Grace Casselberry is one of those people you just want to tag along with to all of her field excursions-- the cool thing is, we kind of did for this interview! She told us all about the amazing work she is a part of and what the future holds for her. So sit down with a good cuppa and read her Behind the Fins interview.
The Fins United Initiative: Thank you for meeting with us, Grace. Tell us, did you always want a science job or did another subject peak your interest first?
Grace Casselberry: I have always wanted a science job, but I didn’t always know what kind of scientist I wanted to be. My mom was a soil chemist and dad was an environmental chemist so they were always very encouraging of my interest in the sciences. When I was five or six, I wanted to be a chemist for Halloween. My dad brought me a lab coat that went down to my ankles and some way too big safety goggles from work and I dragged him around the neighborhood with a pumpkin bucket for my candy in one hand and a volumetric flask in the other.
TFUI: This sounds amazing.
GC: I’m sure I looked more like a mad scientist than anything else! The chemist phase was short lived though. I went through a pretty serious geology and paleontology phase in my early teens. I still think paleoecology is super cool! If I hadn’t found my current career path, I think that is the road I would have gone down. Throughout all of those phases, I had always been very interested in ocean life and fish in particular, but I hadn’t really thought about pursuing those interests as a career until I was in college. Once I started conducting undergraduate research in a fish physiology lab, my focus became marine ecology and I haven’t looked back.
TFUI: What are you currently studying right now?
GC: Right now I am finishing my Master’s research and am about to start my PhD at the University of Massachusetts Amherst where I am co-advised by Dr. Andy Danylchuk and Dr. Greg Skomal. My Master’s work is centered in a marine protected area (MPA) in St. Croix, U.S. Virgin Islands, called Buck Island Reef National Monument. Fishing is banned within the boundaries of the Monument.
TFUI: Can you tell us a little bit about that area?
GC: Fishing is banned within the boundaries of the Monument. It is one of the oldest MPAs in U.S. waters (established in 1961) and was originally designed to protect an extensive coral reef and sea turtle nesting beaches. Despite its long history, very little is known about how sharks use this area. My work focuses on using acoustic telemetry to track the movements of four shark species (lemon, nurse, Caribbean reef, and tiger sharks) in and around the MPA. With this data we can learn how regularly sharks use the MPA, what habitat types they prefer, and how space use differs among species.
TFUI: So your work is all about shark movements.
GC: There are multiple ways that researchers can study where sharks travel in the water by catching, tagging, and releasing the animal. Two of the most prevalent forms of electronic tagging are satellite telemetry and acoustic telemetry. Satellite telemetry works on a more broad scale. It is best for studying wide-ranging animals because the tags communicate directly with satellites, letting you track the animal wherever it decides to go in the water. Scientists often use this type of telemetry to observe long distance migrations. But as you can imagine, this type of technology is very expensive. I use the latter, acoustic telemetry, which is a bit more affordable. Acoustic telemetry is best for answering more fine scale questions about how animals use a specific area. Acoustic telemetry works with a system of tags and receivers.
TFUI: What do you use?
GC: I catch and tag my sharks with small electronic tags that have a battery life of about 10 years.
GC: Every two minutes or so the tag will make a pinging noise that travels through the water and can be picked up by a receiver. In and around the MPA, my collaborators and I have over 100 receivers anchored in the water. These receivers are constantly listening for the pings from my tags, but they can only listen so far, about 150 meters. So when one of my tagged sharks swims within the listening range of one of our receivers, the unique tag number, date, and time are recorded. Since we know where that receiver is anchored in the water we know who was there, when they were there, and where they were once we download the data. As the tag detections accumulate over time you can start drawing conclusions about patterns of space use for each species.
TFUI: That has to be so much data...
GC: I’m working with a dataset that spans four years for my Master’s and I’ve heard from some of my sharks every day in those four years! It’s a lot of data!
TFUI: And in your opinion, why is your work so important?
GC: Many studies have shown that shark populations around the world are declining. Christine Ward-Paige et al. (2010, PLoS ONE) showed that sharks are largely absent from Caribbean coral reefs, where you would expect them to be found, and some of the highest remaining concentrations of sharks in the greater Caribbean are in South Florida, The Bahamas, and the U.S. Virgin Islands (USVI). Sharks in South Florida and The Bahamas have been studied for decades, but we know very little about the spatial ecology of sharks in the USVI, and to date no one has explored how sharks are using the waters around St. Croix. Preserving healthy populations of sharks in the USVI will be important for the persistence of shark populations throughout the Caribbean. It is impossible to effectively manage or protect any species if you do not know what habitats are important to them and how they interact with their environment. So not only is my project helping to fill knowledge gaps about the spatial ecology and habitat use of sharks in St. Croix, it is also helping managers understand to what extent an existing MPA is protecting shark populations and which shark species could benefit most from MPAs that may be established in the future.
TFUI: You are a very early career scientist, but can you give us a sneek peak on what fin-tastic stuff have you found from your research so far?
GC: Absolutely! So far I have found that all of my species exhibit fairly high residency within Buck Island Reef National Monument, even the tiger sharks!
TFUI: My (Melissa's) favourite! YES!
GC: This is really interesting because tiger sharks are known to be pretty wide ranging animals. I was very surprised to consistently hear from our tagged tiger sharks throughout the year. I am also seeing connectivity between the Monument, where fishing is banned, and other areas around St. Croix that are open to fishing, like Lang Bank and Teague Bay. So we know that the MPA is important for all species but no species is receiving 100% protection. Excitingly, just the other day I was contacted by another researcher working in the Caribbean Netherlands who had heard from one of our tagged nurse sharks on his receivers! We used to think of nurse sharks as homebodies, but increasingly that perception is being contradicted. Wes Pratt and collaborators (2017, Environmental Biology of Fishes) found that some nurse sharks in Florida migrate long distances seasonally. I’m hoping that my traveling nurse shark will decide to make a round trip and come back to St. Croix soon. How cool would that be?
