Tagging data reveals where sharks are roaming in NZ

  • 24/10/2023

A programme sponsored by New Zealanders has revealed where sharks are located in New Zealand waters.   

Last summer, shark expert Riley Elliot was able to use satellite tracking tags to pin the location of four great white sharks, as part of a research project that aims to answer three questions - where did the sharks come from, why are they here, and how do their movements overlap with people?  

The programme, which was sponsored by New Zealanders, shows exactly where those sharks are in New Zealand's waters.   

"Thanks to the New Zealand public, they funded a bunch of tags and we got out there with a hiss and roar, tagging four great white sharks, identifying 15 of them and then the floods came which the sharks didn't foresee let alone the mayor of Auckland so they took off and we got amazing tracks out of the four that we did tag," he told AM on Tuesday.   

"People really engaged with the app that's in the Google and Apple Store now and online and we learnt a lot."  

The current tracking shows two of the sharks are in waters near Waihi Beach and the third one is up north near Kaipara Harbour. The website doesn't show where the fourth shark is.  

Tagging data reveals where sharks are roaming in NZ
Photo credit: Sustainable Ocean Society

Elliot said the data showed Tauranga Harbour was a "pupping ground" because he saw two brand new baby Great White Sharks.   

He told AM when the Auckland Anniversary floods and Cyclone Gabrielle hit New Zealand it changed where the sharks roamed.   

"When the flood came, we saw how these sharks moved away, outside of the flood water up north, all the way around the North Cape, utilising some of the small harbours like Doubtless Bay as nursery grounds and then doing magical migrations all the way back to where we had tagged them in the Tauranga Harbour," he said.   

The data showed the sharks tended to be attracted to the Waihi area, which Elliot put down to it being a good nursery ground.  

"I think it's just like a really good bird's nest, as an analogy. It's a big harbour, which is a good nursery ground. It's shallow, it's protected, it's got a lot of prey species," he said.   

"It's like a mall, I guess, they can just hang out and all their needs are satisfied there as opposed to the open ocean is like a big blue desert. The coastline is a vast area of nothingness sometimes. So harbours are really a good microcosm of prey for these animals."   

Elliot said the plan for this summer was to tag more sharks as he's still got 20 tags available and he wants to get them on as many sharks as possible.   

He told AM it's hard to know exactly how many sharks are in the ocean around New Zealand but estimated it to be over 200.   

"They've done genetic population studies. We're linked with the East Australian great white population and they estimate there are only about 200 to 600 adult great white sharks in that population and about 3000-6000 in total, which sounds like a lot or not it depends on how you look at it," he said.   

Elliot told AM sharks are an endangered population and he wants to see more protection for them.  

"It's an endangered population, there's up to 10-20 reported killed in commercial nets every year and that's just reported and almost every week I get a photo sent to me of someone who's caught one accidentally in a fishing line," he said.   

"That's the shark's perspective that they're running that gauntlet every day, so it's important we try and reduce the harm to those animals whilst also learning about them so we can just go have fun in the summer because that's the goal at the end of the day for us, really selfishly.   

"We do enjoy having a unique ecosystem in New Zealand and a healthy ecosystem and sharks are very important for that." 

Watch the full interview with Riley Elliot in the video above.