -1.0095
200-120 - 1498868
200- 1207~ 2. 4983
200-120 +2. 7273

a5 M
INTERVALS

260-120 -.9229
200-120 -2.2619
€00-120 -3. 76€2

60M
INTERVALS

200-120 -.08 58
200-120 -.0459
200-120 © 0092
200-120 0653
200-120 +1233
200-120 «1778
200-126 «F365
200-120 © 629.49
200-120 +3559
200-120 64117
200-120 +4701
200-120 © 5293
200-120 - 5853
200-120 =» 6460
200-120 «7063
200-120 + 7656

ahs

500-200
500-200
500-206
500-200
500-200
500-200

500-200
500-200
500-200
500-200

506-200
500-200
500-200

500-200
500-200
500-200
500-206
$00-£00
$60-200
500-200
800-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

#0000
+0000
+0000
+0000
«0000
+0000

«0000
+0000
+0000
+0000

+0000
+0000
+0000

+0000
+0000
+0000
«0006
«0000
+0000
«0060
+0000
+0000
«0000
+0000
+0000
+0060
+0000
+0000
+0000

10M
a4
20M
em
30M

10M
14
20M

10M
14

10M
1M
20M
eM
30M
3oM
40M
am
SOM
SoM
OM
ul
70M
THM
som


1973 oun STATION 32 DEPTH 166M SWEEP £10 %
MEAN VALUE OF FEGFILES OVER SM INTFhVALS

CH ole & 120-80 «3403 = 200-120
CH 3+ 4 120-60 6 3495 BDO- 120

CH OS 6 120-60 = 6 S98 = E00-120

CH o7- & 120-60 4021 200-120

CH 9-10 120-80 © 40¢8 «= BG0- 120

CH 1-12 120-80 64136 = 200-126

CH 13-14 120-60 ©. 4226 200-120

CH 15-16 180-80 44273 800-120

CH 17-18 120-60 «4353 200- 120

CH «19-26 120-60 4424 © £00- 120

cH e122 120-40 6 4483 = 200-120

CH 23-24 120-60 = 4514 = 200-120

CH 25-26 120-60 64574 = 200-120

CH 27-28 120-60 4613 = 200-180

CH 29-30 120-60 44704 200-120

CH 31-32 120-60 4857 = - 200-120

CH 33-34 120-860 + 5150 200-120.

CH 35-36 120-60 «$337 200-120

CH 37-38 120-60 «5445 200-120

CH 39-40 120-80 +5521 = 200-120

CH 41-42 120-60 =. S664 200-120

CH 43-44 120-80 «573% 200-120

CH 45-46 120-80 5803 200-120

CH 47-48 120-80 «5826 = 200-120

CH 49-50 120-80 =» 5845 200-120

CH 51-52 120-60 + S648 200-120 162305
CH 53-54 120-80 .5901 = 200-120 1. eK Ee
CH’ 55-56 170-60 «594 = 200-120 163417
CH 57-58 1£0-60  - 6025 © BU0-120 1.3980
CH 59-60 120-60 =. €078 «= 200-120 1.4539
CH 61-62 120-60 «6110 = 200-120 1.5118
CH €3-64 120-60 +6173 200-120 1.540
CH 5-66 120-60 6213 200-120 16 6231

1973 guy STATION 35: DEPTH 17 M SWEEP 23 M

MEAN VALUF GF PK@FILES OVE 5M INTERVALS

CH 1-24 120-60 -27731 200-120 -.2594
CH 25-48 120-60 -1.9868 200-120 -.5706
CH 49-72 120-80 -3-2522 200-120 8169

1973 JUN STATIGN 3€ DEPTH 23 M SWEEF 30 M

MEAN VALUE OF PROFILES OVER SM INTEVALS

CH 1-19 126-80 +2627 200-120-2553
CH 20-38 120-60 +824 200-120 1325
CH 39-57 120-80 -.«3€1 200-120 1. 669
CH 58-76 120-80 65869 200-120 1.0506

149

500-200
500-200
$00-200
500-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-£00
500-200
$00-260
500-200
500-200
500-200
500-£00
SG0-260
506-260
500-200
900-200
500-200

‘500-200

500-200
500-200

500-200
500-200
500-200

500-200
500-200
500-200
500-200

20922
22BS
+4655
» 6539
«6425
1.0316
1.6815
164104
1.5999
1. B94
LIDS
21s
Pe SORE
Ee S489
2. 7398
BeIEIS
Be 1E10
3.3164
3. 5035.
3. 6937
3.8639
460744
he 8 O48
4.4550
Ae 6456
466353
5. 02 6B
be k1 ba
Se 4063.
Se 59 73
Se WEE
BeD 75
616

+BAE5
© A588
+6831

763951

+1646
+0313

-.0130

id
rom
1S.
é0m
esM
30M
34
40M
4M
SOM
SoM
€0M
ee
70M
TM
6OM
& SM
yom
om

160M
105M
210%
11
120M
1654
130%
1am
140m
145M
1500
V5ot
16M
16a

10M
14

10m
1S
20M


EPA-660/3-75-021
JUNE 1975

ZOOPLANKTON PRODUCTION IN LAKE ONTARIO AS

INFLUENCED BY ENVIRONMENTAL PERTURBATIONS

Donald C. McNaught
Marlene Buzzard
Steve Levine
Department of Biological Sciences
State University of New York at Albany
Albany, New York 12222

Grant 800536
Program Element 1BA026
ROAP/Task No, 21AKT/35

PROJECT OFFICER
Nelson A. Thanas
National Environmental Research Center
Grosse Tle. Laboratory

NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330

For sale by the Superintendent of Documents, U.S. Government
Printing Office, Washington, D.C. 20402


1973 FER STA 62 PA 10##4 AVG 5 DEPTH 169 M DEPIH 185 M SEAN 250 M
MEAN VALUE GF PROFILES OVER SM INTERVALS

1973

ggegggggeneagaeeeeaege

2
Ba

QASRAIESAAsRgags

STATION G4 FER PA 10#*4 AVE 5 DEPTH 85 M
SM INTERVALS

49-50
51-52
53-54
55-56

120-680
120-680
120-80
120-80
120-60
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-860
120-60
120-0
120-20
120-80
120-80
120-80
120-80
120-80
120-80
120-80
126-80
120-60
120-60
120-80
120-860
120-80
120-80
420-80
120-80
120-80
120-80
120-80
120-80

-+0170
-- 0442
-.0676
-0932
-.1224

724542
mA ATTA
- +5056
- +5320
-.S611
- 65923
--621€
~2G446

MEAN VALUE OF PRGFILES OVEK

CH
CH

1- 3
4-6
1-9
10-12
13-15
16-18
19-21
2e-24
25-87
28-30
31-33
34-36
37-39
40-42
43-45
AG 8
49-51
5a 54

120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-60
120-80
120-60
120-80

+8763
1. 6036
41-5965
1.3559
1.5487
1.63515
1.3375
1.3535
1.3505
123415
163360
123265
1.3242
163175
1.3113
1.3061
143038
1.3036

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
€00-120
200-120
200-120
200-120
200-120
200-120
206-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

€00- 120
200-120
200-120
200-120
200-120
200-126
200-120
200-120
200-120
200-120
260-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

139

“0014
«0058
20154
+0283
20387
20534
+0623
+0668
20776
+0833
20887

DEPTH

= Aho

500-200
500-200
500-200
500-200
500-206
500-200
500-200
500-200
$00-200
500-200
500-200
S00~ 206
500-200
500-200
500-200
500~ 200
500-200
500-200
506-200
500-200
500-200
500-200
50C-200
500-2006
500-200

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

94M SCAN

500-200

1458
1.9501 150%
200151 1554
2.0749 160M
2.13% 16S)
2.2005 170M
266634 174
263249 180M
2.3877 18

1.9290 60M
200216 8
2.1142 904


1972 “AUG STATION 45 DEPTH 200 METERS PREAMP 107#4 AVE 5 DEPTH
MEAN VALUE 9F PROFILES OVER

CH
CH
cH
CH
cH
CH
cH
CH
Ca
CH
CH
CH
CH
CH
CH
CH
cH
CH
CH
CH

CH
CH
CH
CH

2

ge2gggeggegaceagy

23-24
25-26
B7- 28
29-30
31-32
53-34
35-36
37-38
39-40
Ale 42
43-44
45-46
Ae
49-50
51-52
53-54
55-56
57-8
59-60
61-62
63- 64
65-66
OT 6
9-70
71-72
73-74
75-76
11-78
79-80

120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-80
1£0-80
120-80
120-80
120-80
120-80
120-860
126-80
120-80
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-60
120-80
120-80
129-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-80

+0876
+2836
421s
~049 59
=.4790
= 4539
- 04314

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
€00-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

100

SM INTERVALS

24578
1.0111
1.4129
1.6151
1.7748
1.9233
2.001
BeE124
263583
2. SCAG
2.7006
248830
3-008
362568
344A)
36 €320
3-8 209
4.6101
4 19 65
4.3861
Ae 5168
46 76
469547
51455
543283
5+ 5132
5-83
5-88 63
6.0726
6297
64468
Gs 6328
648 189
7.0012
1618 74
163733
Te 5688
To TBA
769385
Be1172

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
800-200
500-206
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00- 200
500-2600
500-200
560-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00- 200
500-200
500-200
500-200
S00-200
500-200
500-200

220

-+ 6339
+4951
-21980
+1067
+39 B
+ 6688
-9811
161713
164191
15605
1691
261657
04129
Be 6554
249064
361510
323976
3 6453
328904
Me 1356
4s 3830
4s 6281
4e8 TAB
5.1185
5. 3 648
Se 6101

S58 S26"

6-09 73
6 3415
6. 8 71
6.8288
760732
Te 3173
Te 5604
128071
B8-0533
8.2976
B- 5416
Be HIS
900277


Table 14. ACOUSTICAL REFLECTIVITY ® c. voLrs/m3), ESTIMATED
COLUMN BIOMASS (g dry wt/m?), COLUMN VOLUME (m3)
AND BIOMASS PER UNIT VOLUME (g dry wt/m>) FOR ALL
STATIONS, JUNE 1973.

Biomass Volume of Unit Volume
Acoustic Biomass mg dry wt depth : Biomass
Fiela st. (120-200-500) (from regression) (xl m@=m3) g dry wt/
1 0.0 0.681 30 02
2 0,0 0.681 15 02
3 0.0 0.681 20 02
5 5.3 72.39 95 76
7 14.9 202.28 25 8.09
8 22,51 305.24 70 436
10 8h 16 1,139.37 115 9.90
2 0,0 0.681 20 +03
wh 0.94 13.40 10 1.34
19 0.0 0.682. 10 07
20 2,08 28,62 15 1.92
2h 38.57 522.53 110 1
26 53.14 719.67 145 4.06
30 2,51 34.64 20 1.73
31 12.18 165.48 25 6.60
32 127.75 1,729.14 170 10.17
35 1.37 19.22 25 TT
36 3.14 43,17 30 1.43
AL 0,0 0.681 25 +03
he 24.81 336.36 15 22.42
46 8.33 113.39 120 9h
48 422 57.78 25 2.31
56 145.49 1,969.16 129 15.26
59 0.0 0.681 25 203
60 0.47 7.04 10 +70
62 10.73 145.86 165 88
6h 0.0 0.681 8&5 +00
66 0.0 0.681 25 +03
67 0.0 0.682 20 +03
72 0.0 0.681 30 03
B 0.0 0.681 15 05
ve) 0.0 0.681 230 +00
78 0-9 13.81 50 28
79 1. 20,44 20 1.02
89 0.16 2.846 6 aon
90 0,0 0.682 10 07
Eg 2335 q.01 65 11.64
ol 138.55 35 3.95
6 4.64 63.46 35 1,81

60


Table 9 (c). DIFFERENCES BETWEEN REFLECTIVITIES AT ADJACENT
FREQUENCY ENVELOPES (120-80 kHz, 200-120 kuz,
AND 500-200 kz)

PRINTOUT GF CHANNEL DIFFS?
>YKS
120-80 KC

01
os
as
ee
2
36
ag
50
7
64
a
18
Bs
92
99

9935
00106
0008
2 OhID
720076
-20002
0011
50157
00045
-00084
20010
-008e
=00087
07832
0045

oe
09
1e
23
30
37
aa
51
3B
65
72
?
aE
93

200-120 KC

oO.
08
as
2e

20049
e1sse
21536
#1980
01946
©1927
©1916
01967
21950
«2010
0 1888
«1909
©1909
07317
1871

oe
Qo
16
a3
30
37
aa
SI
Sd
6S
72
0
86
93
ee

§00-200 KC

01

os
a5
22
29
36
43

we SIG)
+230
©2377
01944
o1920
21926
©1875
+1693
+1898
©1872
01898
1914
21908
01731
018287

37
a4
Ss)

19
be

98
cry

01304 03 60138
20042 10 -.0022
=0044
=20050
=20053
-+0003
- 20056
-+0082
0041
=20105
=20095
= 20049
-20083
907498
20118

©1908 03 2029
+1502 10 +1536
o8715.17 61816
19861 24 61966
©1951 31) 61961
21935 38) .193E
01946 45 41963
01945 SE 01918
21946 59 61938
21955 66 21938
0190 73° 21964
#1950 60 61947
©1950 87 21935
20686 94 21966
0577

©1087 03) 21931

0170694 21742
01555

bE
95

81
8B
oS

-.0010
=.0056
700105
00078

0001
=20060
720011
-e0111
0064
20080
-.0001
00128
-.0096
700354

©2051
01461
01897
01978
+1950
01939
21895
01943
01983
21926
1950
01953
21936
«£003

2198E
08490
22038
21944
019231
01949
01919
21954
©1898
01914
0 18B5
9 1BER
21689
01773

46

os
18
19

&6
33
46
aT
54
él

cy

75
be
69

96

os
ae
19
B6
33
40

Be
8o
96

00084
~ 60066
20094
-20035)
0080
20059
20130
00066
~2b047

20013
~ 0006
2008)
= 20097

20154

01941
01455
21929
21946
01957
01965
21931
21961
21988
©1690
1917
01936
21939
«1990

02074
02455
2082
01895
©1908
01894
ele
188
21915
21894
©1907
21894
0 18K3
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Figure 5. Density (no. /m>) of eutrophic Daphnia
August 1972 in surface waters to -5
60 stations of IFYGL Biology Program

retrocurve on 21 ~ 25

im) of Lake Ontario at


HORIZONTAL DISTRIBUTION OF CRUSTACEAN ZOOPLANKTON
AT SPECIES POPULATION MAXIMA

Water quality is reflected in the horizontal distribution of the
crustacean zooplankton of Lake Ontario. From our sampling during the
1972-73 IFYGL survey, the distributions of each species are available
from a variety of water strata. In this section we will discuss the
horizontal surface (0 - 5 m) distribution of dominant forms at the
time of their seasonal population maxima.

Biologically it is important to interpret horizontal distributions,
Inputs of plant nutrients from rivers tributary to Lake Ontario likely
influence secondary production. Thus areas of unusually high standing
erops of zooplankton are likely indicators of stimulation by pollutants
of the nutrient-poor Ontario ecosystem. Likewise, physical factors
like upwelling, with associated increases in available plant nutrients,
may influence observed horizontal distributions of zooplankton. In
the final interpretation of lake Ontario results, such information
must be considered.

lastly, the Ontario ecosystem is extremely dynamic. Large populations
of warm-water cladocerans, initially developing inshore, may be
carried offshore, with little final correspondence between the location
of a clump in time and the environmental factors which led to its
development.

The Cladocera

The horizontal distributions of the cladoceran and copepod crustaceans
will be discussed as a sequence of possible eutrophic indicators from
Bosmina longirostris, the most useful key to extreme eutrophy, to
Diaptomus sicilis, The most primitive oligotrophic form,

The smallest major cladoceran, Bosmina longirostris, is likely a
eutrophic indicator because of its diet, hice permits grazing on

large forms of algae. It is predominantly an inshore form (Section Vv),
presently close to urban centers. Bosmina longirostris was found in
Ontario over 12 months, but reached maximum density during August 1972.
Clearly the horizontal distribution of B. longirostris is (a) character-
ized by greater densities inshore, and (b) associated with urban
shoreline development and river inflow, At maximum development from

21 - 25 August 1972, it reached densities of greater than 200, 000/m3
off Toronto, Ontario, and 300,000 off Oswego, New York (Figure 3).
Likely the Oswego case was influenced as much by the agricultural
nutrient load of the Oswego River as by the city itself, whereas the
effect from Toronto is likely more directly associated with nutrients
originating from the city. In both cases, of course, such nutrient
stimulation is thought to have its primary impact upon the phytoplankton,
with the response which we have observed so clearly in the zooplankton

1€


19f2 AUG STATION 41 DEPTH 26 METERS AVE 5 PREAMP 108#4 ‘DEPTH 40

igre

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MEAN VALUE 6F PROFILES QVER SM INTERVALS

CH 1-13 120-80 +1004 200-120 =.7465
CH 14-26 120-80 -.3110 200-120 -. 7353
CH 27-39 120-60 ~-.6649 200-120 -. 6441
CH 40-52 120-80 --7376 200-120 -.5264
CH «53-65 120-80 -. 6396 200-120 -.4435

AUG STATION 42 DEPTH 15 METERS@ PRREAMP 10084
MEAN VALUE OF PEOFILES @VEK SM INTERVALS

CH 1-16 120-80 +0990 200-120 1.3608
CH 17-32 120-60 21979 200-120 + 638
CH 33-48 120-80 +0044 200-120 20444

AUG STATIGN 44 DEPTH 174 PREAMP 10*#4 DEPTH
MEAN VALUE OF PROFILES SVEK SM INTERVALS

CH ln 2 120-80 ‘ «8706 200-120 ~-3853
CH BA 120-80 1.2459 200-170 =653580
CH Sr 6 1E0-6O 1463563 200-120 1219
CH T- & 120-60 144160 200-120 + 6090
CH 9-10 120-60 1.76768 200-120 ©6527
CH oll-te 120-80 1.9710 2£00-120 +6555
CH 15-14 120-80 2.0850 200-120 27194
CH 15-16 120-80 2.1324 200-120 ©8388
CH «17-18 120-60 2.1688 £00- 126 29667
CH =19~20 120-80 262081 200-120 1.0894
CH el-22 126-80 2.2409 200-120 1.26190
CH =23-284 120-80 242678 200-120 1463629
CH 25-26 120-80 £42953 200-120 1.5175
CH 27-86 120-60 3339 200-160 1.6743
CH 29-30 120-60 23733 200-120 14686337
CH 31-32 120-80 2.4027 200-120 2.0006
CH 33-34 120-80 244246 200-120 261713
CH 35-36 120-80 2.4405 200-120 2463495
CH = 37-38 120-80 24718 200-120 2.5162
CH 39-40 420-60 25100 200-120 2. 6785
CH 4l~42 120-60 2.5371 2002120 &84e9
CH 43-44 120-80 2.5659 200-120 3.0060
CH ASAE 120-80 245943 200-120 341744
CH 47-48 120-60 2.6209 200-120 3.3421
CH A9~5S0 120-80 2.6500 200-120 3.65105
CH 51-52 120-60 266766 200-120 3+ 6777
CH 53-54 120-60 2.7090 200-120 346468
CH 55-Sé 120-80 £27366 200-120 460165
CH =S7~5é 120-60 267618 200-120 461846
CH 59-60 120-80 @+7901 200-120 4+3479
CH 61-62 120-60 £68162 €00-120 465141
CH 63-64 120-80 €-8477 200-120 4-19
CH 65-66 120-80 €.8721 200-120 28 504
CH 67-68 160-60 2.9014 200-120 560156

99

500-200 eASET
500~ 200 BDS
500~200 143055
500~200 1. 7699
500-200 148984
‘AVE 5 DEPTH
500-200 3011
500-200 +480
500-200 +18
200 METERS

500-200 + 26EE
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560-206 24965
500-200 +9272
s00-£00 1.3656
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10M

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1600
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1973 JUN STATION 94 DEPTH 39 M SWEEF 43M
MEAN VALUE OF PROFILES VER Sf INTERVALS

1973

1973

“MEAN “VALUE OF PROFILES 3V

1973

2222229

1-12
13-24
25-36
37-48
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+6716
-.3225
168748
~1.9256

200-120
200-120
200-120
200-160
200-120
200-120
200-120

JUN STATION 95 DEPTH 29 M SWEEP 36 4
MEAN VALUF @F PROFILES OVER SM INTFRVALS

CH
CH
CH
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1-16
17-32
93-45
49-64
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+7342
1.6290
2. 5813
261100
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200-120
200-120
200-120
200-120
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JUN STATION: 96 DEPTH 37 M SWEEP 42 M

CH
CH
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165756
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167588-

1.7285
1.7813
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200-120
200-120
200-120
200-126
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JUN STATION 97 DEPTH 31 M SWEEP 35 M
MEAN VALUE OF PHOFILFS OVER SM INTERVALS

CR
CH
CH
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CH
CH

1-14
15-28
29-42
43-56
57-70
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1.3671
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156

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SM INTERVALS

+9032
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- 5.9004

©5094
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500-200
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intermediate between the Bosminas in its response, probably closer
to B. longirostris.

Clearly Diaptomus sicilis, often called the most oligotrophic crustacean,
exhibits an offshore distribution, as does Diaptomus minutus. From

our observation, strongly influenced by information in the literature,

we have erected a continuum of species, indicative of early oligotrophy
to eutrophy. For these found in Lake Ontario, the extremes might include:

Early oligotrophy: Diaptamus sicilis
Oligotrophy: Bosmina coregoni

Mesotr ophy: papeoue minutus
Eutrophy: Daphnia retrocurva
Late Eutrophy: Bosmina longirostris

Communities of Lake Ontario Under Stress

Four restricted areas of this tremendously large system are currently
under stress, as indicated by their zooplankton camunities. These
include the waters adjacent to Metropolitan Toronto, those off the
Oswego River, and three shallow and productive Bays, Mexico Bay in
southeast Lake Ontario and Popham's and Weller's Bays adjacent to the
Murray Canal which connects Lake Ontario to the Bay of Quinte on the
northeastern Canadian shore.

We have concluded that these areas are under stress, based on a
consideration of the relative numbers of cladocerans and calanoid
copepods found at maximum density, usually during July and August.

In the four areas under stress, the mean density of Bosmina longirostris
at population maximum was 150, 000/m3, while that for Diapeonus sicilis
and minutus was 312/ » for a Bosmina:Diaptomus ratio of sb (Table 3).
In more oligotrophic waters at stations 17, 77 and 83, the mean density
of Bosmina was 1000/m3 and that of Diaptomus was 255/m3, for a

Bosmina :Diaptomus ratio of 3.9:1. Thus Diaptomus, the oligotrophic
form, is relatively more abundant in oligotrophic waters as indicated.
Bosmina, on the other hand, was 150 times more abundant in eutrophic
than oligotrophic waters in this example.

Clearly, the Environmental Protection Agency should consider solutions
to problems of accelerated eutrophication in U.S. territorial waters
near Oswego and especially in Mexico Bay, and the Canadian government
should be concerned with the same problem in the area of Toronto and
in shallow Popham’s and Weller's Bays on the northern coast of Lake
Ontario. It may be possible to separate cultural causes fran simple
morphometric (depth) relationships in these cases. That is, the
problems associated with the input of nutrients fran the Oswego River
and Toronto may have engineering or other technical solutions. The
problems of high productivity in the shallow bays may be primarily
associated with their morphometry. These bays may be important feeding
grounds for young fishes and a slowing of their eutrophication may

be neither feasible nor desirable.

28


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CH
CH

1972 AUG STATION 92 DEPTH 67 METERS PREAMP 10##4 AVE

1-24
25-48

AUG STATION 90 DEPTH 13°M
MEAN VALUE OF PROFILES GV:

120-80
120-60

2 0488
= 6690

200-120 1.8736
800-120 2.2172

MEAN VALUE @F PEKGFILES OVER SM INTERVALS

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1- €
712
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200-120 2.7970
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1gf2 sUG STATION 94 DEPTH 35 METERS PREAP 108#4 AVE

MFAN VALUE OF PRGFILES OVER SM

ggaegeee

i-11
12-22
23-33
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4555
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120-80
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120-80
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©7611
1.5873
2e1540
267801
3.4210
463513
3.5186

INTERVALS

200-120 14-0744
200-120 145066
200-120 165667
200- 143975
200-121 1.0677
200-120 + 7495
200-120 22747

ig972= AUG STATION 96 DEPTH 35 METERS PER Lore 4 AVE 5
MEAN VALUE GF PEOFILFS OVER SM INTERVALS

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Indd
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200-120 167959
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109

ETERS PREAMP 1O##24 AVE
Ek 54 INTERVALS 5 DEPTH

27
500-200 -.0346
500-200 0018
5. DEPTH 60
500-200 63615
500-200 +9856
500-200 1. 6254
500-200 22605
500-200 2.4926
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s00-£00 761103
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5 DEPTH 45
500-200 +2940
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$00-200 141099
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500-200
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172 yov STATION 90 PA 10##4 AVG 5 DEPTH 24M SKEEF 30M
MEAN VALUE OF PROFILES OVER Sf INTERVALS

@ - e j~ 2 o410€ a4
CH 1-20 120-80 20978 200-120 + 7552 500-200
CH 281-40 120-60 «5087 200-120 ~.6043 500-200 . mie 10M
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CH «61-60 120-30 -1+0150 200-126 -169675 500-200 143324 20”

1972 NOV STATION 92 PA 10%#4 AVG 5 DEPIE 67M SHEFF 100 M

1£0-80 4.4190 200-120 -566360 S00-£00 © E31
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160-80 467017 200-120 -5-.9048 500-200 + WOE
+ 6268 200-120 -5-7151 500-200 ~8056

MEAN VALUE OF

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CH G10 1€0-€0 2.8920 £00-120 -3.0342 S00- 200 - LOE
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CH «16-20 120-60 149396 €00-126 500-200 ~EBT
CH 21-25 120-80 +9189 200-126 s00-200 23375
CH 26-30 120-80 867873 00-120 500-200 - 4005
CH 31-35 120-80 3.7091 200-120 - 5.4865 500-260 ©4574
CH 36-40 1L0-86 401464 €00-120 -5.8055 500-200 2512)
CH 41-45 120-80 462949 EC0-120 -5.8263 S00-200 -5@3
CH

CH

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lg72 NOV STATION 94 FA 10##4 AVE S DEFIH 39 M SwkEF 45 M
MEAN VALUE OF PORILES OVER SM INTERVALS

CH I-1E 120-60 -.2866€0 200-120 =-.3438 500-206 +0636 oM
CH «13-284 120-60 -.8164 200-120 --.5138 S06- £00 +1547 10M
CH 25-36 120-80 +1. 6567 200-120 -.4034 500-00 26005 1M
CH 37-48 120-60 -2.5243 €00-120 -.2 G2 900-200 +3605 20M
CH 49-60 120-60 -3. 3878 200-120 ~21374 800-200 44TE 2oM
CH GI-TE 120-60 ~4.2615 200-120 ~-.0016 500-£00 +5308 30M
CH 73-84 120-80 -5e1361 200-120 ©1407 500-200 +6126 34

1972 NOV STATION 95 PA 10%*4 AVE 5 DEFIN 33M SWERE 40 M
MEAN VALUE OF PECPILES OVER SM INTERVALS

CH 1-13 1£0-86 +0970 200-160 24064 s00-200 =.

CH 14-86 120-30 +8793 200-120 -.9041 b00- 200 aarer 1a
CH 120-80 +360 200-120 -141571 SG0-200 -.156 14
CH 0-80 = 240160 200-120 -1.1618. 500-200 -.1586 com
CH 20-80 +0306 200-120 -1.08 56 500-200 -.1653 E54
CH 120-80 -1.3912 €00-180 ~.9€11 500-200 -.1%0 30M

130


zs

Table 11 (continued), MEAN ACOUSTICAL REFLECTIVITY (D.C. voLts/m3) AND RELATIVE BIOMASS (%) FOR
5 m INTERVALS, LAKE ONTARIO, 1972-73.

