Growth and early life stage of Antarctic silverfish (Pleuragramma antarctica) in the Amundsen Sea of the Southern Ocean: evidence for a potential new spawning/nursery ground

Antarctic silverfish (Pleuragramma antarctica) is the dominant mesopelagic fish species in the high-Antarctic zone and plays a vital role in the food web of Antarctic marine ecosystems. Despite its ecological importance, no studies have been conducted on its age and growth or early life history in the Amundsen Sea thus far. In this study, based on 266 individuals of Antarctic silverfish collected in the Amundsen Sea polynya during January 2020, growth parameters were estimated for larvae and older individuals based on the age information from otoliths. For large individuals, age classes ranged from 1 to 11 years (standard length, SL, 32–167 mm), and the von Bertalanffy growth function (VBGF) was estimated as Lt=203.97(1-e-0.135(t+0.66))\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{L}}_{\text{t}}= \, 203.97(1-{\text{e}}^{-0.135 \, ({\text{t}} + 0.66)})$$\end{document}. The growth performance index (P) was estimated to be 1.75 and was at the lower limit of values observed in notothenioid fishes. For larval specimens, SL ranged from 13.8 mm to 20 mm, with a daily age of 25 to 54 days. The exponential growth model indicated that the growth rate at the mean size of 17.0 mm was 0.19 mm day−1, corresponding to a daily percentage change in size of approximately 1.14% SL. The back-calculated hatching dates showed that the hatching season lasted from December to early January. The results suggested a potential new spawning/nursery ground for Antarctic silverfish in the Amundsen Sea. In comparison with age and growth data available in the literature for Antarctic silverfish, our results from the Amundsen Sea provided more insights into the early life history characteristics of this species across the Antarctic continental shelf.