x Abu Dhabi, UAESunday 23 July 2017

Satellite study to shine light on threatened sea creatures

Marine researchers devising ways to better protect the dugong, or sea cow, are using tracking devices to monitor their movements.

A dugong rubs a sunken coconut tree log to scrape off parasites .
A dugong rubs a sunken coconut tree log to scrape off parasites .

Satellite transmitters attached to three dugongs off Abu Dhabi's Buthina Island are giving scientists new insight into the lifestyle and habits of the shy sea creatures. Although the study by scientists at the Environment Agency-Abu Dhabi (EAD) began only in mid-December, it has already yielded its first results. After two weeks spent adjusting to the transmitter, one of the three dugongs resumed its routine and travelled 30 nautical miles from the site where it was captured.

The other two remain in the Buthina area, probably still getting used to the hardware. "This is only entering the second week and it is early to say much," Dr Thabit Zahran al Abdessalaam, director of marine biodiversity management sector at EAD. "But the news we are getting so far is very exciting." The study aims to track the animals, which are part of the second-largest population of dugongs in the world, throughout the coming months.

The research will help scientists examine the dugongs' migratory patterns, range and how they use their habitat, and also attempt to find out more about the structure and distribution of the dugong population throughout the Arabian Gulf. That sort of information is hard to come by using more traditional methods of study, according to EAD scientists who have been studying Abu Dhabi's dugongs since 2000.

"Dugongs are very shy animals and it is difficult to observe them in the field," Dr al Abdessalaam said. More dugongs could be tagged if things go well with the first three. The first of the dugongs was caught Dec 13, the others two days later. They were tracked by a helicopter crew that signalled to a team on the water in a small inflatable boat. When the dugongs swam to the surface, they hauled them onto the boat and attached a transmitter to their tail ends. They also measured each mammal and took a small skin sample for DNA testing before releasing it back into the water.

Although it has been rare, animals in other countries have died after being chased and captured, making the first part of the study the most crucial. "We did not want to stress the animals and we wanted to make sure we do not cause any harm," said Dr al Abdessalaam. "In the end it went smooth and it was very easy to catch them." The satellite transmitters, which are manufactured by the US company Telonics, cost US$6,000 (Dh22,000), weigh half a kilogram and are made of fibreglass. Each transmitter is powered by batteries due to last six months, and is tied to a three-metre cable that trails behind the dugong.

Pitching in on the study are experts from James Cook University in Australia, one of the world's leading institutions in the field of dugong research. The DNA samples taken in Abu Dhabi will be compared to those from dugongs in Australia; EAD has agreements to do similar genetic comparisons in Kuwait and Qatar. Dugongs are listed as vulnerable to extinction by the International Union for Conservation of Nature.

The creatures can be two to three metres in length, weigh up to 400kg and live for 70 years. Their skin is deep grey or brown and they have a flat, two-pointed tail that propels them through the water. They are herbivores that eat mostly seagrass. They can eat the equivalent of 15 per cent of their body weight in one feeding, earning the nickname "sea cow". Dugongs are found in tropical, subtropical coastal and inland waters of the Indian and Pacific Ocean, off 37 countries and territories.

The Arabian Gulf and Red Sea also host an estimated population of more than 7,000 dugongs, the largest population outside Australia. About 40 per cent of this population can be found in Abu Dhabi waters, making the UAE particularly significant in terms of global conservation efforts. Abu Dubai is attractive for dugongs as almost all sea grass beds in the UAE are here. Dugongs are protected under UAE law, and anyone found to be harming them can be prosecuted and jailed.

The fishing industry used to be the main threat to dugongs, as the animals were targeted deliberately or accidentally caught in drift nets. While new regulations have helped to protect them on that front, the most recent threats to their survival come from coastal development, seismic activity from the oil industry and oil pollution. vtorodova@thenational.ae