Silurian Sets Sail: The 2025 Field Season Begins!
April marked an exciting milestone as the first group of 2025 citizen scientists stepped aboard Silurian, HWDT’s dedicated research vessel. Over eight days, six enthusiastic local volunteers joined our team to collect vital visual and acoustic data across Hebridean seas. Read all about their experiences here…
DAY 1
From the colourful harbour of Tobermory, our crew set off into open waters, cruising past Ardnamurchan continuing northeast around the Small Isles to Canna. A grey seal sighting greeted us early followed by many groups of feeding seabirds - a great indicator of productive waters! Though some volunteers battled early seasickness, spirits were high as the team adjusted to life at sea and began their training in marine mammal surveying techniques.
DAY 2
From Canna to Plockton, the crew was treated to a diverse range of sightings — including otters, seals, and the ever-elusive harbour porpoise. The day started with lots of movement from the sky and sea. Lots of seabirds were recorded as we moved towards calmer seas, enhancing our visibility and survey coverage. Just as the day ended, a perfect rainbow arched over the water, a wonderful way to end our efforts of surveying through difficult seas.
DAY 3
With calm seas and clear skies, we left Plockton and navigated the Sound of Raasay. Porpoises and seals dotted the horizon, but the highlight was a small pod of common dolphins, busy foraging and surfacing close to the boat. That evening, anchored in Loch Gairloch, some of the braver volunteers took a dip in the chilly waters as others relaxed on deck reflecting on a fantastic day at sea.
DAY 4
Leaving Gairloch under a bright sky, we turned south into Loch Torridon, where a pod of 25 common dolphins stole the show. Displaying prolonged bow-riding and surface social behaviours, the dolphins were not only detected visually but were also acoustically detected from our hydrophone.
Monitoring the underwater acoustic environment is a key part of our research aboard Silurian. Sound plays an essential ecological role in marine ecosystems, serving as a primary means of communication, navigation, and foraging for many marine species, particularly cetaceans such as whales, dolphins, and porpoises.
Since 2002, our long-term acoustic monitoring programme has been collecting data on both natural and anthropogenic underwater noise across the Hebridean waters. Passive acoustic monitoring (PAM) offers a powerful, non-invasive method for detecting and identifying marine species based on their unique vocal signatures, enabling researchers to estimate presence and relative abundance with temporal and spatial precision. We can also detect and analyse anthropogenic noise; this capability is critical for evaluating the scale and impact of human-generated sound on marine life and will support ongoing efforts to assess and mitigate emerging acoustic threats to cetaceans in the Hebrides.
DAY 5
From Scalpay through Kyle Rhea and on to Eigg, Day 5 brought calmer seas and excellent conditions for observing seals, porpoises and of course creels! The day ended with sunshine, pizza, and well-earned pints.
DAY 6
A beautiful start to the day saw us sail past Muck and Ardnamurchan Lighthouse towards the Treshnish Isles. It was a very busy bird day with hundreds of puffins, manx shearwaters, razorbills and guillemots covering the sky and sea. Surveying around the islands, we continued as far as Inch Kenneth and then made our way back to anchor at the South Harbour, between Ulva and Gometra. Though marine mammal sightings were fewer as the weather progressively declined, the team gathered critical acoustic data.
DAY 7
Scotland’s weather kept us on our toes, but shifting plans didn’t dampen our progress. Navigating the Sound of Mull, we encountered porpoise after porpoise after porpoise — affectionately dubbed a "Porpoise Party” with 18 individuals encountered in quick succession. A grey seal surfaced with a fish in its mouth just as we entered Loch an Drum Buie and we finished the final night at sea with bangers and mash and many games of pass the pig.
DAY 8
As we sailed the final stretch back toward Tobermory, multiple harbour porpoise sightings were encountered. Just before entering Tobermory Bay, a small group of bottlenose dolphins was observed bow-riding commercial vessels in the Sound of Mull. The research team conducted an opportunistic photo-identification session, contributing images to HWDT’s long-term photo-ID catalogue. It was a fitting finale to a week that saw six species of marine mammals and countless contributions to their protection.
Across the eight days, the group surveyed 529km of Hebridean seas, recording six species of marine mammals across 108 sighting and generated 56 hours of acoustic recordings!
A HUGE THANK YOU TO OUR TEAM OF CITIZEN SCIENTISTS WHO JOINED THIS EXPEDITION: JESS, EMILY, LORRAINE, KATIE, SUSAN AND PETER.