Observations were made from the bows of eight commercial crab boats. Due
to fishing techniques and spatial constrictions, observations were made facing
astern, while fishers were helpful in sighting dolphins ahead of the boat while
scanning for crab pot buoys. Dolphin behaviors were recorded using instantaneous
scan sampling (Altmann 1974, Mann 1999) at 5-min intervals while an
individual dolphin or group was in sight. Group size was defined as all bottlenose
dolphins within 100 m of the boat (Irvine et al. 1981). Because fishers
tended to move rapidly between traps and between fishing areas, dolphins were
often seen only in the first 5-min interval. Standardized behavior categories
(Wells 1996’) were used; however, throughout the study several other behaviors
were observed. These behaviors, defined below, were scored separately and
detailed field notes were kept throughout the event in addition to the 5-min
scan sample