Location seemed to be important to the mantas’ social groupings. The researchers were surprised to find rays returning regularly to particular cleaning stations, given their mobility and the fact that all the sites lay close together, and concluded that groups used them as meeting points.
“Like dolphins, manta rays are intelligent and perform collective behaviours such as foraging and playing,” said lead author Rob Perryman, an MMF researcher and PhD student at Macquarie.
“They are curious, often approaching humans, and individuals appear to have different personalities. It turns out that reef manta rays actively choose to group with preferred social partners.
“We still understand very little of how mantas live their lives, but we know they are socially interactive, and these interactions seem important to the structure of their populations,” said Perryman, adding that understanding their relationships could help predict mantas’ movements, mating patterns and responses to human impacts.
“Knowing how mantas interact is important, particularly in areas where they are susceptible to increasing dive tourism,” said Dr Andrea Marshall, MMF principal scientist.
“The increasing number of boats and scuba divers around reef mantas in Raja Ampat, particularly at cleaning stations, could break apart their social structures and have impacts on their reproduction.”
Manta rays have been protected in Indonesia since 2014.
The study is published in Behavioral Ecology and Sociobiology.