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CRUISE REPORT
Fair Isle Benthic Survey 2024
Moder Dy, Cruise No. 24/01,
4th – 6th September 2024
Fair Isle Benthic Survey 2024 - Cruise Report
Fair Isle Benthic Survey 2024 – Cruise Report
Author:
Tanya G Riley
Field Team:
Rebecca Geisler1, Joe MacDonald1, Geoff Young1
1 UHI Shetland – Scalloway Campus, Port Arthur, Scalloway, Shetland, ZE1 0UN
Corresponding author:
Tanya Riley
Post Graduate Marine Scientist
Marine Spatial Planning
UHI Shetland, Scalloway Campus, Port Arthur, Scalloway, Shetland, ZE1 0UN
tanya.riley@uhi.ac.uk
+44 (0)1595 772010
https://pure.uhi.ac.uk/en/persons/tanya-riley
Recommended citatation:
Riley, T.G. 2024. Fair Isle Benthic Survey 2024 – Cruise Report. Shetland UHI report. p10.
Copyright © Shetland UHI 2024. All rights reserved.
Shetland UHI, a limited company registered in Scotland, Number SC646337
Registered Scottish Charity Number SC050701
Fair Isle Benthic Survey 2024 - Cruise Report
Table of Contents
Acknowledgements ............................................................................................................. 3
1 Summary ...................................................................................................................... 4
2 Research Objectives ..................................................................................................... 4
3 Daily Cruise Log ............................................................................................................ 4
Day 1 – 4th September ................................................................................................................ 4
Day 2 – 5th September ................................................................................................................ 6
Day 3 – 6th September ................................................................................................................ 7
4 Preliminary Results ....................................................................................................... 8
Acknowledgements
This project was supported by players of People’s Postcode Lottery through the National Trust for
Scotland’s Love our Nature project.
Note – All times mentioned in this report are in British Summer Time.
Fair Isle Benthic Survey 2024 - Cruise Report
1 Summary
Scientists and crew from UHI Shetland conducted acoustic and drop down video (DDV) surveys aboard the
vessel the Moder Dy within the Fair Isle Demonstration and Research Marine Protected Area from 4th to 6th
September 2024 as part of the benthic research project.
2 Research Objectives
The Fair Isle Demonstration and Research Marine Protected Area (DR MPA) programme aims to address
key research priorities outlined in the Fair Isle DR MPA Research and Project Plan. The overarching goal is
to enhance understanding of biodiversity and the use of Fair Isle’s waters, supporting a comprehensive
ecosystem-based approach to marine environment management, conservation, and restoration.
Key Objectives:
• Investigate benthic species and habitats within the Fair Isle DR MPA to create the first detailed map
of species distributions and biotopes. This will serve as a baseline for future research and
management efforts.
• survey data to produce a detailed, illustrated research report with maps and figures, guiding future
research and marine management decisions.
• Produce a summary report with maps and photos for public dissemination, particularly targeting
the Fair Isle community, as part of ongoing data collection efforts.
• Present findings to the Fair Isle DR MPA Steering Group and the local Fair Isle community to inform
ongoing discussions and future research priorities.
Hydro-acoustic surveys aim to map the nearshore coastal waters around Fair Isle and will partly be
influenced by previous desk-based analysis. The Shetland UHI’s vessel, Moder Dy, will be used to carry out
a targeted area coverage survey using a hull mounted multibeam (WASSP WMB-160F). The multibeam
system outputs detailed bathymetry information and backscatter data which can be used in the creation
of habitat maps. The outputted information will be ground-truthed through a series of DDV drifts using a
C-Technics camera system comprising a CT3023 SLV full HD video camera.
