Meet the Team - Josh Stewart
May 2020
Shortly after his first experience working with manta rays in the Maldives, Josh helped found the Manta Trust, and has since been an associate director and key member of the Manta Trust team. He has continued working to improving our understanding of the ecology and conservation status of manta and mobula rays.In 2018 he completed his PhD at Scripps Institution of Oceanography, which was focused on the movements, stock structure, and foraging behavior of mobulid rays.
Tell us about your first manta/devil ray encounter.
The first time I ever saw a manta ray was in the Dominican Republic. I was an undergraduate studying marine biology, and I was in the field doing a rapid biological survey of a 17th century Spanish shipwreck. My team was documenting coral and fish diversity around the wreck and, like most Caribbean reefs, there was low to moderate diversity and abundance, so I wasn’t expecting to see much. We were doing our safety stop on the way up, and I was looking out to sea while my three dive buddies were facing the opposite direction, back towards the reef. Suddenly, a 12-15 foot (at the time it felt like 20 foot) wide manta ray came swimming out of the blue. I whipped up my video camera and started recording, screaming at my dive buddies to turn around and look. Staring at the manta and my viewfinder, I was having a National Geographic moment, completely awed by my first interaction with a true marine megafauna. The manta swam off, and I turned around to find that none of my dive buddies had even noticed! No matter, I had it all on video and would get to show off my stunning footage after the dive. I pulled up my video camera to play back the moment for the rest of the safety stop. That’s odd… why is the camera still recording? I remember pushing the record button after the manta swam off to end the clip… Wait, where’s the footage? Of course, while the camera was dangling by my side on the safety stop it was already recording, and when I hit record to capture the moment, it cut the clip off right as the manta was approaching! None of my dive buddies believed that a manta had swum by a few meters behind them, and I had no proof. I never lived that down, and my claims of seeing a manta were frequently disputed.
How did you come to be involved with The Manta Trust?
At the start of my PhD studies I was identifying sites with reasonable access to oceanic manta rays where we could deploy satellite tags to investigate their movements, habitat use, and population connectivity. The Revillagigedo Islands in Mexico are a well-known manta hotspot, so that was a no-brainer. But my collaborators were told by their colleagues in Mexico that oceanic mantas were also frequently seen in Bahia de Banderas on the mainland just southeast of Baja California. We started deploying satellite tags there to see if and how mantas were traveling between coastal Mexico and the Revillagigedo Islands. During our first few field seasons in Bahia de Banderas, we saw some really serious and dramatic injuries from boat strikes and entanglement in fishing gear, and a huge proportion of the mantas there seemed to be impacted. It was clear that there were local conservation issues to tackle, so we teamed up with some great local partners including the Instituto Tecnologico de Bahia de Banderas to form Proyecto Manta Pacific Mexico. We’ve been working closely with local communities for the last six years to study the seasonal visitation and habitat use of mantas in the bay to help support conservation strategies that will reduce those key impacts on the population.
Image credit: Octavio Aburto
What legacy would you like to leave in your field of research/conservation?
What I love most about our project in Bahia de Banderas is that we work directly with community members on important conservation issues. We train undergraduate students from the region to assist with our surveys, our project leaders are from the local communities, and fishermen from the local fishing cooperatives facilitate our research as boat captains and active participants in our monitoring work. I hope my legacy will be building close relationships between conservation scientists and community stakeholders that have foundations in mutual respect, willingness to learn from each other, and a common goal of improving the environment for the next generation. Along those lines, the students that start their careers in our program go on to be scientists, resource managers, and conservationists, and I think that by focusing on training the next generation of conservation scientists we dramatically increase our impact beyond what any one single person can accomplish. The lessons I’ve learned about the value of working with stakeholders, learning from them and understanding their needs have served as a model for how I approach other conservation research projects.
What is the most challenging part of your work?
The hardest part of my work by far is finding funding to support research and conservation efforts. The unfortunate truth is that there are so many issues that need to be addressed in the world of marine conservation, and not enough funds to go around. So it’s a constant challenge to find sources of support for these projects. Luckily for us, manta and devil rays are pretty charismatic, so we often can find support from non-traditional sources, such as private donors and foundations, that are interested in keeping these iconic species around for future generations to enjoy.
What is the most surprising thing you have learnt about manta/devil rays?
I was convinced that oceanic manta rays were going to be these nomadic wanderers crossing the Pacific Ocean and travelling thousands of kilometres each year. That was the paradigm, and we had every reason to think that would be the case. In the last eight years that I’ve been researching these incredible animals, every bit of data so far has instead pointed to them having restricted ranges, showing that they’re not the prolific migrants we once assumed. In contrast, it seems like devil rays do move quite long distances, and I’m still trying to reconcile that fact given I always expected it to be the other way around! But as we learn more about their biology and ecology, we’re starting to see patterns in habitat use and foraging behaviour that can help explain these unexpected differences.
If you could ask people to do one thing to help - what would it be?
Get involved. That’s a bit of a cheat because there are so many ways for people to get involved in manta research and conservation, and every person will be able to get involved in a different way depending on their location and circumstances. There are so many opportunities, whether it’s contributing your manta photo IDs from your latest dive trip (which is a really important data source for us); making a monetary contribution to support manta research; joining a Manta Expedition, which helps facilitate our research while also getting you in the field and directly involved; or simply being vocal in your support for marine conservation action. Every bit contributes!
Dr. Josh Stewart
Associate Director