offshore isles of scilly survey november 2011 · 2013-08-06 · recorded on a sony gv‐hd700e in...

Cefas cruise report C5517

Offshore Isles of Scilly survey November 2011

Authors: Bill Meadows and Jackie Eggleton

Issue date: 30 November 2011

Offshore Isles of Scilly Survey 2011 Page i

Cefas Document Control

Title: Offshore Isles of Scilly Survey 2011

Submitted to: Natural England

Date submitted: 30 November 2011

Project Manager: Kelly Baker

Report compiled by: Bill Meadows and Jackie Eggleton

Quality control by: David Limpenny

Approved by & date: 30 November 2011

Version: V3

Version Control History

Author Date Comment Version

Jackie Eggleton 25th November 2011 V1

Bill Meadows 29th November 2011 V2

Jackie Eggleton 29th November 2011 V3

Offshore Isles of Scilly Survey 2011 Page ii

Offshore Isles of Scilly Survey 2011 Page iii

Title

Offshore Isles of Scilly Survey 2011

Authors: Bill Meadows and Jackie Eggleton

Issue date: 30 November 2011

Head office

Centre for Environment, Fisheries & Aquaculture Science

Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK

Tel +44 (0) 1502 56 2244 Fax +44 (0) 1502 51 3865

www.cefas.defra.gov.uk

Cefas is an executive agency of Defra

Offshore Isles of Scilly Survey 2011 Page iv

Table of contents

1 Introduction ................................................................................................................................... 1

1.1 Survey Project Team ............................................................................................................... 1

1.2 Location Map .......................................................................................................................... 1

1.3 Geological and Biological Context ........................................................................................... 1

2 Aims ................................................................................................................................................ 2

2.1 Search Strategy and Methods ................................................................................................. 2

3 Cruise Narrative ............................................................................................................................ 3

3.1 Cruise Narrative ...................................................................................................................... 3

4 Results ........................................................................................................................................... 5

4.1 Acoustic survey ....................................................................................................................... 5

4.2 Habitat Descriptions................................................................................................................ 6

5 Quality Control .............................................................................................................................. 9

5.1 Positioning ............................................................................................................................... 9

5.2 Acoustic systems ..................................................................................................................... 9

5.3 Seabed Video and Stills ........................................................................................................... 9

6 Human Activities ........................................................................................................................... 9

6.1 Evidence of Anthropogenic Activity ........................................................................................ 9

7 Health and Safety Events ............................................................................................................. 9

8 Annexes ....................................................................................................................................... 10

8.1 Annex 1: Survey Metadata .................................................................................................... 10

8.2 Annex 2 Media catalogue ..................................................................................................... 13

8.3 Calibration/Acceptance Report ............................................................................................. 13


Page 1 of 13

1 Introduction

1.1 Survey Project Team

Bill Meadows (SIC)

Dave Limpenny

Jacqueline Eggleton

Marc Whybrow

Sangeeta McNair (Natural England (NE))

Trainees Manuel Nicolaus

Ken May

Fay Luxford

1.2 Location Map

The survey area fell within the cSAC (dark blue square) of the Isles of Scilly (IOS cSAC) as shown in

Figure 1 below.

Figure 1 Survey area: Isles of Scilly cSAC

1.3 Geological and Biological Context

The rocky reef sub features of interest within the Isles of Scilly cSAC offshore survey are:


Page 2 of 13

Type 1 – Upstanding/pinnacle

Type 2 – Low profile/flat rocky outcrop

Type 3 – Boulder/cobble

2 Aims

1. To undertake the necessary survey work within the offshore areas of the site

according to the chosen sampling design using sidescan, multibeam and camera

2. To map the extent of reef, identifying the varying reef types and to provide data in a format to advise NE staff of the likely geographic limits of reef features.

3. To identify and record the nature and location of any obvious human impacts identified within or near the sites (e.g. trawl marks, dumped or discarded material, gear or nets).

