Aerial photographs of rays – possibly cownose rays – off Redhead offer a glimpse of a barely understood part of the ecosystem, Irukandji Shark and Ray Encounters marine biologist Ryan Pereira said.

“We know they hang out together and there’s safety in numbers, but a lot of the research isn’t there [for stingrays],” Mr Pereira said.

“We don’t even know the gestation time for some of them.”

Stingrays don’t sting to hunt and those that lash out at humans with their barbs, Mr Pereira said, have either been stepped on in the shallows or think they are being attacked.

Beachgoers can avoid startling stingrays by “scuffing” their feet along the sand.

Stingrays are known to lash out at fishermen in boats, and a ray delivered a series of jabs that resulted in the death of the documentary maker and naturalist Steve Irwin at Batt Reef, Queensland in 2006.

The NSW Ambulance Service has treated 15 people in the Hunter for stingray-induced injuries since September 2013, including two late last month.

On December 30 a 25-year-old woman was stung at Stockton beach while another woman, 19, was treated for a stingray wound at Fingal Bay. 

“We generally find with our patients who’ve had an encounter with a stingray, there’s a lot of pain involved. There’s every chance they’ve been hit [by the barb] a couple of times,” paramedic Matt Burke said.

“We’ve also seen pieces of the sting break off and get stuck in the person. You get what’s referred to as a “dirty wound”, because it carries a high risk of infection.”

Mr Burke said anyone stung by a ray should get to shore, stem the bleeding and seek medical help.

Any foreign objects lodged in a stingray wound should be left alone, he said, for a medical professional to deal with.