The Hawaiian spinner dolphin, Stenella longirostris: Effects of tourism.

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only for breaches (p < 0.05). For all other aerial activities (all aerial activities,
headslaps, tail slaps, leaps, spinning leaps and flips), the presence of humans did not
significantly alter dolphin behavior (Figure 11 a). In the afternoon, dolphins were more
active when humans were present than when they were not (all aerial activities p <
0.001, headslaps p< 0.003, tail slaps p = 0.11, breaches p = 0.002, leaps p < 0.001,
spinning leaps p < 0.001, flips p= 0.008,) (Figure 11 b). However, the mean frequency
of aerial activities per dolphin per hour in the presence of humans was not significantly
different between the morning and afternoon.
Human activities impacted dolphin surfacing behaviors differently in the
morning than in the afternoon. Human activities had no impact on dolphin surfacing
behavior before 1115 (p = 0.67). However, after 1115, dolphins were more likely to
surface asynchronously in the presence of human activities (p < .001) (Figure 12).
Dolphin schools surfacing synchronously displayed fewer aerial activities than dolphin
schools surfacing asynchronously (p < 0.001) (Figure 13).
The presence and type of human activities had no impact on the number of aerial
activities per dolphin per hour in the morning (p > 0.5) (Figure 14a). However,
swimmers and kayaks following dolphins within 10 m (p < .002) and motorboats
driving through the dolphin school (p < .076) increased the frequency of aerial activities
in the afternoon (Figure 14b). The mean number of aerial activities per dolphin per
hour was not related to the number of swimmers (Figure 15) or kayaks (Figure 16)
following within 10 m of dolphins.