1. ‘Dugongs – Biology and Sri Lanka Conservation Issues’By
Ranil P. Nanayakkara
IUCN Sirenia Specialist Group Regional Member – Indian Ocean
Co-founder/Principle Scientist BEAR (Biodiversity Education And Research)

2. Dugongs belong to the Order Sirenia, which includes the Manatees

3. Relationship between Sirenians and elephants (mtDNA)
Asian elephant
African elephant
tmammoth
tmastadon
tStellar’s sea cow
Dugong
Ancestral
mammals
West Indian manatee
Brazilian manatee
West African manatee
Other mammals 80 60 40 20
Million of years before present

4. Dugongs and other Sirenians are not closely related to other marine mammals, being more related to Elephants and Hyrax.

7. Differentiating the dugong from the manatee

10. The dugong Order: Sirenia Family: Dugongidae
Scientific Name: Dugong dugon
English Name: Sea Cow or Dugong
Sinhala Name: Muhudu ura
Tamil Name: Kadal pandi or Averya
The Dugong is the only surviving member of the Family Dugongidae, which was once a diverse family. Its closest relative the Steller’s Sea Cow (Hydrodamalis gigas) was hunted extinction in the 18th century.

11. Discovered in 1741, extinct in 1768 – 30ft, 4.4 tons

12. Dugong facts
Low reproductive rate, low generation time and a very high investment in their young
Gestation is between months, calf is dependent on the mother for months
Inter calving interval may very from years
Dugongs have only six vertebrae while most other mammals have seven. Dugongs have only six vertebrae while most other mammals have seven.
Published data show that a dugong can travel >1,000 km

13. The dugong in history
Archaeological excavation carried out in Manthota, an ancient sea port in the Mannar district , fragments of dugong bones have been unearthed from stratified layers dating back 3000 years before present.
Microliths, mostly stone implements together with dugong bones suggest that so called aborigines of Sri Lanka viz., Yakas, Nagas, Rakus and the Asuras were used to eating dugong meats, before the arrival of the north Indian prince Vijaya and his entourage.

14. Excavation at Jetavanramaya Vihara complex (4th-5th Century AD) yielded an artifact curved out of dugong bone that resembles a male genital.
Miodugong brevicranius

15. Millet (1914) states that dugongs are caught in the large shallow lagoons near Trincomalee

16. Being grazers the front teeth are replaced by a heavy, horny, rubbing pad, there remains only vestiges except for upper incisor tusks in the male, the premolars are degenerate, and the permanent set never develops. While the molars are large and, with a wrinkled surface and many bunodont cusps, superficially resemble those of pigs or the bunomastodonts (they do not have canines, but only incisors (the first pair is tusk-like in males) and molars

17. Cymodocea serrulate
Enhalus acoroidea

18. Halodule uninervis
Halophila ovalis

20. Threats Natural Predators – Tiger Sharks and Killer Whales
Dugong are prone to adverse weather e.g. hurricanes, cyclones etc.
Human induced threats

21. Bottom set gill net (Madu del)
The two types of gill nets , that dugongs fall victim to.
Bottom nets (madu-del), gill net (bottom and high) inch mesh size and also 5-6-inch mesh.

22. Bottom trawling

23. Dynamite fishing

26. Iranaitivu and Silavathurai are dugong hotspots
During the first few months of the year, females and young have been taken in Feb and March
Found near to the shore during the southwest monsoon
Largest haul is during the monsoon months of May, June, July
So far in 2017, 17 dugongs have been killed (4 pairs of mother and calf)
Our research has shown that at least one dugong is killed every month

28. What Can You Do to Help Save the dugong???????
Find out all you can about the dugong and share the knowledge with others
Join a conservation group that is working to protect dugongs
Join a clean up campaign in your area to keep our waterways clean
Find out about laws to protect the manatee. Write to lawmakers and ask them to do more.

29. Thank you !!