0) also observed that humpback whales moved from a favored areaon days when parasail boats operated. Bauer and Herman (1986) concludedthat reactions to vessels probably are stressful to humpback whales but thesignificance of the stress is unknown.Research performed by Baker and Herman (1989), Baker, Herman, Bays andStifel (1982), Baker, Herman, Bays and Bauer (1983), and Bauer (1986) inAlaskan waters suggests that humpback whales usually use two main type ofavoidance methods. The first involves a vertical avoidance in which thedive duration increases, with a corresponding decrease in the blow intervaland in swim speed. The second method involves a horizontal avoidance inwhich there is a decrease in the dive duration, longer blow intervals andan increase in swim speed. Baker, Herman, Bays and Stifel (1982) and Baker,Herman, Bays and Bauer (1983) also found that approaching boats oftentriggered some aerial behaviors such as breaching, flipper and tailslapping.There appears to be little doubt that boat traffic may affect the behaviorof humpback whales. Examples of such disturbance by vessels on humpbackwhales in Hawaii can be found in Tinney (1988) and in the humpback whalerecovery team report ( HWRT, 1991). Consequently, the National MarineFisheries Service (NMFS), the Federal agency primarily responsible forenforcing the Marine Mammal Protection Act, has imposed a regulationprohibiting boats from approaching within 91 m (100 yards) of any humpbackwhale in Hawaii ( NMFS, 1987).One issue that has not received much attention is the specific effect ofboat noise on the whales. All boats from the smallest motor boat to thelargest super-tanker produce underwater noise. However, there is limitedinformation on noise produced by small boats typically used in coastalwaters (Richardson, Greene, Malme & Thomson, 1995). Considerably moreattention has been focused on large ocean-going vessels. McCauley, Cato andJeffery (1966) have measured the noise ge...