2.1 Search Strategy and Methods

Multibeam bathymetry (Kongsberg EM3002D) and sidescan sonar (Edgetech 4200MP 300/600kHz)

were used to map the geophysical features of the sea floor within the IOS cSAC. The sidescan was

positioned using a combination of Thales 3011 DGPS position and cable layback entered into the

Discover logging and software package. Raw JSF and XTF files were generated in real time.

Multibeam was deployed on the drop keel, which was lowered to full extent to minimise the effect

of bad weather on the signal. Positioning was obtained using a Cnav 3050 DGPS with kinematic

position derived from the St Mary’s reference station and corrected for the multibeam heads with

an MRU5 motion reference unit. The track plot and 3D map of the seafloor derived from the

multibeam was visible in real time using an Olex system. This allowed potential areas of rocky reef

to be identified and sites selected for drop down video without the need for multibeam processing

on board. The inshore survey ROV video stations and any observed fixed gear marks were also

plotted on Olex.

The drop video camera and stills system was set up following Common Standards Monitoring, and in

particular the MESH guidelines ‘Recommended operating guidelines (ROG) for underwater video and

photographic imaging techniques’. The camera was placed in a drop down frame along with two


Page 3 of 13

Cefas high intensity LED striplights. A Cefas quad Laser scaler was aimed along the boresight of the

camera to give reference dimensions on the seabed as the frame varied in altitude. Video was

recorded on a Sony GV‐HD700E in DV tape format. The video and stills were annotated with time

and position using a GPS referenced video overlay. The Drop frame height was controlled via a

winch operator in sight of the video feed.

On arrival at each site, the drop camera system was deployed from the side gantry and lowered into

position just off the seabed. Once the camera was in position the ship moved along the transect

under dynamic positioning at a speed of 0.2 knots. A real‐time video link was fed to two monitors

positioned in the dry laboratory where a) scientists could observe the footage in order to provide a

summary of habitat types and dominant fauna present and b) to allow the winch operator to see

when the camera needed to be lifted and lowered depending on the bathymetry. Video footage was

acquired for the full length of each transect and still images were taken at 1 minute intervals where

possible. In practice these were collected on an opportunistic basis due to weather and swell

limitations.

Logsheets were populated for each station with the time, position and water depth at the start and

end of each transect along with a brief summary of the main habitat types and species present.

Video footage was simultaneously recorded onto two Digital Video Tapes (DVT) and a media

catalogue was populated to show which tape or disk contained the video footage acquired at each

station. Still images were downloaded from the camera system at regular intervals and were stored

and backed up on two separate portable hard drives.

3 Cruise Narrative

3.1 Cruise Narrative

RV Cefas Endeavour sailed from Portland on Monday 31st October 15:00hrs to arrive in the

Scillies at 07:00hrs Tuesday 1st November. Two pilots and a Natural England representative,

Sangeeta McNair, were transferred to the ship by pilot boat.


Page 4 of 13

The survey commenced during good but deteriorating weather, starting with a combined

sidescan and multibeam acoustic survey around the inner ring of planned lines. On

reaching the south western extent of the cSAC the survey continued northwards in order to

map the north western region. The drop down video survey commenced on the evening of

the 1st November in the north west corner of the cSAC. Four stations were surveyed (NW1,

NW2, NW2b and NW3) that were identified on OLEX as potential rocky reef. The weather

conditions did not allow continuous sight of the seabed therefore stills were taken

opportunistically when the seabed was visible. Deteriorating weather conditions resulted

in cessation of the video survey and continuation with multibeam and sidescan. The

acoustic survey continued in a zig‐zag fashion from north to south overnight, in order to

obtain suitable coverage of the north western region before the weather deteriorated

further overnight. The following day (2nd November) the lee shore found to the north and

north east enabled the drop down video to be deployed along a range of habitats indicated

by the acoustic survey. Stations N4, N6, N7, N8, N9, N10 and N11 were completed heading

south down the westerly side of the Isles of Scilly.

The rough weather gave poor visibility of fixed gear marks. When combined with noisy sea

conditions, it precluded any further sidescan work. Despite the heavy westerly swell further

infilling by multibeam, interspersed with camera operation, was still possible.

During the survey the weather deteriorated to such an extent that survey was abandoned

in the south. Priority was given to survey of the northern and western extent of the cSAC

boundary.

