ETHNOECOLOGY OF SOTALIA GUIANENSIS (GERVAIS, 1853) IN THE AMAZON ESTUARY - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 254

while Type II and III groups were more frequently observed feeding (59.7% and 59.5%,
Table 4).
Table 4. Percent of Sotalia guianensis calves in the Amazon estuary between 1999 and
2001 by degree of occurrence, group size (I = one animal, II = 2-3 animals, III = 4-10
animals, IV = 11-30 animals, V= > 30 animals) and behavior for each habitat.

Habitat Behavoir Occurrence I II III IV V

Common - 60 71.4 50 60

Feeding Rare 100 40 14.3 16.7 -

Seasonal - - 14.3 33.3 40

Open waters

Common - 100 27.3 - 46

Movement Rare - - 36.4 66.7 38.5

Seasonal - - 36.3 33.3 15.5

Common - 53.3 50 100 100

Feeding Rare 100 26.7 16.7 - -

Igarapés and/or Bays Seasonal - 20 33.3 - -

Rare 100 100 - - 100

Movement

Seasonal - - 100 100 -

Common - 6.3 - - -

Ports and Communities Movement

Rare 100 93.7 - - -

Common - 41.9 50 40 -

Feeding Rare 100 38.7 20 20 -

Seasonal - 19.4 30 40 -

Beach and/or Coast

Common - 18.2 22.7 20 66.6

Movement Rare 100 68.2 45.5 40 16.7

Seasonal - 13.6 31.8 40 16.7

Observations of dolphin group size in decreasing order of frequency were: Type II (38%),
III (31.2%), IV (13.4%), V (10%) and I (7.4%), although Type II and III groups also
presented seasonal occurrences in 34.7% and 26.4% of the cases. Type III, IV and V groups
were never seen in the PC habitat and the occurrence of Type I groups was rare (53.3%),
while for Type II groups it was seasonal (43.7%). In the other habitats, the occurrences of
different group sizes were similar, with the greatest percentage equal to 54% (Table 5).

Interactions (*) Among Variables

All of the interactions of three factors were not significant (P > 0.05, Table 6). This
indicates there is no apparent association among the variables when analyzed simultaneously,
but there can be when analyzed by pairs of variables:
H*GS dependent when associated to OD (degree of freedom, df = 36; G = 151.7; P =
3.3x10 -16 ), B (df = 24; G = 163.9; P = 0) and C (df = 36; G = 130.9; P = 1.1x10 -12 ).
H*OD dependent when associated to GS (df = 30; G = 44.9; P = 0.03) and B (df = 12; G
= 25.6; P = 0.01).
H*B dependent when associated to GS (df = 15; G = 64.9; P = 3.5x10 -8 ), OD (df = 9; G =
35.3; P = 5.2 x 10 -5 ) and C (df = 9; G = 24.2; P = 0.004).