One thing that working on CalMac ferries in the Hebrides could never be described as is dull!
Change is always just around the corner; whether that entails a new island or towering mountain, a feeding frenzy of dolphins and seabirds, or simply a change in the weather pattern.
Every Wednesday during the summer season MV Clansman sails from Oban to the islands of Coll and Tiree, and then out across the Sea of the Hebrides to Castlebay on the Outer Hebridean Island of Barra before returning to Oban via the same route. It is a long day, you arrive at the Oban terminal at 6:30am and Clansman returns at 9:30pm. But it is very often a productive day, in terms of public engagement and the marine wildlife recorded, and one that I undertake as Wildlife Officer regularly. It perfectly reflects the ever changing nature of my work here as it crosses different habitats and offers varying opportunities for encounters with different wildlife along the route. This week I was on board again and the sailing provided a continuous range of experiences.
The first stretch from Oban to the Sound of Mull offered the opportunity to pick up some harbour porpoise but there was some wind and subsequently the sea was a little choppy. Harbour porpoise are our smallest cetacean and very difficult to pick up without relatively flat sea conditions, and this was definitely the case today. The narrow Sound of Mull saw us sail between dramatic landscapes until we exited into the open sea. It was here that I was hoping to really spot some marine mammals but sadly the sea state was so poor, due to the wind that we couldn’t find any in an area that often provides sightings of minke whales, common dolphinsdolphins, and in recent days two orcas from the resident West Coast Pod. Between Coll and Tiree a small group of common dolphins raced past the ship, obviously on a mission to find food, giving only a very brief view for passengers in amongst the choppy sea.
At Tiree we said farewell to a group from Butterfly Conservation that were heading to the island for the day to search for an extremely rare moth that had last been recorded in 2007. Our next habitat of interest was Gunna Sound, the channel between the islands of Coll and Tiree that is renowned for basking shark sightings. The currents that surge through this gap provide nutrient mixing and plankton development and is an important feeding area for these massive sharks. But again the poor sea conditions that we were experiencing drew a blank with only a handful of seals spotted in the turbulent waters. I was feeling a little dispirited by at this stage as, even though I know that conditions and sightings can change in an instant here, I wasn’t expecting the wind to drop as we headed out into the open water towards the Outer Hebrides.
How wrong could I have been? A third of the way across the Sea of Hebrides, in a Moses like intervention, the sea state miraculously changed from a very choppy 5 to a pretty calm sea state 2. Then we started picking up those animals that I was certain that we were missing, including five good sightings of minke whales. Patience had paid off and our spirits were raised again.
When we returned to the waters of the Inner Hebrides later in the day we were back to choppy seas and the sightings quietened down once more, showing how sea state can massively affect the recording of marine mammals.
This is why ORCA’s effort based recording is so important: in simple terms, by regularly recording the environmental and weather conditions in which we are sailing the sightings that we get can be analysed relative to the conditions and give us an idea of what numbers were actually present rather than what we simply saw. We were very happy with the sightings that we had had and to finish off a fantastic day the team from Butterfly Conservation returned having found their moth, that is believed to be extinct everywhere else apart from Tiree. In way of celebration we were treated to one of this year’s very cute harbour seal pups playing in the surge of water from the ships thrusters as we took on the final passengers of the day at Coll.
ORCA Wildlife Officer - Hebrides