The survey ended in the south west on Thursday 3rd November at 07: 00 after completing

stations N12a, N13, N17, N5, N14 and N18. After transferring the pilots and NE

representative to the pilot boat, RV Cefas Endeavour left the Isles of Scilly and sailed to

Portland to demobilise staff and equipment. Endeavour docked in Portland at 08:30hrs on

Friday 4th November.


Page 5 of 13

4 Results

4.1 Acoustic survey

Figure 2 Olex depicting overall coverage of multibeam (grey areas) fixed gear observations (red flags) and camera positions (yellow boxes)

Figure 3 Olex used during camera drop along transect (purple arrowed line) – the reef is shown as a raised shadowed area on the grey overlay. The reef profile is shown as the blue contour in the inset box


Page 6 of 13

4.2 Habitat Descriptions

Stn No. Habitat/Faunal Summary Still Image

5

(NW1)

Sand and sandy gravel (with shell) at

start of transect leading to areas of

visible bedrock and cobbles. Fauna

present: Brittlestars (Ophiothrix sp.),

Urticina, erect branching sponges,

faunal turf, Cellaria sp.

6

(NW2)

Sandy gravel with faunal turf at start

of transect, leading to sand over rock

and cobbles. Fauna visible: Ophiothrix

sp., cushion star

7

(NW2b)

Sand scoured bedrock with

Pomatoceros spp. tubes and faunal

turf.

8

(NW3)

Sandy gravel with cobbles at start of

transect leading to sands and rippled

sands with faunal turf overlying

bedrock. Cobbles encrusted with

Pomatoceros spp. tubes. Frequent

Ophiothrix sp.

11

(N4)

Common Ophiothrix and faunal turf

including Cellaria sp. on sand covered

bedrock. Boulder/ upstanding reef

mid‐transect with yellow sponges,

Alcyonium digitatum, Pentapora

fascialis reverting to sand covered

bedrock with common Ophiothrix sp.

and faunal turf, Luidia ciliaris.

No stills


Page 7 of 13


Fixed gear at station

13

(N6)

Common Pentapora fascialis with

attached crinoids on boulders and

upstanding reef (with yellow sponges,

Metridium senile, Holothurian)

interspersed with sand covered

bedrock

14

(N7)

Gravelly fine sand or silt on rock.

Pentapora fascialis, Abietinaria

abietina, jewel anemones, yellow

sponges on boulders

15

(N8)

Flat bedrock and cobbles with faunal

turf and Ophiothrix sp., Nemertesia

antennina and other faunal turf

No stills

16

(N9)

Sand covered bedrock with faunal turf

and common Ophiothrix sp. leading to

sand scoured rock with no fauna and

later to frequent Nemertesia

antennina

17

(N10)

Gravelly shelly sand with occasional

boulder covered with faunal turf,

sponges and jewel anemones.

18

(N11)

Gravelly sand over rock with

Ophiothrix sp. and faunal turf


Page 8 of 13


19

(N12)

Shelly sand – no fauna visible

20

(N12A)

Common Ophiothrix on sand covered

rock with faunal turf. Marthasterias

glacialis. Sand waves in between rocky

areas.

21

(N13

Common Ophiothrix on sand covered

rock with faunal turf

22

(N17)

Sand, gravel and shell on rock with

faunal turf. Occasional Pentapora

fascialis, common Ophiothrix sp.

23

(N4)

Station abandoned due to fixed gear

24

(N5)

Upstanding rocky reef. Jewel

anemones, Cellaria sp., Pentapora

fascialis

25

(N14)

Rocky reef with common Ophiothrix,

Cellaria sp. and faunal turf. Erect

sponges. Towards the end of the

transect the rock is covered with sand

26

(N18)

Upstanding rocky reef with abundant

jewel anemones, Alcyonium

digitatum, Pentapora fascialis, erect

yellow sponges, possible Eunicella

verrucosa


Page 9 of 13

5 Quality Control

5.1 Positioning

Acoustic systems used the Cnav 3050 Kinematic DGPS and Thales 3022 DGPS using Veripos

differential corrections.

