One Whale In Ten Liters Of Water

Effective and non-invasive whale and biodiversity monitoring is now possible with the help of citizen scientists, opening up new opportunities for marine conservation. Water samples collected during whale-watching tours contain enough whale DNA to yield detailed information about the animals sighted using molecular methods. However, as two independently published papers show, samples must be collected promptly and following specific protocols.

Encouraging updates are emerging from the Biodiversa+ project 'eWHALE', which was launched at the University of Innsbruck in 2023. Yet the story behind the new publication in the scientific journal, Environmental DNA, began with every researcher's worst nightmare. Just as Bettina Thalinger and Lauren Rodriguez from the Innsbruck-based eWHALE team were preparing to submit their key findings on eDNA field sampling optimization, they learned that another research group from Canada was planning to publish similar results in the same journal.

"Instead of entering a race with an uncertain outcome, we aimed for co-publication," explains project leader Bettina Thalinger from the Department of Zoology. The approach worked: both the Canadian team and the journal editorial staff supported the idea. In late May, two articles were published in Environmental DNA, presenting the same findings regarding eDNA sampling optimization efforts from different study areas and on different whale and dolphin species.

Both papers describe effective sampling methods that can be implemented relatively easily by citizen scientists onboard whale-watching boats, while still producing high-quality samples. Chloe Robinson, from the NGO Ocean Wise , also welcomed the opportunity to collaborate with the eWHALE consortium: "I was thrilled by the opportunity for a parallel publication with the eWHALE team in Environmental DNA. It's inspiring to see other researchers tackling the complexities of whale eDNA, and this collaboration offered a refreshing shift from the usual 'race to publish first' toward a shared commitment to advancing the science together," says the lead author of the Canadian paper.

Rapid Sampling

"Traditional cetacean monitoring methods are often resource-intensive, expensive, and sometimes invasive. In eWHALE, we aim to explore whether environmental DNA (eDNA) from water samples can provide information on species, populations, or even individual whales-and we are starting to see promising results," says PhD candidate Lauren Rodriguez, first author of the Innsbruck publication.

In 2023, the eWHALE team tested different sampling variables during whale-watching tours in the Atlantic near the Azores, the Italian Mediterranean Sea, and the North Atlantic off Iceland, to refine their protocol. Meanwhile, the Canadian team conducted their experiments in the Pacific.

The researchers focused on factors that influence eDNA detection and signal strength, including water volume (2, 5, and 10 liters), filter pore size, and timing of sample collection (immediately after whale sightings and at intervals of 5, 10, and 20 minutes). Their most significant finding: to obtain a sufficient concentration of whale DNA, water should be collected as soon as possible following the sighting-ideally from the spot where the whale fluked or breached. "Along with timing and location, the volume of water collected played a key role in sample quality with 10 litres exhibiting the best results across study regions," Rodriguez explains. Large-pore filters also performed better than smaller ones. With these optimized methods, the teams were able to collect enough material for molecular laboratory analysis and continued to collect samples following this protocol during the 2024 field season.

Ready for Monitoring

"All of the whale-watching agencies involved in the eWHALE project implemented our method successfully," notes Bettina Thalinger, who sees enormous potential in collaborating with tour operators and citizen scientists. The findings lay a foundation for further international, large-scale monitoring programmes-something that excites more than just the project leader. "All the information we can gather non-invasively, just from the water-that's incredible," says young researcher Lauren Rodriguez. She will continue analysing the samples that were collected over the past two years in the lab during the coming months. More results are expected in the autumn.