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Thysanoessa macrura in the southern Kerguelen region: population dynamics and biomass


Wallis, JR and Maschette, D and Wotherspoon, S and Kawaguchi, S and Swadling, KM, Thysanoessa macrura in the southern Kerguelen region: population dynamics and biomass, Deep-Sea Research. Part 2, 174 Article 104719. ISSN 0967-0645 (2020) [Refereed Article]

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© 2020 Elsevier Ltd. All rights reserved.

DOI: doi:10.1016/j.dsr2.2019.104719


Thysanoessa macrura is well adapted to the strong seasonality of the Southern Ocean. A flexible diet, large lipid reserves and a winter reproductive period provide T. macrura with the ability to capitalise on the pulses of primary and secondary reproduction in spring and summer. The population dynamics of T. macrura were examined over the southern Kerguelen Plateau region as part of a large-scale ecosystem assessment. Larval stages were present in high abundances, exceeding 4000 Ind. 1000 m−3, with a peak in early furcilia (FI − FIV) and lower abundances of calyptopis stages (CI − CIII) indicating the end of a prolonged spawning period. High abundances of T. macrura were recorded throughout the entire study region, although they tended to be highest over the southern extent of the Banzare Bank and Princess Elizabeth Trough. This maximum appeared to be driven by the presence of the copepod Calanoides acutus, a dominant prey source. The first biomass estimates of T. macrura were determined for the region using length-frequency and abundance distributions. A mean biomass of 1.66 mg m−3 (wet weight) was calculated for the region, however localised biomass over the southern tip of the Banzare Bank exceeded 9 mg m−3 in the upper 200 m of the water column. The high biomass of T. macrura highlights their significance as an energy-rich resource for larger predators, inferring they play a currently underappreciated role in pelagic food-webs of the Southern Ocean.

Item Details

Item Type:Refereed Article
Keywords:krill, larvae, Calyptopis, Furcilia, Calanoides acutus, lipids
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Wallis, JR (Mr Jake Wallis)
UTAS Author:Maschette, D (Mr Dale Maschette)
UTAS Author:Wotherspoon, S (Dr Simon Wotherspoon)
UTAS Author:Kawaguchi, S (Dr So Kawaguchi)
UTAS Author:Swadling, KM (Associate Professor Kerrie Swadling)
ID Code:137491
Year Published:2020
Deposited By:Fisheries and Aquaculture
Deposited On:2020-02-17
Last Modified:2020-12-07

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