How do we study the impact of whale watching?

Clara Bird, PhD Candidate, OSU Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

Since its start, the GEMM Lab has been interested in the effect of vessel disturbance on whales. From former student Florence’s masters project to Leila’s PhD work, this research has shown that gray whales on their foraging grounds have a behavioral response to vessel presence (Sullivan & Torres, 2018) and a physiological response to vessel noise (Lemos et al., 2022). Presently, our GRANITE project is continuing to investigate the effect of ambient noise on gray whales, with an emphasis on understanding how these effects might scale up to impact the population as a whole (Image 1).

To date, all this work has been focused on gray whales feeding off the coast of Oregon, but I’m excited to share that this is about to change! In just a few weeks, Leigh and I will be heading south for a pilot study looking at the effects of whale watching vessels on gray whale mom/calf pairs in the nursing lagoons of Baja California, Mexico.

Image 1. Infographic for the GRANITE project. Credit: Carrie Ekeroth

We are collaborating with a Fernanda Urrutia Osorio, a PhD candidate at Scripps Institute of Oceanography, to spend a week conducting fieldwork in one of the nursing lagoons. For this project we will be collecting drone footage of mom/calf pairs in both the presence and absence of whale watching vessels. Our goal is to see if we detect any differences in behavior when there are vessels around versus when there are not. Tourism regulations only allow the whale watching vessels to be on the water during specific hours, so we are hoping to use this regulated pattern of vessel presence and absence as a sort of experiment.

Image 2. A mom and calf pair.  NOAA/NMFS permit #21678.

The lagoons are a crucial place for mom/calf pairs, this is where calves nurse and grow before migration, and nursing is energetically costly for moms. So, it is important to study disturbance responses in this habitat since any change in behavior caused by vessels could affect both the calf’s energy intake and the mom’s energy expenditure. While this hasn’t yet been investigated for gray whales in the lagoons, similar studies have been carried out on other species in their nursing grounds.

Video 1. Footage of “likely nursing” behavior. NOAA/NMFS permit #21678.

We can use these past studies as blueprints for both data collection and processing. Disturbance studies such as these look for a wide variety of behavioral responses. These include (1) changes in activity budgets, meaning a change in the proportion of time spent in a behavior state, (2) changes in respiration rate, which would reflect a change in energy expenditure, (3) changes in path, which would indicate avoidance, (4) changes in inter-individual distance, and (5) changes in vocalizations. While it’s not necessarily possible to record all of these responses, a meta-analysis of research on the impact of whale watching vessels found that the most common responses were increases in the proportion of time spent travelling (a change in activity budget) and increased deviation in path, indicating an avoidance response (Senigaglia et al., 2016).

One of the key phrases in all these possible behavioral responses is “change in ___”. Without control data collected in the absence of whale watching vessels, it impossible to detect a difference. Some studies have conducted controlled exposures, using approaches with the research vessel as proxies for the whale watchers (Arranz et al., 2021; Sprogis et al., 2020), while others use the whale watching operators’ daily schedule and plan their data collection schedule around that (Sprogis et al., 2023). Just as ours will, all these studies collected data using drones to record whale behavior and made sure to collect footage before, during, and after exposure to the vessel(s).

One study focused on humpback mom/calf pairs found a decrease in the proportion of time spent resting and an increase in both respiration rate and swim speed during the exposure (Sprogis et al., 2020). Similarly, a study focused on short-finned pilot whale mom/calf pairs found a decrease in the mom’s resting time and the calf’s nursing time (Arranz et al., 2021). And, Sprogis et al.’s  study of Southern right whales found a decrease in resting behavior after the exposure, suggesting that the vessels’ affect lasted past their departure (Sprogis et al., 2023, Image 3). It is interesting that while these studies found changes in different response metrics, a common trend is that all these changes suggest an increase in energy expenditure caused by the disturbance.

However, it is important to note that these studies focused on short term responses. Long term impacts have not been thoroughly estimated yet. These studies provide many valuable insights, not only into the response of whales to whale watching, but also a look at the various methods used. As we prepare for our fieldwork, it’s useful to learn how other researchers have approached similar projects.

Image 3. Visual ethogram from Sprogis et al. 2023. This shows all the behaviors they identified from the footage.

I want to note that I don’t write this blog intending to condemn whale watching. I fully appreciate that offering the opportunity to view and interact with these incredible creatures is valuable. After all, it is one of the best parts of my job. But hopefully these disturbance studies can inform better regulations, such as minimum approach distances or maximum engine noise levels.

As these studies have done, our first step will be to establish an ethogram of behaviors (our list of defined behaviors that we will identify in the footage) using our pilot data. We can also record respiration and track line data. An additional response that I’m excited to add is the distance between the mom and her calf. Former GEMM Lab NSF REU intern Celest will be rejoining us to process the footage using the AI method she developed last summer (Image 4). As described in her blog, this method tracks a mom and calf pair across the video frames, and allows us to extract the distance between them. We look forward to adding this metric to the list and seeing what we can glean from the results.

Image 4. Example of a labelled frame from SLEAP, highlighting labels: rostrum, blowhole, dorsal, dorsal-knuckle, and tail. This labels are drawn to train the software to recognize the whales in unlabelled frames.

While we are just getting started, I am excited to see what we can learn about these whales and how best to study them. Stay tuned for updates from Baja!

