A wide diversity of rays, sharks and turtles have been discovered in the large lagoon at Umm Al Quwain, leading scientists to declare the area a “critical habitat” for marine species.
Videos from baited underwater cameras and drones allowed scientists to identify 13 species – two sea turtle species, one type of shark and 10 ray species.
Most are classified as globally threatened by the International Union for Conservation of Nature, with some critically endangered.
The researchers praised the UAQ authorities for looking after the “nationally and globally important” lagoon, Khor Al Beidah, and suggested that designating it a marine protected area could ensure its continued conservation.
'Truly astounding'
Dr Daniel Mateos-Molina, head of marine conservation for Emirates Nature – World Wildlife Fund and the first author of a paper detailing the research, described the location as “truly astounding”.
“Despite years of research, the area continues to captivate us with its wealth of biodiversity,” he said.
The lagoon is, Dr Mateos-Molina said, used for “crucial stages” of the life cycle of the 13 megafauna species - meaning large enough to see with the naked eye - including the two sea turtle species.
“Green turtles utilise the seagrass within the lagoon seascape as a primary foraging ground before journeying to lay their eggs, most likely in Omani waters, only to return thereafter,” he said.
“Similarly, hawksbill turtles frequent one of the few remaining coral reefs along the UAE coastline, situated just a few hundred metres from the lagoon.”
Three of the 13 species are listed by the IUCN on its “global red list” as “critically endangered”, which is just one category up from extinct in the wild, while most others are also threatened in some way.
The critically endangered species include the Halavi guitarfish and the giant guitarfish, with numbers of the latter having fallen significantly globally because the creatures are caught so that their fins can be used in soup. One of the two sea turtle species, the hawksbill turtle, is also critically endangered globally.
'Diverse array of species'
Dr Mateos-Molina said that the lagoon was home to several large animal species because it was a “complex seascape” with multiple habitats that, together, created an ideal ecosystem.
“Mangroves, seagrasses, mudflats, coral reefs at the mouth of the lagoon, oyster beds, salt marshes and more – all play vital roles within the ecosystem, operating together seamlessly like a well-oiled machine,” he said.
“The key lies not in any singular habitat, but rather in the synergy of the entire ecosystem, including its diverse array of species.”
The researchers also identified more than a dozen globally threatened bird species in the area.
Khor Al Beidah covers 90 square kilometres, one third of which is the lagoon’s outer area, while the remaining two thirds are made up of a shallow inner lagoon system.
It is connected to the open sea through mouths to the south and north, and a water channel links the two entrances.
“This connectivity enables certain marine animals to move freely between the lagoon and the open sea, enhancing the dynamic ecosystem of the area. Tidal influence plays a crucial role in this ecosystem due to the lagoon’s shallow nature,” Dr Mateos-Molina said.
Apart from channels that have been dredged, the lagoon is less than six metres deep, and has a maximum tidal range – the difference in height between high and low tide – of two metres.
Meticulous study
The study Coastal lagoons in the United Arab Emirates serve as critical habitats for globally threatened marine megafauna was published in the March edition of Marine Pollution Bulletin.
Dr Ivonne Bejarano, a marine ecologist at the American University of Sharjah, was involved in the study and “meticulously” went through the underwater footage with a team of students.
Another author is Dr Rima Jabado, founder and lead scientist of the Elasmo Project, a UAE-based non-profit initiative to conserve sharks and rays, together known as elasmobranchs.
Species were identified using underwater video recorders baited with sardines cut into pieces so that their oil would disperse, and uncrewed aerial vehicles equipped with video recorders.
Researchers said by being low cost and easily deployed, these two approaches have “revolutionised the monitoring of wildlife and habitats in both terrestrial and aquatic realm”.
“Results demonstrate the value of combining aerial and underwater video surveys to obtain spatially comprehensive data on marine megafauna in shallow coastal lagoons,” they said in the report.
Coastal ecosystems across the world have been significantly affected, Dr Mateos-Molina said, because they are often used for human activity.
“Finding pristine coastal lagoons has become increasingly rare across the globe, yet, Umm Al Quwain has successfully preserved its area,” he said.
The researchers said that designating the location a marine protected area and introducing a management plan covering the land and sea area could “protect the natural capital and avoid biodiversity loss in this nationally and globally important coastal lagoon”.
Since 2016 and in collaboration with the UAQ government, Emirates Nature – WWF has been “meticulously studying” the area, Dr Mateos-Molina said and was working with the authorities to introduce measures to further assess and safeguard the area.
