These positions are unpaid at this stage, however, all travel to and from departure locations, food and accommodation costs will be covered. Deployments are across the Antarctic summer period, for a period of 8-12 weeks (further details below). *Brief Background* Representing the most rapidly warming region of Antarctica, the western Antarctic Peninsula (WAP) has a rapidly growing tourist industry and krill fishery (Bender et al., 2016; Schumann et al., 2013; Spence et al., 2017). Its ecological significance has been recognised internationally and is the focus of efforts to establish a Marine Protected Area. As many species recover from past exploitation, it is important to understand the patterns of distribution and relative abundance of marine predators on regional scales. While considerable effort has been expended on understanding key land-based krill predators such as penguins and seals (e.g., Boyd, 2002), there has been wide acknowledgement that information on the temporal and spatial distribution and abundance of cetaceans and other marine mammals not amenable to land-based study is lacking (IWC Report 2019). Antarctic whale stocks were hunted to commercial extinction in 20th century (Rocha et al., 2014) and are understood to be recovering variably (e.g., for humpback whales, *see* Constantine et al., 2014; Fleming and Jackson, 2011; Noad et al., 2019; Olavarría et al., 2007). Yet relatively little is known of the abundance and distribution of baleen whales in the Southern Ocean foraging grounds. Distance sampling sets a gold standard for estimating marine mammal abundance and distribution (Williams et al., 2006). Yet broad-scale distance sampling surveys are prohibitively expensive in remote Southern Ocean waters and often produces only one survey estimate per season, that is subsequently used to characterise the entirety of that season. With commitments from several Antarctic tour operators, we set out to build on the pilot survey program initiated during the 2019-2020 season by standardising a scientifically peer-reviewed distance sampling protocol for estimation of at-sea cetacean abundance and distribution. Specific Aims: (i) Can platforms of opportunity-based distance sampling efforts be improved and standardised in order to contribute to understanding Southern Ocean cetacean status and trends. (ii) What physical ocean properties, environmental variables and/or krill predictors drive cetacean abundance and distribution at temporal scales ranging from within-season to interannual. (iii) What is the total consumption rate of krill by baleen whales relative to land-based krill predators and human krill harvest, and how does this relate to what we know of krill abundance and distribution in time and space? *The roles* We are seeking expressions of interest and commitments (where possible) from volunteers with experience as marine mammal observers or those interested in becoming one. This is your opportunity to be one of the very few people in the world that go to Antarctica. You will have exposure to the wealth of wildlife and stunning landscapes that make this part of the Southern Ocean so special and the opportunity to ‘be a tourist’ at times during the voyage (potentially including landings). Sets of two observers (one trained/experienced lead MMO and one in training MMO) will be deployed from Ushuaia and Punta Arenas on expedition tour vessel (200-500 passengers) across the Antarctic summer (Nov-March) in the 2021/22 and 2022/23 season. We are seeking a commitment of 8-12 weeks; this will include several (3-6) voyages to the Antarctic Peninsula (potentially via South Georgia, the Falkland islands/ Islas Malvinas and/or South Orkney Islands), aboard tour vessels. Preference will be given to residents of Chile and Argentina, and those in closer proximity to voyages departure locations (Ushuaia and Punta Arenas). Observers will take distance sampling measurements of whales and other marine mammals from the bridge of the vessels. MMOs will need to remain focused and on task for many hours, and at times work to weather windows across an 18-hour day. It is critical MMOs are organised, focused, take accurate field recording, and remain on task. Lead MMOs will be responsible for dictating field effort in response to weather, ensuring quality control and data management. Both MMOs will also be required to give a seminar/lecture to guests on board the vessel as part of our agreement in securing berths for observers. MMOs will be required to complete a basic level of induction and training (provided), including the study of marine mammals and birds of the south-east Atlantic sector of the Southern Ocean. *Requirements* · Professional attitude · Excellent verbal, written and interpersonal communication skills · Self-motivated with attention to detail · Must have the ability to conduct tasks independently · Ability to maintain focus and input accurate data · Knowledge of marine ecosystems · High stamina and enthusiasm for the role · Tertiary education in marine science (or another related field) · Fluent in English, writing and speaking. Preference for those with experience · In taking distance sampling measurements · In marine mammal/sea-bird observation at-sea · Identifying Southern Ocean seabirds · At sea Preference to residents of Argentina and Chile and they are encouraged to apply. To register your expression of interest/apply please reply with a cover letter stating why you want the role, how your skills and experience apply and what you hope to get out of it (300-500 words) and a resume detailing your experience (1 page) including the name and contact details of 2 references and/or a short letter of recommendation. If you have any questions or want to know more about the role, please contact me, angus.henderson@utas.edu.au