University Of Tasmania

File(s) under permanent embargo

In situ growth rate estimates of Southern Ocean krill, Thysanoessa macrura

journal contribution
posted on 2023-05-20, 02:14 authored by Jake WallisJake Wallis, Jessica MelvinJessica Melvin, King, R, So KawaguchiSo Kawaguchi

Growth, which is intrinsically linked to environmental conditions including temperature and food availability are highly variable both temporally and spatially. Estimates of growth rates of the Southern Ocean euphausiid Thysanoessa macrura are currently restricted to limited studies which rely upon repeated sampling and length-frequency analysis to quantify growth rates. The instantaneous growth method (IGR) was used to measure the growth rate of T. macrura successfully in the southern Kerulen Plateau region during summer, providing the first IGR parameters for the Southern Ocean euphausiid species. Results of the four-day IGR incubation indicate a period of low somatic growth for adult T. macrura. Males had a longer intermoult period (IMP) (62 days) than females (42 days), but the sexes exhibited similar daily growth rates of 0.011 mm day−1 and 0.012 mm day−1 respectively. Juveniles exhibited the fastest growth, with an IMP of 13 days and daily growth rate of 0.055 mm day−1 indicating a prolonged growth season, similar to the Antarctic krill E. superba. Consequently, we highlight the usability of the IGR method and strongly encourage its use in developing a comprehensive understanding of spatial and seasonal growth patterns of T. macrura.


Tassal Operations Pty Ltd


Publication title

Antarctic Science








Institute for Marine and Antarctic Studies


Cambridge Univ Press

Place of publication

40 West 20Th St, New York, USA, Ny, 10011-4211

Rights statement

Copyright 2019 Antarctic Science Ltd

Repository Status

  • Restricted

Socio-economic Objectives

Biodiversity in Antarctic and Southern Ocean environments