Daniel Lukic had launched his drone at Forster beach on Saturday when he caught a glimpse of hundreds of rays.

"There was probably 400 or 500, maybe even more. It almost looked like glitter," he said.

"I get pretty excited when I see this sort of stuff because it's a single moment in time where you just had to be there".

Marine biologist Alysha Chan from Macquarie University said cownose rays usually travelled in a group, referred to as a fever, of between 10 to 99 individuals.

She said that while the species usually migrated down the NSW coast in summer, to see a group of this size was quite rare.

"It's actually quite surprising seeing a group that large … I haven't quite seen anything that large on social media," Ms Chan said.

"We don't know why they're forming in such large numbers."

Ms Chan is undertaking a PhD on the biology and ecology of Australian cownose rays and their distribution in NSW.

She said the formation of the unusually large fever at Forster could be due to migration, mating, sourcing food or even a way to protect themselves from predators.

"I think there's a lot less risk travelling in large groups," Ms Chan said.

She said the footage would be used in her ongoing research into the species.

The International Union for Conservation of Nature describes the cownose rays as data deficient, meaning little research has been conducted into the species.

Original Story By | Nakita Jager