Drop down camera positions were determined using the Olex system.

All stills positions were fixed using CEMAP Tower Hydrographics software connected to the ships

Thales 3022 DGPS

5.2 Acoustic systems

EM3002D Multibeam running SIS acquisition software

Edgetech 4200MP 300/600 sidescan running discover software

5.3 Seabed Video and Stills

Camera (video and stills) model: Kongsberg OE14‐208

Flash model: Kongsberg 11‐242

Underwater lights – Cefas high power LED strip lights

Video and stills camera settings were variable depending on underwater visibility and ambient light

levels.

6 Human Activities

6.1 Evidence of Anthropogenic Activity

Fixed fishing gear was ubiquitous over the survey area and was logged on the vessels survey

navigation system.

7 Health and Safety Events

No health and safety events or incidents occurred during the survey


Page 10 of 13

8 Annexes

8.1 Annex 1: Survey Metadata


Page 11 of 13

Cruise code Transect Stn No Stn Code Gear Date Time Lat deg Lat min N/S Long Deg Long min E/W Depth

CEND19x11 SOL 5 NW1 DC 01/11/2011 18:23 49 58.532 N 6 28.091 W 90

CEND19x11 EOL 5 NW1 DC 01/11/2011 18:49 49 58.513 N 6 28.016 W 90

CEND19x11 SOL 6 NW2 DC 01/11/2011 19:25 49 59.084 N 6 27.316 W 90

CEND19x11 EOL 6 NW2 DC 01/11/2011 19:40 49 59.097 N 6 27.327 W 90

CEND19x11 SOL 7 NW2B DC 01/11/2011 20:19 49 59.277 N 6 27.226 W 92

CEND19x11 EOL 7 NW2B DC 01/11/2011 20:37 49 59.408 N 6 27.278 W 93

CEND19x11 SOL 8 NW3 DC 01/11/2011 21:15 49 59.941 N 6 27.531 W 92

CEND19x11 EOL 8 NW3 DC 01/11/2011 21:37 49 59.944 N 6 27.415 W 91

CEND19x11 SOL 11 N4 DC 02/11/2011 11:10 49 59.374 N 6 18.405 W ‐

CEND19x11 EOL 11 N4 DC 02/11/2011 11:39 49 59.282 N 6 18.345 W ‐

CEND19x11 SOL 13 N6 DC 02/11/2011 17:03 49 58.423 N 6 15.167 W 52

CEND19x11 EOL 13 N6 DC 02/11/2011 17:26 49 58.310 N 6 15.037 W 58

CEND19x11 SOL 14 N7 DC 02/11/2011 18:05 49 58.511 N 6 15.022 W 62

CEND19x11 EOL 14 N7 DC 02/11/2011 18:36 49 58.398 N 6 14.774 W 70

CEND19x11 SOL 15 N8 DC 02/11/2011 19:43 49 59.085 N 6 14.187 W 79

CEND19x11 EOL 15 N8 DC 02/11/2011 20:08 49 59.008 N 6 14.139 W 79

CEND19x11 SOL 16 N9 DC 02/11/2011 20:44 49 59.411 N 6 15.124 W 80

CEND19x11 EOL 16 N9 DC 02/11/2011 21:10 49 59.485 N 6 15.131 W 80

CEND19x11 SOL 17 N10 DC 02/11/2011 22:46 49 58.996 N 6 16.910 W 66

CEND19x11 EOL 17 N10 DC 02/11/2011 23:05 49 59.031 N 6 16.871 W 77

CEND19x11 SOL 18 N11 DC 02/11/2011 23:45 49 59.591 N 6 16.183 W 79

CEND19x11 EOL 18 N11 DC 03/11/2011 00:07 49 59.571 N 6 16.108 W 79

CEND19x11 SOL 19 N12 DC 03/11/2011 00:39 49 59.820 N 6 16.060 W 75

CEND19x11 EOL 19 N12 DC 03/11/2011 00:56 49 59.860 N 6 16.010 W 76

CEND19x11 SOL 20 N12A DC 03/11/2011 01:15 49 59.930 N 6 15.940 W 77

CEND19x11 EOL 20 N12A DC 03/11/2011 01:26 49 59.960 N 6 15.910 W 77


Page 12 of 13

Cruise code Transect Stn No Stn Code Gear Date Time Lat deg Lat min N/S Long Deg Long min E/W Depth

