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Exploring ecosystem structure and function of the northern Kerguelen Plateau using a mass-balanced food web model

journal contribution
posted on 2023-05-20, 14:07 authored by Roshni Subramaniam, Stuart CorneyStuart Corney, Kerrie SwadlingKerrie Swadling, Melbourne-Thomas, J

Annual phytoplankton blooms on the northern region of the Kerguelen Plateau fuel a productive food web that supports highly valuable commercial fisheries for Patagonian toothfish (Dissostichus eleginoides) and mackerel icefish (Champsocephalus gunnari). The food web on the plateau is understudied in comparison to other regions of the Southern Ocean. Major linkages and energy pathways have not been explored, and the combined effects of fishing and a changing climate on the ecosystem are largely unknown. Single species studies on the plateau have shown that the combined effects of climate change and fisheries are impacting populations, however, it is unclear how these impacts translate to the ecosystem. We extended an existing Ecopath model to describe food web dynamics on the plateau and investigate food web interactions with the fishery. Results from our model highlight, for the first time, the properties of the food web, major energy pathways and energy transfers between trophic levels. Energy transfer from detritus was most efficient at the lowest trophic level while energy from primary production was more efficient at higher trophic levels. Consumption and respiration were high in our system, most likely due to the inclusion of bacteria and microzooplankton. Killer whales, cephalopods and myctophids were key functional groups for energy transfer in the system. These groups were relatively data poor, suggesting a useful focus area for future updates to the model. Patagonian toothfish and mackerel icefish were heavily consumed in the food web, however, the inclusion of fisheries catches and by-catch had little to no impact on food web dynamics.

Funding

Donation via University of Tasmania Foundation

History

Publication title

Deep-Sea Research: Part II

Volume

174

Article number

104787

Number

104787

Pagination

1-18

ISSN

0967-0645

Department/School

Institute for Marine and Antarctic Studies

Publisher

Pergamon-Elsevier Science Ltd

Place of publication

The Boulevard, Langford Lane, Kidlington, Oxford, England, Ox5 1Gb

Rights statement

© 2020 Elsevier Ltd. All rights reserved.

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught fin fish (excl. tuna); Assessment and management of coastal and estuarine ecosystems; Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)

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