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Corporate CalMac

May 2019

VSAS Survey report: Oban to Barra, May 11th and 12th 2019

 

Volunteer Seabirds At Sea (VSAS) surveys were carried out from the bridge of the MV Isle of Lewis on a scheduled return crossing between Oban and Barra on May 11th and 12th 2019. Data was 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 excellent throughout. All observations were made in seastate and Beaufort wind force three or below. Swell heights were generally below one metre.

A total of 197 observations were made of 14 species of seabirds (and a further three 'species groups' where identification could not be made to species level) during the dedicated survey effort. Four species of marine mammals were observed. Numbers of observations and total numbers of birds and mammals recorded are presented below in Table 1.

 

 

Distribution maps

 

Figures 1 - 8 show the distributions of all seabird and marine mammal species recorded during the survey.

 

Observations

Figure 1. Gannet and Fulmar observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 2. Manx shearwater observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 3. Great northern diver and shag observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 4. Skua observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 5. Gull observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 6. Guillemot observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 7. Other auk observations during Oban - Barra survey, May 11th and 12th 2019

 

Observations

Figure 8. Marine mammal observations during Oban - Barra survey, May 11th and 12th 2019

 

 

Species

Number of observations

Total birds observed

Fulmar

3

4

Gannet

3

3

Great black-backed gull

1

1

Great northern diver

2

3

Great Skua

3

3

Guillemot

98

240

Herring gull

4

4

Kittiwake

5

6

Manx Shearwater

23

451

Pomarine skua

1

1

Puffin

7

20

Razorbill

4

4

Shag

3

4

Black guillemot

1

1

 

 

 

Guillemot/Razorbill

8

18

Large gull spp

4

44

Skua spp

1

1

 

 

 

Minke whale

2

2

Common dolphin

15

97

Harbour porpoise

5

9

Grey seal

4

4

 Table 1. Numbers of observations and totals recorded per species

 

Species accounts

See figures 1 - 8 for maps of observations

 

Fulmar(Fulmarus glacialis)

Very few fulmars were recorded during this survey compared to the survey in April (just four birds compared to 220). All four birds were recorded mid channel, away from western areas where densities were highest the previous month.

 

Gannet(Morus bassanus)

As with fulmar, numbers of gannets were greatly reduced compared to the April survey (three birds compared to 47). Bird were observed mid channel and in the east of the survey area, away from western areas where densities were highest the previous month.

 

Manx Shearwater (Puffinus puffinus)

The most numerous species recorded on the survey, with large aggregations observed north east and north west of Coll, in similar areas to the large aggregations observed during the previous month's survey.

 

Shag(Phalacrocorax aristotelis)

Just three records of four birds. This species was not recorded during the April survey.

 

Great northern diver (Gavia immer)

Two observations totalling three birds, both from eastern parts of the survey area. This species was not recorded during the April survey.

 

Great skua(Stercorarius skua)

Three observations of three separate individuals of great skua, a species not recorded on the April survey. All were from eastern parts of the survey area.

 

Pomarine  skua (Stercorarius pomarinus)

A single record of an unaged intermediate bird north west of Coll.

 

Kittiwake(Rissa tridactyla)

Five records totalling six individual birds, all coming from eastern areas, or mid-channel.

 

Great black-backed gull(Larus marinus)

A single observation of one bird, north east of Coll.

 

Herring gull (Larus argentatus)

Four individuals recorded, with three of those observed in the western part of the Sound of Mull.

 

Guillemot(Uria aalge)

The most frequently recorded species, with 98 observations totalling 240 birds. Almost all of the birds were recorded mid-channel or in eastern areas, showing the same pattern as that seen in April.

 

Razorbill(Alca torda)

As with the April survey, there were very few observations of this species, with just four individuals recorded.

 

Puffin(Fratercula arctica)

Seven observations totalling 20 individuals. All records were from areas north east and north west of Coll.

 

Black guillemot (Cepphus grylle)

A single individual observed to the north east of Coll

 

Minke whale (Balaenoptera acutorostrata)

Two minke whales were observed, both in areas north of Coll that had also shown high densities of a variety of bird species.

 

Common dolphin (Delphinus delphis)

An excellent run of records from north of the eastern part of Coll, with 15 records comprising 97 individuals, including a group of 50 animals.

 

Harbour porpoise (Phocoena phocoena)

Five observation comprising nine individual animals. All were from areas north of Coll.

 

Grey seal (Halichoerus grypus)

Four records of four individuals, all from the area to the north of Coll.

 

 

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 MV Loch Isle of Lewis for welcoming the survey team on board, and to 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.

List for May 2019

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