Almost nothing is known about the historical abundance of the ocean sunfish. Yet as an ecologically and functionally important taxa, understanding changes in abundance may be a useful indicator of how our seas are responding to anthropogenic changes including overfishing and climate change. Within this context, sightings from a coastal bird observatory (51.26 $$^\circ$$ ∘ N, 9.30 $$^\circ$$ ∘ W) over a 47 year period (from Apr...