Rare visitor to Firth of Thames waters

By Nicholas Hamon, Biodiversity Ranger

We recently received calls from the public reporting a potential orca stranding (or orca feeding close to shore) at Kuranui Bay, just north of Thames.

Hauraki Operations Manager Avi Holzapfel and I arrived at Kuranui Bay shortly after to find several local residents in the water, assisting a large sunfish away from the shore. A kayak was being used to help guide the sunfish and the locals had managed to move the fish approximately 100 metres from the beach.

An ocean sunfish or common mola, similar to this one, was spotted in Thames waters

Sunfish are the world’s largest bony fish and can occasionally be found in northern New Zealand waters. They feed on jellyfish and can grow to weigh between 250–1000 kilograms.

The local residents at this point retired from the water and for the next half hour we observed the sunfish with Sarah Deadman (from the Thames Sailing Club) to assess if it was going to swim out of the bay with the outgoing tide. As the tide receded we become concerned as the sunfish had only moved out another 50 metres (150 metres total) of the approximately 600 metres that it needed to reach the safety of deeper water. At that point we made the decision to launch a small inflatable craft from the sailing club in an attempt to assist the sunfish the remaining 500 metres to safety.

Sarah and I ‘wet-suited up’ and planned our strategy. The plan was to ease alongside the sunfish to allow me to attempt to secure the fish by its top fin to the side of the craft while Sarah counter-balanced the craft by sitting on the other side and operating the outboard.

Guiding the sunfish to deeper waters – DOC’s Nick Hamon and Sarah Deadman of the Thames Sailing Club

The application of this method proved very successful and we were able to move the sunfish the required 500 metres into deeper water. The sunfish was bumping along the bottom for much of the time it was tethered alongside the craft. Once into deeper water we released the sunfish. At first it moved slowly into the current and we were worried the fish may try and return to shore, but eventually it burst into life and accelerated away from the boat.

We followed the sunfish for a while, watching it dive and resurface. The grateful sunfish, then happy with the deep water (or maybe tired of human intervention) dived under the water and gave us the slip. At which point Sarah and I high-fived each other — it was our first successful sunfish rescue! We headed back to shore, to thunderous applause from the small group still eagerly watching from the beach. The whole episode took about two hours from when Avi and I first arrived at the Bay.

Sunfish — happy in the deeper water

In addition to the actual rescue, Avi Holzapfel reports that DOC received calls from across the peninsula about the orca stranding, which fortunately all turned out to be related to the sunfish.

“Its large fin out of the water looked very much like an orca’s dorsal fin. There had been a pod of orca near the same spot just the day before”, Avi said.

A large ocean sunfish

Avi says sunfish seem to be rather rare visitors to our shores, and not many people had seen one before at the Thames Coast. “We also had great collaboration with the Thames Sailing Club. Without Sarah and the boat I do not think we would have been able to do much.”

“Standing on the beach with binoculars, with a calm sea, it was an amazing site to see Nick hold onto the large fin and guide the fish out into deep water.  Now and then the body would be a bit more visible – it looked like a very big fish!  Though from Nick’s estimate of 200-300 kilograms, it wasn’t really big in sunfish terms!”.

Our rich and complex marine environment is subtropical to subantarctic and contains over 15,000 known species. Find our more about New Zealand’s marine environment on the DOC website.