The population density of the bottom dwelling Antarctic fish Trematomus bernacchii was estimated using the mark and recapture method and underwater video surveillance. Two sites were fished over two seasons: Cape Roberts and Cape Evans. Fishing stations were set up in a grid pattern on the ice over water depths of 20-30m and fish were caught by angling and in baited traps. Each station was ... recorded as a differential GPS location so that sampling could be repeated at the same location the following years. Fish were weighed, measured, injected with a fluorescent marker (calcein) for calibrating growth rings in bony tissue, marked with a numbered tag and returned to the bottom. Scale samples were taken for age estimation. 636 fish were tagged in the first season with 30 recaptures and 563 fish were tagged in the second season with 83 recaptures.