Biology Reference
In-Depth Information
Table 7
.
The number of
S. guianensis
within bycatch across climatic periods (winter =
WIN, winter-summer transition = W-S, summer = SUM, and summer-winter transition
= S-W) and years within the Amazonian estuary. Strata (stratum 1 - S1; stratum 2 = S2)
are also displayed. % = Percentage of bycath for the climatic period.
1996
1997
1999
2000
2001
S1
S2
S1
S2
S1
S2
S1
S2
S1
S2
WIN
n
7
8
41
222
64
254
96
306
%
46.7
53.3
15.6
84.4
20.1
79.9
23.9
76.1
W-S
n
67
115
102
223
%
36.8
63.2
31.4
68.6
SUM
n
26
13
163
516
17
194
%
66.7
33.3
24
76
8
92
S-W
n
45
36
6
6
139
383
%
55.5
44.5
50
50
2.7
73.3
Bycatch and fishing effort
.
The determination of any fishing effort effects on dolphin
bycatches has great assessment value. Although the fishing effort may not intentionally target
dolphins it may be added to other factors and synergistically cause harm to dolphins trapped
in nets.
The regression analysis of fishing effort versus number of dead dolphins for either
stratum showed low correlation coefficients in both periods (
r
= 0.18,
n =
440 first period;
r
=
0.0639;
n
= 927 second period). When the strata were analyzed separately, there were similar
statistical findings for stratum one data (
r
= 0.15,
n
= 350 first period;
r
= 0.1177;
n
= 590
second period), even though both regressions were significant (no practical value). For
stratum two, the regressions were insignificant for both periods (
r
= 0.11,
n
= 90 first period;
r
= 0.008,
n
=337 second period).
Table 8. Monthly distribution of fishing effort (netting hours / crew number) across five
years (1996-2001) using drift gillnets by the artisan fishing fleet in the Amazonian
estuary. Strata (s) levels are listed and months are abbreviated.
1996
1997
1999
2000
2001
S1
S2
S1
S2
S1
S2
S1
S2
S1
S2
Jan
13.5
17.4
16.2
15,18
12.3
16.4
16.5
19.1
Feb
16.3
21.1
14.0
15,38
13.9
15.5
15.3
17.5
Mar
16.4
18.0
18.3
15,4
17.8
15.7
16.5
14.9
Apr
17.6
13,86
17.3
16.9
16.2
15.9
May
16.5
14.5
15,13
13.7
Jun
17.5
13.9
16.4
19.6
Jul
16.1
17.6
15.7
17.8
Aug
16.9
17.6
15.6
11.9
Sep
15.6
16.0
Oct
11.6
13.1
13.6
19.8
Nov
15.1
18.6
16.7
17.5
Dec
13.8
16.0
15.0
18.1
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