A Day in the Life of a Manatee Researcher

The following pieces were written by Caryn Self Sullivan and published in her and Katie's manatee newsletter over the last year.

We idled into one of my favorite coves at the end of Bogue C in the Drowned Cayes, Belize. The Drowned Cayes are a group of mangrove islands between Belize City and the Belize Barrier Reef in Central America. We have come here at least 6 times before and ALWAYS, there has been a manatee resting in the manatee hole on the far side of the cove. As if on cue, before we could even cut the engine and anchor the boat… a single manatee surfaced near the manatee hole. Within minutes a second manatee surfaced in the middle of the cove. Two minutes later, a third animal enteredthe cove. "WOW!” I thought to myself, “this must be a popular resting cove." But, the two animals in the center of the cove were too active – they were NOT resting. I didn’t think they were feeding, either, because previous habitat snorkels found NO sea grass on the bottom. Another four minutes passed and two more manatees swam under the boat to join the active pair in the middle of the cove.

"This is great," I told the volunteers, "we'll be able to see how long it takes them to settle into a resting pattern". But they didn't settle. For the next hour we watched the four manatees in the middle of the cove breathe, roll, dive, and kiss while the first animal appeared oblivious to all the activity less than 50 meters away. I believe we observing a mating herd? When manatees mate they form mating herds which consist of a group of male manatees pursuing one female. Daniel Hartman, who was one of the first people to study manatees in the wild, observed them during his groundbreaking research in the late 60’s. One of the things that we are trying to determine in the Drowned Cayes is when and where do manatees form mating herds.

The Drowned Cayes, Belize -15 January 2001

We identified another manatee today. This animal has the most severe mutilation we've seen, yet. Here's the story…
We idled into an arm of Bogue D just in time to see a manatee swimming very slowly away from us. There is a shallow lagoon at the end of this arm and we suspected that the animal was moving towards the lagoon to avoid our boat. As you will recall, the Drowned Cayes are a group of mangrove islands located between Belize City and the Belize Barrier Reef. These islands are riddled with small channels, coves, and lagoons where many elusive Antillean manatees feed and rest. The water was tannic, but clear and the animal seemed to settle down in a resting hole near the entrance to the lagoon. I entered the water with an underwater video camera to try and get an image for our Manatee Photo ID Catalog. The animal swam away from me at first, then turned and swam under me as I floated like a log on the surface.

At first I thought it's paddle shaped tail was completely covered with mud, but as it came closer, I realized that the paddle had been cut off! Review of the video revealed two extremely large slices across the peduncle (the narrow section between a manatee's body and it's tail) and anterior paddle that appear to be propeller scars. The cuts were well healed and scar tissue was present, indicating an old injury. But, 90% of the paddle is missing! Functionally, this animal has lost its primary method of locomotion. Our Earthwatch Volunteer Research Team decided to name this manatee "Yamaha" because Yamaha makes most of the small boat engines in Belize. But, a much larger propeller - possibly on a tugboat or cargo ship - caused this extreme mutilation. We will keep a sharp eye out for "Yamaha" and let you know if we see him/her again

I snorkeled up to an Antillean manatee feeding underwater just west of The Drowned Cayes, near Belize City – at first, I thought it was dead... I can still recall the adrenaline rush as options flashed through my mind regarding what to do with a dead manatee! It was lying perfectly still on the bottom in about 3 meters of water and appeared to be missing its head. As I floated closer, (heart racing) I began to hear chewing noises and realized that the manatee had buried its head into the muddy bottom and was feeding on the sea grass roots. I soon learned that this is typical of how manatees feed on the sea grass beds near the Drowned Cayes - eating both roots and leaves and probably other benthic organisms living in the mud. Looking for muddy disturbances became another method of finding the elusive manatee.

If you’ve ever tried to dive down and recover a lost item in deep water, you know that you, like most mammals, are positively buoyant and must work to get and stay submerged. Manatee bones are pachyostoic -- very dense and lacking marrow -- except in the vertebrae and sternum. Because of this, manatees are negatively buoyant and can lie on the sea bottom without exerting any energy to stay down. The less energy they use, the longer manatees can remain submerged between breaths - making feeding more efficient. Indeed, we think manatees have the ability to control the volume of air their lungs, enabling them to rise to the surface, take a breath, and return to the bottom with no noticeable effort.

While on a break from our Earthwatch Manatees in Belize project in the Drowned Cayes of Belize this spring, I had the opportunity to help Buddy Powell with his manatee tagging project in Southern Lagoon. Powell’s project is funded by Wildlife Trust. You may remember that two Belizean manatee orphans, Woody and Hercules, were rescued in Belize several years ago. They were soft-released into Southern Lagoon last year after almost two years of care by the Belize Stranding Network.

The final piece in the rehabilitation process was to tag and release the orphans in to Southern Lagoon – a natural manatee habitat, protected by both legislation and local residents. So, with Powell’s help, Woody and Hercules were fitted with radio transmitters and released. Their movements are monitored daily by Mesha Gough and Kevin Andrewin. Gough is the resident manatee scientist in Gales Point Manatee, a small village located on Southern Lagoon, and Andrewin has been working with the manatees there for over 5 years.

During my visit to Gales Point Manatee, I had the opportunity to observe both Woody and Hercules up close and personal! We captured both orphans to weigh and measure them, take blood and urine samples, and change out their transmitters for continued tracking. Both animals were pronounced healthy by Bob Bonde, the visiting scientist from Florida, and Alejandro Ortega-Argueta, the visiting veterinarian from Mexico. Bonde and Ortega have been monitoring Woody and Hercules’ health since they were rescued over 2 years ago.

The rescue, rehabilitation, release, and continued monitoring of Woody and Hercules is just one example of the dedication to manatee conservation by Belizean people. Belize may be the last stronghold for Antillean manatees in the Caribbean and we are proud to play a small part in the Nationwide Manatee Conservation Program.