Updated: Jan 20
Commonly referred to as ‘sea cows’, dugongs are gentle giants which feed on seagrasses which grow along shallow coastlines of the Indo-pacific. Although the name of ‘sea cow’ is typically attributed to dugong, other herbivorous sea mammals belonging to the same order Sirenia, such as the North American manatee (check out the assembly page here), have also been referred to by the title.
Dugongs are large aquatic mammals which can grow up to 4 meters in length and a ton in weight. Given their size, it is perhaps unsurprising that their closest living land relative is the elephant. Adults do not have any natural predators, although calves may be targeted by killer whales and saltwater crocodiles. Dugongs are exclusively marine creatures, and do not enter freshwater regions.
Like their nickname implies, dugongs mainly feed on seagrass. They are picky eaters, however, preferring easily digestible low-fiber seagrass with high nitrogen content. They also dislike eating from ‘meadows’ where seagrass is abundant, instead opting for sparse areas. Contrary to the vegetarian implications of their nickname, some dugongs are omnivorous. E.g. dugongs living along the Australian coast have been known to feed on jellyfish and shellfish.
Dugongs live in coastal regions from the western Pacific Ocean to the eastern coast of Africa, but most of the world’s dugongs are currently found in Australian waters. They have been found in the ocean territories of 37 countries but have disappeared from parts of east and south-east Asia. Dugongs are currently listed as ‘vulnerable’ by the IUCN. Their numbers have decreased significantly in recent times, mainly due to habitat degradation and fishing-related fatalities. Dugongs have historically been hunted for their meat, bones and oil, and although hunting has ceased in most areas, poaching persists.
Today, we release the chromosome-length genome assembly for the dugong (Dugong dugon)! We thank Natasha Tay and Erina Young from Murdoch University for their help with the sample! Sample processing, library preparation and data collection was supported by resources provided by DNA Zoo Australia, The University of Western Australia (UWA). We gratefully acknowledge the computational support from the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia.
This is a $1K genome assembly with a contig N50 = 64 Kb, and a scaffold N50 = 119 Kb. Please check out our Methods page for assembly procedure details, and check out the interactive map of the 25 dugong chromosomes below! 2021 was going, going and is now dugong so follow us on twitter @thednazoo and subscribe to our mailing list below to keep up with all the 2022 releases.