Ontogenetic changes in the feeding strategy of Lepidonotothen nudifrons (Pisces, 46 Nototheniidae) off the South Shetland Islands and the Antarctic Peninsula

BLASINA, G.; LOPEZ CAZORLA, A.; DELI ANTONI, M; BRUNO, D.; DELPIANI, S, M.; DIAZ DE ASTARLOA, J. M.

POLAR RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016

0800-0395

The diet and feeding strategy of Lepidonotothen nudifrons off the South Shetland Islands (SSI) and the Antarctic Peninsula (AP), as well as their variation in relation to ontogenetic stage (juvenile-adult) and sampling area were determined by stomach contents analysis. Additionally, the trophic level (TR) of this species was estimated to determine its position within the Antarctic food web. Out of 247 specimens with preys in their stomach, 144 were caught in the SSI and 103 in the AP. Ontogenetic changes in the trophic ecology of L. nudifrons were observed in both areas and were mainly related to a decrease of copepods and an increase of euphausiids in diet. The diet in juveniles from the SSI was characterized by the dominance of calanoid copepods, followed by isopods and amphipods, whereas diet in the AP was dominated by amphipods and cyclopoid copepods. The diet in adult was dominated by amphipods and euphausiids in both areas. Individual predators specialized on different prey types was observed when considering the whole population of L. nudifrons, but when ontogenetic stages were considered separately, it showed a more mixed feeding strategy, with different dominant preys for each class. Although the trophic level increased with fish size, L. nudifrons can be classified as secondary consumer throughout the whole lifespan.