ABSTRACT
The ocean sunfish are perhaps most notable for their extraordinary size. The means whereby they fuel such a large body has long intrigued ecologists. Although traditionally described as obligate gelativores, recent research has confirmed that these fish actually have a broad ecosystem role and are capable of feeding on a wide range of prey taxa including crustaceans, molluscs and fishes. Specifically, new studies have revealed that ocean sunfish undergo an intriguing ontogenetic shift in diet, where smaller individuals feed broadly on high energy-density benthic prey in nearshore environments, while larger fish move offshore, shifting to a diet of predominantly gelatinous taxa. Considering the ongoing mass bycatch of sunfishes, these findings provide new evidence that the removal of such a wide ranging meso-predator, that feeds at the sea floor before moving to oceanic waters, may have far-reaching implications for a range of marine systems. Evidence is now rapidly building to suggest that the ocean sunfish play a far more important and diverse trophic role than previously thought.
