1

Development of Low Budget Survey Equipment and Techniques for Shallow

Water Ecosystems: A Case Study of the Fal Estuary Seagrass beds

Clive Pollittt and Claire Eatock

Author’s biographical information

Mr Clive Pollitt, FdSc Marine Science student. Falmouth Marine School. Falmouth, Cornwall,

UK. clivepollitt@aol.com.

Dr Claire Eatock. FdSc Marine Science lecturer. Falmouth Marine School. Falmouth, Cornwall,

UK. Claire.eatock@falmouthmarineschool.ac.uk

Claire Eatock is a lecturer and Clive Pollitt a foundation degree student at Falmouth Marine

school. Clive is an engineer interested in promoting marine biology to the general public.

Falmouth Marine School

Killigrew Street

Falmouth

Cornwall

TR11 3QS

United Kingdom

Tel: 01326 310 310

2

Abstract

Seagrass beds are one of the many shallow water benthic habitats that need to be regularly

monitored. This project used the seagrass beds in the Fal estuary in Cornwall UK as a test case

to develop inexpensive shallow water habitat surveying equipment that would be suitable for

colleges and amateur conservationists. It came up with four devices; a simple glass bottomed

box that could be mounted on the side of a boat; a video camera mounted on a long extending

pole that could give close-up pictures of the benthos; a photo/video-quadrat made from industrial

shelving material that could record statistical data for benthic habitats and finally an underwater

towed video monitoring system that could be used to cover large benthic areas. With these

pieces of equipment a successful baseline survey of the Fal estuary Seagrass beds was

completed.

Keywords

Benthic, Survey, Seagrass, Volunteer Bio-monitoring.

Introduction

Surveying shallow marine benthic environments is important for conservation groups,

environmental monitoring, water quality control, pollution monitoring and for monitoring global

warming and ocean acidification. (Rhoads 2004) A large amount of marine life is within the

shallow photic zone just beyond the shore and in the inter-tidal zone.

The costs associated with this type of surveying have become prohibitive due the sheer amount

of area to be covered. This has resulted in large areas being infrequently surveyed, if at all, and

environmental and planning decisions cannot be easily made with confidence if current coastal

survey data is not available. An example of this is in the Fal estuary in Cornwall, England where

a Special Area of Conservation (SAC) was established in 1992 as a result of the European

Habitats Directive. The local harbor commissioners are one of the organizations who have been

3

made responsible for environmental monitoring of the estuary but have very little current data.

This is a very typical situation in Britain and Europe at large. The reasons for this situation are

the costs involved with environmental surveying which are often outside the budget of small

environmental organizations.

The Fal estuary was made a SAC largely because of the maerl and seagrass beds that are present

within it. There is however very little current environmental habitat survey data available, the

habitat map presently in use being more than 20 years old. (Kevan Cook, Lead Advisor, Marine,

Truro, Natural England, personal communication, 23 September 2010)

Volunteer based monitoring programs have been designed and initiated by many organizations

including Seagrass Watch, (McKenzie 2002) but many have found that these programs are

difficult to sustain. This is largely due to the fact that most Seagrass is below the water for much

of the time and qualified volunteer divers are required to do the surveying. (Short 2009)

Different monitoring options are dependent on the structure and resources available, e.g.

cumbersome methods are not practical for volunteer-based monitoring networks and also the

adequacy of different methods for the various species, which requires knowledge of their growth

rates and basic ecology. (Duarte 2003)

Many types of equipment have been used to overcome the difficulty of using professionally

qualified divers. Professional surveying institutions often overcome this by the use of remotely

deployed video equipment (Potts 1982), which has become a well established tool in many areas

of marine research. (Holme 1984) Towed video sledge techniques provide a means to visually

survey large areas of seafloor without the depth or time constraints usually associated with other

techniques such as scuba diving. (Sisman 1982)

In the past, techniques such as this have been used to monitor the condition of features in

candidate Special Areas of Conservation (SAC) (Magorrian 1996) Towed video sledge data can

4

be used to estimate the relative abundance of benthic species using the Visual Fast Count (VFC)

technique. (Kimmel 1985) The main disadvantage of the towed video sledge system is the

potential damage it can cause to the fragile seafloor habitat that it is recording. (Grizzle 2008)

