dugongs in palau - C3

Year: 1977 1 1978 1 1983 2 1991 3 1998 4 2003 5
No. Dugongs
15 34
38 26 33 27
Counted
% Calves 13.3 23.5
7.9 15.4 21.2 25.9
Dugongs/Min
/ Survey Da y + SE
Mean Group Size
+ SE
Largest Group
Seen
Total No. Seen in
Malakal Area
(Sect: I, II & VII)
% of Total Seen in
Malakal Area
0.069 0.086 + 0.119 + 0.042 + 0.116 + 0.051 + 0. 01
0.015 0.020 0.023 0.064
N/A 2.0 + 0.30 1.38 + 0.11 1.37 + 0.16 2.1 + 0.38 1.6 + 0.19
N/A 5(+) 7 3 7 4
9 13 2 9 20 15
60 38.2 5.3 34.6
60.6 55.6
Table 2: Comparison of numbers of dugongs seen, group size and calf abundance
( 1 Brownell, et al. (1981); 2 Rathbun, et al. (1988); 3 Marsh, et al. (1995); 4 Smith (1998,
unpublished da ta); 5 Smith (2003, unpublished data)).
The rate of dugong sightings was highest in 1983 ( 0.119 /min/day) and 1998 (0.116/min/day), although in
1998, Route 3 was not completed and this is the route with historically the least dugong sightings, and if
completed would have most likely lowered the overall sighting rate.
The lowest sighting rates were in 1991 (0.042/min/day) and 2003 (0.051/min/day).
0.14
0.12
0.1
#
0.08
0.06
0.04
0.02
0
1977 1978 1983 1991 1998 2003
survey date
Figure 4: Average number of dugongs seen per unit flight time for the six aerial surveys
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