ABSTRACT
Ocean sunfishes (molids) consist of five currently recognized species of the family Molidae, including the largest teleostean fish, Mola alexandrini (Ranzani 1839), which can exceed a body mass of 2,300 kg. Major developments in our understanding of this group have been driven, in part, by the advent of new methodologies and also by social media, which has helped to increase involvement of citizen scientists. Despite these developments, large knowledge gaps still remain. Here, based on the findings of leading experts in their respective fields, we compile some of the key unresolved questions, most of which revolve around the ecology of wild ocean sunfishes. These questions include: (i) the number of species in each genus; (ii) the extent of movements along coasts, in the open ocean and at depth; (iii) the spatial, temporal and environmental conditions surrounding spawning and spawning grounds; (iv) variation in diet across individuals, sizes and habitats and lastly; (v) the genetic population structure and overall population status and trends of all species. Major, but ill-defined, anthropogenic threats to the group include bycatch in fisheries, impacts of climate change (e.g., ocean warming and acidification), and elemental and plastic pollution. While the considerable progress made has helped unravel many mysteries of the ocean sunfishes, collaborative research is needed to address these remaining gaps and ensure populations across the world ocean can continue to thrive into the future.