Depth August 1972 November 1972 February 1973 June 1973
Interval Acoustical\Relative Acoustical\Relative Acoustical\Relative
(m) Reflectivity Biomass Reflectivity, Biomass RefLlectivity\ Biomass

10-145 15.70 +037 7.63 025 0. 3.74 037
145-150 17.36 OW, 7.91 4026 oO. 3.98 Rrolte}
150-155 20.05 O47 9.0h 2029 0. 421 -oh2
155-160 20.07 +048 9.34 +030 Oo. 4 dS Ob
160-165 21.36 +050 9.63 031 oO. 469 -O47
165-170 2h .38 2057 9.93 032 0. 6.14 061
170-175 29.08 068 10.29 033 om
175-180 35.12 082 11.32 +037
180-185 36.11 +084, 12.62 OWL
185-190 9.53 2022 11.52 037
190-195 9.78 2023 11.51 -037
195-200 9.97 023 11.83 038
200-205 3.02 .007 18.51 060
205-210 3.09 .007 18.97 062
210-215 3.17 +007 19.43 +063
215-220 3.25 008 19.83 064
220-225 3.33 008 20.36 +066
225-230 3.41 008 20.81 068

428.03 1.01 307.34 0.99h 100.56 1.01



1972 AUG STATION 75 DEPTH 233 METELS PIEAMP 10#*4 AVE 5 DERTH @250
MEAN VALUE OF PROFILES OVEN SM INTERVALS

CH
CH
CH
CH
CH

CH

cH
CH
CH
CH
CH
cH
CH
CH
CH
CH

ie 2

STATION 78 DEPTH 53 METERS
MEAN VALUE OF PROFILES OVEX SM

1- &
9-16
17-84
25-38
33-40
41-46
49-56
57-64
65-72
73+80

120-80
120-60
120-60
120-80
120-80
120-60
120-860
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-40
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-60
120-80
120-80
120-860
120-80
120-60
120-60
120-60
120-60
120-80
120-80
120-80

120-80
160-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-60

*o5e1
+0551
+049 €
+18ES
0 24ee
623528
«2155
01989
el7el
+1416
01547
+ L087
20604
20495
+0199
-+0118
-+0453

~6b914
-0 1148
701798

200-120
200-120
200-120
200-120
206-120
200-120
200-120
200-120
200-120
200-120
206-120
200-120
00-120
200-120
200-120
200-120
00-120
200-120
260-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
e00-120
200-120
200-120
200-120
206-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

+6970
21323
21664
+0765
20676
20967
+1326
© 1678
#2059
+2430
25869
0 COKE
6 3348
+ 370€
+4072
«4438
°4651
+ SEG4
° S5E7
+ S96
+ E38
+ 6567
+610
+ 939
©1128
© T4328
© 7760
+6110
«8454
©8763
+9120
444
97
2.0315
1.0475
1-06 30
121170
1.1452
161793
1.2160
142507
168814
163164
1635394
2.3687
164197

500-200
500-200
500-2600
500-200
500-206
506-260
800-200
500-200
500-200
500-200
500-£00
506-200
500-200
500-£00
500-200
500-260
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-£00
500-200
500-200
500-200
500-200
500-200
500-200
500-200
s00-20

500-200
500-200
s00-200
500-200
500-200
500-200
500-200
500-200
500-200

2007E
60368
«06750
21152
01574
©2019
+ £463
+ 2688
+3303
03757
4204
+ 4646
+ 5079
+ S498
«O41
« 6395
+ 6 EL
+ 7330
+ 7783
262ES
«60S
-9183
99ST
1.0037
1.0467
1.0920
1.1362
1s 1838
1.£290

£750
1.3£08
163646
LeALLT
1.4561
2. 5013
1. 5472
1. 3942
1. 6410
1. G42
1. 7231
1.7701
166172
1.8631
1.90865
1.9555
2.0050

PRFAMP 10#*4 AVE 5 DEFIH 60

INT

200-120
200-320
200-120
200-120
200-160
f00-120
200-120
200-126
200-120
200-120

106

BVALS

160877
125975
201723
368303
Se 1S36
6. 4E04
Wels
Te 6423
Te N84
+2346

500-200
500-200
500-200
500-200
500-200
500-200
900-200
$00-£00
500-200
500-200

=. 4405
+ +1336
+2780
+7074
161376
1.5674
1.9947
ge 4ele
2.8492
322749

10M

20
25%
30%

40m
4S
SoM
SM
604
64
704

80M
& SM
90TM

100%
1054
110M
115M
leo
1254
130M
1354
140M
1454
1504
1554
160m
16a4
17014
1734
180M
18 St
190M
19 4
200M
204
2104
2154
220M
een
&30M


requirement that 955 = 1, a normalizing factor is needed, leading to

tbat
z
bel KP AKY jk (18)
“iP
2 42
x ROS
kel ‘kK ik
This can be re-written as
Pp ap
ey RPixP jc
55 (19)

P
42.2

six Re

a2, PiPi

The model developed for herbivorous zooplankton considers a two-
dimensional resource spectrum (or niche). These dimensions are known
as habitat selection and resource allocation (lane, 1971). Habitat
selection refers to the vertical distribution of zooplankton species
in the water column and overlap in this niche dimension is co-occurrence,
Resource allocation refers to size-selective feeding by the zooplankton
(Burns, 1968; Wilson, 1973). In turn the density of the resources,
largely phytoplankton, must be described in terms of both vertical
distribution and size distribution. The resource is now described as
Rye and the utilization function as ia « As discussed for niche
breadth, if it is assumed that the ditiensjons are independent
and 44,9 can be written as ROR) and FERC. Equation (19)" becomes
Bt

i L

PG a(1)A(2),2 (1) (2) (2) (2

“Serge x ® ) De

45 = > a (20)
EE, RO MEDD?

This is the form of “5 used in this study.

Thus we have developed a new approach to examining community inter-
actions, which should in the future replace the a-analysis used in
this study (Section V).

TO


22

Figure 7.

Density (no. /m3) of mesotrophic Diaptomus minutus on 12 - 16
June 1972 in surface waters (0 - 5 z Of Lake Ontario at
60 stations of IFYGL Biology Program


88

Table 19. MEAN ZOOPLANKTON POPULATION DENSITIES. VALUES (vuMBER /m3 ) REPRESENT
ANIMALS COLLECTED WITH A NET (64 APERTURE) AT STATIONS 50 m TO SURFACE.
15-19 | 12-16 | 10-14] 21-25 5-9 | 19-22 | 2h-28 | 12-16

Species May June July Aug Oct-Nov | Nov-Dec] Feb | March | April | June

Cladocera

Bosmina 2 5 157 1%6 ah | 0.7 +09 7
coregoni

Bosmina h 825 7399 35 1 1 0.2 185
longirostris

Daphnia ie) 0.5 29 O.1 0.03 ie} ° ie}
galeata

Daphnia Ok Q 1917 15 0.06 0.8 O.1 2
retrocurva

Dephnia ° ie} 2 0.2 fe) ie) °O 0.3
iongiremis

Ceriodaphnia ie} ie) 279 0.3 ° ° ° ie}
lacustris

Chydorus 0.1 ie} 2 ° 0 ie) ie) O
sphaericus

Holopediun ie} (0) 0.5 ° 10) ie} ° 1)
gibberum

Polyphemus ie} ie) O.1 ° ie} ° ° ie}
pediculus

Diaphanosoma ° ce) 0.5 le} ie} 10) ° fo)

Alona ° 0 ie} 0.1 0.03 O.1 re) O



SECTION IL

INTRODUCTION

The production of zooplankton in Lake Onatrio is closely related to
environmental perturbations, including the input of plant nutrients
and the introduction of exotic fishes. The principal purpose of this
study, during The International Field Year on the Great Lakes, was

to examine the abundance of zooplankton with regard to likely sources
of nutrients and other perturbing factors, and then to evaluate the
quality of this environment using the tools of modern ecology. These
included both mathematical tools, such as expressions for community
stability, as well as electronic devices such as our zooplankton-
sensitive echo-sounder. With the results of this program now analyzed,
we have a much better picture of specific regions along the shorelines
of Lake Ontario where eutrophication is proceeding at an increased
rate; in addition, it has been observed that even the deep-water
communities sometimes exhibit signs of environmental instability.

In Section III we have listed the methods used, including traditional
collection techniques with fine-meshed (64) plankton nets, as well
as acoustical methods for determining the total biomass of zooplankton
in the water column. In addition, a detailed discussion of the
collecting efficiency of nets has been included, with the result that
we have suddenly realized that previous estimates of zooplankton
biomass have been consistently low, by at least a factor of 2 and
possibly by as much as one magnitude.

The seasonal distribution of the zooplankton crustaceans is important
to modelling grazing and fish production. Detailed summeries for all
ten cruises on Lake Ontario have been included in Section IV. In
addition, horizontal distributions of all dominant species have been
interpolated using the 60 station IFYGL grid. Analysis of these
distributions, coupled with a subjective division of the crustacean
zooplankton into oligotrophic and eutrophic indicators, has provided
us with a detailed picture of the polluted regions of Lake Ontario,

so that sources of plant nutrients may be identified and logical steps
taken to reduce the rate of degradation of this vital ecosystem. One
important function of this distribution analysis of the zooplankton
is to identify in-basin sources of pollution, as opposed to perturbations
resulting from the inflow of nutrients from Lake Erie.

Certainly urban concentrations of people, as well as industry and
agriculture, are likely sources of nutrients and other perturbations.

In the Lake Ontario basin most urban centers are also associated

with rivers, whose mouths serve as naturel harbors. In Section V we
have examined the effects of urban centers and associated agricultural
drainage upon inshore communities of zooplankton. Certainly the effects
are most striking.


SECTION VIII
A HYPOTHESIS ON CALANOID SUCCESSION TO CLADOCERANS
DURING EUTROPHICATION

INTRODUCTION

Changes in the species canposition of the crustacean zooplankton have
long been used as an indication of the increased eutrophication of
freshwaters. The best known indicator, Bosmina longirostris, was
observed to replace the larger B. coregoni after 50 years of enrichment
of the Zurichsee (Minter, 1938). B. longirostris likewise replaced

B. coregoni in Linsley Pond following a period of increased productivity
(eevey, 1942).

In the Laurentian Great Lakes a complicated series of changes have been
detailed. In Lake Michigan the cladocerans Daphnia retrocurva and

D. galeata dominated in 1927 (Brooks, 1969) and 1954 (Wells, 1960),
‘gave way to the smaller and likely more predation-free D. longiremis

by 1966, while D. retrocurva was again dominant by 1968 (wells, 1970).
Likewise, Leptod ndtii, the largest cladoceran, was common in
1954, rare in 1900 and common again by 1968, as were the large calanoids
Limnocalanus macrurus, Epischura lacustris, and Diaptomus sicilis
(Wells, 1960 and 1970). Such data have been interpreted as a response
to high alewife predation through 1966 (Brooks, 1969), with a return

to 1954-like populations following the alewife dieoff after 1966 (Wells,
1970). By 1972, Bosmina longirostris and Cyclops bicuspidatus were
dominant (Roth and Stewart, 1973).

Similarly, in Lake Ontario Diaptomus and Daphnia were abundant in 1939,
whereas Cyclops bicuspidatus and Bosmina longirostris took over as in
Lake Michigan by 1969 (McNaught and Buzzard, 1973). Bosmina is now
especially abundant inshore and nearby urban areas (McNaught, 1974).

In Lake Erie similar communities were dominated by D. galeata in 1938,
with D. retrocurva second (Chandler, 1940), whereas by 1959 the smaller
D. retrocurva had succeeded (Bradshaw, 1964). Again we could have
interpreted these observations as evidence of size-selective predation,
but in my opinion the size spectrum of food resources must also be
considered.

Clearly a better understanding of eutrophication will result from a
greater knowledge of selective factors governing changes in species
composition. Brooks (1969) has suggested that, in addition to enrich-
ment, plenktivory by fishes and zooplankton filtering capacity are
primary factors in species succession. But additional factors under
two following headings are also vital; all emphasize the nutritional
aspects of a nutritionally dilute environment:

ues


where intrinsic birth rates (b) were used as designated in Table 7, and
death rates for Diaptomus (0,10 ind/ind/day), Daphnia (0.5 ind/ind/day),
and Bosmina (0.01 ind/ind/day) were based relative to size. Fish preda-
tion was considered negligible in Lake Superior, and high in Lake Ontario.
Production was calculated for a period of 10 days, to illustrate the
potential of these populations. Then to determine the impact of grazing,
we simply multiplied the individual grazing rate (G) times herbivore
abundance (N). As opposed to the organismic subtotal of relative values,
we have termed this the Production-Grazing subtotal (Table 16, Section II).

Once each of these factors of evolutionary significance had been assigned
a relative value, we applied the non-parametric Wilcoxon's paired, signed
ranks test (Sokol and Rohlf, 1969) to see whether one column (components
of adaptation for a species) was significantly different from another.
Under oligotrophic conditions, Diaptomus totaled 481 pts., but was not
significantly better adapted than Bosmina with hol pts. (T = 11, p0.1);
on the other hand, Daphnia was better adapted (T = 0, p<0.1) than
Bosmina. Under mesotrophic conditions, Daphnia was significantly

tt = 6, | better adapted than Diaptomus, while Bosmina was not

T = 9, po.1).

CONCLUSIONS

f

The sum total of all relative Organismic and Production-Grazing subtotals
has been called the Adaptation Value (Table 16). These Adaptation Values
suggest that Diaptomus would be successful in an oligotrophic lake like
Superior, because of its superior filtering capacity and its high inges-
tion rate at low cell densities and high ingestion efficiency at small
cell sizes. Bosmina was not predicted successful under similar condi-
tions, because of its low filtering capacity.

In contrast, in mesotrophic Lake Ontario the feeding generalist, Bosmina,
was predicted successful because of its ingestion efficiency on small and
large cells alike, its small size at maturity, which reduces fish preda-
tion and its high intrinsic birth rate (bygx). Indeed, Diaptomus sicilis
is the dominant organism in Lake Superior ‘(patalas, 1969), and occurs in
all of the Great Lakes (Robertson, 1966), while Bosmina longirostris
dominates in Lake Ontario (McNaught and Buzzard, 1973).

However, in both trophic simulations Daphnia was predicted more success-
ful than observed in nature, due to its high filtering capacity, high
ingestion efficiency on both small and large cells, and its high intrinsic
birth rate. Clearly we have more to consider in this case. and possibly
fish predation upon Daphnia has been undervalued. Also, Daphnia retro-
curve and Dia onus ave been observed to co-occur, made possible through
Yesource allocation (Lane and McNaught, 1973).

Regarding zooplankton succession, we have added the important concepts
of ingestion rate with the size of food, and ingestion efficiency with
the density of algae, to Brooks (1969) emphasis upon filtering cepacity.
Further investigation of feeding habits should detail the successes in
the Great Lakes of species like Daphnia retrocurva, leading to a better
understanding of eutrophication.

TT


TABLES (CONTINUED )

Table

3 Acoustical reflectivity, estimated column biamass,
column volume and biomass per unit volume for
all stations, Lake Ontario, February 1973.

wu Acoustical reflectivity, estimated column biomass,
column volume, and bianass per unit volume for
all stations, June 1973.

15 Comparison of acoustical biomass estimates over
© - 50 m column, with those of Watson (1974).

16 Growth characteristics and a grazing estimate for
hypothetical populations of zooplankton in an
oligotrophic versus a mesotrophic lake,

17 Lakewide average of zooplankton densities.

18 Mean zooplankton population densities, O- 5 m.

19 Mean zooplankton population densities, 0 - 50m.

vii

60

63

13

8h
86

88


1912 pug STATION 71 DEPTH 186 AVE 5 PREAMP 10°#44 DEPTH 235
MFAN VALUF OF PROFILES QVEK Sf INTERVALS

CH I+ @
cH 3 A
CH 5 &
cH 77 B
CH 9-10
CH oLinle
CH 13-14
CH «15-16
CH 17-18
CH 19420
CH 21-22
CH 23-24
CH 25-26
CH 27-28
CH 29-30
CH 31-32
CH 33-34
CH 35-36
CH 37-38
CH 39-40.
CH 41-42
CH 43-44
CH 45-46
CH 47-48
cH 49-50
CH 51-52
CH 53-54
CH 55-56
cH 57-56
CH 59-60
CH 61-62
CH 63+ 64
CH 65-66
CH ET- 6
CH «69-70
CH 71-72
CH 73-74

120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-66
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80

1972 AUG STATIGN 72 DEPTH
MEAN VALUE @F PEOFILES OVEK SM INTERVALS

1-13
14-26
27-39
40-52
53-¢5
678

R22222

120-80
120-80
120-80
120-80
Te0-86
160-80

1972 AVG STATION 73 DEPTH
MEAN VALUE SF PROFILES OVER SM INTERVALS

CH 1-23
CH 24-46
CH AT-€9

120-80
120-80
120-80

01604 200-120
64407 200-120
=e 7016 200-120
39374 200-120
-1.1700 200-120
71-4033 200-160
- 166395 200-120
7168798 200-120
~ 261894 200-120
2.35958 200-160
~ Ge 5999 200-120
nw EB ALG 200-120
300774 €00-120
~3-3123 200-120
+3. 5462 200-120
“3.7712 200-120
- 3.9970 200-120
4.2286 200-120
Ae A6ET 200-120
~ 4. 6888 “200-120
“409194 200-120
501481 200-120
= 503768 200-120
~S- €088 200-120
7568369 200-120
~ 6.0728 200-120
“6.3112 €00-120
= 6. 5465 200-120
~6.791E 200-120
-7-0314 200-120
= 702649 200-120
-7- 5084 200-120
-7e T7342 200-120
7709665 200-120
-8.1971 £00120
8. A287 200-120
+8. 6630 200-120
32 PREAMP

#0035
“00816
«7810
1.5563
1.7830
3+2615

17 AVE 5 PREAMP 10**4 DEPTH

= 60482
= 20077
+8032

200-120
200-120
200-120
200-120
200-120
200-120

200-120
200-120

1.2288
165778
167188
168124
1.9095
2.0154
2.1246
22365
263513
24641
2515
2.006
Be DCE
268938
2.9882
3.0811
3.1803
3. 28
3.3885
3+ 4789
365766
3. 6706
3+ 7638
348596
3.9 561
4.0616
4.1699
Ae 2B 1A
Ae AG1Y
Ae 5146
Ae 6215
467312
Ae AL2
As9517
560563
541597
562719

10#*4 AVE 5 DEPTH

142893
1.8298
261153
2+ 1656
265747
16488 6

+ 6278
©3349

200-120 -«3910

105

500-200
S00- 200
500-200
500-200
500-200
500-200
500-200
506-200
$00-<€00
s00- 200
800-200
500-200
500-200
500-200
500-200
500-200
$00-200
S00-200
500-200
500-200
500-200
500-260
500-200
500-260
00-200
500-200
500-206
500-260
500-200
500-700
500-200
S00- 260
500-200
500-200
500-200
500-200
500~ 200

41

500-200
500-200
500- 200
500-200
500-200
500-200

24

500-200
500-200
500-200

721572
+ 3856
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16 4989

20.0310

£5787

3e11 0

36 693

401965

4e 7347
502780

505064
3344
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769232

66 445E

6.9724

924906

10-0090

10. 5298

11.0588

11.5617

12-0824

12. 6052

13-1186

13. 6348

14.1596

14. 7138

15.250

15-8098

16.5596

1669131

17.4651

18 «008 6

18-5610

1961014

«1968
«9246
1.6104
228962
£29881
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--3105
st471
= B36

MM
16%
154
20t
est
30M
34
40t4
asa
50M
SoM
60m
65%
70%
7o4
BoM
6S
90%
9st
100M
10 S4
1104
11s
120"
1294
130m
135
140%
14sh
150M
1594
160M
165M
170M
1754
180M
16. SM

10M
14
20M

30%

10M
1m


Filtering rate
( ml /animals / day )

Ingestion rate
(cells x 10°3/ animals /day )

Daphnia
1OFr
L Diaptomus—”
Ol n a 1 p 1 il NJ
100 - SPaphnia
olus
r IN rejection
Diaptomus—x
“Daphnia
OF
| 1 1 1 | 1 an oo | 1 , 4
| 10 100 600
Cell concentration / 10mI
Figure 19.

Filtering rate compared to food concentration for Daphnia
(MeMahon end Rigler, 1963) end Diaptonus (Richman, 1366)
and ingestion rates at these same food concentrations

‘e)


1972 AUG STATION 46 DEPTH 120 METERS PREAMP 108*4 AVES DEPTH 150
MEAN VALUF OF PROFILES OVER 5M INTERVALS

1gt2

igza

Ragggegggsocagggsagggagaag

AUG STATION 48 DEPTH 26 PREAMP
MEAN. VALUE GF PROFILES OVER 5M

22222

AUG STATION 49 DEPTH 20 DEPTH
MEAN VALUF OF PEGFILES GVER SM

1- 3
a 6
1-9
10-12
13-15
16-18
19-2)
pened
25-27
£8~30
31-33
34-36
37-59
AQ LE
43-45
AG 48,
49-51
5é- 54
55-57
58~ €0
61-63
64= 66
61- ©
10-72

1-14
15-28
29-42
43-5€
57-70

1-20
21-40
Al- 60
61-80

120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-30
126-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60

120-80
120-80
120780
120-80
120-80

120-60

+1903
+615
1.1051
1.2764
124685
1.5042
1.5158
1.5322
1.5511
1.5670
1.5763
1.5633
1-58 €0
1. S86 Ee
1. 94E
166039
1.6034
1.5971
1.5942
1.5916
1.99284
1.5902
1.798
145736

+ 7803
06161
5725
+5964
* 6273

26125

120-80 -1.5937
120-60 -2+3075
120-60 -2e941S

200-120
200-120
200-120
200-120
200-120
200-120
£00120
200-120
200-120
£00-120
200-120
200-120
200-160
200-120
200-186
£00-1£0
200-120
200-120
200-160
200-160
200-120
200-120
200-120
200-126

2.1624
Be 7653
3+ 3084
3. 7686
3+ 7109
36 7329
307431
3.7317
3.7170
367158
3. 7088
3.66
3.671
3.6727
3. 6622
3. 6638
366716
3. G67
3.7085
3+ 7358
347655
3.8021
348386
368790

500-200 -14300
500-200 -1. 6090
500-200 -1. 6026
500-200 -1.90%
500-200 -1- S43
500-260 -1. 5920
500-200 -1- 6156
500- £00 .-1. 6460
500-200 -1- 618
$00-200 -147193
500-200 -1. 7579
500-200 -1. 983
500-200 -1-6404
S00-200 -1-8 6
500-200 --1.9198
500-200 -149594
500-200 -1-99 60
S0G-200 =f 0386
500-200 -£-0811
§00- 200 -26 1247
SCO-200 -261 654
500-200 -fefC65
500-200 -2. 2460
500-200 -€- e846

108*4 AVE 5 DEPTH 35

INTE VALS

200-120
200-120
200-120
200-120
200-120

25 METERS
INTERVALS

200-120
200-120
200-120
200-126

101

+ 6004
148190
2.1446
2.1082
169698

AVE 5.

0037
721135
2210
= 63088

500-200 ~.3011
500-200 -+3170
500-200 -+3083
500-200 -. 2694
500-200 --267€

FREAMP 10"*4

500-206 «18.76
500-200 + 3832
500-200 + 5%3
500-200 +7734

x
10M
1Sy
20M


98

Table 18, MEAN ZOOPLANKTON POPULATION DENSITIES, VALUES (UMBER/m3 ) REPRESENT ANIMALS COLLECTED
WITH A NET (64 u aperture).

0-15m 0-10m 0-20m 0-25m
12-16 10-14 15-19 12-1o 12-16 10-14 15-19 12-16 10-14

Species June July May June June July May | June July

Cladocera

Bosmina 35 87 wa 81 3 107 6 9 76
coregoni

Bosmina 323 9137 70 3909 235 10376 27 125 60h9
longirostrig

Daphnia ie} 127 0.3 19 1 103 0.7 0.2 129
galeata

Daphnia 8.5 us 6 2 4 39 Led 5 57
retrocurva

Daphnia o.4 ° fo) fo) co) Ou ° Ok 2
longiremis

Ceriodaphnia 1 37 ) ) ) oe) ° 0.3 37
lacustris

Chydorus 3 4 1 0.9 0.3 4 0.8 2 4
sphaericus

Holopediun io} ie} ° i} 0 i) ie} ie) (o}
gibberum

Polyphemus ie} 0 oO ° O ie} fe) ° oO
pediculus

Diaphanosoma io) ce) ie) 0.9 co ie) ie} re) Le)

Alona ° 8 ie) ce) ° 0 0.7 O.L 13



Table 12, ACOUSTIC REFLECTIVITY (D.C, vouts/m>), ESTIMAT!
COLUMN BIOMASS (g dry wt/m*), COLUMN VopuMe (m3)
AND BIOMASS PER UNIT VOLUME (g dry wt/m>) FOR ALL
STATIONS, LAKE ONTARIO, AUGUST 1972.

Total
Column
Acoustic Biomass Volume Unit Volume
Biomass g ary wt /n® depth _m Biomass
Field St. (120-200-500) (from regression) (x im) g dry wt/m3
1 211,15 151.541 30 5.05
2 1.77 24.629 15 1.64
3 13.79 187.260 20 9.36
5 74.00 1,001,901 95 10.54
7 6.38 87,002 25 3.48
8 46.38 628,20 70 8.97
10 50.58 685.03 115 5.95
12 8.21 111.76 20 5.59
uw 1.26 17.73 10 1.77
a) 59.04 799.49 100 7.99
17 95.98 1,299.29 130 9.99
19 1.22 17.19 10 1.72
20 1.70 23.68 15 1.58
ak 30.92 418.89 110 3.80
26 83.79 1,134.36 U5 7.82
30 11.37 154.52 20 1B
31 49.45 669.74 25 26.78
32 429 .9h 5,817.77 170 34.2
3u 24.95 338.26 85 3.98
35 14.62 198.49 25 7.94
36 20.08 272.36 30 9.07
38 131.13 1,774.87 125 14.19
ho 153.03 2,071.18 170 12,18
ay 6.23 84.97 25 3.40
he 3.55 48.71 15 3.24
Ly 367.88 4,978.10 170 29.2
45 350.11 4,737.67 200 23.68
6 86.43 1,170.08 120 9.75
48 8.63 117.45 25 4,70
hig 1.90 26.39 20 1.32
52 4.17 192.40 65 2.95
3 122.64 1,511.17 135 12.19
59 2.98 41,00 25 1.64
60 1.58 22,06 10 2.21
62 91.25 1,235.29 15 + 7.48
64 51.55 698.15 85 8.21
66 403 55.21 25 2.20
67 2.71 37.35 20 1.87

5h


Table 10. ACOUSTICAL RELFECTIVITY (D.C. VOLTS) FOR THREE
FREQUENCY ENVELOPES (120-80 kHz, 200-120 kHz,
AND 500-200 kHz), FOR 21-25 AUGUST 1972.
(average over 5 m intervals)

Meters No. of Stations 120-80 kHz 200-120 kHz 500-200 kHz

5 58 1516 23755 0989
10 58 +2222 5884. 2381b
15 54 +1686 «8815 +7182
20 hg +1500 1.2811 +9395
25 An 4181 1.keho 1.1877
30 32 ~3023 1.2665 1.7210
35 29 =3819 1.1621 1.9927
ho 27 +1746 1.2860 2.4312
45 26 +3236 Lbs 2.6259
50 26 4201 1.5642 2.9302
55 25 +5493 1.4088 3.2152
60 25 26532 1.5200 3.5127
65 25 +7583 1.6323 3.8100
70 23 1.1152 1.7753 3.9904
ve} 22 1.3273 1.92h5 1.2193
80 21 8720 1.5114 2.8713
85 21 9278 1.6023 3.0559
90 19 1.2515 1.7767 3.2211
95 19 1.3220 1.8696 3.4035

100 17 - .090 1.9648 5.6283
105 16 «Oho 1.9873 6.1378
no 16 +0213 2.0753 6.4365
5 15 7h 2.3157 7.0064
120 wy 243K6 3.6347 7.5339
125 13 «3407 3.7682 8.6384
130 12 +2243 39223 9.1292
135 1. +1361 40181 9.8857
ako 10 +0770 1,,2136 10.9437
145 10 +0639 4.3700 11.3369
150 9 -.1263 4.9523 12,4129
155 8 - 1264 6.2623 13.7948
160 8 - 1446 6.4664 1h .2ke5
165 8 - «1634 6.6709 14.6905
170 7 - 0553 7.6473 16.7466
175 5 - .6382 8.8057 20.2833
180 4 - 8859 9.5345 25 5993
185 k - 9191 9.8014 26.3118
190 2 - 2769 4 L468 5.0913
195 2 - 2877 45589 5.42358
200 2 ~ -2913 4 6666 5.3754
205 1 -.7470 1.2507 1.7701
210 1 --7T10 1.2814 1.8172
215 1 - 8052 1.3164 1.8631
220 1 - 8364 1.3534 1.9085
225 1 - 8714 1.3887 1.9555
230 1 - 9040 1.4197 20050

50


cas

Table 1. INSHORE ZOOPLANKTON POPULATION DENSITIES. Values (number /m3 ) represent

animals collected with net (64 u aperture) at stations in waters less
than 30 m in depth, over vertical range of O- 5 m.

