Scotland: Studying & protecting basking sharks, whales, dolphins and other cetaceans around the Hebridean Islands through citizen science
- Matthias Hammer
- Olivia Harries
Abstract In 2013, Biosphere Expeditions and the Hebridean Whale and Dolphin Trust (HWDT) together ran four marine mammal and basking shark monitoring surveys from Tobermory, Isle of Mull, Scotland. Visual and acoustic surveys were carried out by HWDT, as well as photo-identification of target species between May and the end of September, with Biosphere Expeditions teams involved for two months between June and September. In total, 2,868 nautical miles (nm) of visual and 2,681 nm of acoustic surveys were conducted. During the whole survey season, 722 visual sightings were recorded: 408 of these sightings were of cetacean species, 282 were of pinnipeds and 32 sightings were of basking sharks. Photo-identification data were collected during encounters of 14 common dolphin, 6 white-beaked dolphin, 1 bottlenose dolphin, 1 Risso’s dolphin, 1 orca and 26 basking shark. There were 821 harbour porpoise acoustic detections. Acoustic recordings were also made of common dolphin, white-beaked dolphin, bottlenose dolphin, Risso’s dolphin, orca and the two pinniped species (common and grey). In total, 325 items of marine litter were recorded, as well as 3,051 static fishing gear marker buoys. In addition, 782 half-hour bird and boat traffic surveys were completed. The species sighted in 2013 were consistent with previous years, with harbour porpoises being the most regularly sighted marine mammal species, closely followed by the pinniped species. The data gathered in 2013 will be incorporated into HWDT’s databases, where they will be available for future comprehensive analyses of species distribution, relative abundance and habitat preferences.