UNUSUAL DISPERSION AND MORTALITY OF ROCKHOPPER PENGUINS. AN EVENT RELATED TO ADVERSE MARINE CONDITIONS?

MORGENTHALER, ANNICK; FRERE, ESTEBAN; REY, ANDREA RAYA; COLLM, NATALIE; GANDINI, PATRICIA; MILLONES, ANA

Puerto Iguazú

Congreso; Ornithological Congress of the Americas; 2017

Association of Field Ornithologists, USA

Between February and May2016, a largenumber of Southern Rockhopper Penguins(Eudyptes chrysocome) werefound molting and in part subsequently dying, apparently from starvation, alongthe southernmost coasts of Argentina. Inorder to report on the extent of this unusual dispersion and mortality event, directcounts of live and dead penguins were conducted along several coastal sites of SantaCruz and Tierra del Fuego Provinces. To determine if this event might berelated to changes in oceanographic conditions, chlorophyll a concentrations (productivity) and sea surface temperatures ofthe Southwest Atlantic Ocean were obtained for February and March 2016; and thencompared with the 2010-2015 averages of the corresponding month. At least 1039molting Rockhopper penguins were reported along the surveyed shores and 50-89 %ended dying, depending on the site. The 2016 oceanographic data showed lowerproductivity and higher sea surface temperature around Islas Malvinas,supporting the hypothesis of a shortage of food late summer close to breedingand feeding grounds from these islands, which could explain the dispersion ofthese penguins towards the Patagonian shores, and which finally led to amassive starvation event. This mortality phenomenon reminds one occurred in1986 which was suspected to be related to El Niño event. Coincidentally during 2015-2016El Niño manifested itself with great intensity. This studyhighlights the severe effects that changes in oceanographic parameters prior toa critical period (molting) might have on the survival of this endangered(Vulnerable) penguin species.