12-16

10-14

15-19 21-25 Oct- Nov- 5-9 19-22 24-28 12-16
Species May” June July Avg Nov Dec Feb Mar April June
Cladocera
Bosmina 13.4 | 62.2 | 20h0, 547. 3628, | 12h6, 64.5 | 62.7] 20.5 152.
coregoni
Bosmina 1-4 | 887. | 904%. 197, 71. BOTS. 16.5 B.8 3.5 | 10.2 | Ofe3-
longirostris A
Daphnia 0.5 | 23.8 75.6 299. an.8 {50.8 |] 13.1 19 6.1 2.3
galeata
Daphnia o. 22.8 %.0 B67. 2331. 689. BT pa BS 39.5 |
retrocurva
Daphnia 0. 0.3 0.3 0. . 0. 0. oO. 5.e 6.0
longiremis |
Ceriodaphnia o. 0.5 | LOL. 3009. 138. Us) oO. oO. 13.6 27eL
lacustris
Chydorus O.1 | i9.7 on 358. 7. 610. oO. T.5 | 12.0 2.3
sphaericus
Holopedium [O. 0.7 0. 30. W5 oO. 0. 0. 0. 0.
gibberun
Polyphemus 0. oo | O Te o. 0. o. o. co o.
pediculus |
Diaphanosoma Oe OL 0. 20, 3.8 5.0 oO. 9.0 oO. 0.
Syelopoida
Cyclopoid .o | 428, 1193. =| 21,552, 111,003. 7532. 11893. 1145. |1341. 17482.
copepodites
Cyclops 170.1 / 534. 5818, hey, | (9326 723. 145. 184. 11363. 639.
bicuspidatus q
Cyclops O7 | 25.7 | il. BEL. 262. 9. 8.3 [ i1.6 | 11.0 203.
vernalis



Relative Backscattering Strength (M)

F

Figure 13. Reletionship between beckscattering strength (Appendix B),
used to caleculete biomass of zooplenkton, and size of
spherical particles for five frequencies (80, 120, 200, 500
and 1000 kHz). (From McNaught, 1969)

al


Table 9 (b). CORRECTED ACOUSTICAL PROFILES

Fon

CORRECTED PROFILES F9
AVG S PFRIH 130 SCAN 176

AUG £14 17 FA 1ORe
60 KC

OL sEP10 OR o87SS C3 aT Of 2176) OF 01770 06 21742 07 of761
OB 63636 OF 617K0 10 217FK 12 21777 1G 017% 13 217K 14 61 KO
15 61690 16 61702 17 LOSE WH oA TAL 190 01TH BO 61715 BE)
22 61793 23 017P0 24 21745 FS el 7Ea BE 17ND 27 21750 es
2 3G 61719 3) 01705 GE LEED GS ANTS SA ONT SS 61 TET
BG 61600 37 6 1TGO BE 6 IT17 SO 41700 40 «61700 AL 6170 42 21TKS
AB 63690 44 61713 45 A ITLE AG IGG AT eS Tes 46 61TSI 49 OL TEG
5G 61797 SL 61754 52 616K 5B 61749 54 61761 55 61755 56 61 BO
S57 «3700 SS 61702 59) 61751 GO 61726 GL 61783 62 61751 63 21610
64 61700 GS 6174S EG 61706 67 21786 GH 014 O 21766 10 01746
Tl 63703 72 61755 73 61747 74 01660 75 01K 16 614 77 21 wE
TS 01710 79) 61734 BO 61761 GL WIT BL 61GE 83 .1ET! BA «1700
65 8705 BE 61728 BT «1693 BY 617DL BD 6176490 64516 91 63ST
92 13660 93 1.065494 «464 95 61870 96 2157 97 6165798 «1762
99 e17EE FF 2IOIY

120 KC

O1 162145 02 «3062 03 61920 OA 21756 O5 21745 06 013725 07 61717
O08 61741 OF 61751 10.1705 33 61721 12 CATE 13 21656 14 61677
YS 61691 16 «1657 17 21654 18) 61635 19 41645 20 61656 21 21 1
22 21674 23 61669 24 21677 25 61 65E EG CLOT ET 21664 2H 6 1GT
29 «1670 30 61665 31 41652 3% 23659 S33 21674 SA 61654 G5 1 EHD
36 61089 37 +1QG 3 61659 3D 1GHO 40 21640 41 21631 AZ 61855
42° 61700 44 61657 45 6 1E52 46 61S AT 21657 46 216% 49° 21652

50 «16606 51 22673 52 21601 53° 21637 54 21655 55 56 21674
57 566 1661 59 41638 CO 216682 G1 21676 68 63 6 16H
64 €5 61640 66 21656 67 161657 & 21707 & 70 0 G74
cei 72 21660 73° 61629 74 «1659 75 211 76 77 6 1G1E
18 79) «1665 BO oe I1ECH BL 61ESD BA EEL G3 W16E7 BA 61H

85
92
99
200 KC

0) 1.2194 02 44970 03 «3948 0A «3809 05 «307 06 «3830 07 +34E1
08 435323 09 43253 10 «3241 11 2318S 12 «316613 6314714 «3158
4S 63288 1G 63373 17 «3470 18 4353319 43575 20 «3600 21 -3615
22 .362h 23 «3651 BA 43643 PS «362A H6 13633 27 23649 BB +3645
29 43616 30 23616 31 43613 32 63609 33 «3631 34 49615 55 634
3G 23616 37) 6363) 36 463591 39 65579 40 636825 41 65634 42 «3b
AB 68616 44 43603 45 43615 AE 63581 AT «3586 AB 23624 AD» 3630
50 63627 53 «3618 52 «3603 53 «3531 54 4635616 55 «63997 56 «3615
57 «3604 56 63607 59 43576 60 +3545 61 23004 62 «362K 63 -3E1G
€4 2.3625 65 «3596 66 2.3594 C7 «3A CH 23597 DO 63685 1 + 3E1E
71 63601 72 «3628 73 43613 74 «3609 75-3596 76 .386 77 «3601
7% .3997 79 63615 60 23615 61 63612 BE 635V7 HB «3A BA 230
85 3590 86 6350447 «350A BS 63501 89 »3606 90 «582991 63579
9B 6377593 63876294 6374495 63715 96 6372197 63598 +3672
99 23642 8% 41713

500 KO

01 4703302 .€057 03 «5679 0A .5791 05
08 «5202 65653 10 .S5é41 TE 6 S6AI LE
15 «5605 16 «559617 «5576 16 «5571 19
2 .5h63 23 65574 BA 65574 25 «SECU BG
29 65537 30 +5543 31 «5545 32 «5540 33
36 «5542 37 25540 36 65525 GY. S5es AD
43 «5491 44 +5523 45 .5585 46 65500 47
50 45520 51 +5504 52 2.5506 53° 4 S514 54
57 «5503 53 25503 59 65475 Co BASS OI
64 65497 65 «S506 CG +5483 C7 D497
71 «5800 7% «5463 73 SMO TH 6 BHA 15
78 «5511 72 25500 60 6547 GI 65404 BE
BS «5492 BG 15450 BT - SAIL BE + SABO BD
92 «880693 5459 94 SME OS -5491 96
od 540) 9& 32%

66 «lé44 ST 61G59 BB 61655 BY 6166790 «575791 1670
293 23157 94 6375595 6171596 ©3751 97 61700 98 «3749
eR 61136

+5718 07 +8764
+561) 14 6 5607
+5576 £1. 556%
+5540 2B 6 S54
+5528 35 25514
+ S525 42 6 SS1L
«5517 49 6 S517
+5500 56 + S4s7
«S820 63 6 Sad
«5806 70 S51)
DE TT 6 She)
2894 BA 6 Sha
25491 91 6 55GB
+5483 98 6 S480

45


Daphnie ma and Richman (1966) on Diaptomus oregonensis have been
compared (Figure 19). The ingestion rate I,) has been described by

the above authors in terms of cells ingested, where:
Ip = cells ingested/animal/day

Thus Diaptomus feeding in a concentration of cells characteristic of
oligotrophic lakes (925 cells/ml), ingested cells at a rate of 1800
cells/an/day (Figure 19). Daphnia, filtering at similer rates, would
ingest only 400 cells/an/day. In contrast, at an mesotrophic concentra-
tion of 2600 cells/ml, these graphs would indicate an ingestion rate
for Diaptomus of 5000 cells/an/day, while Daphnia would ingest 1300
cells/an/day. Clearly at oligotrophic and mesotrophic concentrations
of planktonic algae, Dieptamus has a higher ingestion rate (Figure 19).
Diaptomus thus has e hi ingestion efficiency at low densities. In
these experiments, Daphnia was fed yeast and Dieptomus algae. While
more such efficiencies must be determined for natural assemblages,
these comparative results suggest that Diaptonus is adapted to existing
on a more dilute food source than Daphnia, which is better adapted to
the rigors of life in eutrophic waters, with its highly developed
respiratory system.

Just recently, Bogdan and McNaught (1974) have examined ingestion
efficiency with regard to the size of algal foods. Diaptomus, the
nemnoplankton specialist, is three times more efficient on nannoplankton
(.016) than netplankton (.005), but Daphnia, the generalist, was
equally efficient on both (065 and .002). These findings again suggest
Diaptanus to be well adapted to oligotrophy.

The last nutritional item, the evolution of the efficiency of digestion,
relates to both the size and packaging of the algae resource, Recently
Porter (1973) has found that green algae encased in thick gelatinous
sheaths pass the gut of Daphnia galeata in viable condition. Much needs
to be done relating the efficiency of digestion to size, packaging,
available digestive enzymes, etc. and this parameter will not be given
a value here,

Growth related responses have likely evolved with regard to fish
predation. Evolution toward small size of the adult at the time of
first brooding is of considerable benefit rend predation. We
have examined the size of Diaptowus sicilis (1.6 mm), Daphnia galeata
(1.0 mm), and Bosmina longirostris (0.26 mm) at Le of first
birth. Quite obviously, Bosmina has a considerable advantage in this
regard. Within genera, certain species also have an advantage, as
B. longirostris is smaller than B. coregoni (0.5 mm) of oligotrophic
waters, possibly one of the important factors explaining the often
noted succession between these two species.

In a similar fashion, r-selection organisms can withstand considerable

predatory pressure through a high intrinsic growth rate. Additionally,
selection for high growth rate (r) in planktonic organisms has enabled

TH


1973 “FEB STA 32 PA 10*#4 AVG 5 DEPTH 171 M DEPTH 160 M SCAN 200 M

MEAN VALUE OF PROFILES OVER

CH
CH

CH
CH
CH
CH

1- 2
3- 4
6
8

“FEB STA 34 PA
MEAN VALUE OF

1-4
S &
9-12
13-16
17-20
21-284
25-28
29-32
33-36
37-40
41-44
AS- 48
49-58
53-56
57~ CO
€1- 64
65-8

120-80
120-80
120-80
120-80
120-60
120-80
120-60
120-60
120-60
120-86
120-80
120-80
120-80
120-80
120-360
120-80
120-60
120-80
120-86
120-80
120-80
120-80
120-80
120-80
120-26
120-80
120-80
120-80
120-86
120-80
120-80
120-80
120-80
120-80
120-80
120-80

10##4 AVG 5S DEPTH 85

~01997
1937

SM INTERVALS

200-120 + 5542
200-120 «5742
200-120 S824
200-120 58.08
200-120 «5767
200-120 «5785.
200-120 «5615
200-120 «5736
200-120 «5622
200-120 «5567
200-120 «5475
200-120 + 5350
200-120 «5295
200-120 + 5248
200-120 + 5118
200-120 + 5004
200-120 «4957
200-120 + 48 64
200-120 «4792
200-120 64796
200-120 «4755
200-120 4625
200-120 +4600
200-120 «456:
200-180 A367
200-120 24264
200-120 HEAD
200-120-4079
200-120 «3945
200-120 +3901
200-120 3774
200-120 «3563
200-120 +3505
200-120 «3465
200-120 «3305
200-120 «3246
DEPTH 88 M

PEGFILES OVFR &4 INTERVALS

120-80
120-80
120-80
120-80
120-80
120-60
120-680
120-80
120-80
120-80
120-80
120-80
120-60
120-60
120-80
120-80
120+80

0954

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

136

7.1242
+9 629
- 1.0829
~ 1.0558

7160744
-1.0743
1.0844

500-200
500-200
500-200
500-200
500-200
500-£00
506-200
500-200
500-200
500-200
500-200
500-200
506-200
500-200
500-200
500-200
500-200
500-200
S$00- £60
500-200
560-200
500-200
500-200
500-200
500-200
s$00-200
S00- 200
So0- 200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

SCAN 125

500-200

00288
#1310
237
©3437
+ 446 6
+ 5563
+ 6635
+ 7TH 6
«8 740
+9 BG
1.0819
161843
1.2664
31.3925
1.4957
1. 59868
1. 7026
1.8055
169099
2.0149
£61182
Be B04
&- 3244
&. 4265
2. 8300
&- 631
2. 7331
268333
209337
3.0343
3.1348
3.6342
3. S311
3. 4294

M

-21152
--0080
+0973
21987
629

11 Sa
1204
1254
130%
135%
140%
1ASM
156%
1585
1601
1654
170%
175%
18 0%

aM
10M
1M
20%
amt
304
34
AM
aay
50M
5a4
60M
6s
TOU
TS
80M
eat


1972 NEV STATION 65 PA 10®*4 AVE 5 PEPIH 168 M SWEEF 192 M
MEAN VALUF OF FEORILES OVER SY INTERVALS

ig72

CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
cH
CH
cH
CH
CH
CH
CH
CH
CH
CH
CR
CH
CH
CH
CH
CH
CH
cH
CH
cH
CH
CH

in 2
3-4
S 6
7 6
9-10
W-1e
13-14
15-16
17-18
19-86
el-2e
B3eEL
BS- EE
21-E6
29-30
31-52
33-34
35-56
37-38
39-40
Ain ae
A3- 44
45-46
47-48
49-50
51-58
53-54
55-56
57-58
59-60
61-6

€5- 66
OT~ &&
€9-70
W972
13-74

1£0-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-#0
120-¥0
120-80
120-80
160-80
1£0-86
120-86
120-80
120-60
120-60
1£0-&0
120-80
120-60
126-80
120-66
120-80
120-80
120-80
120-80
120-80
120-60
120-60
120-80
120-80
120-80
120-80
129-86
120-66
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Figure 1. Design of a continuous-efficiency net calibrator

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VERTICAL PROFILES OF RELATIVE ZOOPLANKTON BIOMASS

Since the trophogenic zone, or the waters where phytoplankton photo-
synthesis exceeds respiration, is confined to the upper 30 m in Lake
Ontario, previous studies of zooplankton abundance have centered upon
the upper 50 m of water (Patalas, 1969; Watson, 1974), A major
contribution of the zooplankton acoustical samples is an indication of
abundant, zooplankton size particles at greater depths than 50 m.

Once acoustical data have been placed in 5 m depth intervals for each
station (Table 9), it is relatively simple to produce a lakewide
estimate (Table 10) for each cruise. On 30 October - 3 November 1972,
2 - 3 mm particles (200 - 120 kHz) and 0,8 - 2 mm particles (500 - 200

_ kHz) were both most abundant in the deepest waters at 230 m depth
(Table 10). Summaries for the distribution of 0.8 - 3.0 mm particles,
the size-range for most crustacean zooplankton, are presented in Table 1]
and Figure 15. During 21 - 25 August 1972 particles were relatively
most abundant between 100 and 200 m depth. Fran 30 October - 3 November
1972 zooplankton sized particles were most common in the deepest waters.
Over the period 12 - 16 June 1973, these same particles were most
abundant between 60 and 130 m depth. ‘These average estimates of biomass,
made using acoustical techniques, are for all 60 stations of the IFYGL
grid and usually represent a mean derived from 5 days of measurements
made both day and night.

49


10

Us

FIGURES

Design of a continuous-efficiency net calibrator.

Filtering efficiency with depth for 3 vertical tows
(100 m- Om, 50m - Om and 25 m - Om) made in
lake Ontario.

Density (no./m3) of eutrophic Cladoceran Bosmina

longirostris on 21 - 25 August 1972 in surface waters
G - 5 mm) Of Lake Ontario at 60 stations of IFYGL

Biology Program.

Density (no./m3) of oligotrophic Bosmina coregoni, on
21 - 25 August 1972 in surface waters (0 - 5 Meee

Density (no./m3) of eutrophic Daphnia retrocurva on
21 - 25 August 1972 in surface waters (O- 5 Mjes.

Density (no./m3) of ultra-oligotrophic Diaptomus sicilis
on 10 - 14 July 1972 in surface waters (0 - 5m)...

Density (no./m3) of mesotrophic Diaptonus minutus
on 12 - 16 June 1972 in surface Waters ~Bim)ece

Density (no./m3) of Cyelopoid copepodites on 21 - 25 August
1972 in surface waters (0- 5m)...

Density (no./m>) of Cyclops bicuspidatus on 10 - 14 July
1972 in surface waters c = 5 M)eoe

Density (no./m) of Cyclops vernalis on 21 - 25 August
1972 in surface waters = 5m)...

Density (no. fn?) of ropocytlops sinus on 3 October
2 November 1972 in surface waters 6 = 5 m)se.

lake Ontario, divided into three areas of differing
trophy and community structure...

Relationship between backscattering strength and size
of spherical particles for five frequencies...

Regression of zooplankton biomass (g._dry wt/m3) against
acoustical reflectivity (D.C, volts/m>), made fran
actual samples and acoustical profiles collected
simultaneously on Lake Ontario,

iv

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17

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48


TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)

THTPORT NO,
EPA~660/3-75-021

J. RECIPIENT'S ACCEBSIONNO.

F
4. TITLE AND SUBTITLE ee

ZOOPLANKTON PRODUCTION IN LAKE ONTARIO AS
INFLUENCED: BY ENVIRONMENTAL PERTURBATIONS

IS. REPORT DATE
June_1975
(6. PERFORMING ORGANIZATION CODE

66030

AUTHORS

McNaught, D.C., M. Buzzard, and S. Levine

|S. PERFORMING ORGANIZATION REPORT NO.

[p. PERFORMING ORGANIZATION NAME AND ADDRESS

Department of Biological Sciences
State University of New York at Albany
Albany, New York 12222

70, PROGRAM ELEMENT NO-

iT. ae ee TGRANT NO.

Grant 800536

12, SPONSORING AGENCY NAME AND ADORESS
Environmental Protection Agency
National Environmental Research Center
Grosse Ile Laboratory

Grosse Ile, Michigan 48138

13. TYPE. OF REPORT AND PERIOD COVERED
Final
'14, SPONSORING AGENCY CODE

76, SUPPLEMENTARY NOTES:

Te ABSTRACT
The Crustacean zooplankton are excellent
especially if enough of their biology is

in Lake Ontario suggested that eutrophic
of major urban centers.* Furthermore, ma

nature.

conclusion.

increase with nutrient enrichment of lakes.

indicators of environmental perturbation,
known to explain certain species

The distribution of zooplankton
indicators were found in the vicinity
thematical indices, including diversity,

the community competition coefficient, and carrying capacity, separated urban
inshore from rural inshore waters, further evidence of perturbation.
estimates made with new acoustical techniques indicated that most of the
zooplankton biomass was in deep waters, thus the eutrophication of Ontario's
waters, both nearshore and in the vicinity of cities, is still localized in
Mathematical techniques have been developed to model such perturbations.

Biomass

The report was submitted in fulfillment of an EPA project, Grant No, 800536,
by the State University of New York at Albany under the sponsorship of The
Environmental Proteetion Agency. Work was campleted as of 15 August 1974.

¥fhe ratio of the number of Bosmina longirostris, the most successful eutrophic
species, to Diaptomus sicilis, the most oligotrophic form, supported this

KEY WORDS AND DO

ICUMENT ANALYSIS

“DESCRIPTORS

Ib. IDENTIFIERS/OPEN ENDED TERMS |c. COSATI Field/Group

Zooplankton, perturbed watermasses

Lake Ontario, IFYGL,
Zooplankton

iH, DISTRIBUTION STATEMENT,
RELEASE UNLIMITED

19. SECURITY CLASS (This Report) 21, NO. OF PAGES

20. SECURITY CLASS (This page) 22. PRICE

EPA Form 2220-1 (9-73) U.S, GOVERNMENT PRINTING OFFI

ICE: 1975-698-781 JI71_ REGION 10



1

is used and an adjusted competition matrix A” is formed with elements

aj
a5 = 5 5 (3)

Neve

These elements indicate the relative competitive impact of species j
on species i.

While a comparison of communities can be made using the %,, or al, ,
values directly, data reduction techniques can often fecilitete the
analysis. A number of these techniques are based on averaging over
the competition matrix in different fashion.

Vandermeer (1972a) suggested two approaches. First is the row averege,

which he termed the community effect. It measures the competition
faced by e species. The ith row average, Oe (or “ » is defined as

(4)

(where 4 means "is defined as")

A second measure is the column average, termed the species effect.
This is defined as

n
- is
Sj A ty (5)
and similerly for obs. This measures the impact of a species on the
community. Oe 5 can Be written
m
4
= =1 J ~
ory =f yn (6)
ave

and considered to be a normalized effective population density (normal-
ized by n e)? where effective refers to competitive impact. This
measure is Useful in rank ordering species in terms of their importance
in the community as a function of competition.

Row and column averages are species’ properties and can be used in
comparing the roles of species within and between communities, Another
species measure, not a function of the a's, is niche breadth. If
species i has a one dimensional niche divided into r micro-environments

66


Te

Figure 6, Density (no. /m3) of ultra-oligotrophic Diaptomus sicilis
on 10 - 14 July 1972 in surface waters (0 - 5 m) of Lake
Ontario at 60 stations of IFYGL Biology Program


SECTION VII

COMPARATIVE MATHEMATICAL ANALYSIS OF ZOOPLANKTON COMMUNITIES

INTRODUCTION

One of the important topics of ecology is the comparison of different
communities. Communities found in similar environments as well as
those occupying very different environments can be compared for species
composition, species interactions and mass and energy flow, as well as
other community properties. Comparison can be descriptive and qualita-
tive, or some quantitative measures of community structure and the roles
of species can be developed.

This study utilizes the competition matrix by Levins (1968) as a model
from which to develop such measures. A very simple definition of
community is implied by this model, simply a group of species interacting
at a time and place --- the question of whether the community is a
natural biological unit (Poole, 1974) is of no concern.

The use of the competition matrix restricts the concept of community
to a group of competitors and therefore to essentially one trophic
level. This study considers a community consisting of only the
dominant herbivorous zooplankters as the cladocerans, Daphnia galeata,
Dephnia longiremis, Bosmina, Diaphanosoma, and the calanoid copepods,
Diaptomus minutus and Diaptomus sicilis. Omnivores and carnivores are
excluded from the model.

Three different levels of community structure are investigated with
measures developed from the competition matrix. First, the individual
interactions between species can be considered. Then the importance of
each species in terms of competition levels can be investigated. Finally,
at the community level, the average intensity of competition and
community stability can be studied.

Additional measures not directly related to the competition matrix are
also considered in this study. Niche breadths, as a property of species,
and community diversity, a community property, are essentially informa-
tion measures which can be applied to comparing communities.

Utilizing these measures of the entire community the following hypothesis
can be investigated; During the period between spring and fall turnovers
of the lake the zooplankton community evolves toward reduced competition,
increased stability and increased diversity.

The competition matrix is based on a model of interacting species first

used by Volterra (1926), This model has been given two interpretations.
First, it cen be considered as a simple model of population dynamics in

64


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HORIZONTAL DISTRIBUTIONS OF ZOOPLANKTON BIOMASS
(ACOUSTICAL EST.) :

Detailed analysis of horizontal distribution of column
biomass (zooplankton g dry-wt/m',

21-25 August 1972 ---

The lakewide distribution of zooplankton biomass reached a maximun
during late summer 1972 (August). As expected the largest biomass per
surface area was in deepwater. During 21-25 August 1972, notable
concentrations of biomass were observed at stations 85 and 89 in
eastern Lake Ontario and stations 32, 44 and 45 in western Lake Ontario
(Figure 16). The mean biomass per unit volume of lakewater, considering
all stations at ell depths, was estimated to be 11.84 g dry wt/m3. This
very high value resulted, as indicated in the previous section, as a
result of a large acoustical reflectivity from targets located at

100 - 200 m depth (Table 12).

5-9 February 1973 ---

The lekewide distribution of zooplankton biomass in February 1973 was,
as expected, lower than in August 1972, but again greatest in deepwater.
Three large cells are noted (Figure 17), one in the mid-western section
of the leke with a large arge greater than 500 6 /w! » one in midlake

off Rochesgers with 300 e/a » and one in eastern midlake with a biomass
of 150 ef . A single large inshore area of high zooplankton biomass
was obsgrved off the Oswego River, with a small area greater than

150 g/m, rather high for shallow water (Table 13).

June 1973 ---

By Jyne 1973 the lakewide biomass had increased to a mean of 3.0 gm dry
wt/m? (per unit volume), as shown in Table 14. Two large cells were
located in western Lake Ontario, centered upon stations 10 and 32, An
inshore cell was Located west of Rochester, centered on station 56,

and a high concentration of particles was observed in Mexico Bay. Again
the general principal of a predominantly deepwater distribution of
biomass is evident (Figure 18).

Comparison with Previous Estimates of Zooplankton Biomass

Zooplankton biomass estimates for Lake Ontario were made by Watson (1974)
from animals taken in vertical tows fran 50 m to the surface (Table 15).
It is immediately obvious that our estimates are about 100x those made
previously. This is because (a) the efficiency of net sampling, about
4, was not considered, and (b) because we have placed much of the
biomass (estimated acoustically) below 50m. It is necessary at this
time that our acoustical estimates be considered preliminary. But they
should provide a considerable stimulus to verify or deny the existence
of considerable zooplankton biomass at depths greater than 100 m in
Lake Ontario.

aT


qT

Table 2. OFFSHORE ZOOPLANKTON POPULATION DENSITIES, Values (number /m3 ) represent
animals collected with net (64 u aperture) at stations in waters greater
than 30 m in depth, over vertical range of 0 - 5 m.