An alternative is to have a Drop Down Video System (DDVS) which is a camera mounted on a

frame, often associated with a quadrat. (Holt, Sanderson 2001) This is lowered to the seafloor

where it remains stationary whilst recording the benthos. The position is given by a Global

Positioning System (GPS) receiver and the equipment is then moved to a new location often on a

pre-set transect. DDVS recording techniques have been used in a variety of applications and are

appropriate for the identification of seabed habitats. (Sanderson et al. 1999)

An underwater Remotely Operated Vehicle (ROV) is a self propelled underwater camera system

often with artificial lighting capable of descending to depths unreachable by divers and is

considered suitable for biotype surveying and monitoring. (Arbour 2004) The ROV is usually

connected to a surface support vessel via a tether cable which controls the ROV’s movements

and passes the underwater video image to the operator for control and recording purposes. Due

to their maneuverability these systems are able to acquire great detail of the biotype. Together

with GPS equipment and on-board recorders these systems combine the flexibility of a diver

together with the advantages of remote control.

The disadvantage of ROV, towed and drop down video systems is the expense of the equipment

and of the support vessel, deploying equipment and tethers and the need for highly trained

personnel. (Epstein 2010) These factors usually place these survey techniques out of the reach of

small, low budget surveying organizations and volunteer initiatives. (Short 1984)

The purpose of this project was to develop inexpensive and safe shallow benthic surveying

equipment using basic skills and the recent development of inexpensive high definition digital

video cameras and recording equipment. The Seagrass beds in the Fal estuary were chosen as a

test case.

5

1) Aqua-scope

The first device developed was built along the lines of a glass bottomed boat. (See figure1) This

piece of equipment was a large wooden box 75cm high by 75cm long and 40cm wide. The

bottom of the box had a glass water-proof window installed with handles and boat attachment

points placed along the sides of the box. The inside was painted matt black and a removable top

with an observation port were added. It was named the Aqua-scope.

Deployment

When the boat had reached the right location to be surveyed the position and depth were taken

using the boats onboard fish finder and GPS. The Aqua-scope was then placed in position over

the side of the boat and secured with its fastenings. Viewing of the seafloor was simply done by

looking into the viewing port. The boat was allowed to drift and the depth, GPS positions and

benthos were noted as it did so. Still camera and video photography was possible with the

camera placed at the viewing port or lowered to the glass pane where a very wide field of view

was possible.

Results

General observation underwater to a depth of 4 to 5 meters in bright, calm conditions was

possible at slack low tide. (See figure 2) The Aqua-scope was successfully used to map the

position of the major sea-grass beds in the Fal and in particular the St. Mawes Eelgrass meadow

near the Fal entrance.

Four surveys were conducted in the summer months of June, July and September and three

during March using the Aqua-scope. It was also used in conjunction with the other surveying

equipment developed in the project to help observe the performance and deployment of the

equipment.

6

Materials and Costs (See table 1)

Capabilities and limitations

The data collected by the Aqua-scope could be considered to be equivalent to the data obtained

from surface snorkeling i.e. a general visual survey of areas of the seafloor where the benthos

type , coverage and location could be observed and recorded manually.

The main limitation of the Aqua-scope was the limited depth to which it can be used and the

inability of the boat to maneuver with it deployed. Any movement by the boat against the tide

resulted in turbulence and bubbles around the observation glass. The weather conditions had to

be bright and calm and the survey had to take place during slack tide, preferably spring low tide,

when the water had the lowest turbidity conditions.

A suggestion for its improvement would be to have a more streamlined design with strong

attachment points to the boat that would make limited maneuverability possible.

2) Scubar

In order to have a closer look at the benthos, and in this case the seagrass, observed with the

Aqua-scope it was necessary to develop a simple video system that could get within centre

meters of the seagrass. A simple all-in-one water-proof video head- camera (Oregon Scientific

Action Camera ATC-3k) was mounted on a 5 meter fiberglass extending window cleaning pole

and used to place the camera into the desired position below the boat. This system was called the

Scubar.

The camera was set to record and its timer synchronized with the boats onboard clock along with

the GPS position and depth. This was blind recording but worked well where the general

7

condition of the seagrass was required. The footage recorded was analyzed in conjunction with

the recorded depth and position afterwards by re-synchronizing the results.

