The early life history of the widely distributed Antarctic grey rockcod (Lepidonotothen squamifrons) in high-latitude regions is poorly known. During a zooplankton survey in the Amundsen Sea polynyas in March 2022, we collected an exceptionally high abundance of larval L.squamifrons - the first record of this species' larvae from such high latitudes. Otolith microstructure analysis of 41 larvae (9.6-15.3 mm standard length, 6-11 days old) revealed key early life traits. Notably, multiple primordia were observed in the otoliths for the first time in this species. Compared with lower-latitude populations (Duhamel & Ozouf-Costaz, 1985), larvae from the Amundsen Sea exhibited later hatching dates (early March) and faster growth rates (0.66 mm day^-1). Our findings suggest that the Amundsen Sea polynyas may serve as a previously unknown high-latitude spawning ground for L.squamifrons, significantly extending the known distribution of its spawning areas. The observed spatial differences in early life traits provide critical insights into the species' early life history adaptation to high-latitude environments and offer important implications for the conservation and management of Antarctic fish resources, particularly in the context of climate-driven environmental changes in the Southern Ocean.

Reference
Duhamel G and Ozouf-costaz C (1985) Age, growth and reproductive biology of Notothenia squamifrons Gunther, 1880 from the Indian sector of the Southern Ocean. Polar Biol 4 (3):143-153. https://doi.org/10.1007/BF00263877