15-19 12-16 = 10-14 921-25 Oct- Nov- 5-9 19-22 2b-28 12-16
Species May June July Aug Nov Dec Feb Mar April June
Cladocera
Bosmina 0.5 31.3 | 389. | 1453. 2050. Tl. 11.0 Ah 5.8 66.1
coregoni
Bosmina 28. 288. { 13206. |63,691. 1784. BH 0.3 1.2 2.1 | 972.2
longirostris
Daphnia 0.4 22.2 | 3027. 99. 13.6 8.5 0. 0.2 oO. 0.9
galeata
Daphnia 0. 15.9 | 149. [11,965. 1733.9 66.7 0. 0. 0.21 25.7
retrocurva
Daphnia 0. oO. 29k, 0. 0.7 0.2 0. oO. 0. 0.2
longiremis
Cericdaphnia | 0. 0.7 | 103. 4202, 149.8 59.6 o. 0. 0.5 6.7
lacustris
Chydorus 0. 16.0] 641, 100. 33.5 0.7 0. 0. 0. 5.9
sphaericus
Holopedium oO. 0. 53.9 7. 1.5 0. 0. 0. 0. oO.
gibberum
Polyphemus 0. 0. oO. 3. 0. - 0. 0. oO. 0. oO.
pediculus
Diaphanosana [ 0. 0. 0. 2.5 0.3 oO. 0. oO. 0. 0.
Gyelopotaa
Cyclopoid 8.7 | 322. 2201. |29,143. | 10,803. 6820, |2260, {1600, 664, 9674,
e odite 5
cyclone Bub, 1h2h, 478, [12,113. 1182, 345.9 | 121.0 | 268, 452, 538.5
bicuspidstus q
Cyclops 0.7 28.1 {| 190. 643, 132. 131. 13.2 4,9 0.9 34.9
vernalis



to detect the ecological impact of in basin inputs of nutrients and
other substances. This will be attempted by dividing Lake Ontario

into three segments, with special attention given to proximity to

human influence. These designated ereas thus include (1) inshore

waters adjacent to urban centers and less than 30 m in depth, (2) inshore
waters not offshore from but adjecent to rural areas, and (3) offshore
waters greater than 30 m in depth.

Vertical plankton hauls were taken from the NOAA R/V Researcher at the
60 IFYGL sempling stations (Figure 12) on the cruises of 12 - 16 June,
10 - 14 July and 21 - 25 August 1972. Fortunately these 60 stations
selected by the IFYGL management were comparable within the framework
of our lakewide division. The urban inshore stations had a mean depth
of 14.0 m, whereas those stations designated rural inshore had a mean
depth of 18.5 m.

COMPARISON OF ZOOPLANKTON COMMUNITIES

Basically three types of comparisons will be made between populations
inhabiting urban inshore, rural inshore, and offshore waters. First
the relative densities of each species will be contrasted. Secondly,
traditional measures of Shannon-Weaver diversity, richness and evenness
will be utilized. Lastly, community indices, including the theoretical
comunity competition coefficient (4) and community carrying-capacity
(K) (Levins, 1968) will be used. Discussion and application to Great
Lakes problems of these indices by Vandermeer (1972), Lane and
McNaught (1970), and McNaught and Buzzard (1973) may be consulted for
information on formulations and application.

Density Differences

In canparing densities (Table 4), relatively higher numbers, but fewer
species of many cladocerans were found in urban inshore waters.

Daphnia longiremis was limited to offshore waters, while Bosmina
longirostris, Ceriodaphnia, Chydorus, Polyphemus and Diaphanosoma were
usually more abundant offshore. However, on a unit volume basis (no./m3)
the cladocerans, usually considered warm water organisms, were more
abundant inshore than offshore during June-August (mean of 64,325/m3
versus 33,737/m3). Roth and Stewart (1973) found a similar situation
in Lake Michigan. In contrast to the cladocerans, the cyclopoid
copepods did not exhibit such an obvious trend. Among the calanoid
copepods, both Diaptomus minutus and D. oregonensis were more abundant
offshore, as was Limnocalanus, a cold water form. A two-way analysis

of variance demonstrated that zooplankton densities varied significantly
(p < .01) with time (Table 7), but not with location. Clearly there
are seasonal pulses in zooplankton densities, as we have long realized,
put the differences between urban inshore, rural inshore and offshore
waters are not effectively described in terms of total crustacean
zooplankton densities.

31


1973

1973

1973

JUN STATION 56 DFFTH 129 M SWEEP 160 M
MEAN VALUE OF PROFILES OVEK SM INTEKVALS

1- 3 120-60 -.0852 200-120 = OE 66
4- 6 120-60 0844 200-120 +0767
To 120-80 08 53 200-120 +1296
10-12 120-60 =.0874 200-120 21834
13-15 120-80 0898 200-120 © 2382
16-16 120-80 -.0913 200-120 ee9e5
19-81 120-80 ov25 200-126 2347)
ee 24 120-80 0910 200-120 *4Ule

25-27 120-80 ~.09e%8 206-120 +4536
28-30 120-80 0933 200-120 +5060
31-33 120-80 0940 200-120 +5567
34-36 120-80 09 €4 200-120 © C07
37-39 120-60 1006 200-120 + 6608
A0- 42 120-60 1030 200-120 + TlE4a
43-45 120-80 -.1027 200-120 «7608

AC 48 120-80 1027 200-120 -6067
49-51 120-80 1045 200-180 +6594
5e@- 54 120-80 1067 200-120 29110
55-57 120-80 1069 200-120 +9593
58- €0 120-60 1060 200-120 1.0082
€1-6€3 120-80 1096 200-160 140612
€4- 66 120-80 1090 200-120 3.118)
7-9 120-60 ~.1107 206-120 1.1641
10-72 120-80 1157 200-120 142193

gQegegeggggoogoogrggggsgooee2

73-75 120-60 ~.1159 200-120 148715

JUN STATION 59 DEPTH 16M SWEFF 25 M
MEAN VALUE SF PROFILES OVER SM INTERVALS

CH 1-el 120-80 «ge 200-120 --1365
CH 2e-4e 120-60 +4157 200-120 -.0527
CH 43° €3 120-80 + T34E 200-120 --0909

JUN STATIGN 60 DEPTH 16M SWEEP 25M
MEAN VALUE GF PROFILES OVER 5M INTERVALS

cH 1-21 120-80 9337 200-120 +0674
CH 2e-42 120-80 -2.02817 200-320 ©1784
CH 43-63 120-60 -3.1040 200-120 2210

151

500-£00
500-260
500-200
500-200
506-200
500-200
S00-2£00
506-200
500-200
S0G- 200
500-266
500-£00
500-200
500-260
500-200
500-200
500-200
560-200
500-200
500-206
500-200
S00-200
300-200
500-200
500-200

500-200
500-200
500-200

500-200
500-200
500-200

+2663
+5741
“9414
163118
16877
200413
£43987
2. 78 60
361943
3. 6144
4.0321
A ADT
4.9467
5. 42.39
569134
6 38
8 208
LES
Te 164
bene
6.6151
9+3450
9.8 4
10.372
10.9133

=+ 5320
-+3452
215%

+0000
- 0000
+0000

10M
1M
20M
eo
30M
3m
40M
4a
SOM
SoM
60M
Cot
70M
7M
som
bo
90M
aM
100M
10M
110%
114
120M
1ega

10m
i

tom
14


Table 11. MEAN ACOUSTICAL REFLECTIVITY (DiC. vous, , 777A" TFE_RIOMASS (4) FOR
5 m INTERVALS, LAKE ONTARIO, 1972-73.

TS

Depth August 1972 November 1972 February 1973 June 1973
Interval Acoustical\Relative Acoustical\Relative Acoustical\Relative

(m) neflectivit}\sioness nefloctivit) stones peflectivit) Bienes

0-5 46 001 0. 0 0. oO.
5-10 96 «002 om 0 0. 0.

* 10-15 1.59 008 +11 0004 oO. oO.

15-20 2.21 +005 1 «0004 Oo. 15

20-25 2.60 006 08 -0003 oO. oO.

25-30 2.98 007 0. +0 com +13

30-35 3.15 007 +03 «0001 0. 225

35-40 3.72 009 oil 000}, 0. “Tl

ho-ks, 4.06 +009 31 001 0. oh

45-50 hug 010 53 002 O. 1.16

50-55 461 -O1L 88 +003 oO. 1.39

55-60 5.03 +012 1.09 004 oO. 1.58

60-65 5 4b +013 1.32 004 Oo. 1.82

65-70 5.76 +013 2.29 007 oO. 2.08

10-75 6.13 O14

75-80 4,38 010 2.58 008 oO. 2.2

80-85 4.65 -O11L 2,83 +009 oO. 3.61

85-90 4.99 012 3.07 +009 Oo. 4.38

90-95 5.25 +012 3.32 010 0. 4 U8

95-100 7.58 012 3.81 012 0. 4 83

100-105 8.11 019 4,18 OU 0. 5.19

105-110 8.50 +020 443 201d oO. 5.56

110-115 9.31 2022 5.22 -O17 Q. 5.93

115-120 11.16 026 5.26 +017 oO. 6.30

120-125 12.39 2029 5.95 2019 Oo. 6.71

125-130 13.08 +030 6.23 +020 0. 7.12

130-135 13.89 +032 6.51 021 0. 3.26

135-140 15.15 +035 6.79 022 0. 3.53



LT

Figure 3. Density (no. /m?) of eutrophic Cladoceran Bosmina longirostris
on 21 - 25 August 1972 in surface waters (0 - 5m) of Lake
Ontario at 60 stations of IFYGL Biology Program


1973 staTI ON 46 FEB PA 10**4 AVE 5 DEPTH 120 DEPTH 130 SWEEP 180
MEAN VALUE OF PROFILES OVER S4 INTERVALS

1973

1973

22eQaeea

CH
cH
CH
CH
cH
CH

FEB STA 60 PPAMP 10##4 AVG. S DEPTH 12 DEPTH

“FEB STA 4& PA
MEAN VALUE OF

dnd4
15-28
29-42
43-56
57-70
71-84

120-60
120-80
120-80
120-66
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-£0
120-80
120-80
120-80
120-80
120-€0
120-60
120-80
120-80

10®#4 AVG 5 DEFTH 26 DEPTH

+0404
©0345
+0299
+0305
20246
20183
+0106
+0061
20013
- 20062
-.0113
20191
60857
20336
20379
~-0441
0516
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+0657

-20715
- 20763
~ 6 0848
20949

200-120
200-120
200~120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

500-200
500-200
500-200
+2364 500-200
22502 500-200
«2642 500-200
+2783 500-200
00934 500-200
©3143 500-200
#3322 500-200
03455 $00-200
#3609 500-200
+3601 500-200
«3976 500-200

«AMEE 500-200
4598 $00-200
+4730 500-200
+4886 S$00-200
+5036 500-200
©5237 S00- 200
5484 500- £00
25541 500-200
«5710 500-200
+5895 500-200

29 SWEEP 35

PROFILES OVER 54 INTERVALS

120-80
120-80
120-80
120-80
120-80
126-80

=2 6173
©3128
+9339
8715
«4674
+0103

e0c-120
200-120
200-120
260-120
200-120
200-120

1.2849 500-206

9321 500-200
-+4614 500-200
1.0192 500-260
2.3054 500-200
3-65 500-200

MEAN VALUE OF PROFILES OVER SM INTEAVALS

CH
cH

1-30
31-60

120-80
120-80

01107
68597

200-120
200-120

138

+5831 500-200
#9655 500-200

-«4419
-+4403
465
+4465
0 A558
=e A540
AGES
A631
474
4770
4900
49 48
5076
“25126
“25857
“0 S314
72843)
= 94
-25613
-.5@9
-+5B6
2 S71
-- 964
~+ 6085
+ 6153
- 2 6260

12M SCAN 20M

©1354
«1448

10m
isa
20M
est
30M

10M


ne

Table 17.

LAKEWIDE AVERAGE OF ZOOPLANKTON POPULATION DENSITIES. VALUES (B/m> )
REPRESENT ANIMALS COLLECTED WITH A NET (64 APERTURE) AT STATIONS IN

WATERS LESS THAN 30 m IN DEPTH, OVER A VERTICAL RANGE OF O - 5 m.

15-19] 12-16] 10-14] 21-25 5-9 | 19-22) 2h-28) 12-16

Species May June duly Aug Oct-Nov | Nov-Dec| Feb | March{ April] June

Cladocera

Bosmina 8 ak 532 997 2755 978 2h 19 T 52
coregoni

Bosmina 48 382 | 11786 | 78230 | 1913 9 3 1 5 1755
longirostris

Daphnia °O 827 186 16 ak 0.7 0.2 O.1 1.3
galeata

Daphnia 6 6 55 | 10169 2001 352 0.6 | O.1 | 0.7 18
retrocurva

Daphnia ° 0.05 15 ie) Ou 0.2 ° QO Ou 0.2
longiremis

Ceriodaphnia 0 1 23 4028 128 34 ° ° 0.9 6
lacustris

Chydorus O.1 3 oh 213 35 4L o | 0.05 | 0.3 a
sphaericus

Holopediun le} 0.1 0.9 17 1.3 oO °O QO ° 10)
gibberun

Polyphemus ° ° py 4 0 i) ° ° () 0
pediculus

Diaphanosoma ie} ie} O 10 0.2 0.7 ie) 0.5 fe) °

Alona 0 te) 0.6 0.2 3.5 18 0.2 | 0.05 fo) °



Table 7. ANALYSIS OF VARIANCE (2-WAY ANOVA) FOR EFFECT
OF LOCATION AND TIME UPON DENSITY, COMMUNITY
COMPETITION COEFFICIENT, THE RATIO DENSITY TO
CARRYING CAPACITY (N/K), NUMBER OF SPECIES (S),
AND DIVERSITY (H), -- = p<.Ol, - = p<.05,
Effect upon density: Sum_of Sq. af. Mean Sq.
Total 10.6x107° 26 8
Location 11. 7x10), 2 5 8x10,
Time 98x10! 8 123x102
Residual 7.3x10 16 4 5x10
Effect upon
competition coefficient:
Total 412 26 +005
Location 118 2 «003
Time «2h9 8 0003
Residual «00K 16
Effect upon N/K:
Total 002 26
Location ~00005 2 00002
Time +0006 8 «00008
Residual 002 16 0001
Effect upon number species:
Total 335.4 26
Location 6.5 2 48.2
Time 158.7 8 19.8
Residual 80.1 16 5.0
Effect upon diversity:
Total we. 26
Location 12.4 2 6.22
Time 1.2 8 158
Residual kl 16 2.59

38

NS


Beeton, A. M. 1969. Changes in the Environment and biota of the
Great Lakes. im: Eutrophication; Causes, Consequences,
Correctives. Nat. Acad. Sciences, Washington, D.C. pp. 150-157.

Bogdan, K. 1974. pers. com,

Bogdan, K. and D. C. MelNlaught. Selective feeding by Diaptomus and
Daphnia. Verh. Internat. Verein, Limnol. 19.

Bradshaw, A. S. 1964. The crustacean zooplankton picture: Lake Erie
1939-49-59; Cayuga 1910-51-61. Verh. Internat. Verein. Limnol.
15:700-708,

Brooks, J. L. 1969, Eutrophication and changes in the composition
of the zooplankton, In: Eutrophication; Causes, Consequences,
Correctives. Nat, Acad, Sciences, Washington, D.C. pp. 236-255,

Brooks, J. Le and S. I. Dodson, 1965. Predation, body size, and
composition of plankton. Science 150:28-35,

Burns, C. W. 1968, The relationship between body size of filter-
feeding cladocera and the maximum size of the ingested particle.
Limnol, Oceanogr. 13:675-678.

Chandler, D. C. 1940, Limnological studies of western Lake Erie.
I. Plankton and certain physical-chemical data of the Bass
Islands Region, from September 1938 to November 1939, Ohio
J. Sci, 40:291-336.

Deevey, E. S. 1942. Studies on Connecticut lake sediments, III.
Biostratonomy of Linsley Pond. Amer. J. Sci. 240:233-264, 313-338.

Dodson, S. I. 197%, Zooplankton competition and predation: An
experimental test of the size-efficiency hypothesis. Ecol.
553605-613,.

Gliwicz, Z. M. 1969. Studies on the feeding of pelagic zooplankton
in lakes with varying trophy. Ekologia Polska 17:663-708.

Hell, D. 1964, An experimental approach to the dynamics of a natural
population of Daphnia galeata mendotae. Ecol. 45;94-112.

Hrbacek, Js, J. Dvorakova, V. Korinek and L. Prochazkova, 1961.
Demonstration of the effect of the fish stock on the species
composition of zooplankton and the intensity of metabolism of
the whole plankton association. Verh, Internat. Verein. Limnol,
142192-195.

Hutchinson, G. E. 1957. A Treatise on Limnology, Vol. 13 Geography,

Physics and Chemistry. John Wiley and Son, Inc., New York.
pg. 1051.

19


9S

Figur
e 16
- Column
bioma
ss (
& ar;
y wt /aP
m=) di
uring
Augus
it 19’
72


Lane, P. A. 1971. A comparative study of the structure of zooplankton
communities. Ph.D. Thesis, State Univ. of New York at Albany.
216 pp.

Lane, P. A. and D. C. McNaught. 1973. A niche analysis of the Gull
Lake (Michigan, U.S.A.) zooplankton community. Verh. Internat.
verein. Limnol, 18:1441-14h7,

Levins, R. 1968. Evolution in Changing Environments. Princeton
University Press, Princeton. 120 pp.

MacArthur, R. H. 1972. Geographical Ecology. Harper and Row
Publishers, Inc., New York. 269 pp.

May, R. M. 1973. Stability and Complexity in Model Ecosystems.
Princeton University Press, Princeton. 235 pp.

MeWahon, J. W. and F. H. Rigler, 1963. Mechanisms regulating the
feeding rate of Daphnia magna Straus. Can. J. Zool, 413321-332.

McNaught, D. C. 1968. Acoustical determination of zooplankton
distributions. Proc. llth Conf. Great Lakes Res. 1968, 76-8h.

MeNaught, D. C. 1969. Developments in acoustic plankton sampling.
Proc. 12th Conf. Great Lakes Res. 1969, 61-68,

McNaught, D.C. 1973. Zooplankton Production in Lake Ontario with
regard to environmental perturbation. First Annual Rept. to E.P.A,

McNaught, D.C. 1974. ‘Impact of urban areas on inshore zooplankton
populations of Lake Ontario. Proc. 17th Conf. Great Lakes Res.
1974 (unpub. )

NeNeught, D.C. and M. Buzzard. 1973. Changes in zooplankton
populations in Lake Ontario (1939-1972). Proc. 16th Conf.
Great Lakes Res. 1973, 76-8.

iinter, L. 1938. Der dtrichsee als Eutrophierwmgs-phdnomen. Geol.
Meere Binnengewlsser 2;28b-299,

Munawar, M. and A. Nauwerck. 1971. ‘The composition and horizontal
distribution of phytoplankton in Lake Ontario during the year
1970, Proc, lth Conf. Great Lakes Res. 1971, 69-78.

Nauwerck, A. 1963. Die Beziehungen zwichen zooplankton und Phytoplankton
im See Erken. Symp. Bot. Upsal. 17:1-163.

Patalas, K. 1972. Crustacean zooplankton and eutrophication of
St. Lawrence Great Lakes. J. Fish. Res. Board Can. 29;1451-1462.

Patalas, R. 1969. Composition and horizontal distribution of crustacean
zooplankton in Lake Ontario. J. Fish. Bd. Can. 26:2135-2164,

80


1972 Nov STATION 24 PA 108#4 AVG 5 DEPTH 123 M SWEEP 160 M
MEAN VALUE OF PROFILES OVEE 54 INTEKVALS

age

geegagceggergggegge2e2

22222

CE
CH
cH
CH
CH

1- 3
a& 6
1-9
10-12
13-15
1618
19-21
22-24
25-27
28-30
31-33
34-36
37-39
40-42
A3-45
AG 48
49-51
52-54
55-87
58-60
61-63
6h= 66
67-9
10-72

“NOV STATION 31
MEAN VALUE OF PHOFILES OVER SM

1-14
15-26
e9-42
A3- 56
57-70

120-80 «0600

120-80 1806
120-80 3633
120-80 =64917

120-80 53028
120-80 ~-.4990
120-80 =.4963
120-80 --. 4889
120-860 5172
120-80 5190
120-80 5155
120-60 -.5195
120-80 ~.5364
120-860 -.5255
120-80 -.5064
120-80 -.4946
120-60 -.4713
120-80 -.47T27
120-80 -.4819
120-80 -.4956
120-80 -.4921
120-80 -. 4969
120-60 -.4986
120-60 -.4906

PA 10#®4 AVG

120-80 -+8770
120-80 -1.3649
120-80 -144034
120-80 -1-38 48
120-80 -1.4316

200-120
200-120
200-120
200-120
200-160
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
260-120

16307
2. 7553
5.5751
6 616)
7.2420
765275
7-59 66
76351
T+ 640
76 TASE
2 DSL
78473
709073
709632
7.9996
6.0464
6.0908
8.1473
B. 2062
6.2667
8.3200
8.3861
B+ 4398
8.4983

5 DEPTH 28 M SCAN

200-120
200-120
200-120
260-120
200-160

115

INTERVALS

--5026
= +6732
-2 754)
= BER
-- 7315

500-200 -1.3089
500-200 ~1+ 7289
500-200 -1+ S620
500-200 -1- 3918
500-200 -1-2306
500-200 -1-0708

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
506-200
500-200
500-200
500-200
500-200
500-260
500-200
500-200
500-200
500-200

39M

500-200
500-200
500-206
500-200
500-200

29079
=. 1494
~. 924
~ +4283
26863
=+1130
+0488
+2080
+3605
2 5166
26774
+8325
298 63
1.14284
1.2932
164484
1.9949
1. 7435

21422
9 86EE
+36
65107
«6487

104
14
20m
ene
30M
SM
40M
4m
50m

60M
6M
70M
TM
80M

90M

95M
100%
1054
110M
1154
1204


1972 NOV STATION 40 PA 10##4 AVG 5 DFPTH 175 M SCAN 220 M

1972

agra

MEAN VALUF OF F

gegege2eeo2e9

CH

CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH

NOV STATION 41

CH
CH
CH
CH
CH
CH
CH

NQV STATION 42 PA 10**4 AVG 5 DEPTH 35M

1- 2
3 4
Ss é
7- &
9-10
ble-1e
13-14
15-16
17-18
19-20
21-22
23-24
25-26
27-28
29-30
31-32
33-34
35-36
37-38
39-40
41-42
43-44
45-46
41-48
49-50
51-52
53-54
55-56
57-58
59- 60
61-62
63-64
65-66
€7- 68
9-70

inal
12-22
23-33
34-44
AS-55
5G 66
67-77

120-80
120-60
120-60
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
126-60
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80

PA 10##4 AVG 5
MEAN VALUE OF PROFILES OVER SM

120-80
120-80
120-80
120-80
120-80
120-80
120-80

FILES OVER

25987
693
7048
-0 6984
+4636
24349
6 36628
3015
2343
177€
wel ZO
= +0843
-.0285
2 O264
+1058
+1563
22099
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+3305
23855
+4241
+4950
+5333
+ 5830
«6448
+7087
+ ThE9
+6059
oBS17
29100
29461
1.005)
1.0520
1.11286
1.3581

+0259
«6699
+0634
«007
«0976
©1170
oe 1178

SM INTERUALS

MEAN VALUF OF PKGFILES OVER SM INTERVALS

222

29
Eas

CH

2

nah
12-22
23-33
34-44
45-55
56- 66
61-77

120-80
120-80
120-80
120-80
120-80
120-80
120-80

20963
21923
22685
#3844
94614
«5775
© 1466

200-180, «2188 500-200
200-120 «A561 500-200
€00-120 +51 500-200
200-120 *87ES 500-200
200-120 +879 500-200
200-120 140591 500-200
200-120 1.28135 500-200
200-120 1463674 500-200
200-120 1.5255 500-200
200-120 1.6896 500-200
200-120 168754  S00-200
200-120 2.0920 500-200
200-120 2635163 500-260
200-120 €.5455 500-200
200-120 2.7679 800-200
200-120 3.60191 500-£00
260-120 3.2560 500-200
200-120 365154 500-200
200-120 3+ 7532 500-200
200-120 369907 506-200
200-120 4.2404 s00-200
£00-120 464607 500-200
200-120 4 7262 $00-200
£00-120 449613 500-200
200-120 5-206 500-200
BO0-160 Seaar7 SoG- e200
200-120 Se KER $00- 200
200-120 S9846 500-200
E00-160 Ge 158K 500-200
200-120 6.3933 500-200
200-120 &+ 6417 500-200
200-120 6.6822 500-200
200-120 7.1263 500-200
200-120 743683 500-200
200-120 7.6135 500-200
DEPTH 35 M SCAN 46M
INTERVALS

200-120 +0144 500-200
200-160 +0504 500-200
200-120 11le 500-200
200-120 21S 500-206
200-120 +2361 500-200
200-120 ©2931 500-200
200-120 +3404 500-200

SCAN 45M

200-120. +5172 500-200
200-120 -.17228 500-200
200-120 --6570 sc0-200
200-180 -1. 6203 500-200
200-120 ~-.5276 500-2060
200-120 ~01307 500-200
200-120 01 BS 500-200

18

~s 0616
09 €4
19 60
oni
~e 0616
= +0758
1155
646
e151
“28721
70 3285
3745
= +4690
= 2 4804
-25E97
~2 637
7+ 6320
2 BEE
=. T38€
o+ 62
~ +8420
~ +6963
09475
71-0053
1.0611
7161145
“1.1719
-1e8872
wile 2RER
21-3440
- 1.3990
~1.4565
71.5177
71.5725
-1. 6312

#1390
EDGE
eAlTe
© 5554
+ O46
#8350
1.0808

+ 5161
+ 7388
29375
1.1432
163466
2. 5483
168545

co]
10M
iad
20M
em
SOM
oot
40M
4m

os
10M
154
20M
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304
3a4

10M
1
20M
end
30"
3m


Se

Figure 9. Density (no./m3) of Cyclops bicuspidatus on 10 - 14 July
1972 in surface waters (0 - 5 m) of Lake Ontario et 60
stations of IFYGL Biology Program


1973 JUN STATION 41 DEPTH 24M SWEEP 30 M
MEAN VALUE OF PROFILES OVER 54 INTERVALS

1973

1973

1973

CH 1s20
CH 21-40
CH 41-60
CH 61-8n

120-80 -.6813
120-80 -1.5633
120-60 -2.4400
120-80 -3.0622

200-120
200-126
200-120
200-120

JUN STATION 42 DEPTH 24 M SWEEP 40 M
MEAN VALUE OF PROFILES O®VEh SM INTERVSLS

CH I-15
CH 16-30
CH 31-45
CH 46-60

120-80 20161
120-80 +3133
#$20-80 =.9740
120-80 -2.1247

200-120
200-120
200-120
200-120

JUN STATION 46 DEPTH 128 M SWFEF 60 M.
MEAN VALUE OF PROFILES OVER 54 INTERVALS

CR 1l- 6
CH THe
CH 13-18
CH «19-24
CH 25-30
CH 31536
CH 37-42
CH 43-46
CH 49-54
CH 55-60
CH 61-66
CH «67-78
CH 73-78
CH 79-84
CH 8590
CH 91-96

120-60 -.6775
120-0 -1.1761
120-80 -1.1346
126-86 -&£.0774
120-60 -& 5017
120-80 -2. 6669
120-80 -£.6752
120-80 =2+6654
1E0-80 -2.6583
120-80 -2. 6542
120-80 -2. 6454

120-h0 - 2. 6253
120-60 -2.6153
120-60 ~2- 6067
120-60 ~2.5985

200-120
200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
£00-120
200-120
200-120
200-120

JUN STATION 48 DEPTH 33 M SWEEP 40 M
MEAN VALUE GF PROFILES OVER SM INTERVALS

1-13
14-26
27-39
40-52
53-65
66-76

geeeaee

120-80 +GETE
120-80 «3252
120-60 -.08e1
120-60 -.7952
120-60 -1. 6802
120-80 -2.4513

200-120

+0138
eI S6E
+5096
= 6 A188

2 649 6
5.0390
7.4906
9.6900

+0238
2 08 6S
21574
+2207
= E8ED
73504
+4815
4901
«S603
+ 6270
*@ill
© 7573
+8282
68911
9601
1.0305

727383

200-120 -1-5277
200-120 -2.0739
200-120 -2.300
200-120 ~2.3536
200-120 -2. 3469

150

500-200
500-200
500-200
500-200

500-200
500-260
500-€00
500-£00

500-200
500-200
500-260
500-200
500-€00
500-206
500- £00
500-£00
500-260
500-200
500-200
500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-200
500-200
500-200
500-200

+0000
+0000
+0000
«0000

+0000
+0000
+0000
»0000

+0000
«0000
.co00
+0000
«ocao
+00C0
+0000
+0000
+0000
0000
«0000
-0000
0000
+0000
+0000
+0000

e192)
+3998
+ 6053
26119
1.0168
1.28257

10M
20M

10M
1
20m

10M
1M
20M
aM
30M


SECTION I

CONCLUSIONS AND RECOMMENDATIONS

The horizontal distribution of the crustacean zooplenkton of Lake
Ontario suggested that eutrophic indicator species were generally
found in the vicinity of Metropolitan Toronto, the Oswego River,
Mexico Bay, and Popham and Weller's Bays. The shallow bays of Lake
Ontario likely represent areas of natural eutrophication, whereas
conditions off Toronto and Oswego deserve special attention, as these
areas of the lake are likely in a stage of accelerated cultural
eutrophication (Section IV). Action in the near future is important
to reverse eutrophication in these perturbed regions.