An improvement of this system was to replace the head-camera with a waterproof closed circuit

television (CCTV) camera that was connected to a boat mounted monitor and recorder via a long

tether cable. A video monitor and a mini digital-video recorder were used. The monitoring and

recording could be performed by a laptop computer with basic video recording web-cam

software and video input adaptor. (The lap-top computer monitoring and recording system was

used on the Delta-wing, see later) This allowed real time monitoring and a recording for later

analysis.

Deployment

The Scubar was simply put over the side of the boat on arrival at the chosen survey location. The

pole was extended to the required depth and held above the benthos by using the boats on-board

depth meter and a graduated scale on the Scubar lowering pole. The Scubar was allowed to

record the benthos for a preset time and then raised to the surface and the boat moved to the next

location where the same procedure was repeated.

Results

This system was very simple to use and required minimal set up and preparation. Being totally

waterproof it was used on a small inflatable dinghy and canoe allowing access to areas not

normally accessible to motorboats. This system was aided by the simultaneous use of the Aqua-

scope to position and orientate the camera at the end of the pole.

The CCTV system was more complicated, requiring external power for the monitor, camera and

recorder. The length of the tether cable had an effect on the video signal quality and hence the

recorded image.

8

The Scubar was able to examine the outer limits of the Seagrass areas with more detail than with

the Aqua-scope, when it was often unclear whether the seafloor coverage was seaweed or

Seagrass. (See figure 3) The Scubar was able to positively identify the Seagrass and seaweed in

these situations. Eight successful surveys of the Fal Seagrass beds were conducted with the

Scubar in June, July, September and October in 2010 and in March 2011.

Materials and Costs (See tables 2 and 3)

Capabilities and Limitations

The data collected by the Scubar could be considered to be equivalent to the data obtained from

scuba diving down to 5 meters, i.e. a close visual survey of the seafloor where the benthos type,

coverage and position could be observed and recorded manually in detail.

The limitation of the Scubar was the inability of the boat to maneuver with it deployed.

The boat was only able to drift with the tide, as to maneuver the boat with the pole extended,

threatened to break the pole. A drifting transect was possible but not a preset transect. The

Scubar had to be used as part of a fixed point survey method where it was deployed and

recovered between preset way-points.

Another limitation of the Scubar was the limited depth to which it could be used. Like the Aqua-

scope, the weather conditions had to be bright and calm and the survey had to take place during

slack tide, preferably spring low tide, when the water had the lowest turbidity conditions. The

Scubar was also limited to the depth rating of the camera used.

A suggestion for improvement would be for a sturdier pole with a boat mounting to hold it in

position and a high definition camera with lighting to enable deeper surveys in darker

conditions.

9

3) Photo-quadrat.

In order to collect data that could be statistically analyzed a Photo-quadrat system was

developed. This survey would traditionally be undertaken by a diver with a quadrat and possibly

an underwater camera. The Photo-quadrat was a metal cage fitted with an underwater digital

stills camera, connected to a remote triggering system. The cage was lowered to the seabed and

the camera triggered from the boat above.

The cage had a 0.5m square base and was one meter tall with a grid pattern built into the base.

(See figure 4) It was constructed of galvanized metal “Dexion”, an industrial shelf rack system

that can be used for construction of framework due to its narrow (3cm) L section, long lengths

and its multiple pre-drilled mounting holes. The grid pattern was made of fine nylon cord that

was laced at measured intervals along the bottom of the cage. The cage was held together with

nuts and bolts through the multiple holes in the Dexion lengths. Small half Kilogram zinc

weights were added to the base to provide better stability.

The camera was mounted on the top of the cage using its tripod fitting and was positioned

pointing towards the base. The trigger release mechanism was a small water-proofed electric

solenoid positioned on the frame to activate the camera shutter via the solenoid’s plunger. (See

figure 5) The solenoid was connected via a long cable connected to a 12v battery and activation

trigger on the boat.

Deployment

The camera was pre-focused on the Photo-quadrat base and lowered to the seafloor whilst the

GPS position and depth were recorded from the boats instruments. Once the Photo-quadrat had

reached the bottom, it was left for a couple of minutes for any disturbed sediment to settle and

the camera trigger activated. The equipment was then raised to the surface and moved to the next

point and the process repeated.

