Meet the Scientist Tracking Whales in Antarctica with Expedition Guests

Every summer in the Antarctic, humpback whales gather from all over the southern hemisphere to feed and rest. For Dr Susana Caballero, it’s a fascinating melting pot of different groups of whales, and an opportunity to learn more about these majestic creatures.

Happily, Hurtigruten Expeditions’ cruises sail to Antarctica at this time of year, full of conservation-minded guests who’re eager to take part in scientific discoveries and learn from experts.

It’s a match made in heaven for the team led by Dr Caballero, who joined the expedition ship MS Fridtjof Nansen before its departure from Ushuaia in southern Argentina. Dr Caballero was just preparing to leave her home in Colombia when she spoke to us.

Congratulations on gaining funding and support for your exciting project. How did it feel when you heard you had been successful?

It was absolutely amazing – it meant we would actually be able to do all of the work we had planned. In Colombia, there are few sources of research funding and it’s difficult to get a good amount, so this support is fantastic. It means we can buy equipment that will enable us to produce high quality data and documentation.

Going on Hurtigruten’s ship is also a tremendous opportunity. I had never thought of going to Antarctica before! It’s hard to get on the Colombian programme that goes there, and sometimes conditions are not the greatest.

“In Antarctica, the whales are feeding a lot. They are so busy getting food that we can get much closer.”

Why do you want to do research in Antarctica?

Antarctica is prime destination for humpback whales, and not just any whales – the ones we see in Colombia. I’ve been researching humpback whales in Colombia for 23 years, where they’re mostly taking care of calves, and their mating happens here too.

We see them doing completely different things at the Antarctic Peninsula, where they have a completely different mindset. In Antarctica, the whales are feeding a lot. They are so busy getting food that we can get much closer. It’s not like in Colombia where they have their calves, so they’re shyer and don’t want us to approach them. In Antarctica, they don’t care; they’re so busy eating.

This will be our second trip doing research there on Hurtigruten’s ship. Last time I made the discovery that in Antarctica the whales sleep a lot. We also took a hydrophone to check if they sing when they’re there. We found they’re much quieter. They do sing, but not as much as in mating areas.

This is a wonderful opportunity to see the other part of their life, so it really closes the circle. We can even see if a whale we see in Colombia is the same one we see in Antarctica.

“From just a few litres of water, we can see what animals have been there in the last 24 hours. It’s still magic to me!”

How do you investigate the whales?

We use a biopsy rifle that shoots a dart into the whale and then floats to the surface with a sample of the whale’s skin. The whales don’t react to the dart – they’re so busy eating they don’t care; it’s like a mosquito bite.

We can tell so much about an individual whale from this sample, such as which sex it is, and which population it belongs to. We collaborate with a lot of researchers worldwide, in Chile, the US, New Zealand, and Australia. Each investigates a different area of the southern Pacific, where the whales go to mate and bring up their young.

By looking at the whale’s genetics, we have found whales that move between groups. Using such data, we can think of hypotheses about why they change their breeding destination. For example, what happens as the climate changes. Will there be enough food for them to keep going to the Antarctic Peninsula?

“The guests are so engaged with it! When we go out to look for whales, everyone gets excited.”

How do expedition cruise guests help you?

Guests come out on small boats and take pictures of the whales’ tails. Each whale has a unique tail, so we can identify them from it. Back on the ship, guests can upload their pictures to a database, and we can connect the tails to the biopsy samples of the whales. From this, we can see how they’re related to other whales and compare the data with other samples and sightings.

Later, guests can see their photos and ‘their whale’ on our website and follow it on our blog, where we add more information and results from the DNA profiling. It’s really interesting for people – they love being part of it.

Another way guests help is by gathering water samples, from which we can extract eDNA, which means environmental DNA.

What does eDNA show you?

eDNA means we gather any animal DNA that remains in the water after they have swum onwards. From just a few litres of water, we can see which animals have been there in the last 24 hours. It’s still magic to me!

This shows us the whole ecosystem around the animals. We identify whales, fish, penguins, seals, birds, and other animals. It’s a window into the whole biological community of which the whales are one part, putting them in a better context.

We can also see how the community changes with the whales. When the whales arrive in Colombia, we see fewer species of fish present, and more of the larger fish species. One of my masters students found the ecosystem displays a clear break between when the whales arrive and when they leave. We still have a lot to understand; it’s why we need to gather much more data.

I love this method. It is so simple; it helps to engage guests and local people. People feel close to the science and interested in it.

“The reason some people don’t believe in science is because we scientists can be far removed from ordinary people.”

What do you enjoy about working with Hurtigruten Expeditions’ guests?

The guests are so engaged with it! When we go out to look for whales, everyone gets excited. Then we come back for lunch, and everyone is full of questions, excitedly asking for more information. It gives my team a lot of energy that helps to keep us going.

I believe we need to bring science closer to people and show them what we do. One problem of the modern world, and the reason some people don’t believe in science, is because we scientists can be far removed from ordinary people. We explain things in a complicated language that is hard to understand.

I think we need to make people feel involved and connected. We need to show them why science is important, so they can see that we’re not just doing sophisticated, academic studies that have no clear purpose. This project shows them clearly how empirical data goes into conservation.

Is it new that you will be investigating leopard seals?

Yes. There’s a funny anecdote about this! About three years ago I was studying elephant seals, and as usual, we were collaborating and sharing data with worldwide institutions. One was the Argentine Antarctic Institute, which doesn’t do a lot of genetic work, so they sent us some biopsy samples to analyse, which they thought were from Weddell seals. We did DNA analysis on them and then tried to compare them to Weddell seal DNA on the internet. Imagine how shocked we were when the results came back that they were leopard seals!

So, we started looking for genetic data on leopard seals among the scientific community, and there was nothing. I was shocked: no one had ever researched this charismatic, popular species that people know about; the one that eats penguins.

We know leopard seals are highly genetically diverse and live in the sea ice, where they move around a lot. But they are a big mystery. Is there a huge population of them? What goes on? It’s very much into the unknown. We’ve sampled seals in the past on land, and it’s challenging. I hope it works this year.

Are you pleased with the results your project has achieved so far?

I’m super pleased, from many different perspectives. For the science, it’s new and interesting, and it perfectly complements other work I do in Colombia, so it’s very fulfilling.

Also, I’m very happy because not only do I get to go to Antarctica, which is a dream for most people. I get to go twice!

What makes me even happier is the response we get from Hurtigruten Expeditions’ guests. When I hold up as white cloudy liquid in a test tube and say: “This is humpback whale DNA,” they find it mindblowing. It gives me a real sense of achievement to be able to show people our work and get their reactions. Getting people so close to the science is amazing.

Dr Susana Caballero is Associate Professor at Universidad de Los Andes University in Bogotá.

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Where can I learn more?

You can read more and follow the scientists’ progress on their blog.

If you would like to learn more about travelling to Antarctica, see Hurtigruten Expeditions’ cruises to Antarctica