Biology Reference
In-Depth Information
Table 6
.
Summary of the literature on seasonal reproduction in
Inia.
Seasonal
comparisons are based on water levels and not month of the year, as peak water levels
vary by river basin and latitude. Flux is defined as the difference between highest and
lowest water levels. Mating: F =Falling, L = Low, R = rising, YR = Year round, NI = no
information, NO = Not observed.
Country
River
Basin
Neonates/calves
Mating
Authors
Flux
(m)
Bolivia
Amazon
(Mamoré
sub-basin)
year-round
(peaks
F & L
Aliaga-Rossel 2000,
2002; Aliaga-Rossel
et al.
2006, McGuire & Aliaga-
Rossel 2007
7
during
falling
water)
Brazil
Amazon
high and early falling
NI
Best 1984, Best & da
Silva 1984, da Silva 1994
13
Colombia
Amazon
year-round
(few seen during rising)
NI
Hurtado 1996
10-15
Colombia
Amazon
year-round,
(peaks during high water)
NI
Galindo 1998
10
Colombia
Amazon
& Orinoco
falling (Amazon Basin)
no info (Orinoco Basin)
L
(Amazon
and
Orinoco
basins)
Beltrán & Trujillo 1993.
Trujillo
et al.
1998
no
info.
Ecuador
Amazon
falling/low water
(other
NI
Herman
et al
. 1996
no
info.
seasons
not
sampled)
Peru
Amazon
year-round
(fewest
NI
Henningsen 1998
7
during
high
water)
Peru
Amazon
rising and falling water
(other
NI
Leatherwood 1996
7
seasons
not
sampled)
Peru
Amazon
year-round
peak during falling
YR
McGuire 2002, McGuire
& Aliaga-Rossel 2007
7
Venezuela
Orinoco
end of low water
R
Caranto
&
Gonzalez-
no
info.
Fernandez 1998
Venezuela
Orinoco
rising water and end of
low water never during
falling water
(high water not sampled)
NO
McGuire 1995, McGuire
& Winemiller 1998,
McGuire & Aliaga-Rossel
2007
5
Seasonal Mortality
Necropsy results from Venezuela, Peru, and Bolivia are summarized in Table 7. It was
rare for us to encounter dead dolphins, and in remote tropical areas, carcasses were usually in
advanced stages of decomposition with significant loss to scavengers. Furthermore, local
people in Peru reported that dolphins that had been intentionally killed by fishermen were
sometimes hidden from survey teams (Reeves et al., 1999).
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