Short-term effects of a prolonged blackwater event on aquatic fauna in the Murray River, Australia

considerations for future events

Alison Jane King, Zeb Tonkin, J Lieshcke

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Blackwater contains high levels of dissolved organic carbon that can be rapidly consumed by microbes, sometimes leading to extremely low levels of dissolved oxygen (hypoxia) and drastic consequences for aquatic life, including fish kills. Drought-breaking rains in late 2010 inundated large areas of the BarmahMillewa Forest, southern MurrayDarling Basin, Australia, and resulted in a prolonged hypoxic blackwater event within the forest and the Murray River downstream. This study investigated the short-term effects of the blackwater event on fish and crayfish. Compared with non-affected sites, blackwater affected sites had: significantly higher abundances of emerged Murray crayfish (Euastacus armatus) that were vulnerable to desiccation, predation and exploitation; large numbers of dead or dying shrimp and yabbies; significantly reduced abundances of native fish; but contained similar abundances of alien fish species (particularly common carp, Cyprinus carpio). The nature of the mechanisms that caused these changes and the longer term significance of the event on the river system remains an important area for future research. We also propose a range of management considerations for reducing the blackwater impacts, such as the timing of environmental water delivery after prolonged drought and the importance of maintaining riverfloodplain connectivity during flood periods.
    Original languageEnglish
    Pages (from-to)576-586
    Number of pages11
    JournalMarine and Freshwater Research
    Volume63
    Issue number7
    DOIs
    Publication statusPublished - 2012

    Fingerprint

    Rivers
    Fishes
    fauna
    crayfish
    Cyprinus carpio
    Astacoidea
    rivers
    Carps
    Droughts
    fish
    drought
    river
    fish kills
    range management
    aquatic organisms
    hypoxia
    dissolved organic carbon
    desiccation
    Desiccation
    river system

    Cite this

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    abstract = "Blackwater contains high levels of dissolved organic carbon that can be rapidly consumed by microbes, sometimes leading to extremely low levels of dissolved oxygen (hypoxia) and drastic consequences for aquatic life, including fish kills. Drought-breaking rains in late 2010 inundated large areas of the BarmahMillewa Forest, southern MurrayDarling Basin, Australia, and resulted in a prolonged hypoxic blackwater event within the forest and the Murray River downstream. This study investigated the short-term effects of the blackwater event on fish and crayfish. Compared with non-affected sites, blackwater affected sites had: significantly higher abundances of emerged Murray crayfish (Euastacus armatus) that were vulnerable to desiccation, predation and exploitation; large numbers of dead or dying shrimp and yabbies; significantly reduced abundances of native fish; but contained similar abundances of alien fish species (particularly common carp, Cyprinus carpio). The nature of the mechanisms that caused these changes and the longer term significance of the event on the river system remains an important area for future research. We also propose a range of management considerations for reducing the blackwater impacts, such as the timing of environmental water delivery after prolonged drought and the importance of maintaining riverfloodplain connectivity during flood periods.",
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    Short-term effects of a prolonged blackwater event on aquatic fauna in the Murray River, Australia : considerations for future events. / King, Alison Jane; Tonkin, Zeb; Lieshcke, J.

    In: Marine and Freshwater Research, Vol. 63, No. 7, 2012, p. 576-586.

    Research output: Contribution to journalArticleResearchpeer-review

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    T2 - considerations for future events

    AU - King, Alison Jane

    AU - Tonkin, Zeb

    AU - Lieshcke, J

    PY - 2012

    Y1 - 2012

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    AB - Blackwater contains high levels of dissolved organic carbon that can be rapidly consumed by microbes, sometimes leading to extremely low levels of dissolved oxygen (hypoxia) and drastic consequences for aquatic life, including fish kills. Drought-breaking rains in late 2010 inundated large areas of the BarmahMillewa Forest, southern MurrayDarling Basin, Australia, and resulted in a prolonged hypoxic blackwater event within the forest and the Murray River downstream. This study investigated the short-term effects of the blackwater event on fish and crayfish. Compared with non-affected sites, blackwater affected sites had: significantly higher abundances of emerged Murray crayfish (Euastacus armatus) that were vulnerable to desiccation, predation and exploitation; large numbers of dead or dying shrimp and yabbies; significantly reduced abundances of native fish; but contained similar abundances of alien fish species (particularly common carp, Cyprinus carpio). The nature of the mechanisms that caused these changes and the longer term significance of the event on the river system remains an important area for future research. We also propose a range of management considerations for reducing the blackwater impacts, such as the timing of environmental water delivery after prolonged drought and the importance of maintaining riverfloodplain connectivity during flood periods.

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    KW - Murray River

    KW - Murray-Darling Basin

    KW - Victoria [Australia]

    KW - Astacoidea

    KW - Crustacea

    KW - Cyprinidae

    KW - Cyprinus carpio

    KW - Decapoda (Crustacea)

    KW - Euastacus armatus

    KW - Maccullochella peelii peelii

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    U2 - 10.1071/MF11275

    DO - 10.1071/MF11275

    M3 - Article

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    JO - Marine & Freshwater Research

    JF - Marine & Freshwater Research

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    ER -