The feeding strategies of the antarctic lanternfish electrona antarctica (pisces: myctophidae) in the amundsen and cosmonaut seas (southern ocean), assessed with a classification tree analysis

Myctophid fishes represent an important trophic link between zooplankton and higher trophic level predators in the oceanic ecosystems of the Southern Ocean. The Antarctic lanternfish (Electrona antarctica) is one of the most abundant myctophids in the Southern Ocean; however, information on their feeding habits is sparse, representing a key area of uncertainty in efforts to model Southern Ocean food web dynamics. Using a classification tree approach based on stomach content data, we explored the feeding strategy of E. antarctica in the Amundsen and Cosmonaut Seas during January and March 2021, as well as its variation in relation to ontogenetic stage and sampling area. An ontogenetic shift in the feeding preference of E. antarctica was identified in the Cosmonaut Sea: Fish smaller than 48 mm fed on ostracods and copepods, while larger fish (SL > 62 mm) relied primarily on krill. Conversely, there was no ontogenetic shift in the diet of E. antarctica in the Amundsen Sea, and this species feeds almost exclusively on Themisto gaudichaudii. The diet composition of E. antarctica presented spatial differences: Copepods (48