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Dietary analysis reveals the vulnerability of the endangered Maugean skate (Zearaja maugeana) to benthic changes in Macquarie Harbour

journal contribution
posted on 2023-05-20, 00:21 authored by Weltz, K, Jeremy LyleJeremy Lyle, Bell, JD, Jayson SemmensJayson Semmens

Species occupying high trophic positions with a small population size, limited diet and restricted range are vulnerable to extinction. The endangered Maugean skate (Zearaja maugeana) in Macquarie Harbour is potentially threatened by changing benthic environmental conditions (declining dissolved oxygen concentrations and decreased macrofaunal diversity). To inform investigations on potential indirect impacts of benthic environmental changes on the Maugean skate and its prey, non-lethal techniques were used to identify dietary composition and trophic position of the species. The Maugean skate occupies a high trophic position (3.70) in the food web, with both stable-isotope (median 86% contribution to isotopic signatures, credible interval (CI) = 44–100%) and stomach-content analysis showing crustaceans, particularly brachyuran crabs (58.5% index of relative importance), as the dominant prey type. Aquaculture feed from salmonid fish farms operating in the harbour was not found to be important in skate diet. This study showed that the Maugean skate consumes a small number of benthic prey species, highlighting its vulnerability to changing environmental conditions in the harbour.

Funding

Holsworth Wildlife Research Endowment

History

Publication title

Marine and Freshwater Research

Volume

70

Issue

5

Pagination

745-753

ISSN

1323-1650

Department/School

Institute for Marine and Antarctic Studies

Publisher

C S I R O Publishing

Place of publication

150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066

Rights statement

Copyright 2018 the authors.

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught fin fish (excl. tuna)

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