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Arranz, P., Glarou, M., & Sprogis, K. R. (2021). Decreased resting and nursing in short-finned pilot whales when exposed to louder petrol engine noise of a hybrid whale-watch vessel. Scientific Reports, 11(1), 21195.

Lemos, L. S., Haxel, J. H., Olsen, A., Burnett, J. D., Smith, A., Chandler, T. E., Nieukirk, S. L., Larson, S. E., Hunt, K. E., & Torres, L. G. (2022). Effects of vessel traffic and ocean noise on gray whale stress hormones. Scientific Reports, 12(1), Article 1.

Senigaglia, V., Christiansen, F., Bejder, L., Gendron, D., Lundquist, D., Noren, D., Schaffar, A., Smith, J., Williams, R., Martinez, E., Stockin, K., & Lusseau, D. (2016). Meta-analyses of whale-watching impact studies: Comparisons of cetacean responses to disturbance. Marine Ecology Progress Series, 542, 251–263.

Sprogis, K. R., Holman, D., Arranz, P., & Christiansen, F. (2023). Effects of whale-watching activities on southern right whales in Encounter Bay, South Australia. Marine Policy, 150, 105525.

Sprogis, K. R., Videsen, S., & Madsen, P. T. (2020). Vessel noise levels drive behavioural responses of humpback whales with implications for whale-watching. ELife, 9, e56760.

Sullivan, F. A., & Torres, L. G. (2018). Assessment of vessel disturbance to gray whales to inform sustainable ecotourism. Journal of Wildlife Management, 82(5), 896–905.

Reporting back on the Whales in a Changing Ocean Conference

Solène Derville, Entropie Lab, Institute of Research for Development, Nouméa, New Caledonia (Ph.D. student under the co-supervision of Dr. Leigh Torres)

My flight back to New Caledonia gives me time to think and process all that I have experienced in the last few days. From April 4th to 6th, I had the great opportunity to attend the “Whales in a Changing Ocean” conference held in Nuku’alofa, in the Kingdom of Tonga. This conference organized by SPREP (Secretariat of the Pacific Regional Environment Programme) as part of the “Protect Pacific Whales – Ocean Voyagers” campaign brought together members of the Pacific Island governments, whale-watching operators, NGOs, IGOS and scientists.

Opening ceremony

As a relatively novice PhD student studying humpback whale spatial ecology in New Caledonia this was my first experience attending a conservation and management focused conference. To be completely honest, when I was asked to attend the conference as part of the work I am conducting on the effect of environmental changes on humpbacks of the South Pacific breeding grounds, I gladly accepted the offer, as an opportunity for me to learn more about the political mechanisms underlying international conservation plans. However, I was a little sceptical as to what tangible outputs could come out of such event. How would the science be integrated into this rather political event? How many delegations would be able to make it? Would they manage to agree on strong objectives regarding the conservation of cetaceans in the region?

Leena Riekkola, a PhD student at University of Auckland, and I with traditional flower necklaces offered by the organizers

On the first day of the conference, we sat through several hours of formal opening ceremony and comments from the governmental delegations that had travelled to Tonga from all over the Pacific: Samoa, Papua New Guinea, Tuvalu, Niue, French Polynesia, New Zealand, Australia, the Cook Islands, Palau, Fiji and many others. These comments mainly consisted of a succession of (well deserved) acknowledgments to the Tongan government for hosting the event and the enumeration of the endless list of threats faced by cetaceans in the region. Despite the tedious nature of this inevitable display of etiquette, I was impressed by the sight of all these governmental and non-governmental delegations sitting around the same table to discuss the future of whales. I was surprised to hear a note of emotion in several of the speeches that day. I clearly had not realized how valuable whales are to the Pacific islanders. Valuable economically of course, as whale watching is one of the most important drivers of tourism to several of these islands, most of all to Tonga. But also importantly, whales and dolphins bear a strong cultural value to the people of the Pacific. Many of the attendees shared stories and legends about whales, and I quickly realized that these animals were indeed a “cultural heritage” that people were eager to protect and preserve.

The next two days of the conference were built around a series of plenaries and workshops surrounding 3 themes: sustainable whale-watching, scientific research and emerging threats. While I was initially a bit lost and did not quite understand where all of this was going, I progressively saw several recommendations and objectives emerging from the discussions. By the end of the conference, I realized how much had been accomplished in only three days and that these achievements were more than just words. Four main outcomes resulted from this conference:

  • The commitment to adopt and sign a Pacific Island Year of the Whale Declaration by 11 nations/territories of the region (out of 21), namely: Australia, the Cook Islands, Fiji, New Caledonia, New Zealand, Palau, Papua New Guinea, Samoa, Tonga, Tokelau and Tuvalu. Not all of the governmental representatives were able to sign but it is likely that some will join later.

  • The agreement to a voluntary commitment to “Protect, conserve and restore whale populations in the Pacific islands, which will be presented at the UN Oceans conference in June 2017.
  • A technical and scientific input from international working groups to help establish the next SPREP Whale and Dolphin Action Plan for 2018-2023

  • Tonga’s announcement of a whale sanctuary in their waters.

    Governmental representatives group photo after signing the Pacific Island Year of the Whale Declaration

Whether these declarations of intentions and recommendations will actually lead to tangible actions in the short term, I could not tell. But I am glad I got the opportunity to witness the very first regional conference on whales in the Pacific Islands, and the celebration of these beautiful creatures and their place in Pacific cultures.