Readers have been contacting the Otago Daily Times in recent days with a series of stingray sightings in the harbour.
On Thursday, the ODT reported the close encounter two Dunedin brothers, Arlo (11) and Philip (12) Ruston-Wood, had with a large stingray while swimming near Portobello last week.
Arlo, who was wearing goggles, was underwater when, through a large cloud of mud, he saw two large eyes and wings swim past him about an arm’s length away.
"We quickly ran out of the water because it was only knee-deep. It was kind of slow for me, though, because I had my flippers on," he said.
The encounter prompted another report from Gavin Palmer, who said he caught, and then released, three stingrays in 30 minutes while fishing in the harbour on Thursday night.
"There was quite a lot . . . we saw them in the water, swimming around.
"They were pretty big. It was a bit of a challenge to hold on to the first one. I didn’t actually want to catch them, but I couldn’t help it," he said.
Another reader, Annette Cross, sent in a photograph of stingrays for the Otago Daily Times’ Magic Moments competition after spotting two large ones, and three smaller ones, in Portobello Bay on December 20.
Dr Malcolm Francis, a Wellington-based fisheries principal scientist at Niwa, said stingrays frequented shallow coastal waters throughout New Zealand every summer, presumably to feed.
So, too, did humans, as more people ventured out on the water, and to the beach, to fish and swim.
"It’s no coincidence that sightings of rays and sharks in coastal waters around New Zealand usually go up on Boxing Day and last until people head home from their holidays," he said.
University of Otago marine science masters student Rob Lewis agreed, saying sighting could be "a bit of a loaded thing" as "it really heavily depends on how many people tend to be using the water at any time".
Mr Lewis’ research was focused on sharks, which were closely related to stingrays, but he believed a combination of factors, all linked to higher-than-usual southern water temperatures, were at play.
"The stingrays are happier in the current temperatures that they’re in, and there’s more prey for them to feed on, and, because it’s been so nice and warm, we’ve probably had a bunch of people using the water more than usual."
Stingrays could grow to an impressive size, up to 4m from wingtip to wingtip in some cases, although most were smaller, at no more than 2m across, he said.
There was always a population of stingrays in Otago Harbour, but swimmers could be reassured they were docile creatures which liked to feed on scallops, crabs and other shellfish, he said.
"If someone accidentally steps on them, they might get a barb to the leg, but they’re absolutely docile creatures.
"The Steve Irwin thing happened a few years ago, but he was right in that poor stingray’s face. He kind of just had bad lack with that one."
