KOTA KINABALU: The sightings of dugongs off Sabah’s coast and in marine parks several times in recent years put paid to public perception that the marine mammal may have gone extinct in the state’s waters.
Marine experts said the almost non-appearance of dugongs, also known as “seacows”, did not mean the species had been wiped out. Nevertheless, one has to be lucky to spot them.
Between 2003 and 2010, Universiti Malaysia Sabah’s (UMS) first and most comprehensive studies on dugongs showed that the species tend to inhabit a particular area. The population in Sabah is small, with about 60 individuals.
The purpose of the studies was to investigate the distribution and abundance of dugongs, while highlighting the need for urgent management of seagrass for dugong habitat and feeding ground.
Based on the research, UMS’ Borneo Marine Research Institute (BMRI) director Professor Dr Rossita Shapawi said these dugongs usually inhabit the waters off Brunei Bay and Sandakan Bay.
“Other areas, such as Mantanani Island (off Kota Belud), Banggi Island (off Kudat) and several areas in Marudu Bay, have also shown presence of dugongs,” she told the New Straits Times.
Pulau Mantanani, for example, is known for dugong sightings. Some tour operators have promoted the area as “dugong beach” to lure tourists to the island.
However, because sightings at the island have dwindled to almost none, many assumed they no longer exist.
“There is no proof of dugongs going extinct. Based on anecdotal information, dugongs can still be found in Pulau Mantanani, but sightings are rare with some local fishermen having reported seeing dugongs during the night or early day.
“The presence of dugongs in a particular area is highly dependent on the availability of food resources, especially seagrass bed. They may occasionally visit an area for feeding, especially when seagrass is abundant in a particular season,” said Rossita.
Unfortunately, she said there was no current study of dugongs by UMS researchers on Pulau Mantanani, while noting that sightings of dugongs by local fishermen were common in Brunei Bay, Marudu Bay, Bangi Island, Pitas and in the east coast.
These areas, she added, had thriving seagrass beds and fewer human activities.
Rossita said accelerating loss of seagrass bed was considered the most important factor behind the dwindling dugong population in Sabah and Malaysia in general.
“Dugongs feed exclusively on seagrass, especially young shoots and roots. Excessive sedimentation due to uncontrolled anthropogenic activities mainly of coastal development will smother seagrass bed.
“This results in the disappearance of habitat and food for dugongs. Other factors, such as accidental catch by fishermen and use of destructive fishing methods, also contribute to the direct mortality of dugongs, as well as the loss of food resources.”
BMRI researcher and senior lecturer Dr John Madin said the institute was monitoring the presence of dugongs in Sabah waters, including in Brunei Bay, based on available public reports on either live sightings, stranded or dead specimens.
“More studies have to be conducted on dugongs in Sabah waters, with particular focus on the restoration of seagrass areas. This is important to ensure that dugong habitats are maintained and well preserved,” he said.
FACTS ABOUT DUGONG
Madin said dugongs were gentle mammals and prefer to travel with companions, especially their close family which comprises at least three to five members.
He said they were usually not seen to be in close contact (with humans) but rather at a distance, adding that these mammals were active during the day.
“However, they have reportedly been seen moving at night or in the early morning, especially during their feeding trips.
“To our knowledge, in Malaysia there are few cases where dugongs have approached humans underwater.
“In such cases, the animal should be allowed to go. Do not approach them for safety reasons. While dugongs look gentle, they may turn aggressive in unknown situations, especially during their mating season,” he said on the do’s and don’ts when encountering a dugong.
The low reproduction rate of dugongs, Madin said, was among the factors leading to their low population.
He said conflict of interest with humans over the use of the same resources, such as marine environment, was a critical factor in their low population.
“This included overexploitation of natural resources by humans for various purposes leading to habitat destruction, limited food resources and nursery ground, especially for dugongs to raise their calves.
“Male dugongs usually sexually mature at about nine to 10 years, the females usually at three years.
“The duration of oestrus (state of receptivity to mating in females), being likely to be prolonged and possibly induced (i.e. suitable habitat and food availability) leads to relatively low reproduction rates.
“The estimated gestation period for dugongs is about 13.9 months. Most single calves are born during a particular time of year, but it usually coincides with food abundance (seagrass). Their lactation period can last at least 1.5 years, but a calf remains close to its mother for up to two years,” he said.
Noting that dugongs were large in size, John said these mammals were long-lived animals with maximum estimated life spans of between 70 and 75 years.
They could spend around 49 per cent on their daily activity time on feeding and could eat up to 10 to 15 per cent of their body weight in vegetation daily.
“Some favourite food of the dugong includes Halophila sp. and Zostera sp. (types of seagrass), which are seasonally abundant in Sabah waters.”
The dugong is a totally protected species under Schedule 1 of the Wildlife Conservation Enactment 1997, which puts this marine mammal in the same totally protected category with pangolins, Sumatran rhinoceros, orang utans, sun bears, proboscis monkeys, clouded leopards, green turtles and hawksbill turtles.