Alaska CamSled: High Resolution Benthic Imaging

Alaska CamSled is a towed optical imaging system developed by Alaska Department of Fish and Game (ADF&G) for scallop research in coastal waters at depths <350 m. The system is portable and designed to be deployed from vessels 20-40 m in length such as commercial fishing or small research vessels. A single downward-facing GigE Vision camera and six xenon-flashlamp machine vision strobe lights are mounted in pressure housings on the open-framed, bottom-tending vehicle. This arrangement allows us to image a one-meter wide strip of seafloor and collect an evenly lit, overlapping stream of megapixel digital images while towing at speeds up to 8.0 km/hr (4.3 knots).

Data telemetry via gigabit ethernet is accomplished using commercial-off-the-shelf components and an oceanographic winch equipped with a fiber optic rotary joint and armored fiber optic tow cable. Images and auxiliary data are monitored aboard the tow vessel in real time and recorded on computer hard drives in a portable deck module. Software for operation of the system during deployment and for manual review of image data including image adjustment and database connectivity for storage of results was developed by ADF&G. The system is simpler and less expensive than many AUVs and ROVs used for underwater imaging and has proven extremely robust, with over 1,750 km towed on bottom.

CamSled research is focused on stock assessment and habitat mapping for commercially exploited Alaska populations of weathervane scallops Patinopecten caurinus. Additional applications include crab research, benthic ecology, and monitoring effects of commercial fishing activites on benthic habitat.