A SURVEY that included North Stradbroke Island has collated more than 11,000 manta ray sighting records.
The survey collected by scuba divers, aerial surveys and online submissions has helped researchers better understand reef manta ray distribution around Australia, and scientists says they have confirmed "missing" ray populations.
Point Lookout on Straddie, particularly the Gorge area, is popular with visitors wanting to see rays.
The study, led by University of Queensland PhD candidate Amelia Armstrong, is the first step towards understanding how reef manta ray populations might connect.
"Prior to this study, official reef manta ray distribution maps showed the species as absent from Australia's northern coastline between the east and west coasts," she said.
"We thought this gap was probably due to a lack of information rather than a true absence, given reef manta rays' preference for warm, shallow waters.
"It can be challenging to find confirmed sightings of manta rays in Australia's north as the coastline is vast and sparsely populated. The threat of crocodiles puts people off."
Ms Armstrong said the team was not surprised to find reef manta rays in Australia's north, but they were surprised at the number of records, and how much information was on fishing and travel blogs.
"The latest International Union for Conservation of Nature Red list assessment lists the species as 'vulnerable to extinction' and suggests reef manta ray populations are declining," she said.
"In some places declines are up to 90 per cent in the last three generations, likely due to fishing targeting them for use in traditional Chinese medicine."
The combination of aerial surveys, online sighting reports and images submitted to the Project Manta databases allowed researchers to reassess and map the Australian distribution for two manta ray species.
Researchers were also able to make use of the Northern Territory Government's dugong monitoring aerial surveys where the presence of other large marine animals had been recorded.
"Dugong monitoring aerial surveys allowed us to fill in sighting gaps for large stretches of remote coastline in the Northern Territory and Gulf of Carpentaria," Ms Armstrong said.
The research was also helped by more unconventional information sources, featuring more than 500 manta ray records from places like Facebook and Youtube.
"Photos and videos uploaded to travel blogs, Facebook, Instagram and Youtube were a surprisingly valuable source of sighting information," she said.
"Overall, we were able to collate an incredible 11,614 records with 378 from aerial surveys, 521 from online reports and the rest from Project Manta's dedicated photo-ID databases.
"We've been able to confirm a continuous distribution for reef manta rays northwards from Shark Bay in Western Australia and around to Coffs Harbour in New South Wales."
Records of the larger manta ray species (the oceanic manta ray) were rarer, with researchers finding just 32 sightings spanning as far south as Tasmania.
"...Manta rays are a valuable source of tourism income both in Australia and globally, with many tourists visiting places like Ningaloo Reef, Lady Elliot Island or North Stradbroke Island, just to get the chance to see a manta ray for themselves."
UQ, the Sunshine Coast University, James Cook University and Murdoch University took part in the research.
To contribute manta photos or sightings email project.manta@uq.edu.au.
