Vessel response

We study the response of whales to whale-watching vessels, working towards a sustainable and more beneficial industry

The whale-watching industry is key to whale conservation. By showing the beauty and wonder of whales and dolphins to millions of people each year, whale-watching drives a public interest in, and passion for, the protection of cetaceans and our ocean generally. It also supports coastal economies, generating $2 billion in 2008 – this value is likely far higher now.

However, whale-watching vessels do have the potential to disturb whales. This has been shown through numerous behavioural studies, with some evidence of population-level effects. Moreover, variables such as the number, speed and type of boats influence the magnitude of impacts. In other words, if we understand which factors lead to significant impacts, we can figure out how to watch whales from boats with little disturbance. This would make whale-watching an even greater force for marine conservation.

To this end, we study the response of humpback whales to whale-watching vessels in North Iceland, particularly Skjálfandi Bay, using a variety of methods. These local responses have not been previously studied in depth and we hope to expand on global research by modelling population-level impacts from individual responses.

This is a large collaborative effort, with research partners at the University of Iceland and the University of Edinburgh. Crucially, we also work with whale-watching companies. North Sailing boats are our main platform for behavioural observation and have been so helpful since we started in 2018. We have shared our research plans with all companies in Skjálfandi and have received positive, constructive feedback from each. Our ultimate aim is to develop a revised code of conduct with the companies towards sustainable whale-watching. To be clear, we do not want to prevent whale-watching – we love to watch whales and have no right to threaten the industry’s economic and conservation benefits.

Below, we outline each research method used in the project.

Current methods
Blow sampling & body condition

Perhaps the most exciting part of our research involves blow sampling, whereby we collect samples of a whale’s exhaled breath (the blow). Like our own breath, whale blow is an incredible source of biological information, containing substances such as DNA, bacteria and whale proteins. We are currently interested in whale hormones, particularly cortisol (a stress-related hormone found in most mammals). Generally, cortisol levels increase during times of high stress. Our idea is to collect blow samples in areas and times of high and low vessel activity in order to measure the physiological stress actually caused. We could simply rely on behavioural indications of stress but these may be misleading. For example, a hungry whale which has just migrated from its tropical breeding grounds may not sacrifice feeding in the presence of vessels, but this does not eliminate the potential for stress.

How do you collect whale blow?

Early attempts at blow sampling relied on a long pole holding a collection device (such as Petri dishes or nylon mesh) extending from a research vessel. Since the vessel must travel in close proximity to the target whale, this may both confound our results and conflict with our goals, to determine the potential stress response to vessel activity.

So, how can you collect samples of whale blow whilst minimising disturbance?

The potential answer: drones.

As with other areas of whale research, drones have revolutionised blow sampling and represent a relatively inexpensive, simple and unobtrusive alternative. Now, we can attach Petri dishes to a drone using a simple frame (which in our first season was improvised from some coat hangers) and fly the dishes through whale blow. We first attempted this in June 2018 – the first study of its kind in Iceland and the most northerly attempt to date, collecting 16 samples. We collected another 16 samples in 2019. Following a brief intermission in 2020 due to Covid-19, in 2021 we collected 55 blow samples from sites around North Iceland with differing levels of vessel traffic in order to answer our question.

Although we see drones as a less disruptive alternative to research vessels, they still have the potential to disturb whale behaviour and cause stress. When blow sampling, it is important to minimise the time spent flying in proximity to whales. We constantly monitor surface behaviour when conducting drone research and leave the whale if there is any sign of distress or disturbance. In order to mitigate our impact and inform future research studies, we conducted a drone impact study in 2021 (results available in the near future).
Beyond disturbance, many factors can affect hormone levels, like body size. Therefore, we are also using drones to capture aerial images of whales. From these photographs, we can measure the length and width of individuals (known as photogrammetry), and thus assess their body condition. This way, we can determine whether size affects our results.
Following the collection of whale blow, we take our samples to the lab, back in the University of Edinburgh, where we can measure the levels of specific hormones. Our method of choice is liquid chromatography-mass spectrometry, a selective and sensitive analytical technique. By working with the Mass Spec Core the university’s clinical research facility, we can make use of advances in medical research for the purposes of whale conservation.

We want to be clear that this part of our research is very exploratory- blow sampling has yet to be used to demonstrate the impact of human activity. As such, we are cautious with our expectations – simply, it may not work. However, with a solid theoretical basis, careful planning and help from other researchers, we are cautiously optimistic.

Behavioural observation

All previous assessments of whale-watching impact have focused on behavioural responses. How do vessels alter the feeding, resting, travelling and social behaviour of different whale species? Such studies have indicated that whales may perceive vessels as a predatory threat and then behave accordingly to minimise this perceived threat. As a result, whale-watching can reduce feeding and resting, whilst increasing travelling. Recent studies have built on this by translating behavioural responses into changes in energy acquisition and expenditure. This allows consideration of the impact of whale watching on entire populations.

In our current project, Whale Wise aims to follow the methods of previous studies by observing whale behaviour in the presence and absence of whale watching vessels in Skjálfandi Bay. Whale behaviour and movement patterns are collected from North Sailing whale-watching vessels, using a camera and electronic rangefinder. However, we also hope to take this further by assessing the relative impact of different types of encounters. For example, is the behavioural response of whales dependent on vessel size or the number of vessels? Are whales sensitive to the minimum approach distance of a vessel? Does engine noise play a role in whale-watching impact?

This is key to our overall principle. Instead of halting whale-watching, we aim to promote practices which minimise any observed negative impact, whilst allowing high quality and profitable encounters. Therefore, we must consider how different practices impact whales in multiple ways.


Observing whale behaviour above the surface is an often-effective way of assessing the response to disturbance. However, to truly understand the influence of vessels and other humans activities on the lives of whales, you have to dive beneath the surface. Therefore, since 2020, we have monitored the underwater soundscape of Skjálfandi Bay to determine the primary drivers of underwater noise and, in particular, the contribution of vessel traffic.