Updated: Oct 28, 2020
Dugongs Dugong dugon are peaceful and tranquil animals. They appear fat, but are in fact fusiform (being they have a wide middle and taper at either end). They are hydrodynamic, and highly muscular, reaching up to 3 meters in length and weighing up to 500 kg. They are exclusively bottom feeders, primarily feeding on sea-grass and aquatic vegetation which they uproot by digging furrows in the seafloor with their snouts. The species' preferred habitats include warm and shallow coastal waters, with healthy ecosystems that support large amounts of vegetation.
As mammals, Dugongs regularly surface to breath and dive to feed, explore, rest or travel. The reproductive cycle is characterized by a long gestation period of 13 months, after which the female will give birth to a single calf that will receive considerable parental care until it reaches sexual maturity. This is believed to be between aged 8 and 18 years. Dugongs can live for up to 50 years (sometimes more), but because of the long effort invested in their young, females only give birth a few times during their life span.
Dugongs descended from terrestrial mammals that grazed in shallow grassy swamps during the Eocene and their closest modern relative is the elephant. Their smooth skin is slate-grey in colour and their bodies are more stream-lined than manatees, with a fluke-shaped tail and a pig-like head. Calving occurs in the shallow waters of tidal sandbanks. A newborn calf usually measures approximately 1.2 metres long, weighing 30 kg and relies primarily on its mother’s milk for up to 18 months.
Our knowledge of the social behavior of dugongs is fairly rudimentary. The habits and habitats of dugongs make them difficult to observe and the lack of distinct size classes or obvious sexual dimorphism limits the data obtained from direct observation. The only definitive long lasting social unit is the cow and her calf.
As stated above, Dugongs feed primarily on sea-grasses. Recent studies indicate that they prefer sea-grass species higher in nitrogen and lower in fibres such as Halophile ovalis. They can manipulate sea-grass beds to encourage regeneration of fast-growing pioneer species, which is preferred. Maintaining a highly palatable area of food has been coined ‘cultivation grazing’. They generally uproot whole plants producing distinctive feeding trails. Like the hippopotamus, which supplies freshwater habitats with up to 50 kg of processed plant material a day, the dugong also recycles marine meadow nutrients (although the extent of the importance of this ecological process is yet to be quantified).
Sea Cow feeding on Sea-Grass
Dugong movements have been tracked in studies using VHF and satellite transmitters. Most movements are within areas of sea-grass beds and are dictated by the tides. At the southern limits of their range, dugongs make seasonal journeys to warmer waters. Both short-distance movements (between 15-40 km a day) and long distance movements (up to 600 km) have been recorded, highlighting the importance of international collaboration in their management.
The Sea Cow Dugong dugon Distribution map
Dugongs can be located all over the world, with an extensive range spanning at least 37 countries and territories. Their range occurs in association with coastal and island seagrass beds in the tropical and subtropical waters of the western Pacific and Indian Oceans. Approximately 85,000 of the world’s dugongs are located in the inshore waters of northern Australia. This is thought to account for at least three quarters of the global population (possibly considerably more!). Elsewhere, populations are small and fragmented and in some areas, such as Mauritius, the Maldives and parts of Cambodia and Laos, dugongs have already disappeared. Dugong meat tastes like beef. Dugong hunting for food and oil was once widespread throughout the dugong’s range and still occurs in at least 31 countries. However, thanks to global conservation efforts, today the dugong is legally protected in most countries.
Old photo from Dr.Hamed Gohar's collection of Egyptian fishermen hunting Sea Cow
Photo courtesy of the National Institute of Oceanography and Fisheries - NIOF | Hamed Gohar Research Station
Dugongs in Egyptian Red Sea
In 1957, an Egyptian biologist, Dr.Hamed Gohar published the first scientific study of dugongs in the Red Sea. There is evidence that the animals were known and hunted by ancient cultures in the area and, in fact, were legally hunted in Egypt until just a few decades ago. There is limited information on dugong distribution and abundance along the African Red Sea and the situation of the Egyptian Red Sea is still relatively unknown as well. However, several Egyptian locations have become increasingly popular for the presence of resident individuals or groups of dugongs, and as consequence, continue to attract increasing amounts of tourists. More tourism is leading to increasing construction along the coastline of Egypt which is negatively impacting the dungongs natural habitat habitat, as it causes alteration and degradation. A series of community-based management initiatives should be undertaken to protect the species, including the conservation of coastal sites where the dugongs exist or are likely to be present.
Code of Conduct and Best Practices for Scuba Diving and Snorkeling
Do not attempt to touch, ride, or chase a Sea Cow.
Do not restrict normal movement or behaviour of the Sea Cow.
Maintain a minimum distance of 3 to 4 meters from the Sea Cow.
Take plenty of pictures but avoid flash photography which can scare the Sea Cow. Photograph any characteristic features which may help re-identify the Sea Cow in the future.
Do not use underwater motorized diver propulsion.
Avoid underwater acoustic signaling devices.
Limit your observation to a maximum time of 30 minutes.
Groups of swimmers should stay together and ideally remain at the surface.
Don not conduct any Skin diving / Free diving near the Sea Cow.
Don not feed the Sea Cow.
Scuba divers Should keep safe distance from the bottom and DO NOT move the sand or sit down on the Sea-Grass.
DO not throw litter onto the beach or over the side of the boat before or after diving / snorkeling trips.
Pick up underwater litter that looks fresh.
Report any violations to the authorities.
Important note for Boat Captains, Zodiac / Speed boat skippers
Code of Conduct and Best Practices for Boating
Dugongs are believed to be the most endangered large mammal on the African continent, and in East Africa, there is growing concern that they are in grave danger of local extinction unless immediate conservation measures are taken. Dugongs are listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and classified globally as ‘vulnerable to extinction’ due to a population decline of at least 25% in the last 90 years (IUCN, 2000). Their habitat requirements and slow rate of reproduction render them particularly vulnerable to anthropogenic activities, and they are threatened by hunting, incidental net captures, pollution, coastal development and disease.
It is hoped that this document will initiate the process of wider public awareness of the plight of dugongs in the Egyptian Red Sea. There are many ways this could be achieved either nationally or locally. Educational materials on aspects of dugong conservation and methods to minimize incidental catches could be developed. Information should be disseminated through district authorities and the existing network of marine protected areas and conservation projects along the coast and via the media. At the local level, especially in key fishing villages and touristic resorts, education activities should be enhanced with the support of the Egyptian Government and district authorities via public meetings e-learning platforms. New roles that suites the current situation and should apply; Continues education, proper management and monitoring are a MUST.
Author: Ahmed Fouad
RED SEA PROJECT™
Download your FREE copy in High-Resolution of the Code of Conduct and Best Practices for Scuba Diving and Snorkeling / Boating and more from our E-Library on the Red Sea Dugong Project section.