Tagging Fiordland sharks to monitor climate change

Tracking changes in broadnose sevengill sharks' behaviour in a warming climate.

Scientists from NIWA and Te Herenga Waka—Victoria University of Wellington are studying sharks in Fiordland to understand the effects of climate change. 

The team spent a week in the South Island attaching transmitters to broadnose sevengill sharks to track their behaviour and movements. 

NIWA fisheries scientist Dr Brit Finucci says that sharks are an apex predator with a crucial role in the ecosystem and can be indicators of the health of an environment.  

“Fiordland National Park is an incredibly unique ecosystem. We know very little about the sharks that live in this area, but we do know that the Fiordland environment is at risk from climate change. Now is an opportune time to study how sharks may be impacted by a changing environment in the future,” said Dr Finucci. 

The broadnose sevengill is commonly observed in Fiordland, reaching over 2.5m in length. It is a globally threatened species, with fishing activity reducing shark numbers in some locations. However, little is known about the impacts of climate change on their health and population. 

The project, funded by the Save Our Seas Foundation, saw 11 sharks tagged, with divers installing 29 acoustic receivers on the seafloor.  

Dr Alice Rogers, Victoria University of Wellington
Dr Brit Finucci (NIWA) guides in a broadnose sevengill shark reading for tagging and measurements
Dr Alice Rogers, Victoria University of Wellington
On their backs, the sharks are calm allowing the scientists to take measurements and attach the acoustic transmitter.

“The sharks that we tagged were calm and relaxed, and it was amazing to see them so close when usually we only get glimpses of them whilst diving. The tags will transmit data for up to the next 10 years and the receivers we put on the seafloor will collect data every time a shark swims near it,” said Dr Finucci. 

Project lead Dr Alice Rogers, a Senior Lecturer in fisheries science at Victoria University, said it is an exciting project to be working on. 

“The team on the boat were great and it’s one of the most beautiful environments I’ve ever worked in, so I feel privileged to be doing this research. I also love this species – its ancestors date back to the Jurassic period, so they’re almost like dinosaurs. It’ll be great to see how resilient they are to the effects of climate change and warming seas,” said Dr Rogers. 

The team will return to Fiordland every six months to gather the data from the receivers. They will monitor the short- and long-term information on their movements to understand the sharks’ behaviour and how this may be changing.