Is there a symbiotic cleaning association between ocean sunfish and pelagic seabirds in the Patagonian Shelf?

Abstract

The removal by a cleaning organism of ecto-parasites, diseased or wounded tissue, or other particles of another organism is termed cleaning symbiosis. In oceanic environments, an example of such symbiosis can be found between the ocean sunfish (Mola mola) and pelagic seabirds. To date, these observations have been restricted to the North Pacific, with an important asymmetry of what is known for other regions like southern South America. Here, we report observational and photographic records of pelagic seabirds (albatrosses and petrels) associated and interacting with ocean sunfishes opportunistically obtained in waters of the Argentinean Continental Shelf (< 200 m depth) in the South West Atlantic. Records of Southern giant petrels (Macronectes giganteus) and Black-browed albatrosses (Thalassarche melanophris) were performed in 2016 and 2019, respectively. Seabirds might have been involved in cleaning symbiosis activities, possibly feeding on ecto-parasites attached to the body or fins of ocean sunfish given their spatial co-occurrence. The present study is the first photo-documented report regarding the association between the ocean sunfish and pelagic seabirds and possible symbiotic relationship between them in the open ocean of the southern Hemisphere.