10

A further development of the Photo-quadrat was the substitution of the still camera with an

underwater high definition (HD) video camera. This camera was attached to the Photo-qaudrat in

the same way as the stills camera and lowered to the seabed. The camera was set to record

before it was lowered as it required no trigger release mechanism and could be left on the

seafloor unattached to the boat. The lowering rope could be tied off to a buoy on the surface for

collection when the recording was complete.

This system was very inexpensive and simple to construct and was easy to adjust for cameras of

different focal lengths due the multiple fixing holes in the Dexion material.

Results

The Photo-quadrat system allowed close inspection of the seabed in high definition still image

snapshots but also close observation of the seabed in 10 minute video recordings showing

transitions and activity during that time. The GPS position, its depth and other data could be

recorded from the boats instruments as the Photo-quadrat was lowered.

The grid pattern on the Photo-quadrat base allowed accurate data collection for quantitative

statistical analysis. The percentage coverage could be measured together with individual

measurement of leaf, rhizomes and flower size and quantity. (See figure 6)

Materials and costs ( See table 4)

Capabilities/ Limitations

This system was successfully tested in two surveys in October 2010. A problem encountered

with the still camera system was the camera lens became fogged from the sunlight when the

Photo-quadrat was brought to the surface between deployments. This was remedied by placing a

dark, wet towel over the camera when it was lifted clear of the water. Another problem

encountered was that the rate of drift of the boat was often rapid, allowing insufficient time for

11

the sediment to settle around the Photo-quadrat before a photograph could be taken. This could

be rectified by having a longer cable for the trigger release mechanism.

The waterproof HD video camera system also suffered lens fogging problems between

deployments and limited camera battery life. A large battery would be required for meaningful

surveys.

4) Delta-wing

To overcome the boat maneuverability limitations of the Aqua-scope and Scubar, a towed video

camera system was developed. This allowed continuous close-up monitoring of the seabed at

greater depths, over a large area whilst travelling along a pre-set transect. This required a

waterproof CCTV camera connected to a devise that kept the camera approximately a meter

above the seabed. It was required to be stable when towed below the boat whilst being connected

to a boat mounted monitor and recorder. It was important that the devise could give accurate

GPS positions and depths of what was being recorded. In order for this to happen, the devise

needed to be towed directly beneath the boat. This devise was named the Delta-wing. This

system would give similar results to that obtained from an ROV system.

The Delta-wing was a one meter triangular wing shaped piece of 6mm ply-wood with 30cm

triangular vertical stabilizing fin and a 10 kg metal weight bolted to the underside of the wing.

(See figure 7) The camera was mounted at the front of the wing and a tow rope attached in such

a position that the Delta-wing pointed 30 degrees down from the horizontal when towed.

The Delta-wing was tested using a lap-top computer to monitor and record the benthos. The

depth of the Delta-wing was monitored from markings on the tether rope whilst the depth of the

water and position and speed were measured using the boats onboard fish finder, log and GPS.

12

Deployment

The Delta-wing was lowered over the side of the stationary boat with the tether rope together

with the electric cable. The depth of the Delta-wing was indicated by measurements on the tether

rope. The lap-top video recording was started and the depth, position and times were all noted.

The boat moved forward until the Delta-wing had orientated itself in the direction of travel and a

steady course steered along a transect at approximately 4 kph.

Results

Three successful transect surveys were conducted in March 2011 over the seagrass beds in the

Fal Estuary at approximately a meter above the seafloor. The boat was moving at approximately

4 kph and good quality images could be observed and were recorded. The boat speed had to be

adjusted when the Delta-wing was moved closer to the seafloor as the image on the monitor was

moving too rapidly for accurate identification. The advantage of the system was that when a

particular area of interest came into view the boat could stop for closer analysis and the Delta-

wing could even be lowered onto the seafloor. The Delta-wing orientated itself well in the

direction of travel and could be positioned directly below the boat at 4 kph giving an accurate

GPS position and depth. The Delta-wing could be used to cover large areas more rapidly by

raising it to give a broader field of view and increasing the boat speed. An extra light was fitted

to the Delta-wing but it was found to be unnecessary.

