How do we gather data? NatureScot join us to find out
Rona Sinclair, Mobile Species Advisor for NatureScot and funding manager for our Cetacean Monitoring Programme, joined us on board our research vessel, Silurian, to understand how data is collected. Read all about her experiences below…
I recently got the amazing opportunity to jump onboard Silurian, to join the crew for a delivery trip from Ullapool back down to Silurian’s home in Tobermory on the 01 - 03 July. This was a great opportunity to get an insight into how cetacean sightings and acoustic data is collected and processed in the field. And being relatively new into my role, it was a chance for me to meet some of the HWDT team which we work closely with for the first time in person.
The Hebridean waters on the west coast of Scotland contain a huge diversity of species and habitats. The area is a global hotspot for harbour porpoise and home to internationally protected species including bottlenose dolphins, minke whales and killer whales. The long-term monitoring data collected by over a thousand trained citizen scientist volunteers over the last 20 years onboard HWDT’s research vessel Silurian has provided vital evidence to support and inform the identification and designation of three mobile species marine protected areas (MPAs). The Sea of the Hebrides MPA is designated to protect minke whales and basking shark, the North-east Lewis MPA is designated to protect Risso’s dolphins, and the Inner Hebrides and the Minches SAC is designated to protect harbour porpoise.
Three MPAs designated to protect minke whales, Risso’s dolphins, harbour porpoise and basking shark on the west coast of Scotland.
NatureScot support the HWDT’s research programme of work collecting long-term visual and acoustic monitoring data around the whole west coast of Scotland, across a wide variety of fine scale environmental variables (e.g., sea surface temperature, depth, tidal flow etc). The dedicated summer and winter surveys provide us with a wide scale assessment of cetacean distribution and population size and enables us to answer questions about species habitat preference, site usage, and the behaviour and health of individuals (through photo-ID). The visual sightings transect data that is collected ‘on effort’ has recently been used to support predictive density surface modelling work. Predictive modelling enables us to understand changes over time in how these protected whales and dolphins use the west coast waters and within MPAs, mapped with associated confidence intervals, as predicted seasonal and annual changes in densities of animals.
DAY 1 - PIZZA AND PORPOISES
Before I arrived, the crew and a team of volunteers had just spent the past month surveying the waters as far west as the Flannan Islands on the west coast of the Outer Hebrides and within the northern Minches – their 6th and 7th research expedition surveys of 2023 completed. As I joined in Ullapool it was a drizzly evening, but this didn’t put a damper on anyone’s sprits as we met the two skippers and HWDT’s wonderful Fieldwork Research Manager Jenny with big smiles and had delicious take-away pizza. It was a full boat with 10 people onboard, including social media content creators and colleagues from the Scottish Marine Mammal Strandings Scheme and the National Biodiversity Network Trust. We picked up anchor that evening and motored out past the summer isles in glass calm water, which made for perfect porpoise sighting conditions. Everyone jumped up on deck for a few fantastic views of harbour porpoise, ID-able by their triangular dorsal fin, and numerous seabird species and a couple of curious seals. But the focus of everyone’s binoculars was on looking out for John Coe and Aquarius, the west coast community killer whales, which had been spotted earlier that day near the summer isles!
The first night was spent tucked away behind the Isle of Ewe in anticipation of the wet and wild conditions forecast for the days ahead.
DAY 2 - ACROSS THE SEA TO SKYE
The sea was rolly as we headed away from the sheltered coastline the next morning, but plenty lemon and ginger tea and biscuits worked a treat and enabled us to continue scanning for cetaceans. We saw common dolphins leaping out the waves, however our ability to detect animals was limited by the sea state as we motor-sailed down the coast to Skye and through the Sound of Rassay to our second anchorage. Even though we couldn’t see many animals, the towed hydrophone was picking up lots of activity beneath the surface.
Jenny talked us through how the hydrophone, towed at 6 knots, is used to record acoustic data; including dolphin echolocations and porpoise clicks, snapping shrimp, and human activities producing underwater noise. We had the hydrophone in the water for the duration of the trip, and I spent some time with Jenny below deck at the research station computers to listen to the recordings and see how the harbour porpoise mark-up is done using PAMGUARD viewer software. Clicks are automatically identified and displayed visually with their bearing, waveform, frequency spectrum and Wigner plot in the PAMGUARD Viewer program window. Each click is then manually checked to remove false detections and separate the clicks into acoustic events. Among other criteria, clicks can be classified as harbour porpoise clicks if the peak frequency was between 130-140kHz.
After we had tucked into a delicious haggis dinner a few of us went up to the top deck to do some sunset yoga and to stretch out the sea legs which had been well used that day!
Towed hydrophone coiled on deck. At anchor on the second night in the entrance to Loch Sligachan, Skye. (C)Rona Sinclair / NatureScot
DAY 3 - ROUND ARDNAMURCHAN POINT
The final leg of the journey was from Skye down to the Isle of Mull; under the Skye bridge and past the small isles of Eigg and Muck to the notorious Ardnamurchan point. Sailing under the Skye bridge conditions were favourable for people to climb up the crow’s next and take in the views, but once we got through the narrows at Kyle Rhea and past the Sandaig Islands the sea was bumpy with waves and spray coming over the deck and the showers were plenty. We were all still hopeful for some sightings despite the conditions – a minke whale would make my day, but I wasn’t in luck this time.
Soon we saw the multi-coloured houses of Tobermory and knew our time on Silurian was almost over. What a fantastic experience and wonderful to have made so many new connections with organisations that NatureScot work closely with. It was invaluable to hear about the survey protocols HWDT use on the research expeditions and see first-hand the data collection equipment and data processing onboard.
All smiles onboard enroute from Ullapool to Tobermory. Photo credit: Rona Sinclair
DAY 4 - TOUCHING BASE AT HWDT HQ
Before the journey back up to Inverness navigating multiple legs of buses and ferry, which miraculously all linked up, I had the pleasure of seeing HWDT’s headquarters and meeting HWDT’s Director Alison and Science and Conservation Manager Lauren in person (much better than virtual Teams meetings!). We discussed approaches to future monitoring of cetacean species and the designated MPA’s in the Hebrides, and different policy and conservation priorities and exciting uses in future for the incredible amount of citizen science data collected and managed by HWDT.
At the end of the trip with views of the famous Tobermory bay, home of Silurian and HWDT’s headquarters. Photo credit: Lara Jackson
Anyone can join HWDT’s surveys onboard Silurian, including teenagers through their dedicated youth trips. Inspiring the next generation of environmentalists and teaching the fundamental skills required to forge a career in marine conservation is crucial to the continuity of long-term monitoring data collection, scientific research, and protection of Scotland’s seas; their 2024 research expedition timetable is live now!