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

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Cook monument were not counted because they were often blocked from view by
tourist vessels. Instantaneous scans (Altman 1974) were also conducted every 15
minutes to determine environmental conditions and the number of swimmers, kayaks,
and motor boats within 100 m of a dolphin school.
Numbers and types of dolphin aerial activities and human activities were
observed using 10x binoculars and continuously recorded onto microcassette between
each instantaneous scan (see Introduction). Definitions of aerial activities were
obtained from Norris et al. (1994a). Data were collected on the following dolphin
activities: head slaps, tail slaps, back and side slaps, salmon leaps, spinning leaps, flips
(tail-over-head leaps) and the number of times dolphins were observed bow riding in
front of kayaks and motorboats. The types of human activities recorded include number
of times motor boats approach, drive through, or follow within 10 m of dolphins,
number of swimmers following within 10 m of dolphins, and number of kayaks
following within 10 m of dolphins. Individual swimmers were identified by gender and
color of swimsuit. Kayaks were identified by boat color and gender of occupants.
Data Analysis
Hourly scans from 128 days (57 days without dolphins and 71 days with
dolphins) were analyzed by a Mann-Whitney U test to determine if significant changes
in human activity in Kealake’kua Bay occur between days with and without dolphins.
Transcripts from 10 days with BSS 3 or less and over five hours of continuous
observations of dolphins were compared using a Mann-Whitney U test to determine if
the bay is utilized equally by males and females on days when dolphins were present.