Abstract
Using 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 the video was challenging, although improvements in identification rates were realized by modifying our camera system and lighting. This approach provides an alternative methodology to acquire abundance and distribution data for groundfish stocks. We described the iterative approach used to develop the video trawl system and discussed the future direction of the video processing and analysis.