TFUI: That would be amazing. And hey, as an early career scientist, have you found the science industry (particularly marine biology) welcoming (re: diversity, inclusion, gender balance)?
GC: For the most part, I have felt very welcomed and supported throughout my career by both the men and women I work with. I worked in a lab as an undergraduate with a male PI and mostly male graduate students, but they never made me feel like I didn’t belong or couldn’t do what I wanted to do. I then went on to intern and subsequently work at the NOAA – Fisheries lab in Panama City, FL with the Shark Population Assessment Group. I got to work with some incredibly smart and talented women while I was there, who are still my mentors and friends today even though it has been several years since I left that lab to go back to school. Those women really helped me build my confidence and find my voice as a researcher.
TFUI: That is fin-tastic.
GC: That’s not to say that there aren’t times when things are hard or people say ignorant things. I once had a researcher tell me that shark science would be too hard for me and I really should stick to something like trout (whatever that means). There are a few ways that you can respond to those situations. You can believe the people that doubt you or you can believe in yourself. My feeling is that there are plenty of people out there that will see your value and your talents, regardless of your gender, race, disability status, etc. Those are the people that I choose to work with, and that has served me well so far.
TFUI: That is a great attitude to have in the face of tough times. And speaking of those times, what has been your toughest experience out on the field or lab?
GC: Field work is always challenging because it is physically demanding. It doesn’t matter how in shape you are 12 hours in the sun on a boat takes it out of you! I’ve been really fortunate because I learned how run a field-based research program from Dana Bethea of NOAA - Fisheries, who is the queen of organization. There’s no way that you can prepare for every possibility, but she certainly does try and because of that I have had very few mishaps in the field. I think my toughest experience was when I was working with Dana on NOAA’s Smalltooth Sawfish Population Abundance Survey in Everglades National Park. We were out with a new batch of interns and had caught a juvenile sawfish. While we were measuring the sawfish, its tail jerked out of the intern’s hands and the base of the rostrum (saw) hit the base of my index finger just right so that it partially dislocated it.
TFUI: Oh my goodness!
GC: It popped back in fine, but unfortunately it was the first day of a week-long trip. I never realized how much lifting I did on those trips until my knuckle was screaming every time I picked something up for the next few days. In the grand scheme of field injuries it was really minor, and I don’t hold it against the offending sawfish (they’re my favorite Elasmobranch!). I’ll have no complaints if that stays my worst field work injury!
TFUI: Phew! Hopefully that stays your worst. Let's talk a little bit more about your research: do you see a difference in attitude between the Caribbean and the USA in regards to ocean conservation?
GC: St. Croix is part of the USVI, so they follow the same rules and regulations for fishing and conservation that the mainland has. In terms of attitudes, I think that no matter where you are in the world there are going to be people that care about ocean conservation and those that don’t. We need to rally those that do care to make positive change. In the last five or so years, there has been a great effort in the USVI and St. Croix in particular to learn more about what habitats are important to the fish that live there which is really vital information for fisheries management.
TFUI: What about in attitude towards elasmobranchs?
GC: When it comes to attitudes towards elasmobranchs, the Caribbean is really a mixed bag. There are some countries that are working for proactive conservation and there are other countries that don’t have particularly strong regulations. This can make effective conservation complicated when you are trying to manage very mobile species that don’t care about where humans have made borders! Most people have been pretty excited to hear about my sharks in St. Croix though so I take that as a good sign.
TFUI: Was your work in the Caribbean disrupted by the 2017 hurricanes? If so, in what way?
GC: Thanks to the wonders of the internet and my awesome collaborators, I actually do most of my work outside of the Caribbean. I am based out of Massachusetts, so I personally was not effected by the hurricanes and my Master’s timeline had a data collection cutoff set for May 2017 just before the hurricanes struck.
TFUI: That's good to hear!
GC: However, just because I had to defend doesn’t mean that it was the end of the project. My sharks are just a small piece of the Buck Island Reef National Monument spatial ecology project. There are teams in the area using acoustic telemetry to track everything from queen conch to multiple species of reef fish and sea turtles. Hurricane Irma skirted north of St. Croix, but Hurricane Maria went right over my study site. Fortunately, the staff at the National Park Service in Christiansted, who manage the Monument and all of our receivers, removed some of our shallow water receivers before Maria hit. We ended up with minimal damage to our gear, which was very lucky, and everyone that I work with made it through the storm safely, which was a huge relief. It will be interesting to look at the data we collected from the receivers that remained in the water to see if and how the sharks responded to the storm.
TFUI: Definitely will be interesting to check that data set out! I wonder if the sharks left for safer waters... so what’s next for you?
GC: I just found out that I’ve received funding to stay at UMass Amherst for a few more years, so I will be starting PhD research soon. I will likely headed back to St. Croix for another field season, this time with both satellite and acoustic tags in tow, and I’ll be starting up a new project in the Florida Keys. I’m really excited to see my little project grow!
TFUI: And we are excited for you! Congratulations!
TFUI Founder Melissa C. Marquez is author of all animal bios and "Behind the Fins" segments.
SEE MELISSA'S TEDx TALK HERE:
SEARCH BY CATEGORIES