The impact of urban areas upon the crustacean zooplankton was also
visible when using community matrix techniques to characterize
watermasses, Zooplankton communities, considered together, showed
greatest perturbation when in shallow waters near urban areas;
correspondingly, least perturbation was associated with communities
of deep waters (Section V). Thus the deepwater communities still
contain important oligotrophic species vital to a stable community
structure.

Biomass estimates made with new acoustical techniques indicated that
previous estimates of zooplankton biomass were low (10 - 100 times),
and that much of the biomass was associated with deep waters (3100 m).
These conclusions will be important in modelling the Lake Ontario
ecosystem (Section VI). They are both new and surprising, and require
further confirmation.

The small cladoceran, Bosmina longirostris, has been described as a
eutrophic indicator, likely because it utilizes a variety of algal
foods, including larger phytoplankton and avoids fish predation
(Section VIII). The ratio of B. longirostris to Diaptomus sicilis

may be a useful indicator of perturbed communities (Section IV). This
index is simple to determine, as the two species are easily recognized.
Hopefully it will have future application in detailing areas of the
Laurentian Great Lekes suffering from pollution.

New techniques developed for calibrating plankton nets indicated that
samples collected with a 644 mesh net over depth interval of 0 - 5m
may underestimate zooplankton abundance by a factor of 2x, while tows
made over a path of O - 50 m may underestimate by a factor of 3x.
These new results are vital to using historical data in calibrating
and valideting ecosystem models (Section III).


1973 FEB STA 1 PA10%#4 AVG 5 DEPTH 33M DEPTH 35% SCAN 50 M

1973

1973

MEAN VALUE OF PHOFILES OVE SM INTERVALS

CH 1-10 120-80 21125 200-120 22220
CH 11-20 120-80 © 2678 200-120 25775
CH 21-30 120-80 141600 200-120 + 7082
CH «31-40 120-60 21962 200-120 1.0101
CH 41-50 120-80 +6561 200-120 ~-.0086
CH 51-60 120-80 200-120 -.8 504
CH 61-70 120-80 200-120 -1-5034

STATIGN 3 FEB PA 10**4 AVE 5 DEPTH 15M DEPTH
MEAN VALUE OF PROFILES OVER SM INTERVALS

CH 1-284 120-80 -163841 200-120 +5 BO
CH 25-48 120-80 -3-0380 200-180 -.0353
CH 49-72 120-80 = 4. 6428 200-120 ~~. 7348

500-200
500-200
500-200
500-200
500-200
500-200
500-200

23060
60952
«1095
«3151
5217
« 7301
«9390

18 M SCAN 25 M

500-200
500-200
500-200

FEB STA 7 PA 10**4 AVG S DEPPTH 16 DEPTH 24M SCAN 35 M

MEAN VALUE GF PROFILES OVER SM INTERVALS

CH 1-17 120-80 +7373 200-120 -1.2644
CH 18-34 120-60 -.1422 200-120 -1.1144
CH 35-51 120-80 +5749 200-120 -2.4339
CH 52-66 120-60 +8997 200-120 -3.5311

500-200
500-200
500-200
500-200

=. 970
-* 5348
64 T40

-20314
* 0248
oe
«1100

FEB STATION 8 PA **4 AVE 5 D¥PTH 15 M DEPTH 65M SWEEP 72 M

MEAN VALUE @F PHAFILES OVER 94 INTERVALS

CH 1s 6 120-80 60982 200-120 -.0886
CH 7-12 120-80 ©7623 200-120 -+ 7466
CH 13-16 120-60 1.1129 200-120 -2.2914
CH 19-24 120-80 «5492 200-120 -2.5793
CH «25-30 120-80 +0418 200-120 -2. 6226
CH 31-36 120-80 -.3578 200-120 -2. 5898
CH 37-42 120-80 -.5799 200-120 -2e S678
CH 43-48 120-80 -67505 200-180 - 2. 5267
CH 49-54 120-80 --835968 200-120 -2. 5099
CH 55-60 120-80 -.6722 200-120 -2. 4949
CH 61-66 120-80 -.9014 200-120 -2.4705
CH 67-72 120-60 -.9282 200-120 ~8-4559
CH «73-78 120-0 -.9562 200-120 -2-4405

STATION 14 FEB PA 10%#4 AVE 5 DEPTH 10 M DEPTH
MEAN VALUE @F PHOFILES OVER SM INTERVALS

CH 1-50 120-80 ©1038 200-120 +543)
CH S1-#* 120-80 98514 200-120 1.08528

133

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

723443
23762
~+ A043
4338
6 4863
72 S141
5455
5667
6011
-+ 6337
2 6648
“2 O55
=2 7239

14M SWEEF 14M

500-200
500-200

+ 488
-- 696

10M
184
20M
eM
30M
aot

aul
10M
15M

&M
10M

€04

10M


1973 STATION 77 FEB PA 1084: AVE 5 DEPTH 114M DEPTH .117M SWEEP.170 M

1973

MEAN VALUE OF PROFILES OVER 5M INTERVALS

geeoeaggaggeeageogor2eoa2
~

120-80
120-80
120-80
120-80
120-60
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-86

~ 60287
©6334
1.0943
1.09 6€€
1.1000
1.1023
1.0905
1.0861
1.0769
1.0697
1.0632
1.0527
1.0261
1.0206
+9865
+9 66E
+9511
+9404
+9351
9121
+6915
+8676
+8 633

200-120 +2137
200-120 =. 6268
200-120 -1.2711
200-126 -1.3357
200-120 -1.3169
200-120 -1.3169
200-120 -1.3089
200-120 -1.3026
200-120 -1.2899
200-120 -1.2836
200-120 -1.2872
200-1220 -1.2903
200-180 -1.2909
200-120 -1.2876
200-120 -1.2902
200-120 ~1-2996
€00-120 -1.3022
200-1280 -1.2993
200-120 -1.2996
200-160 =-1.3050
200-120 -1-3050
200-180 -1.2963
200-180 -1.2988

STATIQN 78 FEB PA 10##4 AVE S DEPTH 53 M DEPTH
MEAN VALUE GF PROFILES OVEH 5M INTERVALS

1- 8
9-16
17-24
25-32
33-40
Al-46
49-56
S7-64
65-72
73-80
81-88
89-96

gagggeaeeeag

“FEB STA 79 PA

CH 1-20
CH 21-40
CH 41-60
CH 61-80

120-80
120-80
120-80
180-80
120-80
120-80
120-860
120-80
120-80
120-80
120-80
120-80

01114
«2226
21835
7+ 5899
163536
-1.4856
-2.10285
Be 3286
= 223058
72.3735
203784
263732

200-120 -+ 6706
200-120 -1-6379
200-120 °-261752
200-120 -2. 7118
200-120 -2.8909
200-120 -28857
200-120 -2-8616
200-120. -2.696
200-120 -28701
200-120 -2-857€
200-120 -2-6424
200-120 -2.8323

500-200
500-200
500-200
500-200
500~200
500-200
500-200
500-200
500-200
500-200
s00-£00
500-200
500-200
500-200
500-200
500-200
500-260
500-200
500-200
500-200
500-200
500-200
500-200

60 M SWEEP 62°M

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

10##4 AVG 5 DEPTH 20 DEPTH 20 SCAN 25
MEAN VALUE OF PROFILES OVE SM INTERVALS

120-80
120-80
120-80
120-80

+4707
«3578
- 163082
~ 268882

200-120--1+1038
200-120 -.5487
200-120 --0337
200-120 +6505

aan

500-200
500-200
500-200
500-200

#3350
© 3489
+3570
©3656
+3737
+3646
©3943
«4031
4122
«41921
+4256
722371

+0150
+0340
20511
+0710

a
10M

204
eat
30M
3o4
40M
AM
50M

60M

10M
ist
20m


1973 gu STATION 12 DEPTH 20 M SWEFP 35 M
MEAN VALUE OF FHOFILES OVER. &% INTEAVALS

CH 1-14 120-60 1.0789 200-120 -.9582 500-200 +0000 4
CH «15-288 120-60 26749 200-120 -2.2200 500-200 «0000 10M
CH 29-42 120-60 2.6272 200-120 -1.4739 500-200 +0000 1m
CH 43-56 120-60 2 60284 200-120 =.7371 500-200 =0000 20M

1973 JUN STATION 14 -DEPTH 10 M SWEEP 16M

MEAN VALUE OF PROFILES @VEK §% INJERVALS

CH 1-31 120-860 1.7635 200-120 031E9 $00-200 ~.1166 M
CH 328-62 120-80 1.68336 200-120 +5652 500-206 +0736 10M

1973 JUN STATION 19 DEPTH 24 M SWEEP 30 Mm
MEAN VALUE GF PROFILES @VEh SM Ih

EBVALS
CH 1-20 120-86 -. 1666 200-120 -1.4687 500-200 +0000 MY
CH 21-40 120-80 -.4055 200-120 -2.9683 500-200 +0000 10M
CH Al- 60 120-80 =.3634 200-120 -4-4732 S00- £00 +0000 164
CH «61-80 120-60 =. 3663 200-120 -5.7904 500-200 +0000 20M

1973 YUN STATION 20 DEPTH 20 M SWEEP 95 M
MEAN VALUE OF PROFILES OVER 94M INTERVALS

CH 1-14 120-80 + 3988 200-120 -.4693 500-200 +2099 oY
CH 15-28 120-80 » 58 9 200-120 -+67431 500-200 +4192 10M
CH e9~4e 120-860 +7083 200-120 -.9830 500-200 +6307 1%
CH 43-56 120-80 +6313 200-120 -1.2037 500-200 +6432 20M

1973 JUN STATION 24 DEPTH 118 M SWEEP 60M
MEAN VALUE @F PROFILES OVFR SM INTERVALS

1- € 120-60 + E9AE 200-120 +6519 500-200 -. 659 4
cH 7-12 120-80 1.0669 200-120 147899 $00-€00 -.4675 106M
CH 13-18 120-80) 1+ S644 200-126 2.8507 500-200 -.2935 bid
CH «19-84 120-80 260488 200-160 243649 500-200 -.1154 20K
CH 25-30 120-60 2. 5€21- £00-120 20919 500-400 2009 &SM
CH 31-3€ 160-66 BET 200-120 1-8 680 500-200 22534 Sore
CH 37-42 1£0-80 3. 1063 200-120 1.7165 500- £00 +4377 SoM
CH AS- 46 126-80 3.2490 #0U0-1£0 1. 6447 500-200 «6208 40M
CH 49-54 120-60 364023 200-320 165558 900-260 +BOIS ASM
CH 55-660 120-80 Se E563 200-120 163718 500~ £06 296 Eb 5UM
CH 61-66 120-80 367983 200-120 143005 500-200 1.1678 54
CH 7-76 1E0-6U 368 5E3 200-120 1463154 500-200 143589 €0M
CH 73-78 120-60 369625 200-120 1435181 500-200 te S391 64
CH 79-64 120-60 369475 200-120 1.3687 500-00 167217 OM
CH &5-90 120-80 369438 €00-120 1.4357 500-200 169045 75%
CH 91-96 120-60 3.9465 200-120 11,5015 506-200 F0% 7% BOM

17


SECTION VI

ACOUSTICAL ESTIMATES OF ZOOPLANKTON BIOMASS

THE ACOUSTICAL METHOD FOR DETERMINATION
OF ZOOPLANKTON BIOMASS

The echo-integrating sonar, especially designed to be sensitive to
particles of the size and density of zooplankton, has been described
previously (McNaught, 1973). The approach was to transmit an exact
waveshape (sound-wave) and detect the return, using a 100 channel
signal averager. Each channel thus corresponded to 1% of depth (or
time). The returning signal was simultaneously fed into an synchronous
demoduletor, then to a storage oscilloscope, providing a picture of
zooplankton abundance with depth over time. The data from the signal
averages, the heart of the system, were also displayed on an X-Y
plotter, and later processed from paper tape using a program described
below.

The 5-frequency sonar (53 or 80 kHz, 120, 200 and 500 kHz) operates

on the principal that the maximum reflectivity from small targets
(zooplankton) nearly the same density as water itself is obtained

when the wavelength of sound is equivalent to the diameter of the
(sphaerical) target (McNaught, 1968, 1969). Thus, as successively
higher frequencies are employed, smaller and smaller organisms can

be detected. For example, sound at a frequency of 200 kHz is maximally
reflected by particles 2 mn in diameter, with reasonable sensitivity to
particles down to 1 mm in diameter. Sound at a frequency of 500 kHz

is maximally reflected by particles 0.8 mm in diameter, and to some
extent by particles as small as 0.4 mm (Figure 13). Thus these two
frequencies combined can be employed to give an estimate of the biomass
of zooplankton between 0,8 and 2 mm in diameter. In the same way,
signals from the 200 kHz and 120 kHz projectors provide an estimate of
the biomass of zooplankton between 2 mm and 3 mm in diameter, and the
120 kHz and 80 kHz projectors provide an estimate of the biomass
between 3 mm and 5 mm, which is chiefly fish larvae and fishes. These
low-frequency projectors are thus used to eliminate echoes from fishes
from the zooplankton biomass estimate (or alternatively, to estimate
the biomass of fishes in Lake Ontario),

Corrections for properties of Sound and Transducers

In determining the zooplankton biomass with depth using acoustical
techniques, only physical correction factors have been employed. The
necessary factors are (a) the relative strength of the acoustical
output (frequency normalization) for each frequency transducer, (b) the
relative attenuation of sound at 80, 120, 200 and 500 kHz, and (c) the
beam angle of the transducer (Table 8), These correction factors have
been employed in writing a program to correct raw field date.

ho


ACKNOWLEDGMENTS *

This study was undertaken as a part of the International Field Year for
the Great Lakes, a joint United States and Canadian contribution to the
International Hydrological Decade. Logistic support ~-s provided by
National Oceanic and Atmospheric Administration, with special thanks
to the men of the R/V Researcher. ‘Mr. Nelson A. Thomas, the Project
Officer, was of help in many aspects of this study including arrangement
of field operations. Dr. Tudor T. Davies, Director of Grosse Ile
Laboratory, provided facilities for data processing and-writing during
my tenure there. Robert Zeh designed the sonar and net efficiency
device. Messrs. S. Markello, J. Mylroie, R. Zeh, and R. Schmidt
assisted aboard ship. Dave Griesmer assisted in plotting the figures,
which Ryland Loos drew. .

viii


Diversity Differences

Comparison of the three lake regions, using Shannon-Weaver diversity,
as well es the richness and evenness components, illustrated same
significant differences between watermasses (Tables § - 6). In all
three summer months, the urban inshore areas exhibited the lowest
diversity (1.13 - 1.66 bits), with rural inshore areas intermediate
(2.43 - 2.93) and offshore waters most diverse (2.94 - 3.31). Note
that these ranges in diversity do not overlap. During the months
June and July fewer species (12 - 14) were found in urban inshore areas,
and the richness component was lower (2.49 - 3.85) than in offshore
waters (3.76 - 4.32). In August the evenness component accounted for
reduced diversity in urban inshore waters. The location and time
effects on diversity were both highly significant (p< .01), as shown
in Table 7.

Differences in Community Indices

Biotic communities should evolve toward a moderately low level of
interspecific competition, otherwise species extinction will force
such evolution. In apparently stable planktonic communities, as in
oligotrophic lakes, the mean community competition coefficient might
be on the order of 0.3. For a larger number of samples collected fron
Lake Michigan the mean community alpha was 0.31 (Lane and McNaught,
1970). Thus a third comparison, between location and alpha, was
attempted (Table 7). During the months of June, July and August, 1972,
the mean community alpha was highest for the communities of urban
inshore waters. In two of three cases, alpha was lowest for communities
of offshore waters. These indices suggest that offshore communities,
with reduced levels of potential interspecific competition, are the
most stable ecologically. In contrast, the urban inshore comnunities
were again judged least stable, and by using an index independent of
the previous Shannon-wWeaver diversity computation. The effect of
location upon alpha was highly significant (p < .01), while there was
also a significant effect (p < .05) of time of year (Table 7). Thus
two ecological indices have suggested greater instability in urban
inshore regions,

Similarly, a second community index, carrying capacity (K), was higher
for urban inshore waters, as compared to rural inshore areas (Tables 5 -
6). Since this theoretical estimate of carrying capacity is calculated
using alpha (Levins, 1968), this conclusion is not unexpected. However,
the ratio (N/K) of observed density (N) to theoretical carrying capacity
(K) is probably a better index of eutrophication. During these same
three months the N/K ratio suggested that urban are?s were closer to
carrying capacity than rural inshore waters. Moreover, since we are
dealing with r-selection organisms, which fill only a small fraction

of their carrying capacity, it was logical that these ratios would
remain below 15%, It should also be noted that the offshore communities
of zooplankton are closest to theoretical capacity (11 - 12%). A
two-way ANOVA suggested that the effect of location on the ratio of n/K

3h


1972 NOV STATIGN 17 DEPTH
MEAN VALUE OF PR@FILES OVEH SM INTERVALS

i972

gegegegoggessagageo292

22g

CH

22

CH
CH
CK
CH

I- 2
a 4
5 6
7-8
9-10
1i-1e
13-14
15-16
17-18
19-20
21-22
23-24
25-26
27-28
29-30
31-32
33-34
35-36
37-38
39-40
41-42
43-48
45-46
AT 46
49-50
1-52
53-54
55-56
51-58
59-60

120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60

150 M PA

+ 7646
©7174
+9666
+1466
~-06S!
-20731
--0605
720856

200-120 -14 4088
200-120 -2.1263
600-120 -2e3593
200-120 -~2-2655
200-120 -2.1834
200-120 -2-1011
200-180 -2.0094
200-120 -149209
200-120 -1.8297
200-120 -147473
206-120 -1- 6593
200-120 -145713
200-120 -1-4823
200-160 ~ 1.3905
200-160 -1.3078
200-120 -1-2633
200-120 -1.2298
200-120 -1-13869
200-120 -1.0520
200-120 +6960
200-120 -.6 73
200-120 -.7925
200-120 7087
200-120 -« 6245
200-120 -.5399
200-120 -+45€9
200-126 -43668
€00-120 -+62763
200-120 --1971
200-120 -.1126

1972 STATION 15 PA 108*4 AVG 5 DEPTH &4 M SWEEP

MEAN VALUE GF PROFILES 6V

CH
CH
CH
CH

1-20
21-40
41-60
€1-60

120-80
120-80
120-80
120-80

60971
0194)
+2909
+3876

7 SM -INTERVALS

200-120 25313
200-120 1.0619
200-120 1.591€
200-120 261204

10##4 AVG 5 DEPTH 180

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-260
500-200

500-260
500-200
500-200

30 4

500-206
500-200
500-200
500-200

Nov STATION 20 PA 10**4 AVG 5 DEPTH £9 M SCAN 364%
MEAN VALUE OF PROFILES OVER 54 INTERVALS

22299

1-36
17-22
33-48
A9= 64,
65-80

120-80
120-80
120-80
120-80
120-80

«0968
21935
+ 2696
+ 3860
+ 6402

200-180 +520
200-120 1.0531
200-120 1.5765
200-120 2.01288
200-120 1.3910

14

$00~ 200
500-200
500-200
500-200
500-200

011
©2739
+4835
+5737
©7231
+86
1.0180
1.163
1.3231
164746
2. 6296
1. 7832
169365
240903
€62e45)
2. 4029
2.5621
2. 1177
268773
3-0363
3.1982
3.3555
3. 5149
3. 6707
3.6250
369774
461341
Ae 8637
Ae 4364
Ae BO

-0e 728
701256
--0037

+2508

+4800
“93715
“08615
=+1490

#313

Rul
10%
1m
20M
eo
304
35%
40M

10M
1a
20M
es


eT

Table 1 (continued). INSHORE ZOOPLANKTON POPUIATION DENSITIES. Values (number/m>) represent
animals collected with net (64 u aperture) at stations in waters less
than 30 m in depth, over vertical range of 0 - 5m.

15-19 12-16 10-14% 21-25 Oct- Nov- 5-9 19-22 24-28 12-16
Species May June July Avg Nov Dec Feb Mar April June
Cyclopoida (cont )
Tropocyclops 0.5 | 25.6 | 2h7. 2000. | 14,185. 1278. | 189.5 53.5 65.1 140.
prasinus
Mesocyclops = - + ++ ¥ = = ~ = +
Calanoida
Calanoid 0.8 | 68.8 | 209. 148, doh, 218. | 45.4) 63.4 | 122.7 266.
copepodites
Diaptomus 28.4 - - 0. - 11.3 0. 15.9 - -
ashlandi
Diaptomus 0. O. 0. 0.2 21.9 13.0| 7.0 2.1 1.5 6.0
siciloides
Diaptonus 0. 50.3 BY hg, 43.3] 33.7] 45.5 | 37.8 228.
minutus
Diaptomus 0.7 | 25.4 | 105. 17.5 60.9 90.3] 71.5] 13.4} 43.8 6.8
oregonensis
Diaptomus 12.7 | 39.8 | 117. 8.8 63.3 54.4) 41.0] 39.3 | 39.0 1h.g
sicilis
Limnocalanus [59.6 | 309. 88.7 8.0 33.7 38.9/ 40.2] 52.2 | 124.7 38.0
macrurus
Eurytemora 0. 16.8 oO. 2350. 161.3 28.2/ 3.0 0. 22.6 16.1

affinis



% Efficiency

80

Figure 2.

iltering efficiency with ge
BE Beas ana 28% 26 AS

50 25
Depth (m)

RERAEE ZaveTShEaE Ewe C100 m - 0 m,


17
18
19

FIGURES (CONTINUED)

Relative biomass (%) per 5 m interval versus depth (m)
for 21 = 25 August 1972, 30 October - 3 November 1972,
and 12 - 16 June 1973.

Column biomass (g dry wt/m?) during August 1972.
Column biomass (g dry wt /m?) during February 1973.
Column biomass (g dry wt /m? ) during June 1973.
Piltering rate compared to food concentration for

De: a and Diaptomus and ingestion rates at these
same food concentrations.

53

56
59
62
15


1gi2

igre

NOV STATION 73 PA 10##4 AVE 5 DEFTH 17M SWEEF 27M

MEAN VALUE OF PROFILES OVER 5M INTERVALS

CH
CH
CH

1-20

21-40
41-60

120-80
120-80
120-80 -

“07611
= 6103

21354

200-120
200-120
200-120

143960
12-4903
203782

NOV STATION 75 PA 10##4 AVG 5 DEPIH 235 M SWEFP 270 M
MFAN VALUE OF FOFILES OVEh

CH
CH
CH
CH
cH
CH
cH
cH
CH
CH
CH
cH
CH
CH
CH
Ci
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
cH
cH
CH
CH
cH
CH
cH

1-
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19-19
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40~ 40
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126-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
126-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-80
160-80
120-60
120-80
120-80
120-80
1£0-80
120-80
120-80
10-80
180-80
1E0-80
120-60
120-80
120-80
120-80
140-80

+0631
steed
+316)
+3323
+3822
+3792,
+3965
+4253
+4543
sAT14
ATES
«49 38
+5090
+5151
+5273
+5407
+ 5658
+5768
+5953
+6124
+6353
+ SBE
+6750
+6851
«6948
+7103
+7259
+7418
+7590
+7696
+7844
+6063
+6299
+8520
+8651
+8763
+8982
+911
+9206
+9369
+9539
19731
HDDS
1.0096
1.0192
1.0329

200-120
200-120
200-140
200-120
200-160
260-120
£00-120
200-120
200-166
200-160
200-120
#£00-120
200-120
200-120
200-120
€00- 120
200-120
200-160
200-120
200-120
206-120
200-120
200-120
200-120
€00-120
206-126
200-120
200-120
200-120
200-1280
200-120
200-120
200-120
200-120
200-160
200-120
200-120
200-126
€00-120
200-120
208-120
200-120
£00-120
206-10
200-126
200-126

126

SM INTEVALS

14be
© ES 46
26681
©4018
«5534
«7095S
+6773
1.0425

165636
1.7441
169391
2.1086
B.b8O5
2e A6E8
2+ 6330
268155
£69670
3. 1608
343373
3- 5090
3+ 07
368553
4.0895
4.2010
40 3748
4. 5488
We
4e89 CE
5. 0698
5.2385
Se4115
Se BAE
Se 7560
59319
61072

761543
16 SEK E
Te 5041
766793

500-200 =. 6087
500-200 -» 5652
500-200 -. 5128
800-206 62774
500-200 5674
500-200 BEES
500-200 161718
500-200 1-470
500-200 1.7706
500-200 £0610
500-200 f+ 3431
500-200 2. 6257
500-200 249108
s00-200 3.1917
500-200 3.4710
500-200 3.7561
§00-200 4.0365
500-200 43200
S00-£00 4+ 6042
500-200 4.6910
500-200 5-1 738
500-200 5.4574
500-200 5. 7352
500-200 6 0149
500-200 3007
500-200 € S813
500-200 686%
500-200 741465
500-206 7% 4310
S00-200 7.7104
500-£00 749997
500-200 8 +2830
500-200 8+ 5é71
500-£00 8.8551
500-200 961382
500-200 944248
500-200 9.7182
500-200 9.9998
500-200 10-2857
500-200 10+ $708
500-200 10-8 Su
500-200 11.1417
500-200 11.4292
500-200 116.7198
500-200 12.0062
500-200 1k. E89E
500-200 12.570
560-800 1268613
5U0-200 13.1465

Mt
10M
1M

aM
16M
156
eum
eM
SUM
oot
40M
4a
SoM
5a
604
em
70M
7M
60M
bo
90M
9 SM
1004
10 4
110M
1b
126”
1eSM
1304
134
1404
145M
150M
155M
1604
1654
170%
1754
180M
is 34
y0M
19 50
€00M
£054
410M
elsa
260M
22 ot
€30M


1g72 AUG STATION 66 DEPTH ®6 DEPTH 30 PA 10##4 AVE 5
MEAN VALUE @F PROFILES OVER SM INTERVALS

CH 1-17 120-80 -.3700 200-120 «1266 500-200 +1896 a
CH 18-34 120-80 -.5099 200-120 «1770 500-200 +3870 10M
CH 35-51 120-80 ~.5419 200-120 #6291 500-200 ©B60 154
CH 5a 120-60 =.5302 200-120 +2840 500-200 + %Eee 20M
CH «69-85 120-80 -.5112 200-120 23471 500-200 998% BEM

1972 avG STAVION 67 DEPTH 20 METERS PREAMP 10*4 AVE 5 DEPTH 25
MEAN VALUE GF PROFILES OVER 54 INTERVALS

cH 1-20 120-60 20975 200-120 «5574 500-200 -.169 ga
CH 21-40 120-80 © 6068 200-120 03514 500-200 -+0423 10M
CH 41-60 120-80 -.0899 200-120 +8 659 500-200 ©0770 19M
CH 61-80 120-80 -.2030 200-120 142535 500-200 ©1856 20%

19712 pug STATION 69 DEPTH 152 DEPTH 160 PREAMP 10#°4 AVE 5
MEAN VALUE OF PROFILES OVER S4 INTFRUALS

120-80 0672 200-120 --0933 500-200 +0594 Mt
120-80 +0314 200-120 -.2580 500-200 22172 10M
120-80 +0043 200-120 -.3654 500-200 ©3728 154
120-80 -01876 200-120 --4749 500-200 +5394 204
120-60 -.2187 200-120 --S5747 500-200 + O46 298
120-80 -.1928 £00-120 «7134 500-200 *8563- 30%
120-80 -.1824 200-120 ~-8416 500-200 140119 354
120-80 -21794 200-120 -+9566 500-200 1462111 40M
126-80 -21777 200-120 ~1.0699 500-200 1.4122 454
120-60 -.1851 200-120 -1-217350 500-200 1-086 SOM
120-60 -.1796 200-120 #2652 500-200 1.8087 5&4

CH 120-80 -.1859 200-120 -1.39911 500-200 149889 60M
CH B5-286 120-80 -.1951 200-120 -1.4966 500-200 2@1721 651
CH 87-26 120-60 =.2009 200-120 ~1. 6010 500-206 23552 70M
CH £9-30 120-80 -.2073 200-120 -1. 7477 500-200 25377 751
CH 31-32 120-60 -.21284 200-120 -1.8936 500-200 2 7258 60M
CH 33-34 120-80 ~-.2837 200-120 -2.0365 500-200 29023 6&
CH 35-36 1£0-S0 -.2309 200-120 -2. 1884 500-200 3-078 904
CH 37-36 120-80 -.2373 200-120 -2.5346 500-200 362505 9
CH 39-40 120-80 -.2470 200-120 -2.47¢60 500-200 364137 100M
CH 41-428 * 120-80 -.2528 200-180 -2.¢e44 500-200 3.65732 10S
CH 43-44 120-60 ~.2587 200-120 ~2. 7636 50G-200 3.7377 1104
CH 45-46 120-80 -.2635 200-120 -2.9120 500-200 3-86 60

CH AT-4g 180-80 -.8633 200-120 -3.0536 4. 0520

Ci 49-56 120-80 -. 2588 200-126 - Aef132 16
CH «51-52 120-80 -.2648 200-120 - Ae364G 1304
CH «53-54 120-60 -.2707 €00-120 -364763 4.5177 1354
CH 55-56 120-50 -.8764 e00-120 -~3.6132 Zl Ae 6820 140M
CH 57-58 120-80 =.2760 200-120 -3.7510 500-200 46036 145%
CH 99-60 120-80 -.2891 200-120 -366897 500-200 4.9395 150M

104


£9

Table 15.