The value of the Delta-wing was shown by the discovery of two other wise undetected seagrass

beds. The Aqua-scope and Scubar were unable to detect these very small sparsely populated

beds using the point survey system. The Delta-wing however using continuous recording was

able to detect these thinly populated Seagrass beds easily amidst a large area of deserted seabed.

(See figure 8)

13

Materials and Costs (See table 5)

Capabilities/Limitations

The Delta-wing was heavy and cumbersome to use. Lowering and raising it was strenuous work

and the tether rope, electric cables and connections to the lap-top and battery were awkward. A

boat with sufficient deck space was necessary. It was found that for extended recording the

computer lap-top method of monitoring and recording was the most satisfactory however the

laptop needed extra battery power. Connecting this particular lap-top to the boats 12v power

source caused interference from the boats alternator which affecting the CCTV camera timing

signal.

Overall equipment comparisons (See tables 6,7,8)

Discussion

In line with the project’s objective, it has been shown that inexpensive home built surveying

equipment can be developed and used successfully for shallow benthic habitat surveying that

could be performed by colleges, enthusiasts, clubs and boatmen to a scientifically robust

standard. (Holt 2001) The costs can be kept low due to the use of equipment already available

like under water cameras, lap-top computers and standard on board boat equipment like fish

finders and GPS.

Other factors not included in this report were the size and type of boats used, the fuel and boat

costs, the detailed health and safety issues with each different system, the affect of time and

seasons on the surveys and the qualifications of the participants in the project.

The Aqua-scope was the most user-friendly, easiest to build and deploy and gave good enough

results to establish a basic presence to a depth of 5 meters on sunny days at low slack tide. The

14

Scubar made it possible to refine the perimeters of the Seagrass beds and examine the general

condition of the Seagrass but was more difficult to use. The Photo-quadrat produced quantitative

data making it possible to perform statistics on the Seagrass beds and the Delta-wing made it

possible to search larger areas for new Seagrass beds although it was the most complicated to

use. The ability of the Delta-wing was proved by the discovery of two previously undetected

seagrass beds.

The surveys conducted during this project using this equipment developed has formed a

baseline survey of the Fal estuary Seagrass beds that can be built upon by further use of the same

equipment or for more detailed professional surveys in the future.

3691 words including abstract.

15

References cited

Arbour A. 2004. Applications for Mini-ROV sustems for coastal and estuarine monitoring.

Alliance for coastal technologies. UMCES Technical Report Series: TS-463-04-CBL / Ref. No.

[UMCES]CBL 04-128. (Novenber 2010. www.act-

us.info/download/workshop_reports/ACT_WR04-07_Mini_ROV.pdf )

Duarte CM. Krause Jensen D et al. 2003. European seagrasses: An introduction to monitoring

and management. The M&MS project. ( November 2010; www.seagrasses.org)

Epstein J. 2010. Hawkes Unveils New ROV Class. Marine Technology reporter. October 2010.

(November 2010. http://dwp.marinelink.com/pubs/nwm/mt/201010/ )

FHC 2011 . Falmouth Harbour Commissioners . (March 2011. www.falmouthport.co.uk)

Grizzle R E et al. 2008. Bottom habitat mapping using towed underwater videography: subtidal

oyster reefs as an example application. Journal of Coastal Research: volume 24.

Holme N A. MacIntyre A D.1984. Methods for the study of marine benthos 2nd edn. Oxford:

Blackwell Scientific Publications, for International Biological Program. [IBP Hanbook, no. 16].

Holt R. Sanderson B. 2001. JNCC Marine Monitoring Handbook March 2001, Procedural

Guideline No. 3-5 Identifying biotopes using video recording. ( November 2010.

www.jncc.gov.uk/PDF/MMH-Pg%203-5.pdf )

Kimmel J. 1985. A New species-time method for visual assessment of fishes and

its comparison with established methods. Environmental Biology of Fishes 12.

16

Magorrian BH. Service M.1996. An acoustic bottom-classification survey of Strangford Lough,

Northern Ireland. Journal of the Marine Biological Association of the United Kingdom 1995.75.

McKenzie L J. Campbell S J. 2002. Manual for Community(citizen) Monitoring of Seagrass

Habitat – Western Pacific Edition. Seagrasswatch. Townsville. Australia. (November 2010.

www.seagrasswatch.org/Methods/Manuals/SeagrassWatchWesternPacific_Manual.pdf )

Potts G W et al.1982. Scuba diver-operated low-light-level video system for use in underwater

research and survey. Journal of the Marine Biological Association of the United Kingdom , 67.

