29 January 2025

ORCA 2024 end of year summary

ORCA Ocean Conservationists, have had a brilliant survey season travelling on our ferry network during 2024.

Summary of ORCA's 2024 Survey Season

815 individual animals recorded in 2024 - this is less than in 2023 (1,054 animals) and highlights the importance of the year on year, continued monitoring by ORCA across CalMac vessels, with trends and shifts in distribution being reported on in real-time which is critically important for cetacean conservation
12 different marine species seen, including whales, dolphins, porpoises, seals and sharks - the highest number of species recorded in one year since our partnership started in 2017
A distance of 3,896 km was travelled whilst surveying
27 surveys were conducted between April and October across 5 different routes - unfortunately a few surveys were cancelled during the season due to the weather and no surveys could be conducted on the Ardrossan Campbeltown route in 2024 due to the ship being out of action
97 ORCA volunteer Marine Mammal Surveyors, many of which were from the local area conducted these important surveys - the highest number of volunteers surveying on this route in a single year since our partnership commenced in 2017
Common dolphins were the species recorded most frequently, 565 animals seen throughout the year and they were recorded on every route
There were increased sightings of humpback whales on the Ullapool-Stornoway route - 4 in 2024, 2 in 2023. This route in general appears to be a hotspot for baleen whales out of all of the routes surveyed, with fin whales and minke whale also recorded regularly on this route
Compared to 2023, the high density marine wildlife areas seem to have shifted north from the Oban-Castlebay route which saw less than half as many animals than in 2023, to Uig-Lochmaddy-Tarbert and Ullapool-Stornoway routes which saw almost double the number of animals seen in 2023
Less common dolphins were seen in 2024 (565 animals) compared to 2023 (706 animals) and fewer minke whales were also recorded. A possible explanation is that these two species have similar responses to environmental conditions and this year saw less favourable conditions around the Hebrides or more favourable conditions elsewhere, but further analysis would be needed to confirm this. If this is true, this has implications for understanding how species might respond to climate change, a key challenge in cetacean conservation
The first sei whale was recorded on the Uig-Lochmaddy-Tarbert route. This species is rarer than its relatives the fin and minke whales and comparatively little it known about its distribution and ecology which is why data collection is essential to better understand this species and the threats it faces