CEND19x11 SOL 21 N13 DC 03/11/2011 02:00 49 59.530 N 6 17.090 W 75

CEND19x11 EOL 21 N13 DC 03/11/2011 02:15 49 59.567 N 6 17.130 W 77

CEND19x11 SOL 22 N17 DC 03/11/2011 02:49 49 59.310 N 6 17.940 W 75

CEND19x11 EOL 22 N17 DC 03/11/2011 03:21 49 59.440 N 6 18.070 W 75

CEND19x11 SOL 24 N5 DC 03/11/2011 04:30 49 59.250 N 6 18.960 W 72

CEND19x11 EOL 24 N5 DC 03/11/2011 04:51 49 59.345 N 6 19.080 W 76

CEND19x11 SOL 25 N14 DC 03/11/2011 05:17 49 59.123 N 6 19.770 W 73

CEND19x11 EOL 25 N14 DC 03/11/2011 05:17 49 59.179 N 6 19.927 W 77

CEND19x11 SOL 26 N18 DC 03/11/2011 06:53 49 55.196 N 6 26.090 W 56

CEND19x11 EOL 26 N18 DC 03/11/2011 07:17 49 55.216 N 6 26.220 W 65


Page 13 of 13

8.2 Annex 2 Media catalogue

Cruise Code Label Stations Label

CEND19x11 DVT 1 5,6,7, DVD 1 5,6,7

CEND19x11 DVT 2 8,11 DVD 2 8,11,13

CEND19x11 DVT 3 13,14, DVD3 13,14

CEND19x11 DVT 4 15,16 DVD 4 15,16

CEND19x11 DVT 5 17,18, DVD 5 17,18,

CEND19x11 DVT 6 19,20,21 DVD 6 19,20,21

CEND19x11 DVT 7 22,24 DVD 7 22,24

CEND19x11 DVT 8 25,26 DVD 8 25,26

8.3 Calibration/Acceptance Report

Multibeam/DGPs calibration is covered by the report of survey (ROS) Cruise CEND2C-1

and can be provided on request.

© Crown copyright 2011

About us Cefas is a multi-disciplinary scientific research and consultancy centre providing a comprehensive range of services in fisheries management, environmental monitoring and assessment, and aquaculture to a large number of clients worldwide.

We have more than 500 staff based in 2 laboratories, our own ocean-going research vessel, and over 100 years of fisheries experience.

We have a long and successful track record in delivering high-quality services to clients in a confidential and impartial manner. (www.cefas.defra.gov.uk)

Cefas Technology Limited (CTL) is a wholly owned subsidiary of Cefas specialising in the application of Cefas technology to specific customer needs in a cost-effective and focussed manner.

CTL systems and services are developed by teams that are experienced in fisheries, environmental management and aquaculture, and in working closely with clients to ensure that their needs are fully met. (www.cefastechnology.co.uk)

Customer focus With our unique facilities and our breadth of expertise in environmental and fisheries management, we can rapidly put together a multi-disciplinary team of experienced specialists, fully supported by our comprehensive in-house resources.

Our existing customers are drawn from a broad spectrum with wide ranging interests. Clients include:

international and UK government departments

the European Commission

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non-governmental and environmental organisations

regulators and enforcement agencies

local authorities and other public bodies We also work successfully in partnership with other organisations, operate in international consortia and have several joint ventures commercialising our intellectual property

.

Head office

Centre for Environment, Fisheries & Aquaculture Science Centre for Environment, Fisheries & Aquaculture

Science

Pakefield Road, Lowestoft, Barrack Road, The Nothe Suffolk NR33 0HT UK Weymouth, DT4 8UB

Tel +44 (0) 1502 56 2244 Tel +44 (0) 1305 206600

Fax +44 (0) 1502 51 3865 Fax +44 (0) 1305 206601

Web www.cefas.defra.gov.uk

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