Development of a Video Trawl Survey System for New England Groundfish

AbstractUsing an iterative approach and extensive field testing we developed a new video trawl survey system that used a live-feed video camera mounted in the cod end of a demersal trawl to record, identify, and quantify fish as they pass through the net. The majority of tows are made with an open cod end, allowing the fish to escape the net after being recorded by the camera. Periodically, closed cod end tows are made to collect biological samples and validate the video data. Eight field trials were conducted on Georges Bank and in the Gulf of Maine, and 229 h of video were recorded. The in-trawl camera system performed reliably under harsh conditions in the field. Preliminary data analysis showed that the in-trawl camera system can be used to count and identify roundfishes, such as Atlantic Cod Gadus morhua and Haddock Melanogrammus aeglefinus with a high degree of accuracy (97%), and the video can be used to calculate absolute abundance estimates. However, identifying flatfishes to the species level in...