Jellyfish and other gelata as food for four penguin species in the southern oceans - insights from predator-borne videos

KEN YODA; JUAN EMILIO SALA; FLAVIO QUINTANA; MITAMURA, HIROMICHI; KENTARO ITO; GRACE J. SUTTON; JEAN-BAPTISTE THIEBOT; YAN ROPERT-COUDERT; TIMOTHEÉ POUPART; THOMAS MATTERN; AGUSTINA GÓMEZ-LAICH; AKINORI TAKAHASHI; PHILIP J. SEDDON; THIERRY RACLOT; TAKUJI NODA; AKIKO KATO; JOHN P.Y. ARNOULD

Hobart

Conferencia; MARINE ECOSYSTEM ASSESSMENT FOR THE SOUTHERN OCEAN; 2018

Integrating Climate and Ecosystem Dynamics in the Southern Ocean

Jellyfish and other pelagic gelatinous organisms ("gelata") are increasingly perceived as an important component of marine food webs, including in the southern oceans, but remain poorly understood. Their importance as prey in the oceans is extremely difficult to quantify due in part to methodological challenges in verifying predation on gelatinous structures. Miniaturized animal­borne video data loggers now enable feeding events to be monitored from a predators perspective. Over the past years, we gathered a substantial video dataset (over 350 hours of exploitable footage) from 106 individuals spanning four species of non­gelatinous­specialist predators (penguins), across regions of the southern oceans (areas south of 30°S). Among other prey, we documented nearly 200 cases of targeted attacks on carnivorous gelata (Scyphozoans and Ctenophores) by all four species, at all seven studied localities and during different years; however the videos never showed the penguins attacking gelatinous herbivores (Salps). Our findings emphasize that gelatinous organisms actually represent a widespread but currently under­ represented trophic link across the southern oceans, even for endothermic predators, which have high energetic demands. Notably, the videos show that penguins captured gelata even when other prey were locally available. Hypotheses about why penguins would capture these energy­poor prey are discussed. Over the two upcoming seasons (2017/2018 and 2018/2019), video loggers will further be deployed on penguins at a number of localities around the Antarctic continent, to test for potential differences in this behaviour across regions, with a special emphasis on the importance of salps. The use of modern technological tools, such as animal­borne video data loggers, will help to correctly identify the ecological niche of gelata.