Remarkable video of basking sharks engaging in what’s believed to be courtship behaviour has been captured by drone off Co Clare.

As RTÉ News reports, members of the Irish Basking Shark Group (IBSG) shot the footage of nine sharks swimming in a circle around their research boat last month.

Basking sharks, the world’s second largest fish species, are typically seen on the surface of Irish inshore waters in the spring, and rarely this late in the year.

“But we realised immediately that they were not feeding,” said Dr Simon Berrow, co-founder of the IBSG and chief executive of the Irish Whale and Dolphin Group (IWDG).

“This was something else, something special.”

The research team also took the opportunity to collect DNA samples from the massive marine wildlife, which which may reveal if they are genetically distinct from those big fish seen in the same waters earlier in the year.