Researchers are studying whales' stress levels in their hormones by sampling cortisol in water droplets from the whales' spray, also known as the blow.
Do whale watchers bother whales? A number of studies on tourism's impact on whales, which were based on behavioural observations, have concluded that tourism caused only minor disruptions to the mammals.
For example, in 2015, a study led by Marianne H. Rasmussen, director of the University of Iceland Húsavík Research Centre, found that whale watching as currently practised does not seem to be having any long-term negative effects on the life expectancy of minke whales.
On the other hand, a 2011 study showed that whale-watching activity near Reykjavik was disrupting minke whales. A 2006 study, titled "Estimating Relative Energetic Costs of Human Disturbance to Killer Whales (Orcinus Orca)" published in Biological Conservation, showed that frequent disturbances on the whales' important activities could lead to more energetic costs over time. Another 2006 study showed that levels of dolphin–boat interactions in the region of Fjordland, New Zealand, could not be sustained by the bottlenose dolphins, and that the interactions have both short- and long-term effects on both individuals and their populations. So, which is it?
To find out, a group of biologists from Whale Wise use drones to collect samples from the water sprays of whales and tested them for traces of cortisol, a hormone related to stress that can determine the physiological stress levels of the whales. The researchers aim to collect samples before a whale-watching boat arrives and then afterwards, then compare the two samples to determine the direct impact of that encounter on stress levels.
According to the International Whaling Commission, whale watching has contributed a significant amount to the world economy and has employed thousands of people since 2009. In Iceland alone, more than 360,000 whale watchers were registered in 2019, three times the number a decade ago.