There remain parts of our planet that are seldom visited by humans, let alone scientists. In such locations, crowd-sourced or citizen scientist data can be critical in describing biodiversity and detecting change. Rangitāhua, the Kermadec Islands, are 750 km from the nearest human-habitation. Although our knowledge of this near pristine location has increased with recent biodiversity expeditions, we still lack comprehensive understanding of the marine biodiversity surrounding the islands. In 2015, professional underwater videographers were commissioned to produce a nature documentary focused on Rangitāhua's reefs. We strategically surveyed the raw documentary video and examined how biodiversity estimates differed from traditional scientific surveys. We uncovered three new fish species records for Rangitāhua, extending the known distribution for each species, two of which are also new records for New Zealand waters. Comparison of documentary video footage with scientific survey methods showed that estimates of reef fish species richness from the documentary video were similar to stationary surveys, but lower than non-stationary surveys. Moreover, all survey methods, including documentary video, captured different fish assemblages, reflecting each method's particular bias.
Overall, we provide a proof-of-concept for how collaborations between scientists and professional natural historians, such as videographers and photographers, can provide valuable biodiversity information.Despite the efforts of scientists to catalogue the global distribution of biodiversity, we continue to record species in new locations (the "Wallacean shortfall" 1 ; reviewed in 2 ). New species records change our understanding of individual species ranges and improve our biodiversity knowledge for a given location. Our knowledge of species distributions in the ocean is particularly incomplete 3,4 . Even for many relatively well-researched coastal environments, new species records continue to accumulate. In remote locations, biodiversity inventories are often inadequate due to the logistical and financial challenges of implementing long-term research or monitoring 5 . Biodiversity surveys in such areas are often opportunistic and lack continuity, meaning that scientists and managers wishing to understand the biodiversity values of remote locations have to be resourceful when sourcing data.Alternative means of biodiversity cataloging are now commonplace as modern biodiversity informatics platforms (such as: iNaturalist, www.inaturalist.org; the Range Extension Database and Mapping project, REDMAP, www.redmap.org.au) are geared toward harnessing the collective knowledge of natural history observers in our society. In order for this citizen-sourced data to be incorporated into biodiversity research, there must be some form of quality control 6 . Verification of citizen-generated biodiversity records typically involves a professional scientist checking photographs and associated sighting metadata for accuracy. The citizen-sourced data may then be co...