The tragic end of the humpback whale “Timmy” has demonstrated how little research still knows about many whales and their behavior. But the eWHALE project wants to change this – with the help of volunteers and liters of sea water. The principle: During whale watching, tourists take a sample of water from where a whale had recently dived. The whale DNA contained in the seawater can then help to determine the whale’s population affiliation, its origin and other characteristics.
Many whale species migrate hundreds to thousands of kilometers, and their populations are spread across vast ocean regions. This makes it difficult to find the marine mammals, observe their behavior and determine the genetic diversity of their populations. As a result, many fundamental questions remain unanswered, including why whales often appear to become disoriented and stranded, as was the case recently with the humpback whale Timmy.
Water sample from the “fin print”
A new project could now help to close the information gaps. In the eWHALE project, biologists collect whale DNA from different ocean areas by recruiting whale-loving tourists to help them. These are supposed to collect seawater samples including whale DNA during whale watching trips. “In theory, it’s really simple,” explains project coordinator Bettina Thalinger from the University of Innsbruck. “People on a whale-watching boat scoop up a bucket of seawater and then filter the water through a fine filter that retains all of the environmental DNA – eDNA in English.”
In initial tests in the Mediterranean and Atlantic, Thalinger and her colleagues have already investigated how these DNA samples can best be obtained – and what needs to be taken into account. “Of course, we are not allowed to get too close to the animals on the tours, and we are certainly not allowed to touch them,” emphasizes the biologist. Therefore, obtaining a good sample of seawater depends on timing: When a whale dives, it leaves a kind of imprint on the sea surface, a zone where the water is particularly calm. This print can be clearly visible in the water for more than half a minute. If you take a sample from this water, it most likely also contains genetic material from the whale that has just submerged.
“Unfortunately, it’s not always as simple as it is in theory,” says Thalinger. Nevertheless, the project has been a success so far. The first tests have already confirmed that trained laypeople can successfully collect environmental DNA from the sea. “With over a hundred participants in Italy, Iceland and the Azores, we were able to show in this project that our approach works,” reports Thalinger.
First tests successful
The environmental DNA from the collected samples is then analyzed in the laboratory using various molecular biology methods. With so-called metabarcoding you can determine which species are represented in the DNA traces. By comparing it with other samples, it can then be determined which population the whale in question belongs to, how the individual whales in it are related to each other and how great the genetic diversity of this population is. The latter is important because greater genetic variation can help animals adapt to changing environmental conditions such as climate change.
“We were able to detect sperm whales, humpback whales, fin whales, but also dolphins and even sharks in the samples, which are difficult to detect using conventional methods,” reports Thalinger. “We are currently working on further evaluation of the data collected, but I can already say that the project is a complete success. And I constantly receive inquiries from people who would like to help with possible follow-up projects.”
The biologist is already planning the next project on environmental DNA in the sea: “My dream would be to roll out this program on a larger scale.” In the future, collaboration with citizen scientists will be expanded across Europe. In this way, the international eWHALE team can collect data on whales and other sea creatures on an even larger scale and help protect the marine mammals, which are among the oldest animals, and their habitat.
Source: Austrian Science Fund FWF; Project: eWHALE