Rolling in the deep
A congregation of short-tailed stingrays from around the world was the biggest this century – and it happened in our own backyard, writes
With a swift undulation of its wings, the giant discuslike fish dipped its snout and passed gently below me. Collision avoided. Barely.
I was scuba diving at the world famous Poor Knights Islands last weekend. I’d barely dropped into the water and descended to 10 metres when I found myself head-to-head with a giant stingray.
Looking inwards at the blue water sandwiched between the walls of our dive site, Northern Arch, it was jam-packed with short-tailed stingrays. Layer upon layer of them.
I’ve been diving at the Poor Knights for years. In that time I’ve experienced some amazing underwater events, but never anything that comes close to that one-in-15-year event. The short-tailed stingray
Dasyatis brevicaudata inhabits the waters of South Africa, southern Australia and New Zealand.
But every summer they gather at the Poor Knights Islands Marine Reserve off the Tutukaka Coast in Northland in what is the only meet-up of its kind that has been documented for this species.
During this time, lucky divers or snorkellers might catch 10 or 15 of these rays gliding through one of the island’s many volcanic underwater archways, in a good year.
Of course, if you’re unlucky you could have a stingray encounter of a different kind. Each year the ACC fields around 80 claims as a result of stingrayrelated injuries.
I have a dog-eared copy of Glenn Edney’s book, Poor Knights Wonderland, a field guide to the islands and marine reserve. There’s a captivating photograph that shows Northern Arch stacked full of silhouetted stingrays.
I’d never seen it. Until last weekend.
I didn’t even think twice, I raised my camera, started firing off shots and, before I knew it, the current had sucked me into the arch and I was surrounded by large rays. They were above me, below me, next to me.
There must have been 50 rays in the arch. Possibly more. It was difficult to count.
I wasn’t afraid.
Maybe it’s because I used to work at Kelly Tarlton’s and jumped into the stingray tank regularly to hand-feed the rays while speaking to the public.
Perhaps it’s because I’ve been scuba diving for years and I’ve had many harmless encounters with stingrays.
But the real reason I think I wasn’t afraid is because stingrays aren’t that scary.
Media hype and headlines have led us to believe that stingrays are man-killers. But the truth is that stingrays are placid fish and only use their barbed tail to defend themselves. I wasn’t at risk because I didn’t pose a threat.
The rays were colliding with each other and sometimes they bumped into me. I saw no sign of aggression.
Glenn Edney took his iconic image of stingrays stacked in Northern Arch in 1999, on film.
Edney is the Director of Ocean Spirit Ltd. He’s captained dive boat charters to the Poor Knights Islands for years.
‘‘The last time stingrays congregated like this was in 1999,’’ said Edney.
‘‘We had pretty good stingray numbers in 2000, too. By 2001 the numbers were already decreasing and then they really dropped away. Northern Arch went from pancakes to empty. 1999 was the peak year.’’
What triggers stingrays to gather in a single arch in such large numbers? Professor John Montgomery from the Institute of Marine Science and School of Biological Sciences at the University of Auckland has been researching the answer.
‘‘We don’t know much about the behaviour of short-tailed stingrays,’’ wrote Professor Montgomery.
‘‘There’s good evidence that the stingrays at Northern Arch are a mating aggregation – but although fresh mating scars are evident – we don’t see the actual mating behaviour.’’
Most of the stingrays in Northern Arch were females.
Edney says that Northern Arch is the perfect meeting place.
‘‘For some reason that we don’t know about it’s a magnet for stingrays,’’ he says.
‘‘As divers we only get to participate in an event like this like this roughly every two decades. Forget trying to decipher it all. It’s a beautiful mystery.’’