Disturbance by whale-watching boats

Around the globe, the whale-watching craze continues to grow. According to the most recent statistics, 13 million people took to the seas in search of whales in 2008. They spent nearly US$2 million in 119 countries and territories. People often talk about ecotourism, as it represents an incomparable occasion to make these legendary animals ambassadors of marine environmental stewardship. Yet, there is concern about the impact that boats might be having on cetaceans.

  • Photo credit : © GREMM

In response to these concerns, codes of ethics, guides of conduct and regulations have been put into place virtually everywhere that whale-watching excursions are offered. Even the International Whaling Commission (IWC) adopted general principles to regulate whale-watching practices worldwide in 1997. All of these guidelines are based on the experience of captains and marine scientists with whales, and, sometimes, scientific studies that document disturbance to cetaceans. But the design of these studies presents many challenges, the results are often difficult to interpret and the response varies with the species, time of year, activity in which the animal is engaged, etc. This is why the IWC recommends that regulations and codes of conduct be flexible, so that they might be adapted as new information becomes available. We must still ask ourselves if short-lived behavioural changes can have a an impact on whales in the long term.

Is whale-watching really a conservation issue? Jon Lien, a Newfoundland-based researcher that has spent his life with whales, drafted a document on the topic in 2000, at the request of Fisheries and Oceans Canada. He sounds the alarm: cetaceans’ characteristics make them vulnerable to disturbance. Indeed, many whale populations are still fragile, their environment is undergoing significant and rapid changes, and the animals depend on critical habitats where they congregate, which in turn leads to a concentration of whale-watching activities. The disturbance then becomes repetitive, and the effects can be cumulative, which can result in repercussions on their health and thus their chances of survival and reproduction. It is thus critical to exercise caution and do one’s utmost to respect the whales and avoid disturbing their essential activities. The future of these fascinating animals is at stake, as is that of the riverside communities who live today by the rhythm of the whales.

What disturbs whales?

Science in a nutshell

  • Photo credit : © GREMM

Here’s how Jon Lien summarizes the results of all studies conducted on boat-induced disturbance to whales: the essential activities of whales may be interrupted if there is a large number of boats, if the boats approach too closely, if the boats are travelling too fast or too noisily or if the animals are being chased. Some studies did not demonstrate any reaction, but emphasize that whale behaviour is also dictated by other factors such as social and geographic conditions, their physiological state and their past experience.

Vox Pop: what the seamen think

Even if researchers agree almost unanimously that disturbance by boats can have a serious impact on whales, it is not easy to determine precisely which behaviours should be avoided. Captains and naturalists working in the whale-watching industry in the Saguenay-St. Lawrence Marine Park share their opinions: What constitutes disturbance:

  • Les déplacements rapides et répétés sur les sites d’observation.
  • Fast, repetitive movement on the observation sites.
  • Numerous changes of direction.
  • Numerous loud boats (more than five).
  • Changes in engine speed (rpm).
  • Boats that encircle a whale.
  • Chasing (advancing rapidly and repetitively toward a whale moving away).
  • A boat that cuts off a whale.
  • Competition amongst boats vying for a good observation. We then forget that the whale is not there for us, creating the potential for abusive and disruptive behaviour.
    For blue whales: any rapid approach, even at a considerable distance.