June 2019
VSAS Survey report:Oban to Barra, June 8th and 9th 2019
Volunteer Seabirds At Sea (VSAS) surveys were carried out from the forward viewing platform of the Oban to Barra ferry on scheduled return crossings on 8th and 9th June 2019. Data were collected to European Seabirds At Sea (ESAS) standard, by trained volunteers, using the JNCC VSAS app to digitally record data in real time.
Environmental conditions were excellent for surveying, with visibility recorded as either good or excellent throughout. Both Beaufort wind force and seastate ranged between 0 and three, Swell heights were generally below one metre.
A total of 383 observations were made of 13 species of seabirds (and a further six 'species groups' where identification could not be made to species level) during the dedicated survey effort. Three species of marine mammals was observed. Numbers of observations and total numbers of birds and mammals recorded are presented below in Table 1.
Distribution maps
Figures 1 - 7 show the distributions of all seabird and marine mammal species recorded during the survey.
Figure 1. Observations of tubenoses, Oban - Barra survey, July 2019
Figure 2. Observations of gannet, Oban - Barra survey, July 2019
Figure 3. Observations of miscellaneous seabirds, Oban - Barra survey, July 2019
Figure 4. Observations of gulls, Oban - Barra survey, July 2019
Figure 5. Observations of guillemot and guillemot/razorbill, Oban - Barra survey, July 2019
Figure 6. Observations of other auks, Oban - Barra survey, July 2019
Figure 7.Observations of marine mammals, Oban - Barra survey, July 2019
Species | Number of observations | Total birds observed |
Black-headed gull | 1 | 1 |
Common gull | 1 | 1 |
Fulmar | 11 | 11 |
Gannet | 57 | 140 |
Great Skua | 3 | 3 |
Guillemot | 157 | 356 |
Kittiwake | 28 | 44 |
Manx Shearwater | 10 | 49 |
Puffin | 8 | 11 |
Razorbill | 37 | 92 |
Shag | 2 | 2 |
European storm petrel | 12 | 14 |
Black guillemot | 5 | 8 |
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Auk spp | 1 | 1 |
Common/Arctic tern | 9 | 16 |
Guillemot/Razorbill | 21 | 69 |
Large gull spp | 1 | 1 |
small gull spp | 2 | 3 |
tern spp | 2 | 3 |
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Grey seal | 6 | 6 |
Harbour porpoise | 7 | 10 |
Minke whale | 2 | 2 |
Table 1. Numbers of observations and totals recorded per species
Species accounts
See figures 1 - 7 for maps of observations
Fulmar(Fulmarus glacialis)
11 individuals were noted, with most records coming from mid channel.
Manx shearwater (Puffinus puffinus)
10 observations that comprised 49 individuals in total. Again, the majority of records came from north of Coll, but the numbers recorded here were much lower than in the previous two surveys.
European storm petrel (Hydrobates pelagicus)
12 records of 14 individuals, with all observations coming from more offshore areas.
Gannet(Morus bassanus)
With 57 observations totalling 140 individuals, this was the second most numerous species recorded during the survey. All records were from areas of more open water, and the largest aggregations were observed in eastern areas. As usual, tha majority of birds that were assigned an age code, were adults
Shag(Phalacrocorax aristotelis)
Two individuals were recorded as the boat approached Castlebay
Great skua(Stercorarius skua)
Three birds were observed, all in areas of open water
Black-headed gull (Croicocephalus ridibundus)
Just a single bird noted, an immature flying south, mid channel.
Kittiwake(Rissa tridactyla)
28 observations that comprised 44 individuals. All records were from areas of more open water, and they were observed most frequently in eastern areas.
Common gull(Larus canus)
A single bird noted in the eastern Minch
Guillemot(Uria aalge)
The most numerous species recorded during the survey, with 157 observations and a total of 356 individuals. Records came from all areas of more open water, but with slightly higher densities in more western areas.
Razorbill(Alca torda)
37 observations totalling 29 birds. As with guillemots, these birds favoured more open water, but with a stronger preference for western areas
Puffin(Fratercula arctica)
A relatively poor return of eight records totalling 11 individuals. As with guillemot and razorbill, there was a strong preference for areas of more open water.
Black guillemot(Cepphus grylle)
Five observations of this species, totalling eight individuals were noted. All were in the vicinity of Castlebay and its approaches.
Grey seal(Halichoerus grypus)
Six individuals were noted in total, with animals distributed widely over the survey route.
Harbour porpoise(Phocoena phocoena)
Seven observations totalling ten individuals, and detected from both mid-channel areas and the eastern Minch.
Minke whale(Balaenoptera acutorostrata)
Two separate individuals observed mid channel
Acknowledgements
Thanks to the volunteers who gave up their time to take part in this survey - we hope this report serves as a useful reminder of your time on board! We would also like to thank the Captain and crew of the Islay ferry for welcoming the survey team on board, and Klare Chamberlain and Ruth Rice at CalMac who helped with access and other arrangements. Finally, thanks to Simon Pinder and Rob Petley-Jones at MARINElife for coordinating volunteer effort.