Comparable
Dates

17-21 August 1970 (Watson)
August 1972

3-8 February 1970 (Watson)
February 1973

22-27 June 1970 (Watson)
June 1973

COMPARISON OF ACOUSTICAL BIOMASS ESTIMATES (g dry-
wt/m?) OVER ENTIRE WATER COLUMN, WITH OTHER ESTIMATES
(@ dry-wt/m3) OVER O - 50 m COLUMN,

Acoustical Ratio

Previous Estimate Biomass Acoustical :Pre-
(Watson, 1974) Estimate vious Estimates
+16 11.8 B82
+02 2.9 14521
+03 3.0 10031


a secondary one. But the usefulness of Bosmina longirostris as an
indicator of stress is obvious.

Bosmina coregoni, almost twice as large as B. longirostris at maturity,
has been considered an oligotrophic form. In contrast to the inshore
preferences of B.,longirostris, B. coregoni exhibited offshore blooms
of up to 30, 000/m>, co during 21 - 25 August 1972. These intense
concentrations were largely confined to the eastern end of Lake Ontario
(Figure 4), with large aggregations of 20,000/m3 and 1,500/m3 offshore
of Rochester, New York, and a cell of lesser density at the outflow of
the lake.

The third common cladoceran, Daphnia retrocurva, while not classically
used as an indicator of eutrophication, is a small species which
withstands fish predation well, and thus is very successful. Large
inshore concentrations were found again at Oswego_(35,000/m3) and just
eastward from Oswego at Nine Mile Point (10, 000/m3), the site of a
nuclear power plant complex from 21 - 25 August 1972. A third cell
of maximum densities of 20,000/m3 was located west of Rochester
(Figure 5).

The Copepods

Diaptomus sicilis, in sharp contrast to the cladoceran Bosmina longiro-
stris, is the most oligotrophic form in the Great Lakes, and remains

the dominant species in oligotrophic Lake Superior. As expected of an
oligotrophic indicator, it develops its maximum populetion earlier (July)
than Bosmina longirostris (August), and this development occurs in
deeper, cooler midlake watermasses. Currently not nearly as abundant as
Bosmina, D. sicilis densities during 1972 did not exceed 375/m3. Two
large cells were found in eastern Lake Ontario (Figure 6), one occupying
most of the deepwater basin north of Rochester and Oswego, and the other
between this larger cell and the outlet during the period 10 - 14 July
1972. Less intense inshore development was observed in shallow Mexico
Bay in the extreme southeast corner of the lake and in the western
portion just east of the Niagara River inflow.

Diaptomus minutus, a more mesotrophic species with the predatory
avoidance characteristics associated with small size at maturity, also
exhibited an offshore distribution at maximum development. Large
clumps with relatively low densities of 300 - 1000/1 were found in both
the western and eastern parts of Lake Ontario from 12 - 16 June 1973.
In contrast to the cladocerans, these cells were always centered well
offshore (Figure 7).

The cyclopoid copepods have not been used as indicators of pollution

in the traditionel sense. They are likely predaters which obtain a
living by piercing and sucking body fluids from rotifers and small
crustaceans. Three species are dominant in Lake Ontario. In order

of abundance, these are Cyclops bicuspidatus, C. vernalis and
Tropocyclops prasinus. Cyclops bicuspidatus reached its population
maximum in July, C. vernalis in August, and Tropocyclops in October 1972.

18


1973 FEE STA 35 PA 10®*4 AVG 5 DEFIH 18 M DEI 1¢

2973 -

A973,

MEAN VALUE OF

CH 1-8)
CH 2e-48
CH 43-63

FEB STA 42 PA
MEAN VALUE OF

PROFILES OVER SM INTERVALS

120-80 elllS 200-120 +5798
120-86 #2023 200-120 ~.0810
120-80 +3389 200-120 -.9458

10#*4 AVG 5 DEPTH 15 M DEFTH 29 M
PROFILES OVER 5M INTEKVALS

CH
CH
CH
cH
CH

1-16
17-32
33-48
49- 64
€5-80

220-80 21021 200-1280 = 6362
120-80 +2041 200-120 162714
120-80 +3060 200-120 1.9058
120-80 +4060 200-120 2.5392
120-80 +3497 200-120 3.053

SCAN 25M

S00-200 +8430
$00-200 -1.0417
500-00 -.9306

500-200 ~1.1758
S00-200 -161877
800-200 -1. 1643
500-200 -1. 18 G1
509-200 -1.1863

FEB STATION 44 PA 10%*4 AVG 5 DEPTH L74 M DEPTH 189 M SCAN 200 M
MEAN VALUE GF PROFILES OVER SM INTERVALS

CH
CH
CH
CH
cH
CH
CH

geggegeggaqgesae

1- 2
3-4
5- 6
T- &
9-10
di-12
13-14
1S-16€
17-18
19-20
21-22
23-24
25-26
27-28
29-30
31-32

-33-34

35-36
37-38
39-40
4i-42
43-44
AS-46
AT- 48
49-50
51-52
53-54
55-56
57-56
59-60
€1-62
€3- 64
65-66
€7-
@-70
71-72
73-74

120-80 +6657 200-120 -.8411
120-80 1.4492 200-120 - 149877
120-80 1.7975 200-120 -2.3305
120-60 1.81028 200-120 -2.3275
120-60 147951 200-120 ~2.3139
120-60 1.7988 200-120 -2.306!
120-80 1.7953 200-120 983
120-80 1.7828 200-120

120-80 147760 200-120

120-80 1-4-7662 200-120 -2.8673
120-80 147562 200-120 ~2-2594
2120-80 147448 200-120 -222491
120-60 14736) 200-120

120-60 1.73128 200-120

120-80 1.7251 200-180

120-80 1.7158 200-120

120-80 200-120

120-80 200-120 -2- 1876
120-80 200-120 -2.1756
120-80 3 200-120 -&4 1658
120-60 1. 6666 200-120 -2.1564
120-80 1.6563 200-120 -2- 1466
120-60 1.6480 200-120 -2.1333
120-60 146389 200-120 -2e1216
120-80 1+ 6288 200-120 -2.11284
120-80 1.46185 200-120 -2. 1016
120-80 146106 200-180 -2.0914
120-80 1.6011 200-120 osa4a
120-66 1.5978 200-120 0738
120-80 1.5903 200-120 -2.0678
120-60 1.5827 200-120 - 2.0569
120-60 1.5721 200-120 -2.0439
120-80 145602 200-120 -2-0314
120-80 1.5517 200-120 -2.0206
120-80 1.5432 200-120 -2-0098
120-60 145366 200-1e0 -2.00e8
120-80 1.5293 200-120 -1-9931

137

500-200 -.1005
500-200 ~~. 1018
500-200 ~-1051
500-200 ~.1088
s00-200 ~.1113
500-£00 ~.1150
S00-200 ~.1203
S00-20G0 ~.1266
500-200 ~-+1331
500-200 ~.1401
500-200 ~61456
500-200 -=.1511
$00-200 ~.1572
500-200 -.1645
500-200 ~.1727
500-200 ~.1814
500-200 ~.1895
500-200 ~.1993
500-200 ~.2083
500-200 ~-.281s7
500-200 ~. 2282
500-200 E388
500-200 ~.24D
500-200 -.295
500-200 ~«2707
500-200 -.2795
500-200 -.2912
500-200 --3017
500-200 -.3127
500-200 ~.3220
500-200 -.3293
500-200 ~-3373
500-200 ~+3440
S00-200 -.3507
800-200'° -.3576
500-200 ~-36E5
500-200 -.304

MM
10M
1o4

a4
10M
oy
€0M
eM

150M
154
160u
165M
170M
174
1604
16


In modelling the trophic dynamics of a large ecosystem, not only ere

the fluxes of materials and energy difficult to quantify, but the
stending crops of organisms are both difficult end time-consuming to
estimete if traditional techniques of plankton sempling are employed.

In Section VI we heve presented our new acoustical method for the
estimetion of zooplenkton bianass over the entire water column et

each sampling station. The results suggest that others may have
previously underestimated the abundance of zooplankton in Leke Ontario.
These results will enable more realistic ecosystem models to be
constructed, with a better understending of the magnitude of zooplenkton

grezing.

Our estimetes of the impact of urban ereas upon water quality (Section Vv)
utilize one form of the competition metrix to interpret community
structure on a comparative basis. In Section VII Dr. Steven Levine

has investigated comunity structure with a new modification of this
matrix. This approach enables us to estimate community stability,

or the relative lack thereof, again from information on species
abundance.

The changes in the canposition of the crustacean zooplankton in

Lake Ontario, both on a geogrephicel basis and with historical time,
are certainly related to their trophic relationships, especially
selective feeding upon certain algel forms. In Section VIII we have
suggested a new hypothesis to explein these drematic community changes
occurring as Lake Ontario becomes more perturbed.

The appendix includes summaries of the zooplankton composition on
each IFYGL cruise, as well as a selected sample of results (4 cruises),
from using our acoustical device in estimating zooplenkton biomass.


1973 FER STATION 26 PA 10##4 AVE 5 DEPTH 146M SCAN 175M
MEAN VALUE OF PROFILES QVEH 5M INTERVALS

1973

1973

1- 2
CH 3- 4
CH BS 6
CH 7- &

9-10
CH «11-12
CH 13-14
CH 15-16
CH (17-18
CH 19-20

21-22
CH 23-24
CH 25-26
CH 27-28
CH 29-30
CH 31-32
CH 33-34
CH 35~36
CH «37-38
CH =39~40
CH 41-42
CH 43-44
CH 45~46
CH 47-48
CH 49-50
CH S1-52
CH 53-54
CH 55-56
CH 57-58
FEB STA 30
MEAN VALUE
cH «1-20
CH 21~40
CH 41-60
CH 61-60
FEB STA 31
MEAN VALUE

PA

120-60
120-80
120-80
120-80
120-40
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-60
120-80
120-60

10#* 4 AVG 5 DEPTH 20 M DEFTH 24M

“52514
+5200
+ 6059
+002
+6071
+6022
+6018
+6029
+5967
+ SISE
+5900
+5931
«S95!
+ 6008
5937
+5962
+5933
+5934
+5909
+5907
+5904
+5979
+ €000
+5990
25973
+5975
= 5978
+5046
+5967

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200~ 120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200~ 120
200-120
200-120

71-1803
7264454
~ 2. 6405
2+ 6300
- 2. 6253
7266137
~2+C056
72.5906
265847
72-5761
= 2. 5636
7 €.5530
72. S4EL
265443
~ 2.5334
“26 SEED
~2.5116
245041
+4905
= 264796
“2.466
~264657
~Ee4559
2.4410
Be A4E7E
BAN 73
204105
2.39 &
~ 263840

OF PROFILES OVER 5M INTERVALS

PA

E OF

120-80
120-80
120-60
120-80

10%#4 AVG 5 DEPTH 28 4 DEPTH 29 M

«6594
2917)
1.1878
1.4397

200-120
200-120
200-120
200-120

16472
265723
764
403405

PROFILES OVER 54 INTERVALS

120-60
120-80
120-80
120-80
120-80
120-60

20985
190
«2951
+3930
24907
© 5883

200-120
200-120
200-120
200-120
200-120
200-120

135

500-200 +0054
500-200 -.0012
S00-200 -+0030
500-200 -.0067
$00-200 ~-.0086
500-206 ~-+016€0
s00-200 -.0181
800-200 -.025)

$00-200 --0282
500-200 ~--0373
500-200 --0426

500-200

500-200 -.0617
500-200 -.0700
500-800 -.0776

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
506-200
500-200
500-200

500-200 -+ €290

500-200
500-200

5369
4agl7

500-200 -+3527

SCAN 35

500-200
500-200
500-200
500-200
500-200
500-200

=+ GE1E
~s 274
=» 5889
-+5045
= 24070
702403

10%
1a
20M

M
10M
1S
20M
en
30M


Cyclopoid copepodites, or immatures of the above three species, were
abundant from 21 - 25 August 1972, both inshore and offshore (Figure 8).
A large cell with maximum densities of 50,000/m3 was present in shallow
eutrophic Mexico Bay in southeast Lake Ontario, but the greatest
concentrations were in the central basin of the lake (100,000/m>) and
inshore just southwest of Toronto (90,000/m3). Cyclopoids develop
rather slowly, and it is likely thet large aggregations may drift
about the lake for long periods of time with little relationship to
the origin of the underlying environmental factors responsible for
their initial population explosion.

Cyclops bicuspidatus, the most, abundant of the cyclopoid copepods, is
a spring species reaching a maximum abundance by early (10 - 14) July.
In eastern Lake Ontario it was most abundant over deepwater at Station 75
(20, 000/m3 ). In the western waters a large cell was located in midlake
(70,000/m?) and another inshore at Toronto (50,000/m3), The density
of Cyclops in the inflowing waters from Lake Erie was apparently rather
Yow C10;800/n3), as illustrated in Figure 9, Since Cyclops is a seizer
and serum sucker probably feeding upon rotifers and small crustaceans,
its distribution may reflect the abundance of such foods, but is
likely less closely tied to algal and nutrient distributions and thus
is not useful as an indicator of environmental stress.

Cyclops vernalis was much less abundant than C. bicuspidatus. Two
small concentrations were observed in western deke Ontario during
August (Figure 10), one off of Toronto (1500/m3), from 21 - 25 August
1972. Elsewhere densities ranged between 250 and 1500/m3. Together
with the data on C. bicuspidatus, these densities of C. vernalis may
enable modellers to estimate the incidence of zooplankton {non-fish)
predators.

Tr: clops prasinus is an autumnal form which reached densities of
ys oo yas during October 1972,(Figure 11). It was found in a very
large inshore bloom (200,000/m>) west of the Murray Canal, which
connects the Bay of Quinte to Lake Ontario, from 30 October through
3 November 1972. The relationship of such blooms in Popham's Bay to
nutrient inputs from the Bay of Quinte should be answered.

Generalities Regarding the Horizontal Distribution of the
Crustacean Zooplankton

Certainly the cladocerans are most abundant close to shore, while the
copepods prefer deeper waters. These data illustrate differences
within these two orders, indicating clearly that some cladocerans
prefer more eutrophic conditions than others, while some copepods are
more oligotrophic than others. Bosmina longirostris, clearly the most
eutrophic form, exhibits a tendency to explode in areas of known
perturbation, especially off the Oswego River and the City of Toronto,
Bosmina coregoni, a more oligotrophic indicator on a relative scale,
is found in large offshore clumps, well away from major sources of
inorganic and organic plant nutrients. Daphnia retrocurva is



1972 aug STATION 7
MEAN VALUE OF

CH
CH
CH
CH
CH

1972 AUG STATION &
MEAN VALUE OF

gegeggge2greeo

1-16
17-32
33-48
49-64
65-80

1- 6
7-12
13-18
19-24
25-30
31-36
37-42
43-48
49-54
55-60
€1- 66
61-72
13-78
19-84

DEPTH 26 METERS PREAMP 10##4 AVE 5 DEPTH 32

PROFILES GOVE: SM INTEXVALS

120-60
120-80
120-80
120-80
120-80

200-120
200-120
200-120
200-120
200-120

202553
122019

#35961
-2 1168
03537

DEPTH 70 METERS PREAMP 10*#4 AVE
PROFILES QVEK SM INTERVALS

120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80

1972 AUG STATION 10 DEPTH

MFAN VALUE @F PROFILES OVEk SM INTI:

g2egggggeegggegegagesas

I- 3
a 6
I- 9
10-12
13-15
1616
ig-21
eee
25-27
28-30
31-33
34-36
37-39
40-42
42-45
AER 48
49-51
5e-54
S5- SF
58-60
61-63
G4- 66
61-9

120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
220-80
120-80
120-80
120-40
120-80

0 7544

729273
-99311
= 29325
= 09383
09426

119 METERS PREAMP 10°*4 AVE
VALS

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

200-120
200-120
200-120
200-120
200-120
200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-120

200-120 *

200-120
200-120

= 20040
+0854
21730

06737
“123181
1.6966
~ 8. 5033
73-6897
73. 6652
7462656
= 4.8 600
- 504887
~ 6.1946
= 66 8 528
- 72 4582
“660667
T64
90-278
926 670

200- 120-10-404
200-120-11.0913
200- 120-11. 7079
200- 120-128-3232

200- 120-1

29473

200-120" 1365525
200- 120- 1461330

92

$00-200
500-200
500-200
500-200
500-200

DEPTH ®&

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-206
s00-200
500-200
500-200
500-200

‘S DEPTH

S00~ 200
500-200
500-200
500-200
500-200
500-200
500-200
SO0C-206
500-200
500-200
500-200
500-200
500-200
500-200
s00-200
500-200
‘500-200
500-200
500-200
500-200
500-200
500-200
500-200

+0629
0217
24961
« 7288
©9637

«363
+ 7349
1.1019
124749
166484
2-119
fe BAL
2.9556
3-362
3e 7016
4e 0 728
4s A454
AvB184
Se 1922

150

369554
Ae 1303

104

20M
ai


1973 statigy 19 FEB PA 10*#4 AVE 5 DEPTH 14M DEPTH 21.M SWEEP 24 M
MEAN VALUE OF PROFILES SVER SM INTERVALS

cH 1-21 120+80 -.5907 200-120 +5455 500-200 ~1.2900 M
CH «22-42 120-80 20475 200-120 160907 500-200 -2.0821 10M
CH 43-63 120-80 + 5645 200-120 1+ 6347 500-200 -2.0663 154
CH 64-64 120-80 1462147 200-120 241780 500-200 -2.0553 20M

1973 ‘ER STATION 20 PA 10#*4 AVE 5 DEPTH 18 DEPTH 23 SWEEP 27
MEAN VALUE OF PROFILES OVER 5M INTERVALS

cH wel 120-80 -.7741 200-120 1.65747 500-200 -.2452 aM
CH 22-42 120-80 -141313 200-120 21972 500-200 -.2476 10M
CH 43-63 120-80 -1.2090 200-120 2. 5493 500-200 -.247% 15M
CH 64-84 120-80. -1-216€9 200-120 3.0525 500-200 -.2448 20M

1973 STATION 24 PA 10#*4 AVE 5 DEFTH 114M DEPTH 123 M SWEEP 150 M
MEAN VALUE OF PROFILES OVER SM INTERVALS

1- 3 120-60 01785 200-120 -.2741 500-200
4- 6 18 i?) +3038 200-120 -.31286 500-200
q- 9 120-60 -.€011 200-120 ~-+3417 500-200
10-02 120-80 -.7063 200-120 -.3118 500-200
1g-15 120-80 -e7110 200-120 -.3071 500-200
16-18 120-80 -.7014 200-120 ~+3031 $00- 200
19-21 120-80 -.7G0! 200-120 -.3002 500-200
22-24 120-80 -.6921 200-120 500-200

120-80 =. 6851 200-120 500-200

120-80 6906 200-120 500-200
120-60 2 6894 200-120

120-80 -.@64 200-120

120-80 -.7053 200-120

120-80 ~.7078 200-120 S00-200
120-80 ~.7116 200-120 S00- 200
120-80 ~.7102 200-120 500-200
120-80 -.7211 200-120 500-200
120-80 7234 200-120 500-200
120-80 284 200-120 500-200

120-80 -.7387 200-120 S00-€00 -.2782 106M
120-80 -.7429 200-120 -.2738 500-200 -.£702 1054

geggggggoaceggaegeggooooeaa

64- CE 120-80 -.7505 200-160 -.2734 500-200 ~.2666 110M
61-69 120-80 -.7536 200-120 +22739 500-200 -.2644 114M
70-72 120-80 -.7559 200-120 -.2726 500-200 -.2639 120M

134


sg

Table 17 (continued). LAKEWIDE AVERAGE OF ZOOPLANKTON POPULATION DENSITIES, VALUES (4/m3)
REPRESENT ANIMALS COLLECTED WITH A NET (64 APERTURE) AT STATIONS IN
WATERS LESS THAN 30 m IN DEPTH, OVER A VERTICAL RANGE OF 0 - 5 m.

15-19] 12-16 | 10-14 | 21-25 5-9 | 19-22] 24-28 } 12-16
Species May | dune | duly Aug | Oct-Nov | Nov-Dec | Feb | March| April | June
Cyclopoida
Cyclopoida 70 431 1599 |25331 10892 746 |2077 | 1407 | 987 13890
copepedites
Cyclops THO | 1061 10707 | 8520 105) 519 126 232 887 529
bicuspidatus
Cyclops 1 6 OL B37 176 849 10 7 22 81
vernalis
TropocycLops 0.5 4 26 1754 8022 1066 170 | 1b 163 200
prasinus
Calenoida
Calanoida 37 57 n3 130 405 170 41 69 | 108 219
copepodites
Diaptomus 0 0 0 i) O 0.2 1 | 05 te} +09
ashlandi
Diaptomus 0 ° to) 0.3 pa) 6.8 0.04 0.2 0.3 0.5
siciloides
Diaptomus ab 132 53 60 30 35 37 hg 43 29
minutus
Diaptonus 1b 22 26 6 47 60 42 8 20 1.3
oregonensis
Diaptomus 28 79 he 13 ho 38 35 28 38 1.7
sicilis
Limnocalanus 188 187 65 7 22 ek5 30 50 123 19
macrurus
Eurytemora 08 9 10 1115 133 25 0.3 ° 6 2.3
affinis



SECTION III

METHODS:

GENERAL FIELD TECHNIQUES

Zooplankton net samples

Vertical plankton hauls were taken from the NOAA R/V Researcher at the
60 IFYGL sampling stations on the 10 IFYGL cruises, Fortunately
these 60 stations selected by the IFYGL Management were comparable
within the framework of our lakewide division, described in Sections V
and VI. The urban inshore stations had a mean depth of 14.0 m,
whereas those stations designated rural inshore had a mean depth of
18.5 m. Samples were collected from 5 m depth to the surface,

0 - 25, 0 - 50, O - 100, 0 - 150 and O - 200 m using a plankton net
0.8 m in diameter, with mesh apertures of 154 for cruises 1 - 3

and of 64u thereafter. The zooplankton in these samples were relaxed
with CO, preserved in buffered formalin (pH 7.0), and counted in the
laboratory. Approximately 3% of the most abundant forms in each
sample were counted, whereas all of the rare species were tallied.*
Thus we were able to discover 6 specimens of Diaptomus ashlandi
obscurred among the first 300,000 animals identified to species:

Acoustical profiles

At each station four acoustical profiles were recorded, both on
paper tape and on an X-Y plotter for immediate inspection. These
profiles were made at frequencies of 80, 120, 200 and 500 kHz. The
theory behind acoustical sampling, the program developed for data
reduction, and actual examples of such data will be presented in
Section VI and in the Appendix.

*Note: plankton densities used in analyses found in Sections y and V
are observed densities. That is, the number per unit volume (m°?) was
determined from a consideration of the amount of water in a hypothetical
column of a given depth and from a consideration of the number of
animals captured in those waters. If corrected densities are required
for modelling, multiply observed densities by 2.01 for samples from

the 0 - 5m strata. Likewise the data on density in the Appendix have
not been adjusted. In calculating lakewide biomass (Section VI) the

net efficiency was considered. Thus the densities of zooplankton

and biomass estimates in Section VI are corrected for the inefficiency
of net sampling. These data do not need to be adjusted.


1972 AUG STATION 1 DEPTH 33 METERS FAEAMP 10°*4 AVE 5 DEPTH 45
MEAN VALUE OF PROFILES QVER SM INTENVALS

Agta

iste

iste

2V2V2222

AUG STATION 2
MEAN VALUE OF

CH
CH
CH

AUG STATION 3
MEAN VALUE OF

AUG STATION 5S
MEAN VALUE OF

cH
CH
CH
CH

cH
CH
CH
CH
CH
CH

CH

geegeeaa

1-12
13-64
25-36
37-48
49-60
1-72

1-24
25-48
49-72

1-22
23-44
45-66
61-88

I- 4
SS 8
9-12
13-16
17-20
e164
25-28

“e9-428

33-36
37-40
A144
A5- a8
49-52
53-56
ST~ €0
61-64
65-68
@-72
13-76

120-80

70 5643 200-120 ©5874

120-80 -1.0299 200-120 +9108
120-60 -1.5346 200-120 1.1654
120-60 -1.9403 200-120 1.4220
120-80 -2.2065 200-120 1.6947
120-80 -2.3221 200-120 1.9197

DEPTH 16
PLOFILES

120-80
120-80
120-80

DEPTH 22
PROFILES

120-80

DEFTH 95
PROFILES

126-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-806
120-80
120-80
120-80
120-80
120-80
120-60
120-60

METERS PREAMP 10##4 AVE
OVER SM INTEL VALS

©0983 200-120 2108
21962 200-120 +0009
~e94) 260-120 -.2076

METERS PREAMP 10#* 4 AVE
OVER SM INTERVALS

96661 200-120 1464906
120-80 ~1-1103 200-120
120-80 -1-9279 200-120
120-80 -2+7950 200-120

METERS PREAMP 10884 AVE
OVER SM INTERVALS

«3557 200-120 --0475
+4238 200-120 60712
+4475 200-120 e25it
© AGB 200-120 #4306
©4788 200-120 + 6018
«4672 200-120 «7091
©4938 200-120 99260
+5070 200-120 160752
25191 200-120. 1.62195
«53028 200-120 143599
+5297 200-120 1.4998
«5316 200+120) bs 6348
+5456 200-120 1+ 7659
«5578 200-160 14-8958
«5682 200-120 2.0286
«5785 200-120 2.146
SSE 200-120 26263
© S804 200-120 263883
«5800 200-120 8.5122

91

500-200 20915
506-200 0879
500-200 +4B4
S00-200 + BEE
500-200 +6855
500-200 160674

5. DEPTH 22

500-200 +2730
500-200 + S195
500-200 +8215

DEPTH 25

500-200
500-200
500-200
500~ 200 +5655

5 DEPTH 120

500-200 8367
500-200 ©4987
5067200 0 17B
500-200 1.0670
500-200 143620
500-200 1. 66x!
500-200 149516
500-200 #2204
500-200 2. 438
500-200 &- 7435
S00-200 360027
500-200 3-2610
500-200 3.5204
500-200 3+ 7776
500-200 460364
500-200 498
§00-200 4» 5563
500-200 4818
500-200 %0774

SM
10M
1SM
20M
eat
30M

10M
iSM

tom
i
20M.