3 Daily Cruise Log
Day 1 – 4th September
Table 1. Daily Vessel Activity Log – 4th September 2024 (Figure 1)
Left Port
At Site
Left Site
At Port
Comments
06.00
/
/
12.15
Scalloway-Fair Isle Travel
12.45
13.30
14.00
/
First survey attempt suspended due to dolphin activity
/
14.15
17.15
/
Hydroacoustic survey of South Haven
/
17.25
18.25
19.00
Hydroacoustic survey of North Haven
Fair Isle Benthic Survey 2024 - Cruise Report
At 5:30 a.m., the crew arrived at the Moder Dy, which departed at 6:00 a.m. and headed towards Fair Isle
under favorable weather conditions: visibility exceeded 10 km, with limited cloud cover and a swell of 1-
1.5m. During the transit, several cetaceans were observed, including Risso's dolphins and a Minke whale
off the west coast of Shetland. The Moder Dy docked in North Haven, Fair Isle at 12:15 p.m.
Afternoon surveys commenced with a reconnaissance trip from North Haven to South Harbour, navigating
the eastern side of the island, which was expected to be the most sheltered during the survey period. A
Risso’s dolphin was sighted east of the south-east of the South Harbour upon approach. It was determined
that the swell conditions were unsuitable for DDV drifts, and only the bays provided adequate shelter for
acoustic surveys. Marine mammal observations began en route to Whalebeck, where a Risso's dolphin
mother and calf pair were spotted 14 minutes into the observations, causing a delay in the survey start.
Fourteen minutes later, another pair of Risso's dolphins appeared and remained near the boat for 15
minutes, before the decision was made to move to another bay for surveying.
Observations continued on the way to South Haven, where no marine mammals were sighted. The hydro-
acoustic survey commenced at 2:15 p.m., with observations continuing during the active survey. Towards
the end of the survey, the boat encountered entanglement with a ghost rope, which was resolved by the
crew with no significant impact other than a brief pause. After completing the survey, the vessel relocated
to North Haven for hydro-acoustic surveying starting at 5:25 p.m., as no marine mammals had been sighted.
Survey conditions deteriorated, leading to the suspension of the survey at 6:25 p.m. due to increased swell,
which rendered the data patchy. It is recommended that North Haven be resurveyed, if possible, in future
surveys. The boat returned to port at 7:00 p.m.
Figure 1. Summary images of survey day 1 (4th September 2024, clockwise) all crew photo after first acoustic survey,
South Haven survey site from shore, marine mammal observations and acoustic survey data collection.
Fair Isle Benthic Survey 2024 - Cruise Report
Day 2 – 5th September
Table 2. Daily Vessel Activity Log – 5th September 2024 (Figure 2)
The vessel departed from port at 8:00 a.m. to conduct acoustic surveys in Whalebeck. Weather conditions
were overcast, with the swell having increased to 1.5-2m. Marine mammal monitoring was performed en
route to the survey site, but no cetaceans were observed. This monitoring continued throughout the survey
period, with no marine mammals sighted.
Towards the end of the acoustic survey in Whalebeck, the vessel made contact with an unidentified and
uncharted object on the seabed. Consequently, a decision was made to return to port to inspect the vessel
for potential damage. Upon return, the inspection revealed no visible damage. The crew used the
opportunity to assemble the Drop Down Video (DDV) camera equipment and conducted a trial from the
pier side. This trial successfully confirmed the functionality of the equipment.
Figure 2. Summary images of survey day 2 (5th September 2024, clockwise) skipper conducting acoustic surveys,
crew ready to deploy the drop-down video camera, footage from the drop-down video camera, all crew at their
stations during drop-down video camera drifts.
Left Port
At Site
Left Site
At Port
Comments
08.00
8.35
10.40
11.05
Hydroacoustic survey of Whalebeck
12.45
13.15
16.55
17.35
Hydroacoustic survey and camera drifts in Whalebeck
Fair Isle Benthic Survey 2024 - Cruise Report
Afternoon activities included resuming the acoustic survey in Whalebeck, with marine mammal monitoring
continuing as previously discussed. Conditions were evaluated and deemed suitable for conducting DDV
drifts within the sheltered bay. A total of eight drifts were completed over three hours, guided by acoustic
survey data to identify potential drift sites. However, the effectiveness of the drifts was influenced by the
vessel’s movement due to wind and tide, with the swell potentially impacting video quality. The camera's
drifting was less smooth due to the swell, but the number of camera drops to the seabed during the tows
were increased to try and mitigate this and improve biotope identification.
