Marine research expeditions off the west coast of Scotland recorded record numbers of dolphins last year, says conservation charity Hebridean Whale and Dolphin Trust.

Volunteers and scientists recorded 2,303 individual common dolphins, 42 bottlenose dolphins and 94 Risso’s dolphins in the 2016 research season, up from an average 463, 14 and 12 over the previous 14 years.

Dr. Lauren Hartny-Mills, Science Officer of HWDT, said: “The reasons for the high number of sightings of these charismatic dolphin species – and the broader effects on the marine environment and other species – remain unclear.

"But the intriguing findings highlight the importance of on-going monitoring and research – to strengthen our understanding of what is taking place in Hebridean waters, and to ensure well-informed conservation action.”

The trust’s specialized research yacht Silurian covered more than 5,000 nautical miles in 2016, during which time researchers documented more than 1,300 cetaceans and basking sharks.

Alison Lomax, Director of the Trust, said: “The impressive range of species documented in our at-sea surveys last year is a powerful reminder that Scotland’s west coast ocean environment is home to remarkable marine life.

"Long-term scientific studies of this globally-important habitat and its inhabitants are crucial if we are to ensure a secure future for the Hebrides’ spectacular cetaceans.”