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fisheries-related poisoning (for more details see McGuire, 2000 and Reeves et al., 1999).
Dead
Inia
were never encountered during high water, perhaps because sources of mortality
are reduced during this season, and/or carcasses would have been more difficult to detect in
the submerged vegetation. In Peru's lake San Pablo de Tipishca, nets, traps, and fishing
camps were most common during the period between late falling to rising water (Figure 6).
Fishing effort was minimal during high water. The inverse pattern was observed for dolphin
abundance.
30
25
20
Fishing effort
Mean water
depth (m)
# Inia
sightings
15
10
5
0
Figure 6. Seasonal pattern of number of dolphins, human fishing effort, and water depth in lake San
Pablo, Peru in the year 2000 (McGuire 2002).
Venezuela's Santos Luzardo Park is closed to commercial fishing, and subsistence
fishing is minimal in this sparely populated area. A minor threat from sports fishing does
exist, as some sports fishermen shoot at
Inia
to drive them away from game fish (McGuire,
1995; McGuire & Winemiller, 1998). Sports fishing is most common during the low water
season (especially during the Holy Week vacation), and does not generally occur during the
high water season. The mean CPUE of seine and gill net samples in Venezuela varied by
habitat and season. Maximum gill net CPUE occurred during low water in lakes, and
minimum gill net CPUE occurred during low water in confluence areas. Maximum seine
CPUE was obtained during low water in confluences, and minimum CPUE occurred during
rising water in lakes.
D
ISCUSSION
Distribution
Consistent seasonal differences in encounter rates from the three study areas had been
predicted, but were not observed. Although seasonal differences were observed in Bolivia and
Venezuela, the seasonal patterns between the two sites were different. In Peru, encounter rates
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