Report 502
Biotope analysis of archived stills from the SEA7 region of Scotland's seas (2011)
(2014)
Hughes, D., Nickell, T. & Gontarek, S.
In 2011, JNCC commissioned SAMS to undertake habitat and taxonomic analysis of seabed photos captured research cruises on the Hebridean Slope.
 

Introduction

 

In 2011, JNCC commissioned SAMS to undertake habitat and taxonomic analysis of seabed photos captured during research cruises on the Hebridean Slope.

 

All seabed images were taken using the same photographic system, the Proudman Oceanographic Laboratory (POL) “bed-hop” camera. A 35mm film camera, fitted with a semi-wideangle lens is mounted in a pressure housing near the top of a protective steel frame. The camera looks obliquely downwards and forwards. An underwater flashgun in a pressure housing is mounted near the bottom of the frame and is aligned to illuminate the camera’s field of view. The low, oblique lighting maximizes shadow-detail of any seabed topographic relief. A bottom-switch is actuated when a lead weight hanging on a steel cable below it touches the seabed, releasing the tension on the suspension cable. The bottom-switch fires the camera and flash, which wind-on and recharge automatically. The frame also holds a downwards- pointing acoustic pinger which signals at 1-second intervals.  When  the  hanging weight  touches  the  seabed,  the  bottom-switch  doubles  the  ping  rate,  telling  the operator (listening on the ship’s acoustic system) that contact has been made and a picture has been taken. A magnetic compass is mounted on an arm at the bottom right-hand corner of the camera’s field of view in order to show the orientation of any current-shaped bedforms.

 
 
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ISSN 0963 8901
 
Please cite as: Hughes, D., Nickell, T. & Gontarek, S., (2014), Biotope analysis of archived stills from the SEA7 region of Scotland's seas (2011), JNCC Report 502, ISSN 0963 8901