Southernmost record of the Giant Manta Ray Mobula birostris (Walbaum, 1792) in the Eastern Pacific

Background: Manta rays (Mobulidae), Mobula birostris and Mobula alfredi, are widely distributed in tropical and temperate waters. Still, little is known about their movements and their ecological interactions (e.g. behavior and diet). In Peru, M. birostris has only been reported along the northern shore within the Tropical East Pacific Marine Province. No official reports exist from central or south Peru within the Warm Temperate Southeastern Pacific Marine Province. Methods: On December 22nd 2015, a rare sighting of a ~4 m disc width mobulid ray was recorded as video footage near the Palomino Islets, Lima, Peru. Results: In situ observations and subsequent analysis of the footage confirmed that this single mobulid was a M. birostris with a melanistic color morph. Conclusions: This sighting could be explained by the warm El Niño, primary (chl-a), and secondary (zooplankton) productivity events during that same period. This represents the southernmost record of M. birostris in the southeastern Pacific (12°S) and the first report of this species in the Warm Temperate Southeastern Pacific Marine Province and in the Humboldt Current Large Marine Ecosystem.