Researching the demise of the dugong
The reclusive dugong, the animal that seems to be everyone’s friend, is falling victim to poor fishing practices
Channa Suraweera was shocked when the picture of a dead dugong jumped into his eyes for the first time. Seeing the thick red vestige under its nose indicated how blood would have spurted through its nostrils, says Suraweera, an officer with the Wildlife Conservation Department in Sri Lanka.
“It must have been an extremely painful death. Three dugong deaths have been reported since the beginning of this year, all by Sri Lankan Navy.”
The dugong, a medium-sized marine mammal, can be seen in aquariums around the world, their chubby face, gentle eyes and what seems like a permanent smile endearing them to millions. However, outside the haven that aquariums offer, in many waters that the creature used to call home dugongs have been hunted down to extinction or near extinction.
The waters of Sri Lanka are no exception, including the Gulf of Mannar, a large shallow bay between the southeastern tip of India and the west coast of Sri Lanka.
“Every two months or so we lose an animal,” says Arjan Rajasuriya, of the International Union for Conservation of Nature. Since January 2015, Rajasuriya, who is based in Sri Lank a, has been part of a project in which the United Nations Environment Program teams up with regional and international NGOs and the Sri Lankan government in an effort to protect the endangered species.
But if the dugong is to be protected properly a lot more needs to be learned about the animal, which is notorious for its reclusiveness.
Among the main goals of the program, known as the Dugong and Seagrass Conservation Project, is to map sea grass meadows, the sole habitat and source of food for the vegetarian marine mammal that lives in the shallow seawater off the coast.
“The dugong subsists on sea grass — no sea grass, no dugong,” says Rajasuriya, who has been involved in protecting Sri Lanka’s coast for more than 30 years and yet, astonishingly, has never seen a live dugong in the region.
“On the other hand, the existence of large patches of sea grass meadow, especially those with grazing signs, could be a strong indicator that there are dugongs around.
“With all the mapping we have done and will do — scuba divers are sent to measure the extent and density of the meadows — we are trying to set up a database which would then inform our protection efforts.”
One crucial factor behind the dramatic decrease of dugongs is the destruction of sea grass meadows, often by bottom trawling. Another factor is dynamiting, an illegal method of fishing. Typically, with dugongs killed by dynamiting blood spurts from their nose, in the kind of scene that so shocked Channa Suraweera.
“Bottom trawling is a fishing method whereby the fishnet is towed along the sea floor, damaging everything along the way,” says Laksman Peiris, deputy director of Wildlife Conservation Department. “Ninety percent of dugong killed is killed by this net.
“Though not encouraged, bottom trawling is legal in Sri Lanka. The fishermen may not be aiming for the dugong, but a dugong caught accidentally by the fishnet has a slim chance of survival. That’s because dugong, being a mammal, has to come to the surface of the water every six or seven minutes to breathe. Being caught by a net that lies at the bottom of the ocean, a dugong has no choice but to die a terrible death.”
Suraweera, who once examined the body of a dugong killed by bottom trawling, has an acute sense of what a terrible death means. “Its lungs are filled with water. Can you imagine water seeping gradually into its lungs while the animal struggles desperately but in vain?
“A fisherman, after throwing his net into the ocean, only comes back every half or one hour to examine his catch,” says Prasanna Weerakkody, of the Oceans Research & Con-
Fishermen may not be aiming for the dugong, but a dugong caught accidentally by the fishnet has a slim chance of survival.”
servation Association, a Canadian NGO with a Sri Lankan presence which is also part of the dugong project.
“By that time the dugong may have already died. Even if it’s not dead it’s almost impossible for the fisherman to release the dugong since that means cutting off the entire net and losing all the catch.”
Asked why the government has not required the fishermen to release the dugong and then be compensated for their loss, Suraweera says this is because the dugong, once released, will swim away. “You have to prove that you have indeed caught a dugong.”
Mobile app
However, this concern doesn’t seem like a big issue, bearing in mind that for the past few months the Wildlife Conservation Department has been promoting a mobile app that enables users to take a picture of a dugong wherever they see it and then report the sighting directly to the department.
“The app can be downloaded by any mobile using the Android system,” Suraweera says. “And we are actually giving free mobiles to fishermen operating within what we believe are dugong-active waters. We also have four other categories: dolphin, whale, turtle and unknown. Initially we planned to have a separate category of illegal fishing but later vetoed the idea, since this may ring alarm bells for fishermen and alienate them.”
Weerakkody warned that to achieve any success with the local community, sensitivity is of crucial importance.
“We’ve done research with the local fishermen community. Every time our research team goes into a village we pretend to be someone else — a film crew, for example. And in the initial period we will not show any interest in dugong — just getting to know the villagers and
building trust. We’ll get to our point eventually, but even if someone tells us something that’s really important, we’ll never give out the source.”
Modern technology
TheOceansResearch&Conservation Association team is also trying to track down dugongs with the help of modern technology, sonar for example.
“Sonar, which stands for sound navigation and ranging, is a technique that uses sound propagation for the purpose of, among other things, underwater object detection,” Weerakkody says.
Once a moving object of roughly a dugong’s size — an adult dugong measures up to three meters — is detected, the team sends underwater divers, or a drone, which is essentially a flying camera, to verify it.
“It’s impossible to send the divers during the monsoon season when the sea gets choppy,” Weerakkody says. “As to the drone, we have adapted one that was once used for filming weddings. We would like to have a more advanced one, one used for military purposes, for example. But that would be simply beyond our means at this stage.”
The drone, bought with project money, usually flies to a height of 500 meters. When the sea is clear it can film objects lying as deep as five meters underwater.
“But sometimes, dugongs can be staying somewhere deeper in the ocean — ten meters underwater maybe — and that would be hard for us,” says Weerakkody, who, when asked, says he would also love to have an underwater drone.
Both the sonar and the drone can also be used for mapping sea grass meadows.
Peiris says that most of the time a dead dugong will end up in some black market in Sri Lanka where, weighing between 250 kg and 400 kg, it is chopped up and sold, possibly to local restaurants.
In fact in the early 20th century there was a fishery for dugong in Sri Lanka. One hundred to one hundred fifty dugongs were taken annually in the Mannar Gulf in the 1950s. The Sri Lanka Civil War, fought between 1983 and 2009, meant that the surrounding waters were closed off for three decades. The end of that war was welcomed by animal protectionists with mixed feelings.
“These days thousands of fishing boats that use bottom trawling pass by the same water over one night,” Suraweera says.
“With its long life span of 70 years or more, and slow rate of reproduction, the dugong as a species is especially vulnerable to extinction. I’ve seen dugong bodies — adults’ and babies’. I hope that one day I can see a live dugong, and that would be lovely.”