10M
14

eo
30M
3m
40M
am
50M

6omM
est
70M
TM
80M
6S
90"
9 SM


1972 AUG STATION 30 DEPTH 20 PEF 10®#4 AVE 5 DEPTH 50

gr

agra

MEAN VALUE SF PROFILES SVEK SM INTFEVALS

CH 1-10 120-80 +5450 200-120 +6210
CH 11-20 120-80 98197 200-120 1.66323
CH 21-30 120-80 149730 200-120 262402
CH 31-40 120-80 2. 6396 200-120 361504
AUG STATIGN 31 DEPTH 28 METERS PRE 108®4 AVE 5S
MFAN VALUE OF PROFILES OVEh 5M INTERVALS

CH 1-12 120-80 1.1642 200-120 264777
CH 13-24 120-80 1.4776 200-120 € 4325
CH 85-36 120-80 1.3738 200-120 11-0377
CH 37-46 120-60 32533 200-120 13-7034
CH «49-60 120-60 5.1432 200-120 1568231
AUG STATION 32 DEPTH 171 MFTFES PhE 10**4 AV3
MEAN VALUE OF PROFILFS OVER SM IN VALS

CH = 2 120-80 20424 200-120 93145
CH 3-4 +0329 200-120 +5100
CH S- 6 +0842 200-120 26D
CH In & ~OES4 £00-120 98182
CH 9-10 20176 200-120 0947E
CH 11-18 +G1Ge 200-120 14-0671
CH 13-14 0076 200-120 1.1812
CH 15-16 -003! 200-120 14-6955
CH (17-18 ~ +0036 200-120 1464347
CH 19-20 -0116E 200-120 1.5885
CH 81-82 ~ +0220 €00-120 1.7552
CH 23-84 ~.0298 200-120 1.9242
CH 285-26 120-60 -.0383 200-120 2.0986
CH 27-288 120-80 -.0386 200-120 &-2726
CH «29-30 120-60 -.0441 200-120 24442
CH 31-32 120-80 -.0508 200-120 2.6203
CH 33°34 120-80 -.0563 200-120 267933
CH 35-36 120-80 -.S27 £00-120 269654
CH 37-38 120-86 -.0 29 200-120 3.41407
CH 39-40 120-60 ~-.0916 200-120 343163
CH Al-42 120-80 -.1046 200-120 3.4932
CH 43-44 120-80 -.1078 200-120 3.6628
CH ASR 46 120-80 -.1268 200-120 366365
CH AT-48 120-80 -.1345 200-120 460095
CH 49-50 120-80 -.1545 200-120 4618644
CH SI-52 120-80 -.16€30 200-120 43572
CH 53-54 120-60 --1662 200-120 4-539
CH 55-56 120-60 -.1766 200-120 4.7067
CH 57-56 120-60 -21836 200-120 466841
CH 59-60 120-80 -.19728 200-120 5.0608
CH 61-62 120-60 ~+2160 200-120 562334
CH 120-80 -.224% 200-120 S-4060
CH 65-66 120-80 ~.2310 200-120 5.5758
CH 67-8 120-60 -.2382 200-120 Se7413

96

500-200 0882
500-200. 6114
500-200 1.61592
500-200 1.6984
DEPTH 45
500-200 -» 6082
500-200 -.8262
500-200 -.8072
500-200 -- 972
500-200 -+ 7% 76
5 DEPTH 250
S0C-200 «1344
500-200 + 3412
500-200 =. 5704
500-£00 «048
500-200 1.0072
S00-200 141884
500-200 1.3€24
500-200 1.5345
500-200 1. 7032
506-200 148729
500-200 2.0423
500-200 22119
500-200 23603
500-200 2+ 5485
500-200 2. 7156
500-200 2.8642
500-200 3.0527
500-200 32184
500-200 3.36 59
500-200 3. 5544
500-200 3. 7229
500-200 3.8892
500-200 4.0566
500-200 4.2837
500-200 4.3926
500-200 4.5597
500-200 4. 7267
500-200 4.86937
500-200 5.0623
500-260 5.23520
500-200 5+ 3991
500-200 5. 5&0
500-200 5S. 7369
500-200 59037

104

£04

10M
ist
20M
emt

60M

Bo

90%

9
100"
1094
110M
1154
120M
1254
130M
1394
140M
1454
150M
isc
160M
16m
170M


1972 soy STATION 7 PA 10°%4 AVG S DEPTH 24M SCAN 40 M
MEAN VALUE OF PHOFILES OVER Sf INTERVALS

CH 1-15 120-80 142347 200-120 -1- 5888 500-200 0447 Rul
CH 16-30 120-80 1.8242 200-120 -2.000 500-200 «4964 10M
CH 31-45 120-80 1.7908 200-120 -1.9488 500-200 «7412 1&0
CH 46-60 120-60 1.7380 200-120 -1-8043 00-200 «8117 20M

1972 NGV STATION & PA 108#4 AVE 5 DEPTH. 70 M SWEEP 77M
MEAN VALUE GF PROFILES OVER SM INTERVALS

CH I- 6 120-80 +0953 200-120 500-200 -+ 7070 a
cH 7-12 120-80 «1934 200-120 500-200 --5242 10%
CH 13-16 120-80 -.2051 200-120 500-200 --.3591 ISM
CH «19-24 120-80 +7839 200-120 500-200 -.1931 20%
CH 25-30 120-80 13-1476 200-120 500-200 --0270 2of
CH 31-36 120-86 +8243 200-120 500-200 +1412 30M
CH 37-42 120-80 +2090 200-120 500-200 +3103) 3S4
CH A3- 120-80 -.5305 200-120 500~ 200 *4D7 40M
CH 49-54 120-80 -1.2206 200-120 500-200 +6485 454
CH 55-60 120-80 -166314 200-160 500-200 +6207 50%
CH 61-66 120-80 ~2.5254 200-120 500-200 “9912 SM
CH 67-72 120-60 =3-5171 200-120 500-200 14-1624 60M
CH 73-76 120-80 -4+3524 200-120 500-200 1.3324 6S
CH 79-864 120-80 - 468043 200-120 ~-.1497 500-200 1.5017 70M

1972 NOV STATIGN 10 PA 10#*4 AVG 5 DEPTH 121 M SWEEP 160 M
MEAN VALUE OF PROFILES OVER SM INTERVALS

cH Ie 3 120-80 © 5541 200-120 -144331 500-200 +0103 MM
CH a 6 120-80 0501 200-120 -1.9139 500-200 «1655 10M
cH T- 9 120-80 +0301 200-120 -2.2101 500-200 +3193 1oM
CH 10-12 120-80 --1143 200-120 -2841341 500-200 +4750 20M
CH «13-15 120-80 £00-120 ~2.0619 500-200 +6311 254
CH 16-18 120-80 200-120 -1.99 78 500-200 + POS 30M
CH «19-81 120-80 200-120 -1.9312 500- £60 29458 3ST
CH «28-24 120-60 200-120 -1.8 664 $00-200 1.1082 40M
CH 25-27 120-80 200-120 -166811 500-200 162559 4M
CH 26-30 120-80 =-.3706 200-120 -1. 7459 500-200 1-407 50M
CH 31-33 120-80 ~-3766 200-120 -1.6709 500-200 1.5619 S54
CH 34-36 120-60 -.3872 200-120 -1.€061 $00-200 167167 60M
CH 37-39 120-80 -.3873 200-120 -1. 536° 500-200 1.668% Co
CH 40-42 120-80 --3874 200-120 -14 4880 500-260 2.0289 70M
CH 43-45 120-80 -.3980 200-120 -1-4272 S00-£00 & lkse 74
CH 46-48 120-80 -.4061 200-120 -1-3634 500-200 &3419 80M
CH 49-51 120-80 =~. 4156 200-120 -1-3067 500-200 & 4982 8&4
CH S854 120-80) =243239 200-120 -142431 S00-200 & €499 90M
CH 55-57 120-80 +.4453 200-120 =1.1607 500-200 £48015 954
CH 88-60 120-80 -.4C09 200-120 -161118 500-£00 2.9555 100M
CH 61-63 120-80 -.4051 600-120 -1-0491 800-200 3.1096 1084
CH 64-66 120-80 - 24769 200-180 -.9920 800-200 3.297 110%
CH 67-09 120-80 ~-.4862 200-120 -.9354 500-200 3.44135 115
CH #70-72 120-80 -.5126 200-120 -.8 G4 500-200 3.5068 120M

112


6S

Figure 17. Column biomass (g dry wt /m? ) during February 1973


its own right. Secondly, it can be viewed as an approximation to
certain more complex models in some region around equilibrium. It is
this latter interpretation which we are considering here with the
resulting limiting assumption that the community under consideration is
always in a near equilibrium state. For this reason the zooplankton
communities considered all occur at summer dates when the equilibrium
conditions are more nearly met.

MATHEMATICAL THEORY

Competition Matrix

The competition matrix arises from the Volterra (1926) system for m
interacting species

mn
ko - Fa 30 =1; = 1,2,---1
7 iq 7 et are v1 13 i = 1,2,---m (1)

where on, - population density of the ith species
pi - intrinsic growth rate of the ith species
k, - carrying capacity of the ith species
4, - competition coefficient jth species on the ith species

o;; measures the number of individuals of species, i, displayed by one
individual of species, j, when the system is near equilibrium. The

a 3 can be grouped in an array known as the competition matrix (Levins,
1388). This matrix, Ay is of the form

fl 0 4 1g---- -— om
= 1 2
Aye ' (2)

i

oran '

i

1

' i

i) 1

Omy----~------- am

and contains information on competition between individuals of different
species,

The o,. measure the displecement of species i per individual of species
d. TE is often of more interest to consider the displacement of species
i due to the entire population of species j. If we let nf, represent the
equilibrium population of species j, then oy 385 would be @ measure of
this displacement. We can think of this as He! gating each element sid
by the population density f,. In order that the new elements pegscalea
Nas

similarly to Ge a norma lifting factor (Byyed ts where Bove =i By 5

65


SECTION IV

ANALYSIS OF ZOOPLANKTON POPULATIONS

Both seasonal patterns in species abundance and estimates of

secondary productivity are important in understanding the dynamics of
competing species, let alone relating their dynamics to that of the
primary producers. We have produced detailed information on the
abundance of all species of Cladocera and Copepoda (Crustacea) at the
60 stations of the IFYGL Lake Ontario grid. Estimates of standing
crop are vital in estimating zooplankton grazing. Horizontal
distribution is important to understanding the development of
populations, with regard to the non-homogeneous or clumped distribution
of their food resources.

SEASONAL DISTRIBUTION OF THE CRUSTACEA

Bosmina longirostris, the most abundant cladoceran of Lake Ontario,
began to increase in abundance in April and May in inshore waters,
although rapid population growth does not result in large standing
crops until June (Table 1). Maximum densities were reached in

August inshore, In deeper, offshore waters, the initial standing

crops were lower in May and June, but July and August densities were

as high as 63,691/m3 (Table 2), Following a population crash in
November, Bosmina over-wintered as parthenogenetic females, at densities

of only 0.3-10.2/m>,

Bosmina coregoni, a larger Bosminid considered characteristic of
oligotrophic waters (see Section VIII), is also found in Lake Ontario.
It likewise overwinters at densities of 4 - 65/m>, but is currently
much legs successful in Lake Ontario, reaching a maximum density of
2,050/m> offshore in October (Table 2).

Among the daphnids, Daphnia retrocurva is currently most successful in
epilimnetic waters, again with an August maximum (11,965/m>) offshore
(Table 2). The smaller Ceriodaphnia lacustris is chiefly a summer
form, as is Holopedium gibberum. Dia hanos oma sp. is a winter form,
in relatively low numbers (4 - 9/ from November through March
(Table 2),

Polyphemus pediculus, a non-bivalve cladoceran often considered
predatory, is found only during August in offshore waters (Table 2).

Cyclops bicuspidatus was the most common cyclopoid of the offshore
waters, whereas Tropocyclops prasinus was more common inshore (Table 2).
C, bicuspidatus was most abundant during July_and August (12,478/m?),
and overwintered at high densities (121-452/m3 ) in offshore waters
(Table 2). C. vernalis likewise reached its maximum abundance in

10


1973 JUN STATION 72 DEPTH 19 M SWEEP 25 M
MEAN VALUER SF PROFILES OVER SM INTERVALS

CH 1-25 120-80 ~-.3708 200-120 -.«8728 500-200 «0000 aM
CH 26-50 120-80 -.9020 200-120 -164361 $00-£00 +0000 10M
CH SI-75 120-80 -1.3041 200-120 ~2.0534 500-200 +0000 15M

1973 JUN STATION 73 DEPTH 16M SWEEP 25 M
MEAN VALUE GF PROFILES OVER 5M INTERVALS

CH imei 120-60 ~.6939 200-120 -.26& 500-200 +0000 SM
CH Be-42 120-80 -148630 €00-120 ~.4519 500-200 +0G00 10M
CH 43-63 120-80 -3.1527 200-120 -. 5469 500-200 0000 154

1973 JUN STATIGY 75 DEPTH 865 M SWEEP 250 M
MEAN VALU OF PROFILES OVER SM INTELVALS

CH 1- 2 120-80 +3001 200-120 -- 7141 500-200 ~0000 4
CH 3- 4 120-80 67334 200-120 -1-5796 +0000 10M
CH S 6 120-80 1.1843 200-120 -26448) -0000 154%
CH T- 6 320-80 1.3270 200-160 -3-1870 500-200 -0000 20M
CH 9-10 120-60 144641 200-120 -3.8199 500-200 ~o000 2m
CH ll-12 120-80 1.5084 200-120 -4.2906 500-200 +0000 30M
CH «13-14 120-80 1.5487 200-120 -4+ 6332 500-200 20000 3&4
CH «15-16 120-60 1.5437 200-160 -4.8557 500-200 +0000 40M
CH «17-16 120-80 145375 200-120 - 4.9773 500-200 ~0000 4SM
CH 19-20 120-60 1.4947 200-120 -4.9965 500-200 +0000 SOM
CH ele 120-80 1.4473 200-120 -4.9 746 500- £00 -0000 Soa
CH P3624 120-60 1.4195 200-120 ~4.9 546 500-200 +0000 €0M
CH 25-26 120-80 1.3940 200-120 -4.9206 500-200 0000 654
CH 27-28 120-80 1.3726 200-120 - 4.88 62 500-200 «0000 70M

29-30 120-60) 143549 200-120 -4.6464 900-200 +0000 7&4
CH 31-32 120-S0 143356 200-120 ~4. 7959 S00- 200 +0000 &0M
CH 33-34 120-80 1463276 200-120 -4. 7540 500-200 »0000 8&4
CH «35-36 120-80 1.23201 200-120 -4.7095 800-200 +0000 904
CH 37-38 120-80 1.3183 200-120 -4. 6634 500-200 0000 9&1
CH 39-40 120-80 1.3228 200-120 -4. 6217 500-200 +0000 100M
CH 41-42 120-60 1.63336 200-120 -4. 5613 500-200 +0000 10%
CH 43-44 120-80 1.3387 200-120 ~4+5380 500-200 +0000 110M
CH 45-46 120-80 143429 200-120 -4. 4974 s00- 200 «6000 11%
CH AT~ AB 120-80 143456 200-120 -4. 456€ 500-200 0000 120M
CH 49-50 120-80 143468 200-120 -4-.4160 S00-£00 -0000 1am
CH 51-52 120-60 14-3504 200-120 -463747 500-200 «0000 130M
CH 93-54 220-60 1.6354e 200-120 -~ 4.3342 S00-200 +0000 134
CH 55-56 120-80 1.3570 200-120 -4.2936 500-200 «0000 140M
CH 57-58 120-80 1463584 200-120 -4.2574 500-200 +0000 1454
CH «59-60 120-80 143619 200-120 ~4.2180 500-200 +0000 150M
CH 61-62 120-60 1.3675 200-120 -4.1791 S00-200 +0000 155%
CH 63-64 120-80 143706 200-120 ~461410 500-200 +0000 1€0M
CH 65-66 120-80 1.3741 200-120 -4.0994 500-200 +0000 16m
CH 67-68 120-60 1.3786 200-120 - 4.0600 506-260 +0000 170M
CH =€9-70 120-60 143834 200-120 -4.0217 500-£00 +0000 1754
CH 71-78 120-60 1.3870 200-120 -3-97%9 500-200 +0000 180M
CH 73-74 120-80 143686 200-120 -3.9380 500-200 +0000 18m
CH 75-76 120-80 143916 200-120 -3.4997 500-200 +0000 190M
CH 77-76 120-80 143948 200-120 -366577 500-200 +0000 lym
CH «79-60 120-60 1.3959 200-120 -368165 500-200 -0000 200M
CH «61-82 120-60 143985 200-120 -3.7780 500-200 +0000 20m
CH 83-84 120-60 143994 200-120 -3. 7363 500-200 20000 &£10M
CH 65-86 120-80 1.4087 200-120 -~3. 6953 500~200 +0000 15M
CH 87-88 120-86 1464044 200-120 -3. 6545 500-200 +0000 220M
CH 89-90 120-80 1.4075 200-120 -3.6124 500-200 .0000 225M

15h


1972 AUG STATION 12 DEPTH 21 METERS PREAMP 10*64 ave
MEAN VALUE OF PROFILES OVEK SM INTERVALS S DERM 28

ig72-

igre

CH
cH
CH
cH

1-21
22-42
43-63
64-84

120-80 20971
120-80 S097
120-80 5147
120-80" = 140890

200-120
200-120
200-120
206-120

1. 66
2.0719
1.5431
1.5037

500-200
500-200
500-200
500-200

21297
©2317
+ 4288
+ 6381

AUG STATION 14 DEPTH 10 METERS PREAMP 108*4 AVE 5 DEPTH 17
MEAN VALUE OF PROFILES OVER SM INTERVALS

AUG STATION 15 DEPTH 102 METERS PERAMP 108#4 AVV
MEAN VALUE OF PROFILES OVER SM IN

2egggeggaeeserergegag

I= 3
a 6
- 9
10-12
13-15
16-18
19-21
22-84
25-27
28-30
31-33
34-36
37-39
40-42
43-45
Ab 48
49-51
5a- S4
55-57
58-60

120-80 +1007
120-80 - 3652

120-60 =.5227
120-80 -1-0174
120-80 -1.8682
120-60 -1-9734
120-80 -1.9%19
120-80 -1.9782
120-80 -1.9782
120-80 -1-9940
120-60 -20053
120-60 -2.0046
120-60 -1.9826
120-80 -1.9415
120-80 ~1-8873
120-60 -1.8558
120-80 1.8505
120-60 -1+8423
120-80 -1.6376
120-80 -1.8320
120-80 -1.8320
120-80 -1.6261

200-120
200-120

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-126
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120

93

+ 549 6
23997

VAL S

300015

500-200
500-200

S DEPTH

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

+061
«2605

140

+1461
«2654
«301
24875
+ 6556
+8049
+9541
160749
1.1 B8
162D4
163976
164772
1.5763
1- 6724
de TO
168 675
169656
260644
e012
262563

at
104
it
20M

a4
10M

MM
10M

20M
eat
30M

40M
an
504
SoM
604

70"
731
80M

90M
9 ot
100M


St

Table 2 (continued). OFFSHORE ZOOPLANKTON POPULATION DENSITIES, Values (number /m3 ) represent
animals collected with net (64 u aperture) at stations in waters greater
than 30 m in depth, over vertical range of O- 5 m

15-19 12-16 «10-14 21-25 Oct- Nov- 5-9 19-22 24-28 612-16
Species May June July Aug Nov Dec Feb Mar April June
Gyclopoida (eoht )
Tropocyclops | 0. 10.8| 65.6 | 1676. | 3510. 886.7] 159.8 | 159. | 257.5 | 287.9
prasinus
Mesocyclops - + + ++ + + - - - -
Calanoida
Calanoid 19.9 60.4] 123.9 116. 331. 128.3 | 36.6 24) 94.5 | 155.6
copepodites
Diaptomus 0. 0. 0. oO. 0. 0. 0.8 oO. 0. 0.
ashlandi
Diaptomus Oo. oO. oO. oO. 2.5 5.2| 0.3 oO. 0. 0.6
siciloides
Diaptomus 56.7 | 225. 90.9 B.7 27.8 28.6 | 42,8 54.4 | 50.6 47.3
minutus
Diaptomus 0.8 70.7| 76.1 107.5 35.8 34.5 | 9.3 6.2 | 10.7 1.9
oregonensis
Diaptomus beh [ 18h. 7 119.4 17. 26.1 28.3 | 27.4 24.5 | hh.8 2.5
sicilis
Iimnocalanus 8.2 [| 183. 139. 6. 23.8 22.9 | 20.4 50.8 | 127.0 1.4
macrurus
Eurytemora 0. 0. Oo. 117.6] 110.1 22.6] 0.3 0. 9.5 14

affinis



Table 9 (a).

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EXAMPLE OF UNCORRECTED ACOUSTICAL REFLECTIVITY AT FOUR
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239.40
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+ LTE
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21948
01947
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68

Table 19 (continued).

MEAN ZOOPLANKTON POPULATION DENSITIES, VALUES (NUMBER /m? ) REPRESENT
APERTURE) AT STATIONS 50 m TO SURFACE.

ANIMALS COLLECTED WITH A NET (64

15-19 | 12-16] 10-24] 21-25 5-9 | 19-22 ‘gh-28] 12-16
Species hay June July Aug Oct-Nov} Nov-Dec] Feb | March| April] June
cyclLopoida
Cyclopoid Wh 1363 8840 5753 2963 | 1182 511 2436
copepodites
Cyclops 608 2833 2604 69 25 92 562 250
bicuspidatus
Cyclops 9.3 59 453 Ou ° te) ° 0.2
vernalis
Tropocyclops ° 5h 190 576 163 19 89 23
prasinus
Calanoide
Calanoid 1099 % 58 119 35 52 82 126
copepodites
Diaptomus 0 re) O +05 202 0.2 0 0.2
ashlandi
Dieptomus ah ) 0.9 1 06 te) ° 0
siciloides
Diaptomus 87 17 18 23 2h78 ns 39 15
minutus
Diaptomus 17 4 17 23 6 6 8 1
oregonensis
Diaptomus ay 29 6 20 8 9 8 2
sicilis
Limnoca lenus 182 196 8h 57 16 82 147 143
macrurus
Eurytemore ° 5 22 k ° ° ° O21
affinis
# of Stations 16 fe} 4 20 {o} 20 uw 17 1T 17
counted



Lz

Figure 11. Density (no. /m3) of Tropocyclops prasinus on 30 October -
3 November 1972 in surface waters (0 - 5 m) of Lake Ontario
at 60 stations of IFYGL Biology Program


1972 N@\ STATION 77 PA 10**4 AVG 5 DEFIH 144M S&EEP 170 M
MEAN VALUE OF FROFILFS OVER SM INTERVALS

CH
CH

CH
CH
CH
CH

Regggeggeegeo2e2

1- 3
4- €
ro

10-12
13-15
PO 18
9-21

2e-F4

25-27

26-30

31-33

34-36

37-39

4O0- 48
43-45
46-468
49-51
Se- 54
55-57
S8~- 60
€1-63
€4- 66
€T- ©

70-72

73-75

16-78

1-61

GO-B4

120-60
120-60
120-60
120-60
120-80
120-80
180-60
1E0-60
120-80
120-60
120-40
120-80
126-60
120-60
120-80
120-80
120-60
120-60
120-80
120-60
120-80
120-60
120-80
120-80
120-86
120-80
120-80
126-80

16 6363
204774
3.7617
46 6335
4s 68 52
Ae 6648
4s 6694
467071
407449
47712
447998
ABER
4.8450
408 649
4.6906
49164
49376
Ad 5e4
4.9704
4.9813
5.0046
5. 0348
Se O88
5.0774
5.0905
5e1154
5s 1384
5+ 1550

200-126"
€00-180
200-120
€00-120
200-160
£00-1£0
200-120
200-160
200-120
200-120
200-120
200-126
E00- 10
260-120
200-180
200-120
200-126
€00-120
200-120
£00-180
200-120
200-120
600-120
200-120
200-120
200-120
200-120
600-126

1972 Nov STATION 78 PA 10*#4 AVG 5 DEFIN $3
MEAN VALUE OF PROFILES OVE

CH
CH
CH
CH
CH
cH
CH
CH
CH
CH

- 7
6-14
15-81
ee-€6
29-35
3-46
43-4)
50-56
57-63
€4-70

120-80
120-60
120-80
120-80
120-80
1£0-&0
120-80
120-60
120-80
120-60

23595
+6311
1.5551
3.3663
4.0532
AebS1G
4- 5809
50347
Se 3143
5.4653

723044
-1.1468
~ek903
~ 3.1535
+0758
~ E6894)
Ee 7154
~£+5410
~ Ee 3718
~&61947
~eeOLle
“168190
-1.€176
164157
1.2166
- 1.0047

“67923

7+ S41

we STEE
7e1lérs
+0434
+ BASS
2 4488
©6614
6712

160795

16€657

1.4931

M SWEEF

OM INTERVALS

200-120
00-120
200-120
£00120
200-120
200-120
200-120
200-120
200-120
200-120

~. 5584
71.3589
040%
-3.4425
+3e 7056
~ 369086
2 1STE
Ve 4eay
74. C019
4.5997

1972=NOV STATION 79 PA 10#*4 AVE S DEPIH 25 M S\EEF
MEAN VALUE OF FEOFILES OVER SM INTERVALS

22229

1-16
17-32
33-48
49-64
65-60

120-80
120-60
1€0-80
120-60
120-80

0966
«1930
20654
20956
161285

200-120
200-120
200-120
200-120
200-120

127

253
+ TEBA
20359

=. 0663

09835

500-200
500-200
500-206
560-200
500-200
$00-£00
500-206
S00-200
506-206
S66-2£00
500-260
560-200
500-200
00-206
s00-200
500-200
S00~200
500- £00
560-200
500-200
500-200
500-206
500-200
500-00
500-200
500-200
900-200
500-660

674

500-200
50G6-£00
500-200
S00-2006
500-200
S00- 200
500-¢00
560-£60
500-206
500-200

30M

500-200
500-200
500-200
500-200
500-200

6 SKS
a2 S24)
we SES
=~. 9951
+ €14E
~ + 6408
= 2 6708
~+ 7009
© 1334
1624
“2 13

81Ve
= 9d 48S
28 761
+9042
301
29 600
11
-1.0221
-1-0534
= 1.0830
w)elles
21.1441
w1e1 741
7166054
1. 2 QbE
+1710
- 2.3018

-+1004
~-G49)
+0139
+0785
elEEE
«bees
+£100

+O71€
+1062
01374
«10
220

a
10M
1M
20M
eg
30M
3
40M
45M
SUM
54
OM
€
70%
7M
6OM
6M
90M
9
100M
10 54
110M
115%
120i
LES
136M
i354
1404

10M
1
20%
oy
30M
3
40M
Ase
SoM

ou
10M
1M
Fath
em


August, but never exceeded densities of 650/m5. Tropocycl: is an
autumnal species, which reached densities of vi wees offshore at the
same time. Thus not only do C. bicuspidatus and T. prasinus show
different seasonal patterns, but their gross horizontal distribution,
to be examined further, is complimentary.