Rhoads D C. Germano J D. 2004. Interpreting long-term changes in benthic community

structure: a new protocol. Hydrobiologia Volume 142.

Sanderson et al. 1999. The Human Footprint and the Last of the Wild. BioScience . Vol. 52.

Short F T.1984. Seagrass-Watch Western Pacific Manual for Community (citizen) Monitoring of

Seagrass Habitat .(November 2010. www.seagrasswatch.org)

Short FT.2009. SeagrassNet Final Report: 2005 – 2009. Seagrass-Watch. USA .(November

2010. www.seagrasswatch.org)

Sisman D. 1982. The Professional Diver's Handbook. Submex. London .

17

Figure 1. The Aqua-scope C Pollitt 2010

Figure 2. View through the Aqua-scope. C Pollitt 2010

18

Figure 3. Seagrass recorded by the Scubar. C Pollitt 2010

Figure 4. Photo-quadrat with still waterproof camera. C Pollitt 2010

19

Figure 5. Waterproof, still camera, trigger release mechanism. C Pollitt 2010

Figure 6. Photo-quadrat picture. C Pollitt 2010

20

Figure7. The Delta-wing C Pollitt 2011

Figure 8. The Delta-wing recording C Pollitt 2011

21

Table1. Materials and Costs of the Aqua-scope

Material Measurements Used for Number Cost Supplier

6mm, Exterior

plywood

Sheet, 1220cm

x 2440cm

Aqua-scope

body

1 £30 Hardware

supplier.

Wood

Adhesive.

Everbuild 502

250 ml £4 Hardware

supplier

Pine 12mm x 12mm

x 3m long

Body

construction

1 £10 Hardware

supplier.

Glass pane 6mm thick

60cm x 30cm

Window 1 £10 Glazier

Exterior white

Gloss Paint

1 liter Aqua-scope

exterior

1 £6 Hardware

supplier.

Silicon Sealer

Unibond 2580

310 ml Waterproofing

window

1 £8 Hardware

supplier.

Aluminum

Handles

15cm x 3cm Hand

Mounting

2 £5 Hardware

supplier.

20cm

diameter

Aluminum

tube

3m length Boat

mounting and

supports

1 £10 C&S Non-

ferrous

metals. Metal

supplier

Matt Black

Paint

750 ml Inside Aqua-

scope

1 £5 Hardware

supplier.

Wood screws 12mm Aqua-scope

Body

50 £10 Hardware

supplier.

Total cost £98

22

Table 2. Materials and costs for the basic blind Scubar system

Material Measurements Used for/in Number Cost Supplier

Extending

Fibreglass

pole

5 meters x

50mm

diameter

Underwater

camera

mounting

1 £50 Window

cleaning

suppliers

Head Camera

Oregon

Scientific

atc-3k

10cm x 5cn

diameter

Underwater

image

recording

1 £80 Sports

equipment

supplier

Extra strong

Cable ties

30cm Securing

camera to

pole

5 £3 Hardware

supplier.

Trago mills

Total cost £133

23

Table 3. Materials and costs for the real time CCTV Scubar system

Material Measurements Used for/in Number Cost Supplier

Extending

Fiberglass

pole

5 meters x

50mm

diameter

Underwater

camera

mounting

1 £50 Window

cleaning

suppliers

Swann

CCTV

camera

Color, 380 tv

lines, 1/3 inch

cmos. 12 v.

Underwater

monitoring

1 £30 Electronic

security

supplier

12v battery 12v Powering

cctv camera

1 £15 Electronic

supplier

7” color

video

monitor

Phono (RCA)

or s-video

compatible

Monitoring

cctv camera

images

1 £70 Consumer

Electroncs

supplier

DV recorder 2Gb Sd card

recording

media.

