The High Seas at Your Fingertips: A Case Study of the Living Sailor Leveraging Community Science to Answer Decades Old Questions in High Seas Biogeography

The open-ocean’s surface is host to a community of strange creatures adapted for life at the air-sea interface (neustonic zone). One species, the by-the-wind sailor (Velella velella), occasionally washes ashore in high numbers, and its appearance makes the news. By-the-wind sailors may play a key role in the ecology of the neustonic zone, but we know very little about their biology. Due to their conspicuous nature and rare occurrence, the study of by-the-wind sailors can be achieved only with a community of scientists. Here we introduce The Living Sailor Zooniverse project, which leveraged 11,115 iNaturalist observations to answer fundamental life history questions. A total of 1,169 volunteers classified cumulatively 67,926 subjects to determine three variables: count, condition, and direction of sail. Using a super-majority threshold of agreement among six volunteers per subject, volunteers were able to identify 10,105 by-the-wind sailors for at least one endpoint including 6,377 for sail direction. Subjects on which volunteer consensus proved difficult offered valuable information, and we provide insight for the development of Zooniverse training materials and best practice for shore-based photography for iNaturalist projects. Our results reveal community (citizen) science can support the often-difficult task of studying high seas biology. By unlocking a new avenue for high seas research, we will be better equipped to understand the biodiversity of this largely unexplored habitat for management and conservation. The Living Sailor data in particular will inform ongoing efforts for mapping sea-surface biodiversity hotspots and testing a decades-old hypothesis that sail direction influences by-the-wind sailor global distribution.