Analysis of trawl data from the South Georgia krill fishery

Data from individual trawls carried out by vessels operating in the krill fishery at South Georgia are examined and a range of descriptive measurements reflecting the operation of the fishery are produced. The measurements indicate that the krill fishery at South Georgia is geographically focussed, operating in a limited area along the shelf edge on the northern coast of the island. Each day a large number of trawls were undertaken by each ,vessel, with trawls being shorter in duration during the middle of the day. Daytime trawls were also generally deeper and produced a larger catch. Individual trawls were examined to establish the time required for each phase of the operation. The times associated with shooting and hauling the net were usually short and showed little variation, whereas the time associated with the actual trawl phase was longer and more variable. The distance between consecutive trawls was generally small, indicating that little effort was spent searching beyond the near neighbourhood. However, this phase of the operation took almost as long as the trawl itself and showed similar levels of variability. The range of measurements indicate that differences existed between years. Particular aspects of the variability are discussed in relation to the biology of krill, others are discussed in relation to the fishery operation.