By Michele Charlton
Grad student Taylor Hersh鈥檚 innovative research is helping us learn more about the behaviour, movement and culture of sperm whales 鈥 and the unique dialects they use to develop a sense of community.
She can trace her fascination with marine animals back to three things she encountered in sixth grade: a person, a book, and a photo.
The person was a classmate who wanted to be a marine biologist. Hersh grew up in landlocked Pennsylvania and had never thought of marine biology as a possible career option. The conviction of her fellow student was really inspiring to Taylor.
The book was聽Stranded聽by Ben Mikaelsen. It tells the story of a 12-year-old who helps rescue, rehabilitate and release two stranded pilot whales. Although the book was fictional, Hersh was captivated by the idea of someone her age helping whales.
The photo was National Geographic photographer Brian Skerry鈥檚 full body shot of a Southern right whale. It was the first underwater picture of a whale she had ever seen and was completely mesmerizing.
鈥淥ne of the biggest highlights of my PhD so far has been spending time with the whale families off Dominica. As someone who is holed up in an office with headphones on for most of the year, I cherish time spent in the field because it enriches my research and makes it more rewarding."
鈥淪cience had always been one of my favourite subjects,鈥 says Hersh. 鈥淏ut those three encounters launched me down the path to marine mammal research.鈥
Cracking the code
After a number of marine biology-related internships during and after her undergraduate degree in various places, including Maine, Washington, Mississippi, and Florida, Hersh was able to gain more experience and hone her interests.
鈥淎fter helping with acoustic research on Southern right whales in Argentina, I realized that I loved listening to whales and trying to decode what they were saying,鈥 says Hersh. 鈥淭hat led me to marine mammal acoustics.鈥
And when the time came for Hersh to start looking into graduate programs, 麻豆传媒 quickly shot to the top of her list.
鈥淚 wanted to study marine mammal acoustics, but I also wanted to conduct research that related acoustics back to behaviour,鈥 says Hersh. 鈥淲hen I learned that my now-supervisor, , studied marine mammal culture, including acoustic culture, at 麻豆传媒, his lab seemed like the perfect fit.鈥
For the past three years, Hersh has gone to Dominica each winter to work with the (DSWP). The DSWP was started in 2005 by Dr. Shane Gero when he was also a master鈥檚 student in Dr. Whitehead鈥檚 lab. Now, 15 years into the project, the sperm whales that live off Dominica are one of the best-studied marine mammal populations in the world.
Learning more about whale dialects
Just like humans, different groups of sperm whales have different cultural dialects. These dialects are made up of Morse code-like patterns of clicks, called codas. Human dialects vary with both space and time, and studying these variations can tell us about the behaviour, movement, and culture of their speakers. The goal of Hersh鈥檚 research is to do the same for sperm whales.
鈥淚鈥檓 using acoustic data from 13 locations to characterize different sperm whale dialects in the Pacific Ocean,鈥 says Hersh. 鈥淚鈥檓 also using long-term acoustic data from the Gal谩pagos Islands and Dominica to see if the dialects of certain sperm whale groups have changed over time.鈥
Learning about how sperm whale dialects are similar to and different from human dialects can help us contextualize our own abilities. A better understanding of how many sperm whale cultural groups live in the Pacific Ocean and how their dialects change over time may also facilitate more effective management plans that utilize acoustic data.
鈥淲ith human impact in the ocean increasing and sperm whale populations struggling to survive, effective management will be essential to conserving these animals,鈥 says Hersh.
Developing a sense of family in a small space
Most of the fieldwork that Hersh has been a part of is carried out from Dr. Whitehead鈥檚 40-foot liveaboard sailboat, Balaena. They tow an underwater microphone, called a hydrophone, on a cable behind the boat. This lets them listen to and record sperm whales.
鈥淲hen we hear sperm whales on the hydrophone, we can home in on their location using special acoustic software, which also lets us follow whales overnight,鈥 says Hersh. 鈥淲e spot the whales by looking for their breaths, which rise a few feet off the water and can be seen from over a kilometer away in good conditions.鈥
The whales are recorded for the research Hersh is doing, and pictures are also taken of their tails when they dive to figure out which animals are spending time together. The team also puts temporary,聽non-invasive sound and movement recording tags on individual whales, and flies drones to look at the body condition and health.
The team spends anywhere from a few days to a few weeks out at sea but comes into port when they need to restock fuel, water, and food.
鈥淟iving and working on a small boat with three to six people for months at a time has its challenges,鈥 says Hersh. 鈥淧ersonal space is extremely limited, and your best bet for getting some time alone is to scale the mast and sit in the crow鈥檚 nest.鈥
Working from Balaena lets Hersh spend more time with whales and collecting data than could be done if she was land-based.
鈥淚t can be exhausting, but I love living on Balaena and have spent over 150 days on her so far,鈥 says Hersh. 鈥淎 real sense of family develops among the crew. And there鈥檚 something incredibly special about having a sperm whale be one of the last things you see before you fall asleep and one of the first things you see when you wake up.鈥
An opportunity to spend quality time in nature
Hersh plans to graduate with her PhD in 2021, but there have already been many highlights during her time at Dal.
鈥淥ne of the biggest highlights of my PhD so far has been spending time with the whale families off Dominica,鈥 says Hersh. 鈥淎s someone who is holed up in an office with headphones on for most of the year, I cherish time spent in the field because it enriches my research and makes it more rewarding.
鈥淚t鈥檚 one thing to listen to an acoustic recording and hear sperm whales communicating,鈥 continued Hersh. 鈥淚t鈥檚 an entirely different experience to know that the recording you鈥檙e listening to is of a whale named Rounder communicating with her daughter Accra.鈥
The lab that Hersh works in recently applied for funding to study sperm whales off the Gal谩pagos Islands in 2020. If that funding comes through, she鈥檒l be part of the research team that heads to Ecuador this winter.
鈥淎 huge portion of my thesis uses acoustic data that was recorded off the Gal谩pagos Islands between 1985 and 2014,鈥 says Hersh. 鈥淚 would love to see the whales that I鈥檝e been listening to for three years in person.鈥