Dugongs in the Red Sea and Gulf of Aden

By Dirar Nasr

The sirenians (sea-cows) are a group of marine mammals including the manatees (Trichechidae) and the dugongs (Dugongidae). The only sea-cow occurring in the Red Sea and Gulf of Aden region is the dugong, Dugong dugon. It is a quiet, harmless animal found in sheltered, isolated, shallow bays and lagoons with seagrass beds on which it feeds.
Dugong distribution in the Red Sea is not continuous; populations are found in isolated channels and bays. They are rare but occasionally reported from the Gulf of Aqaba, scarce in the Gulf of Suez, reported regularly but are not common in the Sudanese Red Sea, and are very rare along the Eritrean coast. In Saudi Arabia the distribution of dugongs is concentrated in three locations: the Wejjh Bank, the Al-Lith area, and the Gizan area.
Fishermen interviewed during March/April 1994 at Suez, Hurghada, Al-Wejjh, Rabigh, Tuwwal, Jeddah, Al-Lith, Gizan, Farasan, Hodaidah and Aden have generally confirmed this distribution. Their reports also support the opinion of many research workers that dugongs prefer undisturbed, isolated areas with abundant seagrass beds. Moreover, several of the fishermen suggested that dugongs move from one place to another according to food availability, in the same way as camels. Some regular daily movement between feeding grounds and deeper waters has been reported and it is suspected that photoperiod or tidal changes are the triggers for this activity. Aerial surveys indicate that dugongs migrate though conclusive evidence of extensive or regular migrations is not available.
Optimal dugong habitat has the following characteristics: sea water of 2 - 8 fathoms; shelter from rough winds and heavy waves; an abundant food supply, and water temperature between 21° and 38°C. With the exception of the Gulf of Suez, the temperature of the Red Sea falls within this optimal range. It is well known that dugongs are herbivores feeding on seagrasses and therefore the distribution and abundance of suitable seagrass habitat may be the most important factor determining dugong distribution and abundance.
Seagrass beds tend to occur on soft-bottom substrates in the lower intertidal and shallow sublittoral. Such soft-bottom substrates are restricted in the northern Red Sea by the extensive fringing reefs that drop-off steeply into deep water. Thus the northern seagrass beds are restricted to the shallow, soft-bottom areas of sharms or to intertidal and submarine wadi outwash-plains. By contrast, in the southern Red Sea the continental shelf is both wider and shallower and the sedimentary substrates which favour the development of extensive seagrass communities are more abundant.
The distribution of dugongs matches very well with the availability of seagrass beds; they tend to occur in isolated pockets of suitable habitat in the north and to be more continuous in the south where the inshore environment is more sedimentary.
At present dugongs are not deliberately targeted by fishermen from Egypt, Saudi Arabia or Yemen. If however they are accidentally caught in nets, their meat is eaten. This also occurs in Sudan, Eritrea and Djibouti where it is said that 'the meat is so tasty it cannot be differentiated from cow's meat'.
In Egypt dugong skin has been used in the manufacture of shoes. In Sudan dugongs have, in the past, been hunted from small boats. While the flesh was consumed, the tough skin was also utilized, being used to cover the shields of some of the local Beja tribesmen. When the skins become dry, they are as hard as stone.

This article appeared in Al Sambouk No. 10, October 1999. Al Sambouk is available in PDF format in the Library.