The calanoid copepods, often abundant in oligotrophic waters, are a
diverse assemblage in Lake Ontario, but are never especially abundant.
Unidentified copepodites were most at andant inshore during October-
November, The classical oligotrophic indjcator , Diaptomus sicilis,
was most abundant offshore in June (184/m?) and Pec ecy .

E mora affinis, the recent invader from the sea, never exceeded
390, August) in inshore waters (Table 1).

These data on relative density clearly indicate that Lake Ontario is
characterized by a single seasonal peak in zooplankton production
which occurs during August. Most species overwinter in the lake as

adults, the exceptions being the rare cladocerans, Holopediun,
Polyphemus and Diaphanosoma.

11


Table 12 (continued), ACOUSTIC REFLECTIVITY (D.C, voits/m>) ESTINATEQ
COLUMN BIOMASS (g dry wt/m"), COLUMN VOLUME (m?)
AND BIOMASS PER UNIT VOLUME (g dry wt/m?) FOR ALL
STATIONS, LAKE ONTARIO, AUGUST 1972.

Total
Column
Acoustic Biomass Volume Unit Volume
Biomass g dry wt /m? depth m Biomass
Field St. (120-200-500) (from regression) (x Im*) g dry wt/m3

69 6.79 1,039.65 150 6.92
7 7h Ok 6,425.27 185 34.73
2 23.05 312.55 30 10.4
B 1.97 27.34 5 1.82
ve 75.65 1,024.23 230 4AuS
78 65.26 883.649 50 17.66
79 13.41 182.19 20 9.1
83 422 57.78 95 0.61
85 1,924.05 26 033.08 185 140.7
89 400.82 5,423.78 16) 72.3
90 409 56.02 10 5.60
92 83.09 1,124.89 65 17.3
ok 15.45 209.72 35 5.99
96 9.23 125.56 35 3.59
97 23h 5.28 15 +35
98 6.82 92.96 25 3.71
99 36.17 490.06 20 2h.5
103 «85 12.18 ho +30
105 9.19 125.02 20 6.25
95 11.3 159.39 25 6.37

687.01 11.84
58g ary wt/m?

(Mean for lake, all depth)

39


AM2NOV STATION €4 FA 10°*4 AVE 5 DFFTH 114 M ShEFF 130 4
MFAN VALUF QF PROFILES OVER SM INTERVALS

1972

CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH

NOV

1- 3
a €
9
10-12
13-15
16-16
lg-et
ee- 24
25-27
28-30
31-33
34-36
37-39
40-42
43-45
AE 46
49-51
Se-54
55-57
58-60
61-63
64-66

120-80
120-80
120-60
120-80
120-60
120-60
160-80
120-80

120-80
120-80
120-80
120-60
120-80

2 09 4
21694
0763
“29471
+0702
16 F698
2. 08 67
Ge 2617
2.2605
Be f64E
Be B5e6
8.2484
208493
&e 8479
fe P23)
262318
2.2231
222174
2.2188
06 F136
Pef165
2. 29KE

200-120 +4909
200-120 ., «G47
200-120 =04583
200-160 ~.4829
200-120 -1-6453
200-120 -361107
200-160 -Ges E55
200-120 -4-.0597
200-120 -3.96€5
200-160 -3.931T
200-120 -3+6805
€00-120 -366276
200-120 -3-7705
200-160 -3. 7141
€00-120 -3- 6540
200-160 -3-661281
200-120 -3. 5557
200-160 =364997
200-120 -3.4481
206-180 -343935
206-120 -363417
200-120 -363745

500-200
500-200
500-200
506-206
500-£00
500-200
500-200
500-200
500-200
500-200
500-£00
$00- 200
500-£00
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
800-200

STATION 66 PA 10#*4 AVE S DEPTH 12M SEEEF 29 M
MEAN VALUE OF PROFILES 6VER SM INTEX:VALS

1-26
21-40

STATION 69 FA 10*#4 AVE S DEPTH

120-80 |

120-80

+0704
+0065

NW VALUE OF PROFILES OVER

45-46
AT- 48
49-50
$1-52
53-54
55-56
S7- S68
59-60

120-80 -1.8321
120-80 -1. 4479
120-80 -1.4394
120-80 -1-4131
1E9-80 -1-59 8
120-80 -1-35949
120-80 -1-3941
120-80 -1.39281

120-80 -1.3855

120-80 -1.3801

120-60 -1.3573€
120-60 -1.3712

120-60 -1.3772

120-60 -1.3625

120-80 -1-3531
120-80 -1.3540
120-80 -14340
120-80 -1.3421
120-80 = 143337
120-80 -1.3301
120-60 -1.3360

120-80 ~1-3286

120-80 -143331
120-80 -1.33128

120-60 -143286
120-60 -1.3152e

120-80 -1.2798
120-80 -1.2309

120-60 -1.2236

120-80 -1.2131

200-120 -.2911
200-120 =.7533

SM INTERVALS

200-120 +2080
200-120 +3609
200-120 «5125
200-120 + 6672
200-120 +8136
200-120 o9EIT
£00-120 141032
200-120 168422
200-120 143341
200-120 145410
200-120 1460958
200-120 1466597
200-120 2.0288
200-120 261961
200-120 2.3681
200-120 2.5323
200-120 2.6941
200-120 268635
200-120 3-0319
200-120 3.19%
200-120 34368
200-120 3-5362
200-120 3+ 7097
200-120 348809
200-120 440490
200-120 462116
200-120 4.3439
200-120 4.4661
200-120 4-6£16
200-120 4+ B47

12h

500-200
500-200

152 SULFP 190 .M

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-200
500-200
500-200
500-200
500-260
500-200
500-200
500- 200
00-200
500-200
500-200
500- £00
500-200
500-200
590-200
500-200

=e S11
=» S008
965445
721986
-20411
21109

oECE4

41
«5707
+ 7210
+8 142
1.0505
1. 1688
1.3332
164867
1. 6414
1. DIE
1.9432
£009
be F489
2. 4009
2. 5506

--0181
20264

20478
1173
219286
2739
+3506
+4156
©4753
« 5328
«920
+ 6491
+ 7046
739
“BLES
«8 7228
«9274
29845
1.0379
120939
16 1469
1.2083
142646
163501
163762
144386
1. 4696
1.5421
1.970
le 6486
te 7026
1. 7560

SoM

€UM
€SM
70M
734
60M

90TM
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100M
10
110%

10M

10M
1sM
20m"
est
30M
3a
40"
454
SOM
Sot
€0M
est
70M
734
80M
om
90M
om
100%
10M
110M
11S
120%
1eS4
130M
135M
140M
1454
150M


1972 aug *STATION 85 DEPTH 188 PREAMP 10®*4 AVE 5 DEPTH 230
MEAN VALUE OF PROFILES GVER SM INTEKVALS

1972 -

cH ois &
CH oe 4
CH OS 6
cH 7-8
CH 9-10
CH 11-12
CH «13-14
CH «15-16
CH «17-18
CH 19-20
CH 21-22
CH 23-24
CH 25-E6
CH 87-88
CH 29-30
CH 31-32
CH 33-34
CH 35-36
CH 37-38
CH 39-40
cH 41-42
CH 43-44
CH 45-46
CH 47-48
cH 49-50
CH 51-58
CH 83-54
CH 55-56
CH 57-58
CH 59-60
CH «61-62
CH 63= 64
CH 65-66
CH 61-68
CH 9-70
cH 71-72
CH 73-74
AUG STATI
MEAN VALU
CH oI 4
CH 5 &
CH 9-12
CH 13-16
CH 17-20
cH

cH

cH

CH 33-36
CH 37-40
CH alea4
CH 45-48
CH 49-56
CH $3-56
CH 87-60

120-80
120-60
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-86
120-80
120-80
120-80

IN 69 DEPTH
OF PROFILES OVER

120-80
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80

-20835 200-120 -+7370
1463465 200-120 -+1650
1.24091 200-120 «5084
364916 200-120 168160
166565 200-120 149057
1.8006 200-120 266341
1.9579 200-120 363476
220879 200-120 460772
2.2076 200-120 466099
2 3644 200-120 5.5140
2.4961 200-120 62411
Be 6164 200-120 649727
2.7287 200-120 77033
268409 200-120 864347
2.9098 200-120 941713
3-0910 200-120 949033
3. 2008 200-120 10-6352
3.3270 200-120 11-3659
Be 4410 200-1280 12.0990
3.5612 200-120 12-8698
3. 6890 200-120 13-5607
3661028 200-120 14.6914
369267 200-120 15.0847
4.0378 BO0-120 15+ 75€5
4. 1459 200-120 16-4899
Ae 2638 200-120 1722165
403835 200-120 17-9442
4e 5078 200-120 18.6721
40 6255 200-120 1944059
4 7408 200-120 2061333
466479 200-160 2068674
4.9569 200-120 21. GDEE
Se 0659 200-160 2863345
5Se1816 200-120 £3.0¢52
Se 2936 200-120 23479 69
5.4152 200-120 24.5220
5-533) 200-160 25.2539
76 METERS
SM INTERVALS
+0942 200-120 -.7729
+1881 200-120 «7602
©2819 200-120 2.0366
+3756 200-120 3.2336
+7601 200-120 464253
7+S563 200-120 6.3879
© S447 200-120 669047
1.9281 200-120 765444
363494 200-120 8.2394
Ae TTA 200-180 6.9431
Ge 238 5 200-120 9eG776
Te T3108 200-120 10.3669
901733 200-120 1140593
1066131 200-160 11.7678
12.0490 200-120 1264843

108

500-200
S$00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-06
500-206
500-260
500-200
500-200
$00-200
500-260
500-200
500-260
500-200
500-200
500-200
500-200
SG0-£00
500~ 200
500-260
S00- 260
SoG-200
500-200
S60- 200
500-200
500-200
500-200

PREAMP 10#*4 AVE 5 DEPTH 1!

500-200
500-200
500-200
500-200
500-200
500-200
500-200
560-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200

3.5257
Se 386 7
Te AZ20
9.4740
11. 5120
13-5475
15. 5826
17. 6119
19+ 6432
21.6714
£3. O99
25. 7260
27. 7541
296 O04
31-6047
33-4 E8E
3566 536
37.6 D3
39-6997
Al.GEIS
A349 440
A5e9 638
ALIBEE
50-0050
Sie GE 51
S4e 0448
56-065)
5S 60841
GO. 1045
C201 E56
64. 1440
66. 163E
Be BEE
We EGE)
Tee £203
The E359
76. 2541

10

3.1557

5. S635

709408
10.3287
12-6 7116
1560 %3
17. 4518
19-8226
26.1908
2A. S606
26.9285
29. 29 6B
31-6645
3400336
36. 4006

us
10M
1s
20m
eo
30M
3a4
40M
am
56M
55M
60%
6a



1972 AUG STATION 95 DEPTH I8METERS AVE 5 PE 108#4 DETH 30

ag72

igre

igre

igre

gta:

MEAN VALUE OF PROFILES OVEK

CH
CH
CH

AUG

22229

1-20
1-40
41-60

120-80
120-60
120-80

STATION 97 DEPTH
MEAN VALUE OF PROFILES OVEK

1-13
14=26
27-39
40-52
53-65

120-80
120-80
120-80
120-80
120-80

AUG STATION 98 DEPTH

MEAN VALUE OF PROFILES OVER SM

229

AUG

CH
CH
CH
CH
cH
CH
CH
CH

AUG

AM-12
13-84
25-36
37-48

STATION 99 DEPTH 40 METEH
MEAN VALUE $F PROFILES OVER 54

1-9
10-18
19-27
2B 36
37-45
46-54
55-63
64-72

STATION 103 DEPTH 2%

120-80
120-80
120-80
120-80

120-80
120-80
120-80
120-80
120-80
120-80
120-60
Y20-80

+099
#1936
©2903

200-120
200-120
200-126

84 INTERVALS

25313
1-062)
1.5924

500-200
500-200
500-200

29 MEYTERS PRE 10®#4 AVE 5 DEPTH 42

SM INT! AL, S
62513 200-120 23475 500-200
#9025 200-120 -.0884 500-200
= 7536 200-120 -1.0739 500-200
1.1437 200-120 -2.32e32 500-200
2.0047 200-120 -3.62028 500-200
22 METERS PRE 10*#4 AVE DEPTH 45
INTERVALS
-+300 200-120 ~=.0308 500~ 200
-1-1058 200-120 ©2586 500+ 200
+7366 200-120 ©9961 500-206
~24742 200-120 «8523 500-£00

+2913
+4662
=26070
= 120380
~ 2.0604
-1-061
~1.2880
~1.42610

1.4301
206520
Ae 2 TE

- 63607
+3802
we AB
+ 4588
2 4964

2 ESET
«8625
1.5005
2-106

PREeEMP 10®*4 AVE 5 DEPTH 5}

INTERVALS

200-120 +7097
200-120 29494
200-120 2.2671
200-120 266857
200-120 3. 6385
200-120 264831
200-120 141293
200-120 +1068

METERS PREAMP

10##4 @VE

MEAN VALUE OF PROFILES OVER SM INTERVALS

2eee

AUG

1-20
21-40
41-60
€1-80

STATION 105 DEPTH 26 METERS PKEAMP 10°*4 AVE

120-80
120-60
120-80
120-80

+8973
+4600
©6174
+8885

MEAN VALUE GF PROFILES OVER

2222

1-17
18-34
35-51
52-6
O-85

120-80
120-80
120-80
120-80
120-80

©8742
«2003
“1.2186
“201356
2.9902

200-120
200-120
200-120

+ €000
+2540
~0343E

200-120 -1-1851

200-120
200-120
200-120
200-120
200-120

110

SM INTEL VALS

©3470
©1739
2.1056
269741
304194

500-200
500-200
500-200
$00-200
500-200
500-200
500-200
500-200

5 DEPTH

500-200
5004200
500-200
500-200

5 DEPTH

500-200
500-200
500-200
500-200
500-200

©1723
#9309
1.6757
Be 4133
3-1366
Se 661
Ae BAK
5e 3165

e5

- 6 0f36
=20527
-.08 65
+0052

30

~+ E38
721467
20537
20536
©1530

a
10%
1a

16M
154
20M
ea

10M
184
208i

Mt
10M

20M

16M
14
20M
em


Table

10

le

TABLES

Inshore zooplankton population densities.
Offshore zooplankton population densities,

Comparison of areas under stress with oligotrophic areas
on basis of relative densities of Diaptanus sicilis +
minutus and Bosmina longirostris.

Comparative mean densities of crustacean zooplankton
fron 0 - 5 m depth, contrasting urban inshore versus

offshore community composition.

Big Cities (inshore) community structure,
Inshore (less Big Cities) community structure.
Offshore community structure.

Analysis of variance (2 - way ANOVA) for effect
of location and time on density, comunity
competition coefficient, etc.

Correction factors for acoustical returns necessary
to equate returns to biomass of zooplankton.

Example of uncorrected acoustical reflectivity at
four frequencies over 100 channels of 1% depth
increments. Lake Ontario, Station 17, August 1972.
Corrected acoustical profiles.

Differences between reflectivities at adjacent
frequency envelopes (120 - 80 kHz, 200 - 120 laiz,
and 500 - 200 kHz).

Three profiles at constant 5 m intervals.

Acoustical reflectivity for three frequency
envelopes for 21 - 25 August 1972.

Mean acoustical reflectivity and relative biamass.
Acoustical reflectivity, estimated column biomass,
column volume, and biomass per unit volume for
all stations, August 1972.

vi

E

12
1h
29

33

35
36

3T
38

he
4h

45
46

47
50

51
5h


4g

Table 18 (continued). MEAN ZOOPLANKTON POPULATION DENSITIES, VALUES (NUMBER /m3 ) REPRESENT

ANIMALS COLLECTED WITH A NET (64 u aperture).

O-15m O-1Om O-20m O-25m
12-16 To-I¥" | i5-19 12-6 12-16" 10-1 15-19 12-16 10-14

Species June July May June June July May June July

Cyclopoida

Cyclopoia 580 2bho 222 605 57. 1599 161 362 1102
copepodites

Cyclops 166 500k 520 1332 562 Woh 473 778 7929
bicuspidetus|

Cyclops 10 52 ° 16 7 102 1 12 100
vernalis

Tropocy¢lops 17 55 1 21 28 16 fo) 1 ho
prasinus

Calanoida

Calanoid 20 105 26 57 51 105 25 7 77
copepodites

Diaptomus 5 100 80 Ag 33 Th 69 79 86
minutus

Diaptomus Ont 3h 16 e 93 15 1 52
oregonensis

Diaptomus 0.5 39 a 0.9 17 25 ab 29 46
sicilis

Diaptomus oO re) oO 0 ie} re) fo) fo) ie)
ashlandi

Diaptonus ie} ie} ° ie) ie} ie} ie} 0.6 °
siciloides

Limnoca lanus 1 35 138 29 45 55 96 132
macrurus

Burytemore 6 7 ° fe) 6 2 ° 3 1
affinis

# of Stations lo 17 T 10 i5 26 39 20



ee

TORONTO

HAMILTON
ROCHESTER

Figure 12. Lake Ontario, divided into three areas of differing trophy
and community structure --- including offshore (unstippled),
rural inshore (lightly stippled), end urban inshore waters
(heavily stippled) --- as well as associated cities of
Toronto, Hemilton, Rochester and Oswego, plus IFYGL
sampling stetions (0)

OSWEGO



1973 yun STATION 62 DEPTH 170 M SWEEP 80 M
MEAN VALUE @F PROFILES OVER 54 INTERVALS

1973

1973

33973

gggegeo2ae

QVeeeee

JUN

CH

1- 6
7-128
13-18
19-24
25-30
31-36
37-42
43-48
49-54
55-60
61-66
61-72
13-18
79-84
85-90
91-96

120-80

09108

120-80 -162875
120-60 -143485
120-80 ~1.3381
120-80 -143330
120-80 -1.3195
120-80 -1.3115
120-80 -1.3010
120-80 -1-2679
120-80 -1-2805
120-80 ~1.2726
120-80 -1462664
120-60 -1.2580
120-60 -1.2513
120-80 -1.2422
120-80 -1-62359

200-120-1181
200-120 «18682
200-120 + 3025
200-120 64177
200-126 4743
200-120 «5306
200-120. 5910
200-120 6604
200-120 «7231
200-120 7544
200-120 8451
200-120 «9077
200-120 «9709
200-120 1.0382
200-120 140936
200-120 1.1548

STATION 64 DKPTH 84 M SWEFP 80 M
MEAN VALUE OF PHGFILES OVER

1-5
G10
11-15
16-20
21-25
26-30
31+35
36-40
41-45
46-50
51-55
56-60
61-65
66-70
71-75
16-20"

420-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
129-80
120-80
120-80

+0304
21315
©2035
+4162
25611
«6525
+ 36
oT 28
07277
= T4aT
+7809
+6036
+6051
+8279
+6342
+B4E4

SM INTERVALS

200-120 =~. 7905
200-120 -1-4903
200-120 -1-8483
200-120 -2.0222
200-120 -@- 1323
200-180 -f.1727
200-120 -2.1509
200-120 -2.0970
200-120 -2.0338
200-120 -1.9815
200-120 -1.9420
200-120 -1-8952
200-120 -1-6410
200-120 -1. 988
200-120 -1. 7292
200-160 -1- 6670

JUN STATION €6 DEPTH 24M SWEEP 35 M
MEAN VALUE OF PEOFILES OVE SM INTERVALS

CH
CH
CH

CH

1917
16-34
35-51
S2- 66

120-60
120-80
120-80
120-80

JUN STATION €7 DEPTH
MEAN VALUE @F PHOFILES QVEK 5M INTEKVALS

CH

cH
CH
cH

I-23
24-46
Al~ €9
70-92

120-86
120-80
120-80
120-80

1,005!
263576
1.92863
164810

200-120 =-.1764
200-180 ~. 6584
200-120 -1.2624
200-120 -1.8572

23 M SWEEP 25M

~0013
e1l91
«5065
1.2762

200-120 -.2649
200-120 -.6394
200-120 -1. 7142
200-120 ~2.9300

152

500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00-200
500- £00
500-200
500-200
500-200
500-200
500-200
500-200
500-200

500-200
500-200
500-200
900-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
S00- 200
500-200
500-200
500-200
S00- 200

500-200
500-200
500-200
500-200

500-200
500-200
500~ £00
500-200

«0000
+0060
+0000
+0000
+0000
+0000
0000
+0000
+0000
+0000
+0000
+0000
~ 0000
+0000
+0000
+0600

+0600
+0000
0000
+0000
+0000
+ ccoG
«0000
«0000
«0000
+0000
+0000
+0000
«C000
+0000
+0000
-0000

«0000
+0000
-0000
«0000

+0000
+0000
20000
+0000

10M

20M

ai
Sou
3oM
40M
amt
50M
Sat
60M
6a
70M
TM!
80M

10M

20M
a
30%
oot
40M
45M
SoM
saM
60M
é6SM
70M
74
80M

10M
1”
20M

30M
eB)
20M


1972 NOV STATION 44 PA 10##4 AVG 5 DEPTH 190 M SCAN 250 M
MEAN VALUE OF PROFILES OVER SM INTEIVALS

LQLARALQLLVAAALAASSSLOIAILagee

2

QQRRRS2as

CH
CH
CH

1- 2
eA
S 6
7- 8
9-10
1-12
13-14
15-16
17-18
19-20
21-22
23-84
25-26
27-88
29-30
31-32
33-34
35-36
37-36
39-40
41-42
43-44
45-46
AT~ 48
49~ 50
51-52
53-54
55-56
57-58
59~ 60
61-62
63-64
65-66
61~ 68
9-70
71-78
T3-74
15-76

120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-60
120-60
120-80
120-80
120-60
120-60
120-80
120-80
120-80
120-80
120-80
120-60
120-80
120-80
120-60
120-80
120-60
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-80
120-60
120-60

= 4689
+6043
- +5669
“+ S227
6 A337
2 2TAS
“21951
21328
“20640
--0090
+0510
21067
«1469
+2003
«25280
+ 2889
«3115
+3450
+3807
©4277
«4741
04064
25165
© S516
+ 5858
+6272
+6671
«7165
+7640
018 SB
+8019
«8329
«8 645
29034
«9428
9799
1.02805
160718

200-120
200-120
200-120
200-120
200-120
200-120
200-160
200-126

200-180

200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
£00-120
200-120
200-120
£00- 160
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200-120
200~ 120
200-120

119

+3845
= 6414
+6503
+9284
1408.48
162083
+4019
1. 6029
1.7261
260352
2.2970
2. SEE6
2.6425
3.1240
3.4107
3. 7008

Se 4523
Se 7572
6.0366
3156
&- 5956
666808
Fel 57
7¢A4385
T+ 7099
199 4E
G25
8. 5438
8.6149
9.0895
96362

500~ 200
500-206
500-260
500-200
500-200
500-200
500-200
500-200
500-200
500~ 200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00- 200
500-200
500-260
800- £00
500-200
500-200
500-200
800-200
500-200
500-200
500-260
500-200
500; 200
500-206

16256
1. P86
263 BB
2.9088
3-409 6
3. O04
461070
Ae A665,
4s 6S
4. 7820
4e 7760
Ae 6641
Ae S545
4.4583
46 341d
402618
4a 1618
460603
3.9 758
3-86 53
3-8000
3. 7097
3+ 6260
3.5416
3.4565
$e 3732
3. 2868
3.2037
3.1208
3.0599
2.9535
268)
2. B3l
a. O69
26 6147
Be 5306
26 4446
227

10M
1s4
204
eM
30M
3m
40m
AM
50M
5sa

emt
70%
754
60M
6a
90M
ooM
100%
10 54
11G4
lisa
120M
1254
130M
1354
140m
14a4
150M
1554
1€0M
1654
170M
1734
180M
A G4
190M


1972

asta

agra

AUG STA 17 PA 10®*4 AVG 5 DEPTH 130 SCAN 170
MEAN VALUE OF PROFILES OVER 5M INTERVALS

CH 1- 2 120-80 09935 200-120 «0049
cH 3-4 120-80 141239 200-220 21987
CH S 6 120-60 161377 200-120 ©3986
CH 1-8 120-80 1.1366 200-120 ©6037
CH 9-10 120-80 1.13428 200-120 “DT
CH «11-12 120-80 121323 200-120 “9TES
CH «13-14 120-60 1.1260 200-120 141488
CH 15-16 120-80 1.1366 200-120 143070
CH «17-18 120-80 1414287 200-120 144571
CH 19-20 120-60 141404 200-120 1.6107
CH #l-22 120-80 141349 200-120 16 7566
CH «23-24 120-80 14-1282 200-120 14-9023
CH 25-26 120-60 161211 200-120 2.0514
CH 27-86 126-80 1.1169 200-120 261974
CH 29-30 120-60 161171 200-120 243510
CH 31-32 120-80 161187 200-120 &.5225
CH 33-34 120-80 1.1095 200-120 &. 7041
CH 35-36 120-80 1.0990 200-120 248938
CH 37-38 120-80 1.0696 200-126 35-08 6
CH 39-40 120-80 1.0839 200-120 3.2811
CH Al-42 120-60 1.0806 200-120 344745
CH A3-44 120-80 160687 200-120 3.6694

45-46 120-80 1.0637 200-120 368676
CH 47-468 120-80 1.0589 200-120 4.0642

49-50 120-80 1.0518 €00-120 462613
CH 51-52 120-60 1.0486 200-120 44559

500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
$00-200
500-200
500-200
500-200
500-200
500-200
500-200
500-200
500-260
500-200
506-200
500-200
500-200
500-200
500-200
500-200

722037
=. 0080
2051
©4377
©6777
99234
121705
1.4005
1.6077
166076
2.00e2
Be 1948
Be 38
26 STET
2-703
2.96285
321535
3.3458
3. 5580
3- 7301
329177
461074
4.2989
4. 4900
4.6790
406 BE

AUG STATION 19 DEPTH 14 METERS PREAMP 10**4 AVE 5 DEPTH 25

MEAN VALUE OF PROFILES OVER SM INTERVALS

cH 1-28 120-80 1.2320 200-120 +4721
CH 29-56 120-80 ©9767 200-120 -+3536

AUG STATION 20 DEPTH 18 PA 10®*4 AVG 5 DEPT
MEAN VALUE OF PROFILES ®VEK 5% INTERVALS m3

CH 1-19 120-80 + A776 200-120 -1.5842
CH «20-38 120-80 + 6679 200-120 -.4995
CH 39-57 120-80 +7308 200-120 =. 7441

oh

500-200
500-200

500-200
500-200
500-200

+28 66
©4744

2711
+ 5612
87D

Rt
10M

10M
1”


Se

Table $3. BIG CITIES (INSHORE) COMMUNITY STRUCTURE, Abbreviations in text.

Date

love

15-19 May
12-16 June
10-14 July
21-25 August
20 Oct.-3 Nov.
27 Nov.-3 Dec.
1973

5-9 Feb.

19-22 Mar.
24-28 April

12-16 June

MEAN

(June 72-June 73)

Community

Density cocbrieient thee Coneui ne begnett Species Diversity
[W/ms | var a K EC) S est. S} H Rich Even
2,400 | .53 .12 31,207.08 i) wy 4 1.13 3.85 98
26,020 40 412 192,088 «14 61 12 5 141 2.49 1.31
1220, 486 -56 «11 {3,580,032 .06 81 20 5 1.66 3.56 1.28
19,547 | .58  .121 319,395.06 +90 21 5 1.57 4.66 1.79
9,476 -70 wD 118,479 = .08 25 18 5 1.73 4.27 1.38
2,462 68 .12 33,551 07 88 Ww 5 1.33 3.83 1.16
1,325 61 11 10,571 .13 86 10 4 1.28 2,88 1.28
1,608 61.1 11,45. 81 9 4 94 2.49 92
T 4TH .38 = .10 52,521 1h 7 1 5 1.25 2.58 1.2
32,310 56 483,255 07 81 4.3 1.37 3.40 1.26