Oceans of noise - Whale and Dolphin Conservation Society

• Boats that approached within 30m or approached quickly/pursued whales caused the whalesto display changes in behaviour.Ref: Schilling et al. 1989.Location: Hawaii• Boat traffic speed, numbers, and direction changes were correlated with changes in observedhumpback whale behaviour including respiration rates, diving intervals, swimming speed andaerial behaviour (e.g. breaching).• Humpback whales generally avoided boat traffic.• Aggressive behaviours were sometimes directed towards vessels.• Frequencies of surfacing without blows and dives where flukes were not raised increased asthe result of exposure to boat traffic.• Behaviours were elicited when vessels were from 1-0.5 km away.• Reactions were stronger from groups with a calf or small groups, as opposed to large groupsof whales.• The researchers concluded that exposure to boat traffic is stressful to humpback whales.Ref: Bauer 1986; Bauer and Herman 1986; Bauer et al. 1993.Location: Cape Cod, Massachusetts, USA• Twenty-five years of anecdotal observations of whale behaviour near whale-watching vesselswere reported upon.• Humpback whales, Megaptera novaeangliae, approached whale-watching vessels moreclosely in recent times than they did in the past when the whale-watching industry was newer.• Whales often moved away from whale-watching vessels in response to strong or rapidlychanging vessel noise. This avoidance reaction was particularly strong when boatsapproached whales directly.Ref: Watkins 1986.Location: Hawaii• The presence of boat traffic was correlated with an absence of nursing humpback whales inthe coastal waters of MauiRef: Glockner-Ferrari and Ferrari 1985.Location: Alaska• Observations on humpback whales in the 1970s, suggested that they moved away from vesseltraffic and cruise ships at a distance of several kilometres.• In addition respiration rates and diving durations were altered.150