Unfettered and undeterred. Those words best describe the young woman who came into my lab and life in Anne Theo would get into the Ph.D. programme at the Indian Institute of Science the following year, but she spent her first months tinkering with some secondary data and helping me organize an international sea turtle conference in Goa. It was very clear from the beginning that she was fearless, both in her ideas and the things she did.
But one story captures her spirit and personality best. On our very first dive together in the Lakshadweep Islands, Anne got separated from us. Her fellow researchers and I surfaced after the mandatory search and became increasingly worried as there was no sign of her.
The sea was getting choppy and we were running out of options. Anne surfaced seconds later, about 10 metres away, looked at us and said “Where were you guys?”
Anne was never lost, the rest of the world was!
Anne had not considered in-water research when she began her PhD. In fact, she was not even a particularly good swimmer at the time. But we chanced upon mixed-species groups of reef fish based on a remark by Umesh Srinivasan, who was doing similar research for his PhD on birds. Anne latched on to the idea, and trained herself rapidly in the Institute’s swimming pool and got her dive certification as well. However, a larger problem loomed. Many marine biologists she consulted were not enthusiastic about her plan to study mixed species groups (MSGs) in reefs—they thought that reef fish MSGs were too ephemeral and might not be interesting.
Anne was undeterred. She spent her first field season in the Lakshadweep Islands gathering evidence that MSGs were common, could be video-graphed and that there were a host of interesting ecological questions that one could address about them. She gathered a massive dataset across four years, and made significant contributions to our understanding of fish MSG group types. Her work, which emphasised the fundamental ecological and behavioural differences between shoaling and attendant fish groups, would inform theoretical frameworks that were developed for a global review.
Bina, one of her closest friends from childhood, remembers how much she loved the ocean and how keen she was to share the joy with others through her encouragement and swimming lessons, that she imparted with ‘gentle and obsessive persistence’. Even in the field, Anne had a long history of friendships and partnerships. Over a period of several years, her buddies—on land and in the water —included researchers from multiple different institutions. She started her field work in 2011 with Rucha Karkarey from the Nature Conservation Foundation. Diving during the day, playing the guitar and writing songs in the evening (including classics such as Harami Gourami), the two livened up the Kadmat field station. She was also paired with her fellow student, Bharti, who was scoping a project on green sea turtles. She then worked for several seasons with Mahima Jaini of Dakshin Foundation; Mahima helped Anne with her dives, Anne helped Mahima with Malayalam.

Anne, Mahima and I made a memorable trip to Suheli Island in Lakshadweep in 2015. Uninhabited other than a police camp, fishers visit periodically during the fair season. Suheli is legendary because the late Satish Bhaskar, doyen of sea turtle surveys in India, spent five solitary months there during the monsoons in the 1970s to count and monitor green turtle nesting. We left before dawn, walking down narrow lanes to the beach; while the rest of us had perfunctory field backpacks, Anne had her large pink stroller suitcase that she took everywhere. We had hired two tuna boats to ferry us there, and caught tuna and other fish along the way. The diving was spectacular; at one point, Anne and I turned to see two eagle rays gliding effortlessly through the water. They swum languidly in an arc towards us, realized we were there and veered away with barely a wobble in their trajectory. A moment of surreal beauty that we remembered many times after. And then, later on the dive, work completed, she did a goofy dance underwater and we took some memorable comic photographs with Mahima.
On that trip, I met Jafer, who took our team out on his boat for their dive surveys in Agati and Bangaram. Jafer’s daughter, Nihla Fatima, then three years old was very fond of Anne and Mahima, and endeared herself greatly to all of us. The people I met and the spectacular diving there led to Moonlight in the Sea, an illustrated story about a little girl from the Lakshadweep who learns to snorkel and falls in love with marine life. One day, her boat gets swept away in a storm and she ends up stranded in Suheli, where she learns to fend for herself. When my illustrator was working on the book, she commented that the little girl was far too nonchalant for a 10-year-old stuck on a remote island. It struck me later that Anne had wormed her way into the young protagonist’s personality.
Later that year, when we got advanced dive training at Havelock Island in the Andamans, Anne was on hand to try and convince Priti Bangal, a new student and novice diver, to work on reef fish. Priti ended up working on birds, but Anne would get another opportunity to impart her vast knowledge of reef fish when she helped Bharat Ahuja with his field work in 2021.
We joked that Bharat had the most qualified field assistant that any student had ever had. From getting lost to leading dives, Anne had come a long way. Despite significant struggles with her health during her PhD, she never gave up her passion for science and fieldwork. She mentored a host of junior students doing marine ecology in both analysis and fieldwork, including identifying surgeonfish and parrotfish species that only she could tell apart. She escorted Meenakshi Poti to Lakshasdweep and helped her get started on her project on green turtles. She worked with Ajay Venkatraman on an analysis of her data during the COVID-19 lockdown, when Ajay was stuck in India waiting for the Australian borders to open so he could start his PhD.

She loved the ocean and fieldwork, but she was a whizz at R, and taught courses and workshops in statistics. In the summer of 2022, she was my (vastly overqualified again) teaching assistant for a quantitative ecology course at the department, one that I was teaching for the first time. Having Anne to talk to about my struggle to relearn equations was a relief in no small measure.
In the last year, she also played a key role in developing and proposing a special issue on mixed species groups in the prestigious journal, Philosophical Transactions of the Royal Society B, working closely with her co-editors Todd Freeberg, Nora Carlson and Eben Goodale. The last paper she worked on is included in the theme issue, which is dedicated to her.
Anne’s plans for the world were unfettered. She was innately caring and carefree, but she also wanted to stomp on things that she found unfair, illogical or senseless. She wanted to create a science cooperative that transcended the politics and pitfalls of academia. She wanted to end patriarchy and capitalism. Tragically, before she could do any of those things, Anne passed away on February 6, 2023. She leaves behind a vast community of close friends, colleagues and family who will miss both her fierce arguments and easy affection. She is survived by her husband and fellow ecologist, Guillaume Demare, her brother, Dennis, and her mother, Mary. The lasting impression she made on people and the legacy of her research will live on.
Anne, so long and thanks for all the fish stories!
Anne Heloise Theo (August 28, 1985 – February 6, 2023)