Recording

CCTV

images

1 £70 Consumer

Electroncs

supplier

3 core

13 amp

mains cable

20 meters Transferring

images from

CCTV to

monitor.

power

1 £20

Electrical

supplier

B&Q

Total cost £255

24

Table 4. Materials and costs of the Photo-quadrat

Material Measurements Used for/in Number Cost Supplier

Galvanised

Dexion

shelving

material

3cm L section Frame

construction

10 meters £50 Industrial

shelving

supplier

Dexion nuts,

bolts and

washers

1 x 50 pack

8mm x 15mm

Frame

construction

1x 50 pack £10 Industrial

shelving

supplier

12v car door

locking

solenoid

12v, generic

20mm plunger

travel

Remote

shutter

activation

1 £10 Car parts

supplier

2 Core,

5 amp cable

7 meters Remote

shutter

trigger

1 £10 Electrical

supplier

B&Q

10 mm

diameter

nylon rope

10 meters Deployment

of Photo-

quadrat

1 £10 Hardware

supplier

B&Q

Zinc weights 0.5 kg Frame base

stabilization

4 £10 Hardware

supplier

12v battery 12v, 1ah Solenoid

power

1 £15 Electronics

supplier

Total cost £115

25

Table 5. Materials and costs of the Delta-wing

Material Measurements Used for/in Number Cost Supplier

6mm

plywood

1 meter square Delta-wing

body and fins

1 £10 Hardware

supplier

Zinc

Weights

10 Kg – Boat

engine anode

stabilization

and ballast

1 £30 Boat

Chandler

Swann

CCTV

camera

Color, 380 tv

lines, 1/3 inch

cmos. 12 v.

Underwater

monitoring

1 £30 Electronics

supplier

12v battery 12v , 1ah Powering

cctv camera

1 £15 Electronics

supplier

7” colour

video

monitor

Phono (RCA)

or s-video

compatible

Monitoring

cctv camera

images

1 £70 Consumer

electronics

supplier

DV recorder 2Gb Sd card

recording

media.

Recording

CCTV

images

1 £70 Consumer

electronics

supplier

3 core 13A

cable

20 meters Transferring

images

1 £20 Hardware

supplier

Galvanised

Dexion

shelving

3cm L section Frame

construction

0.5 meters £2.50 Industrial

shelving

supplier

Dexion nuts,

bolts and

washers

I x 10 pack

8mm x 15mm

Frame

construction

1x 50 pack £2.50 Industrial

shelving

supplier

Total cost £250

26

Table 6. Comparison of Aqua-scope with Snorkeling

Aqua-scope Snorkeling

Advantages Disadvantages Costs Advantages Disadvantages Costs

General

visual

benthic

survey

Boat

Maneuverability

when deployed

£98

+ boat

General

visual

survey of

the seafloor

Trained and

Qualified

personnel

required.

Snorkel

equipment

£30

Minimal

Health and

safety, and

insurance

requirements

Weather and

tide dependant

Can be

conducted

from the

shore

Stringent

health and

safety and

insurance

requirements

No formal

training.

Large groups

possible

Limited field of

view.

Wide field

of view

Position and

depth

recording

difficult

Simply

adaptable for

non-

waterproof

video/ photo

recording

Requires

under water

photo and

video

recording

equipment

Weather and

tide

dependant

27

Table 7. Comparison of the Photo-quadrat and a diver quadrat survey

Photo-quadrat Diver Quadrat

Advantages Disadvantages Costs Advantages Disadvantages Costs

Minimal

Health and

safety, and

insurance

requirements

£115

without still

or video

camera

Accuracy Stringent

health and

safety and

insurance

requirements

£1000 for

basic diving

package

No formal

training

required

Blind quadrat

positioning

and

orientation

Preset

quadrat

positioning

and

orientation

Trained and

Qualified

personnel

required.

Large groups

possible

large groups

difficult.

Weather and

tide

dependant

Weather and

tide

dependant

28

Table 8. Comparison of the Delta-wing and an ROV

Delta-wing ROV

Advantages Disadvantages Costs Advantages Disadvantages Costs

Easily

deployed by

untrained

personnel

Depth

limitation

£250 Highly

accurate data

gathered and

recorded

Professional

trained and

qualified

personnel

required

£60 000

initial cost .

Rental £1000

per day

including

operator

Accurate,

recorded

data

Limited

maneuverability

Highly

maneuverable

Professional

Personnel

hire £300 per

day

Suitable for

detailed and

extensive

surveying

Suitable for

detailed and

extensive

surveying

Can be

modified for

other camera

systems

Can achieve

great depth

surveys