Endangered basking sharks get tagged by researchers off Cork coast

7 May 2021

Researchers observing a six-metre long female basking shark that they had tagged. Image: Nick Payne/Trinity College Dublin

Researchers from Trinity College Dublin are trying to learn more about the behaviour of Ireland’s gentle giants.

Basking sharks are the second largest shark species in the world – with some growing to 12 metres in length. These sharks can be seen in Irish waters but they are an endangered species.

So now, researchers from Trinity College Dublin’s School of Natural Sciences have been tagging basking sharks in west Cork in a bid to learn more about these gentle giants.

Assistant professor Nick Payne and PhD candidate Haley Dolton have applied electronic tags to four sharks, which will gather data about their behaviour as they swim around the coast.

‘The more we know about them – especially their behaviour and physiology – the better chance we have of protecting them’

The goal is to learn more about the anatomy and physiology of the sharks, and get information that could guide conservation efforts.

“Basking sharks are an endangered species and at risk of death from fishing bycatch [unintentional catching] and from getting struck by boats,” said Payne.

“So the more we know about them – especially their behaviour and physiology – the better chance we have of protecting them.”

Payne and Dolton deployed their tags last week on free-swimming basking sharks while working with a local marine tourism operator.

Their work also involved dissecting two dead basking sharks that had washed up on the coastline near Clonakilty. These dissections allowed for a detailed examination of the internal anatomy of the sharks.

“Basking sharks are a difficult species to study because they are not very abundant and they only grace our shores for a brief period each year, from April to August, so I am delighted we were able to learn so much about them,” said Payne.

“We would rather not have had the opportunity to examine the two sharks that died prematurely before we took to the sea, but these sad events did at least help us learn more about them.”

Dolton added that the team is currently analysing the results of the work and will share the findings later in the year. “The amount of data we managed to collect throughout the whole week was phenomenal and beyond what I’d hoped for,” she said.

The research was funded by the Irish Research Council and Science Foundation Ireland.

Sarah Harford was sub-editor of Silicon Republic