The skipper suspended the DDV survey at 4:55 p.m. due to deteriorating weather conditions outside the
bay. The return to port was made in rough weather, which would have made surveying outside the
sheltered bay impractical. Conditions were approaching the operational limits of the vessel. Upon return
to the harbour the vessel was refuelled before mooring up for the night.
Day 3 – 6th September
Table 3. Daily Vessel Activity Log – 6th September 2024 (Figure 3)
The vessel departed from port at 8:30 a.m. to conduct benthic survey efforts. The weather conditions were
foggy, but the swell had decreased to ~1 meter, the best conditions encountered during the survey period.
Snapshots of the acoustic data were taken for each surveyed region as a precautionary measure in case of
data issues. A decision was made to conduct DDV surveys in South Haven to provide biotope data for at
least two different regions. During the DDV camera drifts, the fog lifted, and the swell within the bay was
minimal, allowing for good video footage to be collected.
The skipper then decided to return to port to pack away the equipment and head back to the home port in
Scalloway. The vessel departed Fair Isle at 12:30 p.m. with the vessel arriving at Scalloway Harbour at 6:30
p.m., with all crew members disembarking by 7:30 p.m.
Left Port
At Site
Left Site
At Port
Comments
08.30
09.00
09.20
/
Screenshot of acoustic surveys – Whalebeck
/
09.30
09.40
/
Screenshot of acoustic surveys – South Haven
/
09.43
10.52
/
Drop down camera drifts in South Haven
/
11.01
11.09
11.15
Screenshot of acoustic surveys – North Haven
12.30
/
/
18.30
Fair Isle – Scalloway Travel
Fair Isle Benthic Survey 2024 - Cruise Report
Figure 3. Summary images of survey day 3 (6th September 2024, clockwise) drop-down video camera, all crew photo
after the final drop-down video drift and end of the 2024 benthic survey, camera drifts conducted in Whalebeck,
Moder Dy heading out to survey site.
4 Preliminary Results
4.1 Hydro-acoustic Surveys
Three areas to the east of Fair Isle were surveyed using hydro-acoustic methods. However, due to increased
swell and inconsistent data, it is recommended to resurvey North Haven in the future.
Table 4. Hydro-acoustic Surveys Log
Date
Time Start
Time End
Comments
4th September
14.15
17.15
South Haven
4th September
17.25
18.25
North Haven
5th September
08.35
10.40
Whalebeck
5th September
12.45
13.15
Whalebeck
Fair Isle Benthic Survey 2024 - Cruise Report
4.2 Drop Down Video (DDV) Camera Drifts
Two areas to the east of Fair Isle were surveyed using the DDV camera. On September 5th, eight DDV drifts
were completed in Whalebeck (Table 5), and on September 6th, four DDV drifts were completed in South
Haven (Table 6). The calmer conditions in South Haven allowed for better footage to be captured.
DDV drift 2 in Whaleeck was extended to twice the usual length due to decreasing drift speed and the want
to observe the boundary change between habitats as indicated by the acoustics.
