Whale-watching 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 and blue 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 four companies in the bay 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: blow samplingbehavioural observationaerial imageryacousticsclimate response modelling

Current methods
Blow sampling

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 starving 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, of reducing the impact of human activity.

So, how can you collect samples of whale blow without disturbing them?

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. Our current drone of choice is a DJI Phantom 4 – safe to launch from a vessel and manoeuvrable at sea. In 2021, we will assess the potential impacts of vessel traffic on humpback whales by collecting blow samples from two control sites with low traffic (Langanes and Steingrímsfjörður) and two test sites with high traffic (Skjálfandi Bay and Eyjafjörður).

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.

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. Presence data are collected from North Sailing whale-watching vessels, using a camera and electronic rangefinder, whilst absence data are collected from a land base, using a theodolite (angle measurement instrument). 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.

Body condition

From our behavioural observations, we can estimate the impact of whale-watching encounters on the energy acquisition and expenditure of individuals. How do these impacts then influence their welfare, health and survival?

To answer this question, we first need some crucial baseline data, specifically concerning their body condition at the time of an encounter. Naturally, we would expect this to determine the severity of any impacts. A fat, healthy whale might be relatively unaffected by whale-watching disturbance, with their reserves of blubber allowing them to skip a meal with little consequence. However, the story may be different for a starving whale with little fat to spare. For these whales, we would expect every meal to count.

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. Generally, whales which are relatively wider have more blubber, are in better body condition and should be more resistant to whale-watching disturbance.


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.

Cetaceans rely heavily on sound for communication, feeding and even navigation. Many species literally ‘see’ their environment in sound. As a result, loud human activities can disrupt this key sensory system, impeding their hearing, voice and ‘sight’. Vessels are no exception, with noise from the engine and cavitation (exploding bubbles caused by propeller rotation) contributing to an altered underwater soundscape.

As a result, characterising this soundscape is key to understanding the influence of vessels on whale populations. We deployed our first hydrophone (underwater microphones) in 2020 in Skjálfandi Bay, our whale-watching area, to do just that. We also hope to listen to whale vocalisations and, if possible, relate changes in vocalisation (rate, frequency and sound level) to variation in vessel traffic. The team doesn’t have much experience in acoustic research, so we’re extremely fortunate to work with Dr Michelle Fournet, a bioacoustics researcher from Cornell University, who currently supervises our fieldwork and data analysis. .

COVID-19 UPDATE: In these trying times, Covid-19 has provided a unique opportunity to listen to a quieter Skjálfandi Bay – by halting whale-watching activities and reducing vessel traffic generally. We worked with our local collaborators at University of Iceland to deploy a hydrophone to characterise this altered landscape and its consequences for whales.

Climate response modelling

From the results of our whale watching impact assessment, we hope to design a conservation plan aimed at balancing the needs of whales and humans. Crucially, we need a plan that works not only now, but far into the future. With dramatic climate change forecast in the coming decades, with associated shifts in ocean habitats, this presents a challenge. Will the whales of north Iceland still be around in the future? To what extent can whale-watching companies and locals rely on seeing whales on a daily basis? Will north Iceland still represent an important feeding ground in years to come?

To answer these questions, Tom is working with iAtlantic, a collaborative, EU-funded project aimed at monitoring the response of marine life to oceanographic changes in the Atlantic Ocean. Using long-term time-series data for humpback and blue whales in Icelandic waters, we will perform habitat modelling, mapping their distribution against various oceanographic variables such as depth, temperature, plankton and fish distribution. Following this, we will apply climate forecasts to predict how these variables will change in the future. Therefore, we can estimate how the distribution and number of humpback and blue whales will change around Icelandic waters in coming years.