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Groundfish Assessment - Survey Profile

Video Camera Sled

GIF animation showing camera sled, Canadian perspective grid, image analysis, and line transect theory. The video camera sled frame is constructed of hot-dipped galvanized schedule 40 two-inch steel pipe and measures 366 cm long by 213 cm wide by 152 cm high, and weighs about 500 kg. The video camera is a Deepsea Power and Light Autonomous Video Camcorder System (AVCS) powered by two 24 volt/38 amp hour batteries, lighted with two 150 watt SeaLites, and uses Sony Hi8 video inside the housing.

The sled is occasionally used in conjunction with groundfish bottom trawls to compare estimates of fish abundance and size composition. In one such operation, Shortspine thornyhead (Sebastolobus alascanus) abundance estimates, derived from line transect data collected with the camera sled, were compared to area swept estimates using the west coast slope survey trawl. Video and trawl estimates of abundance were compared by completing four paired video sled transects and trawl net tows at each of 3 depths: 450 m, 750 m, and 1150 m. The sled was towed on the west coast upper continental slope sea floor at speeds between 0.75 and 1.0 m/s (1.5 and 2.0 knots) for two to three hours. The Canadian perspective grid and image analysis software were used on video data for estimating thornyhead abundance and size composition.

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