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

• Published in: Polar Research
• Main Authors: Gabriela Blasina, Andrea Lopez Cazorla, Mariana Deli Antoni, Daniel Bruno, Matías Delpiani, Juan Martín Díaz de Astarloa
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 2017
• Subjects: Antarctic fish diet; zone-related changes; dominant prey; feeding strategy; trophic level; food web; Environmental sciences; GE1-350; Oceanography; GC1-1581; Antarctic; Antarctic Peninsula; South Shetland Islands; The Antarctic; Antarc*; Polar Research; Copepods
• Online Access: https://doi.org/10.1080/17518369.2017.1331558; https://doaj.org/article/378c688824d6443b9b5c69c2fc3a7eb4

The diet and feeding strategy of Lepidonotothen nudifrons off the South Shetland Islands and the Antarctic Peninsula, 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 of this species was estimated to determine its position within the Antarctic food web. Out of 247 specimens with prey in their stomachs, 144 were caught near the South Shetland Islands and 103 off the Antarctic Peninsula. 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 the diet. The diet of juveniles from the South Shetland Islands was characterized by the dominance of calanoid copepods, followed by isopods and amphipods, whereas diet off the Antarctic Peninsula was dominated by amphipods and cyclopoid copepods. The diet in adults was dominated by amphipods and euphausiids in both areas. The specialization of individual predators 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 prey for each class. Although the trophic level increased with fish size, L. nudifrons can be classified as secondary consumer throughout its lifespan.