Sharks... even more amazing than you realised

It was back in December 2023, when our research team was on the University of Auckland’s vessel looking for workups – feeding frenzies – in the Hauraki Gulf near Kawau Island.

A large metallic grey dorsal fin signalled a big shark, a short-fin mako. But wait, what was that orange patch on its head? A buoy? An injury? We launched the drone, put the GoPro in the water and saw something unforgettable: an octopus perched atop the shark’s head, clinging on with its tentacles.

This `sharktopus’ was a mysterious find indeed – octopus are mostly on the seabed while short-fin mako sharks don’t favour the deep.

We moved on after 10 minutes so I can’t tell you how what happened next. The octopus may have been in for quite the experience since the world’s fastest shark species can reach 50kph.

This summer, sharks have been on people’s minds. We’ve had the “Please don’t attack me bro” kayaker tailed by a great white shark in remote Northland, the drone footage of a bronze whaler cruising in the shallows at Ōhope Beach, and a number of hasty beach evacuations.
 

The risks to humans from sharks are, of course, minimal – although swimming is not a great idea if people are fishing with bait and sharks are present.

Let’s take a closer look at these amazing creatures, how they are faring, and how we can help them. (Yes, the story of the sharktopus was just to capture your interest.)

I can tell you about the patch that I know best, the Hauraki Gulf - Tīkapa Moana, Te Moananui-ā-Toi.

Monitoring by plane, boat and drone, the Pulse of the Gulf research project has learned a lot about the patterns and behaviour of the bigger sharks in the Gulf over and around the summer months .

Bronze whalers – also known as copper sharks – are the sharks most often seen in the Gulf, sleek and bronze-coloured, encountered by divers and fishers in shallow waters, sometimes chasing kahawai. Worldwide, the bronze whaler is classified as “vulnerable” but not yet threatened with extinction.

The most numerous sharks are smooth hammerheads, big sharks distinctive for their hammer-shaped heads.
 

Our waters are their nursery, the mothers giving birth close to shore.

Baby smooth hammerheads find safety swimming in schools of 20 to 40 in shallow waters before heading to the deep. Like the bronze whaler, the smooth hammerhead is classed as vulnerable to extinction.

Sightings are increasing of large open-ocean species such as the dusky shark, the blue shark, and the short-fin mako, otherwise known as the octopus taxi shark. Warmer water because of climate change may be increasing the presence of tropical tiger sharks.

We know a lot less about the state of smaller sharks and those living near the seabed such as rig (lemon fish), and our native carpet sharks, also known as draughtsboard sharks because of their distinctive patterning.

Shark populations are in steep decline around the world. They are always vulnerable to population collapse from overfishing because they are long-lived, mature slowly, and have a low reproductive rate. Yet, healthy and thriving sharks are integral to marine ecosystems.

Every part of the Gulf is important to these amazing animals – estuaries and nearshore waters are critical pupping (birthing) habitats, pups find safety in the mangroves and seagrass beds, the seabed is a rich source of food, and the open waters are home to the larger fish which pelagic (open ocean) sharks like to eat.
 

The Gulf has received international recognition as an important area for adult and juvenile sharks with the declaration of the ‘Firth of Thames and Inner Hauraki Gulf Important Shark and Ray Area’. The government-led ‘Revitalising the Gulf’ programme aims to improve the health, the mauri of the Gulf.

We need to protect and revive habitats degraded over past decades, limit pollution including sediment runoff entering the ocean, and minimise the chances of sharks ending up as recreational and commercial fishing bycatch.

The sharktopus encounter is a reminder of the wonders of the ocean. One of the best things about being a marine scientist is that you never know what you might see next in the sea. By supporting conservation initiatives, we can help to ensure that such extraordinary moments keep happening.