Short-term reactions of sperm whales (Physeter macrocephalus) to whale-watching vessels in the Azores

Published source details Magalhães S., Prieto R., Silva M.A., Gonçalves J., Afonso-Dias M. & Santos R.S. (2002) Short-term reactions of sperm whales (Physeter macrocephalus) to whale-watching vessels in the Azores. Aquatic Mammals, 28, 267-274.
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This study is summarised as evidence for the following.

	Action	Category
	Introduce and enforce regulations for marine and freshwater mammal watching tours Action Link

Introduce and enforce regulations for marine and freshwater mammal watching tours

A controlled study in 1998 of a pelagic area in the North Atlantic Ocean around the Azores (Magalhães et al. 2002) found that when whale-watching boats followed regulations for approaching whales, sperm whales Physeter macrocephalus changed their swimming speed and performed aerial displays less often than when boats did not follow regulations, but direction of movement, swimming and diving patterns did not differ. When boats followed regulations, whales changed their swimming speed less often (three occasions) and performed fewer aerial displays (two occasions) than when boats did not follow regulations (changed swimming speed: 19 occasions; aerial displays: 20 occasions). No significant changes in direction of movement or swimming and diving patterns were observed when boats did or did not follow regulations (see original paper for details). Regulations were followed during 16 of 40 encounters between whale-watching boats and sperm whales. Regulations required boats to approach whales from behind at an angle of 60°; to maintain a distance of at least 100 m (400 m for ≥2 boats); and to limit encounters to ≤30 minutes. The behaviour of 80 sperm whales was recorded by a researcher on board a whale-watching vessel during each of the 40 encounters in July–September 1998.

(Summarised by: Anna Berthinussen)