During a CCAMLR endorsed fishing survey on board the Chilean trawler ‘Cabo de Hornos’ around the South Orkney Islands and Elephant Island, a trained marine mammal observer conducted a distance sampling survey for cetaceans along track. During 10 survey days, 463.1 km were covered on effort. A total of 44 fin whale (Balaenoptera physalus) groups comprising 61 individuals were recorded on effort, and a total of 28 humpback whale (Megaptera novaeangliae) groups comprising 47 individuals. A single sei whale (Balaenoptera borealis) was also recorded. Off effort, e.g. during fishing operations, 35 sightings of mainly mixed-species groups and feeding aggregations of large whales were observed, comprising 217 individuals, including calves of both humpback and fin whales. The preliminary results of the survey show that the areas around the Southern Orkneys and Elephant Island are important feeding grounds for fin-, humpback and, to a lesser extent, sei whales. If any fishing effort is to be undertaken in these areas, no disturbance within these comparably small areas of high animal density should be tolerated. We recommend standardising any future research cruise by incorporating a set of synchronized video cameras to the bow and stern section of the ship to assess any potential behavioural response to allow further insight into interactions with fishing activities and to help quantify any disturbance or nuisance imposed on cetaceans, seals and birds.