Table 5. DDV camera drift logs – 5th September (Whalebeck)
Table 6. DDV camera drift logs – 6th September (South Haven)
Drift
Time (BST)
Latitude
Longitude
Speed (kt)
Depth (m)
Test
Start
14.07
59⁰31.319
001⁰37.222
0.2
34.0
Test
End
14.16
59⁰31.319
001⁰37.222
0.6
31.0
1
Start
14.31
59⁰31.334
001⁰37.316
0.6
33.3
1
End
14.41
59⁰31.351
001⁰37.345
0.4
32.3
2
Start
14.58
59⁰31.272
001⁰37.014
0.6
34.2
2
End
15.17
59⁰31.290
001⁰37.164
0.1
34.5
3
Start
15.29
59⁰31.372
001⁰36.988
0.6
34.1
3
End
15.37
59⁰31.414
001⁰36.976
0.6
23
4
Start
15.51
59⁰31.365
001⁰37.123
0.6
35.5
4
End
15.59
59⁰31.408
001⁰37.183
0.8
31.2
5
Start
16.09
59⁰31.292
001⁰37.280
0.8
32.8
5
End
16.15
59⁰31.277
001⁰37.344
0.4
31.8
6
Start
16.22
59⁰31.234
001⁰37.111
0.8
35.6
6
End
16.31
59⁰31.238
001⁰37.240
0.8
34.2
7
Start
16.41
59⁰31.251
001⁰37.087
0.8
34.6
7
End
16.51
59⁰31.248
001⁰37.216
0.4
34.5
Drift
Time (BST)
Latitude
Longitude
Speed (kt)
Depth (m)
Test
Start
09.47
59⁰31.917
001⁰36.432
0.2
20.2
Test
End
09.57
59⁰31.943
001⁰36.468
0.6
18.5
1
Start
10.06
59⁰31.876
001⁰36.467
0.8
20.1
1
End
10.16
59⁰31.940
001⁰36.500
0.8
13.1
2
Start
10.21
59⁰31.904
001⁰36.268
0.6
31.7
2
End
10.31
59⁰31.925
001⁰36.283
0.4
30.7
Fair Isle Benthic Survey 2024 - Cruise Report
4.3 Marine Mammal Observations
A total of four dedicated marine mammal observation effort surveys were conducted over the two days of
hydro-acoustic surveys. The first survey, on September 4th (Table 7), observed five Risso’s dolphins in three
separate groups over 45 minutes. This led to the suspension of the first survey and the vessel’s relocation
to South Haven. No further marine mammals were observed during the remaining hydro-acoustic activities.
Table 7. Marine Mammal Observation Effort
Marine mammals were observed on two of the three survey days (Table 8, September 4th and 6th), with a
total of seven separate sightings. Six sightings occurred on the first day, and one on the last day. Four
sightings were around the Shetland mainland, and three were within the Fair Isle DR MPA. The species
observed included Minke Whale, Risso’s Dolphins, and probable White-Beaked Dolphins.
Table 8. Marine Mammal Sightings
3
Start
10.37
59⁰31.923
001⁰36.358
0.4
24.7
3
End
10.47
59⁰31.945
001⁰36.356
0.6
25.8
Date
Time (BST)
Latitude
Longitude
Sea State
Swell (m)
04/09/24
Start
13.30
59⁰30.377
001⁰38.366
3
0.5 – 1.0
End
17.10
59⁰31.756
001⁰36.070
3
0.5 – 1.0
04/09/24
Start
17.15
59⁰31.876
001⁰36.467
2
1.0 – 1.5
End
18.25
59⁰31.940
001⁰36.500
2
1.0 – 1.5
05/09/24
Start
08.25
59⁰31.904
001⁰36.268
3
1.5 – 2.0
End
10.35
59⁰31.925
001⁰36.283
3
1.5 – 2.0
05/09/24
Start
12.55
59⁰31.923
001⁰36.358
3
1.5 – 2.0
End
13.50
59⁰31.945
001⁰36.356
3
1.5 – 2.0
Date
Time (BST)
Latitude
Longitude
Species
04/09/24
06.48
06.50
60⁰05.570
001⁰21.700
Minke Whale x1
04/09/24
07.40
07.42
59⁰59.652
001⁰23.421
Risso’s Dolphin x1
04/09/24
07.58
08.00
59⁰58.027
001⁰24.623
Risso’s Dolphin x1
04/09/24
13.20
13.22
59⁰30.414
001⁰37.966
Risso’s Dolphin x1
04/09/24
13.41
14.10
59⁰30.911
001⁰37.321
Risso’s Dolphin x2
04/09/24
13.57
14.10
59⁰30.834
001⁰37.472
Risso’s Dolphin x2
06/09/24
15.12
15.16
59⁰49.593
001⁰29.511
White Beaked Dolphins ~20