Finding the best hangout spot for manatees in Cuba
Unlike the manatees in Florida, the Carribean manatees don’t need to congregate in warm water areas during the winter to stay warm. In Cuba it is warm all year long. The Carribean manatees like to hang out in two main lagoons.
For her Master’s thesis Mindy is using side-scan sonar to create a sound image of the lagoons these manatees hang out in. She also assists her collaborators at University of Havana with manatee capture attempts. These creatures weight up to one ton!
Cindy Wu: Mindy, tell us more about yourself.
Mindy McLarty: I’m a first year master’s student at Andrew’s University and I’m studying biology and particularly interested in the areas of ecology and conservation biology.
How did you first get interested in Ecology and Conservation Biology?
I’ve always liked science and being outside. When I went to college I didn’t know what I really wanted to do, so I took a foundations of biology course and I fell in love with biology and ecology.
What were some of the things you really loved doing outside?
Hiking, birding, and looking for animal tracks. We used to go into the mountains where there was a mountain stream. We used to love playing in the water, building dams just generally being outside getting dirty.
You grew up in Southern California?
70 miles east of L.A.
Did you find many animal tracks?
Yeah. We live on the edge of a state park. When I was in high school I used to just go out there all the time when I wasn’t at school.
What types of animal tracks would you find?
Coyote, bear occasionally, deer, bobcat, a skunk or raccoon.
What were your first research experiences?
I worked for two years with a professor that works with seabirds in Washington State. I spent a couple weeks out there during the summer helping them with their research. The last summer of college I went to Cuba to work on the project that I am working on now. Originally, I was going to help my professor with the project and it just kind of gradually became my project.
What are some of the biggest challenges of working in Cuba?
The biggest challenges are with equipment because we have to bring all of our equipment with us. Once we are down there if something breaks or stops working it is almost impossible to get any sort of repairs or replacements. Repairs in general take a long time. If we need to replace something then we have to bring it in from outside the country. That’s really hard to do.
Did your team start this project before Cuba was open to United States tourists?
I didn’t go to Cuba before it was really open. My adviser went the year before to see if the project was going to work and talk with the scientists in Cuba. He did some background research before we started the project.
And that was before Cuba was open to United States visitors?
That was in 2014. Before they opened up to tourists, it was still open to researchers.
Last time that you were out in Cuba, what were you working on?
We were working on a pilot study for this project. We went down and used sonar to characterize the habitat. We go out on a small power boat into two different lagoon systems. We used sonar to look at the floor of the lagoons and find out what was on the bottom, to see if it is covered in seagrass or mud, or if there was coral or rock. From there we are hoping to figure out why manatees are using these two lagoons. We also help our collaborators with manatee capture attempts. That was a lot of fun to actually see the manatees.
Can you explain to people what sonar is?
We use side scan sonar. This is different more traditional sonar which is down scan sonar. Down-scan sonar uses one beam that sends a sound signal out into the water and then it bounces back off of hard objects. With the side scan sonars there are two beams so you look sideways as well as just straight down. This is useful because you can do a wider strip instead of just what’s right underneath your boat. And it also helps us look at what’s on the bottom so that when you can’t see through the water because it’s dark or because it’s too deep, or whatever the case may be it lets you see visually what’s on the bottom. It’s not actually a picture, it’s a sound image.
From what image you can tell whether or not there’s sea grass or coral on the bottom?
Yeah, the harder an object is the brighter it appears in the sonar. So if it’s something like rock it’s going to show up as really bright. If it’s softer like mud it’s going to show up a little lighter. It varies. Taller objects like sea grass show up as kind of fuzzy and then also cast shadows.
You scan two separate lagoons because you knew those were areas that manatees were hanging out?
A year or two ago, our collaborators from the University of Havana tagged a couple of manatees with satellite tags so they could track the manatees’ movements. Once they plotted the manatees’ movements on a map, they realized the manatees spending a lot of time in two particular lagoons. We’re looking at those lagoons to see how they are similar and how they are different, what makes them special, what resources are there, why aren’t other manatees using other areas?
And you said you’re also helping with the manatee capture attempts?
There are different ways to do it, depending on where you are. In this particular case there is a river that flows into one of the lagoon systems from kind of a swampy area. It is a dead end channel, but there is fresh water back there. Manatees need fresh water for drinking. They go back to drink and we try to get there in the morning and put a net across the channel. Then we send a smaller boat out there to
the end of the channel and try to make a lot of noise and get the manatees to swim down stream. They don’t like a lot of noise. The manatees make it down into the net. Once we’re they’re in the net, we pull them up onto the boat.
When you capture them, what are you looking for?
They are doing a study on the morphometrics, so how big they are, how long they are, etc. They are also trying to do a survey to see how many manatees there are and what the group composition is. We want to know how old they are, the female male ratio. Sometimes they catch calves. That’s useful so we know that they’re actually reproducing. They also take fecal samples and genetic samples so that they can do a genetic study in comparison with other managed populations from the Carribbean and Florida. The fecal sample can tell us what they’re eating, if they have parasites, all that kind of stuff.
How much does a full grown manatee weigh?
They can weigh up to a ton.
Tell us more about your summer project. What are the main goals?
The main goal this summer is to complete the characterization of the lagoon system using sonar. We weren’t able to finish last year because we ran out of time. They are big lagoon systems and they just take a long time to do, so that is priority number one. The data analysis will take place later.
Once you have finished that how do you plan to share the results?
I’m going to be writing my thesis to start with. That’s step one. And then we’re hoping to be able to publish some of the results. We’re not sure where yet, but we would like to publish them.
What is the main difference between the manatees in the Caribbean vs. Florida?
They are two different subspecies. The ones that live in Florida are a little bit stockier, a little bit thicker because they live in a little bit of a colder climate. You think about Florida, you don’t really think of it as a cold climate, but compared to the Caribbean it is a little bit cooler. The Florida manatees have to congregate in warm water areas during the winter so they can stay warm. They have the added danger of being cold stressed, so they can actually get like skin diseases and sometimes they can actually die getting too cold. The Caribbean manatees live in area that’s basically warm enough all year round they, so they don’t have to congregate like that.
Do the manatees travel between Cuba and Florida?
They are capable of traveling between Cuba and Florida but they don’t do it commonly. There has been one confirmed sighting of a Florida manatee in Cuba with a calf that has been written up. It’s not that far between Cuba and Florida so they can make it. It’s just they don’t usually go that far. They’re not open ocean animals they tend to stay closer to the coast.
Last two questions. If you could give a piece of advice to a younger version of yourself what would it be?
I’d say to get a little more experience in different fields do some more research projects or shadowing to really get a good feel for something before you jump into it. I don’t think I’ve been disadvantaged going the way I have been, but it helps you to really realize what’s out there and what a good fit for yourself might be. Make your horizons as broad as possible.
When you were a kid what did you want to be when you grew up?
Oh my lots of things! I started out wanting to be a veterinarian, and then I thought about being an elementary school teacher for a while, and then a doctor, a nurse, a wildlife photographer, a coast guard pilot. I mean you name it I’ve probably thought about doing it. Once I was in college I started leaning toward biology and biological research, wildlife biology that type of thing.
I’m really excited about this project and really excited to be going back to Cuba. I liked working there. I really liked the people there, so it’s a unique place to work and it’s a cool place to work.
If you have more questions for Mindy, you can ask her directly on her Experiment. You can also support this summer field trip to Cuba, and Mindy will keep you updated on the team’s progress by email.
