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

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48 between time and the frequency of aerial activities. Therefore, a plot of time versus frequency of aerial activities per dolphin per hour was examined, and to correct for interaction, time periods with high frequencies of aerial activities (e.g. before 0715 and after 1515) were eliminated from the data set. A Scheffé test on the modified data set showed no interaction between time of day and level of dolphin aerial activities. Since graphs of human activities showed high levels of swimmers in the morning and few swimmers after 1115, these data were split into two time periods, morning 0715 to 1114 and afternoon 1115 to 1515. Data were analyzed using a one-way MANCOVA because the mean number of swimmers, kayaks and motorboats was higher on days with dolphins than on days when dolphins did not enter the Bay, indicating an interaction between variables. The Scheffé test was used because all possible effects were considered. Results Length and type of interaction between swimmers and dolphins varied. Several local swimmers reported playing the "leaf game" with dolphins (personal communication, Johnson 1993, Ocean 1993). This game consisted of a dolphin transporting a piece of algae, leaf, or plastic with its mouth, flukes, flippers or dorsal fin and leaving it in the general proximity of a swimmer. The swimmer retrieved the object and then transported it to a new location where the dolphin retrieved it, and the interaction repeated itself. The leaf game was initiated by either a dolphin or a swimmer and lasted between a few minutes to over one half-hour.
49 On one occasion, a swimmer observed a dolphin carrying a stick. When the dolphin dropped the stick, the swimmer retrieved it in an attempt to play the "leaf game." The dolphin quickly approached the swimmer and began to tail slap repeatedly near the swimmer's head. The swimmer responded by slapping her fins on the surface of the water. This interaction lasted approximately 1 minute until the swimmer released the stick. The dolphin then retrieved the stick and swam away. The swimmer later reported that she did not think that the dolphin wanted to play the "leaf game" with her, and she was under the impression that the dolphin accidentally dropped the stick while playing alone or with another dolphin. Several types of kayak - dolphin interactions were observed. Some kayakers simply approached the dolphin school and then watched the dolphin from a stationary position. During apparently quite random meanderings, dolphins at times approached and milled within 1 m of stationary kayaks without any apparent change in behavior. Swimmers also used kayaks to approach dolphins and followed them for short periods of time. Once they were in close proximity or in the path of the dolphins, they entered the water and began to swim. Other kayak operators followed (within 10 m) the dolphins around the bay for more extended periods of time. The most aggressive of these kayak operators repeatedly kayaked through the dolphin school in an attempt to obtain bow riders on their kayak. Dolphins were observed riding the bow of kayaks on 13 occasions. In the morning, dolphins generally displayed a greater number of aerial activities when no humans were present, compared to when humans were interacting with them. These apparent differences in dolphin behavior were statistically significant
Page 1 and 2: 1 CHAPTER I INTRODUCTION Documented
Page 3 and 4: 3 avoid areas within 10 km of activ
Page 5 and 6: 5 displayed a significant reduction
Page 7 and 8: 7 a linear model, the vessel explai
Page 9 and 10: 9 decreasing their surface times (C
Page 11 and 12: 11 Hector's dolphins, Cephalorhynch
Page 13 and 14: 13 a killer whale (Herman and Tavol
Page 15 and 16: 15 The Marine Mammal Protection Act
Page 17 and 18: 17 Dearden 1993, Thompson et al. 19
Page 19 and 20: 19 dorsal surface and a white ventr
Page 21 and 22: 21 some areas consistently have mor
Page 23 and 24: 23 Aerial Behaviors Spinner dolphin
Page 25 and 26: 25 Norris and Dohl 1980). Increases
Page 27 and 28: 27 CHAPTER III OCCURRENCE AND BEHAV
Page 29 and 30: 29 Thirty-five observation days wit
Page 31 and 32: Figure 4 31
Page 33 and 34: Figure 6a,b 33
Page 35 and 36: Figure 8a 35
Page 37 and 38: 37 Most human activities that were
Page 39 and 40: Table 1 39
Page 41 and 42: 41 Discussion Norris et al. (1994 )
Page 43 and 44: 43 The correlation between number o
Page 45 and 46: 45 to perform. If the dolphins do,
Page 47: 47 times motor boats approached and
Page 51 and 52: Figure 11a, b 51
Page 55 and 56: 55 Figure 15. Square root of aerial
Page 57 and 58: 57 Figure 18a. Spinner dolphin surf
Page 59 and 60: 59 3.6 2 Square root of aerial acti
Page 61 and 62: 61 Figure 21a. Square root of aeria
Page 65 and 66: 65 Figure 25a. Square root of aeria
Page 71 and 72: 71 Discussion Swimmer and kayak dis
Page 73 and 74: 73 morning than in the afternoon, t
Page 75 and 76: 75 used by some boat operators resu
Page 77 and 78: 77 reduced energy levels, then incr
Page 79 and 80: 79 LITERATURE CITED Acevedo, A. 199
Page 81 and 82: 81 Cooke, J. 1991. Classification a
Page 83 and 84: 83 Gordon, J. and Moscrop, A. 1996.
Page 85 and 86: 85 Montero, R., Martin, V., Heimlic
Page 87 and 88: 87 Associates Inc., Bryan, Texas. F
Page 89 and 90: 89 Wells, R. S. and Norris, K. S. 1

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