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NRW_DS115296

Teitl Amgen

• CCW Drop Down Video North Wales Survey 2012
• 2012 CCW Drop Down Video North Wales Survey MRCCW31600000009

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English

Datganiad

Drop down video survey was conducted from Countryside Council for Wales' (CCW) survey boat Pedryn, an 11.7 m Delta cabined RIB. The CCW camera system is C-Vision HD with a C-vision mantis HD camera video recorder, a 200 m umbilical cable, a video camera in a waterproof housing mounted on a metal frame sled with two HID lights mounted on either side of the camera. In addition, a laser scaling device comprising two parallel laser beams, 10 cm apart, provide an indication of size and scale. The auto stills camera is a Seacam Digital still camera (18 mega pixel CMOS chip) with dual Seabeam underwater Strobe lamps. The surface control unit overlays realtime data such as time, date, depth of camera and position of vessel on the captured video which are recorded to the miniDV recorder. The camera was towed for approximately ten minutes at each location, recording continuous video plus still images every 10 seconds. The sled was towed at 0.5-1.0 knot (ideally) across the seabed either by drifting with the currents or using the drive of the vessel. A manual log was kept of the position and depth at the start and end of transect plus details of substratum type and main taxa observed on the screen during the tow.

Video and stills were subsequently analysed by a experienced marine biological surveyor to record information on habitat character, conspicuous species and their abundance (SACFOR scale), and to assign biotopes from the national biotope classification. Analysis included a QA process to validate and verify the recorded data.

Dyddiad cyfeirnod y set ddata (Cyhoeddiad)

2012-11-30

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