A new group volunteers joined us on board Silurian on a slightly drizzly evening in Tobermory for the start of HWDT08. After travelling from all over the UK and Europe, we all sat down to a welcome bowl of spaghetti bolognese, getting to know each other and talking excitedly about the 12 days ahead. That evening we began to learn all about the cetaceans and other marine megafauna that we might be lucky enough to encounter, as well as what to look out for when trying to spot them. The next morning, we went through more information on how we collect our data, which included listening to some underwater sounds that might be recorded by the hydrophone during our acoustic monitoring. We left that afternoon, full of anticipation for what the coming days would bring.

Spotting cetaceans from the bow of the boat

During the survey, which ran from the 14th – 24th of August, Silurian travelled over 378 nautical miles, collecting visual and acoustic data. Our newly trained citizen scientists spent over 60 hours on effort, scanning the waters looking for marine megafauna and collecting over 55 hours of acoustic recordings!

Unsettled conditions greeted us at the start of the week. However, we were able to shelter behind the east coast of Mull heading south and surveying the waters around Mull, Jura, Islay and Oronsay. This meant that we enjoyed some beautiful anchorages, savouring some sustainably farmed mussels in Loch Spelvie and spending the evening with some inquisitive porpoise in Loch Melfort. With a break in the weather, we used the opportunity to head further afield, surveying waters around Coll and Tiree and even managing to sail to the Outer Hebrides.

We had some incredible sightings of seven species of marine mammals sightings during the survey, including: minke whales, bottlenose dolphins, common dolphins, white-beaked dolphins, harbour porpoise, grey and common seals, as well as some basking sharks. One day in particular highlighted the spectacular marine biodiversity to be found in Hebridean waters, when we encountered all of the species listed above in less than 12 hours! We encountered bow-riding common dolphins, had an incredibly close encounter with a feeding basking shark and even saw a breaching white-beaked dolphin: a day that none of us will be forgetting anytime soon.

One of the hundreds of common dolphins we saw on the survey

A basking shark swam right past the stern of the boat!

We were also treated to some spectacular bird sightings, counting 3447 birds in total. The stars of the show were the manx shearwaters, which were enjoying the somewhat windy conditions with over 1000 individuals gliding past the vessel at one point. The gannets also put on some spectacular displays, diving amongst the common dolphins.

We saw hundreds of gannets, some diving amongst the common dolphins

Massive thanks to the citizen scientist team who joined us on board: Bruce, Claire, Eilidh, Elizabeth, Insa and Livia --- we couldn't collect the vital data without you, and it was a pleasure sailing with you all.

Thanks also to Scottish Natural Heritage who help fund the data collection programme aboard Silurian.

Feeling inspired to get involved with our marine conservation efforts? It’s not too late to join us on board! We still have a few spaces on trips this season departing from Ullapool, which gives us the opportunity to collect data from the northern reaches of our survey area, as well as a great chance to see more of our amazing diversity of marine life!

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Survey Summary: HWDT 10