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

More documents

Recommendations

Info

10 Barr and Slooten (1998) noted that the responsiveness of dusky dolphins (Lagenorhynchus obscurus) to vessels depended upon the dolphins' activity state as well as the type, number, and behavior of the vessels. Dusky dolphins appeared to be more sensitive to human activities during the afternoon. This could be due to sensitization to human activities from repeated contact, or perhaps that they are more vulnerable to disturbance during the afternoon because they are usually in a more restful state at that time of day (Barr and Slooten 1998). The presence of a combination of vessel types (fishing, whale watching, and private boats) in the afternoon was correlated with a significant increase in the number of dusky dolphin aerial activities and directional changes (Barr and Slooten 1998). Barr and Slooten (1998) hypothesized that combinations of different vessel types caused the greatest disturbance, because it may be difficult for dolphins to predict the behavior of individual boats. Reactions to Tourist Vessels and Swimmers The strategy used by tour boat operators significantly affected bottlenose and common dolphin responses to swimmers, and dolphin responses varied by species (Constantine 1995, Weir et al. 1996, Constantine and Baker 1997). Only a small proportion of bottlenose and common dolphin schools in the Bay of Islands, New Zealand, interacted with swimmers (Constantine 1998). Barr (1995) also observed that few dusky dolphins per school (as few as 9 out of 350) would interact with swimmers off the Kaikoura coast of New Zealand.
11 Hector's dolphins, Cephalorhynchus hectori, in Porpoise Bay, New Zealand, formed significantly tighter pods when boats were present (Bejder 1997, Bejder and Dawson 1998, Bejder et al. 1999). The presence of swimmers increased the probability that Hector's dolphins remained in a tight group (Bejder 1997, Bejder and Dawson 1998). Pilot whales off the Canary Islands have been observed to respond differently to boats than to swimmers, with reactions towards swimmers being more negative than those towards boats (Heimlich-Boran and Heimlich-Boran 1995). Whales could be observed 5 - 7 meters from a boat, but would immediately move away if swimmers entered the water. Changes in behavior, such as groups splitting and moving off in different directions or individuals staying away from the surface longer, were more common with swimmers than with boats. Responsiveness varied according to age/sex composition of the dolphin group, and the number and dispersion of swimmers in the water. While mothers with young calves were the least approachable, calves without adults close to them would approach the swimmers much more closely (Heimlich- Boran and Heimlich-Boran 1995). Respiratory intervals also differed in relation to presence and absence of boats (Montero et al. 1993). "Swim With the Dolphins" Programs Two recent studies monitored commercial swim with the dolphin tours operating in The Bay of Islands, New Zealand, and Southern Post Phillip Bay, Australia (Constantine 1995; Weir et al. 1996). Both studies found that the more aggressive approaches used by some tour operators resulted in a higher frequency of avoidance
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: 9 decreasing their surface times (C
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 and 48: 47 times motor boats approached and
Page 49 and 50: 49 On one occasion, a swimmer obser
Page 51 and 52: Figure 11a, b 51
Page 53 and 54: Figure 14a, b 53
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 63 and 64:
Figure 23a, b 63
Page 65 and 66:
65 Figure 25a. Square root of aeria
Page 67 and 68:
67 Figure 26. Square root of aerial
Page 69 and 70:
69 Figure 28. Square root of aerial
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
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?