Knobble the minke whale, recorded off the Isle of Coll

Every year, we welcome aboard teams of students from St Andrew’s University Sea Mammal Research Unit (SMRU) to discover how we collect data on board our research vessel, Silurian, and gain first-hand experience in our survey methodology.

From stormy seas to BBQ’s on the beach, our latest activities aboard Silurian were packed full of rainbows and muddy puddles (our team’s version of highs and lows). From seeing their first UK cetacean, to surfing the wild west coast waves from the mast, our teams from SMRU embraced the elements to have a truly memorable time aboard. Over the course of 10 days, three teams of University students spent time travelling to different areas around Mull collecting vital visual and acoustic data on marine mammals.

With rather turbulent conditions for Teams 1 and 3, a route was planned down the Sound of Mull towards Colonsay and Loch Linnhe, to shelter from the worst of the weather. Both teams were lucky enough to spot harbour porpoise during their surveys, a challenging feat in such unfavourable conditions.

As sea state increases, the likelihood of spotting some species, such as harbour porpoise decrease significantly. If sea state reaches conditions too poor to survey, as it did during some of Teams 1 and 3’s surveys time, we change to acoustic-only survey. One of the key focuses of our acoustic surveys is monitoring harbour porpoises. Passive Acoustic Monitoring plays a key role in HWDT research, as an accurate way of recording the presence of harbour porpoise in all sea states.

During all surveys, the hydrophone array is deployed rand records continuously, gathering acoustic data. At the end of each survey, the recordings are re-analysed and porpoise acoustic encounters are identified. This data enables us to assess density estimates for porpoises. During surveys, our volunteers undertake acoustic ‘listening stations’ and make an aural assessment of natural sounds and man-made sounds.

As well as species monitoring, these recordings are increasingly called upon to assess the changing soundscape of the west coast marine environment and the potential impacts of acoustic pollution on the population, distribution and behaviour of cetaceans in the region.

Both teams fully embraced the wild weather, expressing how they enjoyed surfing the waves from their positions at the mast. While in the evenings, they either ventured ashore - crossing the ‘Bridge over the Atlantic’ and enjoying a wee bevvy in the local pub on Seil Island - or were treated to lemon drizzle cake while taking part in some rather competitive games on board.

Meanwhile Team 2 was lucky enough to get a break in the weather, long enough to venture out towards Coll, where their survey trip started on a high, as they had bow riding commons and encountered 2 minke whales. One, none other than local ‘whale celebrity’, Knobble!

During these encounters, the team come off transect and go ‘with whale’ to collect Photo ID images. Photo ID is a non-invasive research technique used to identify individual whales and dolphins through analysing their distinct dorsal fins and body markings, HWDT researchers can build a better picture of both individual whales and the wider population.

HWDT hold the Photo ID catalogue for minke whales on the west coast of Scotland, with over 300 individuals in the catalogue. Knobble is one of our most well-known individuals, having been seen over 60 times since 2002. But the majority of sightings and photographs of Knobble come from members of the public, a sighting of this much loved minke is rare for Silurian, so a celebratory beach BBQ was very much deserved!

Across 9 days of surveying, the SMRU teams collectively surveyed 552 km, collecting 52 hours of acoustic and visual data. They encountered 43 marine mammals from 29 sightings across 6 different species.