Response of two-spined blackfish Gadopsis bispinosus to short-term flow fluctuations in an upland Australian stream

Ben Broadhurst, J. G. Dyer, Jason Thiem, Peter Pridmore

    Research output: Contribution to journalArticle

    10 Citations (Scopus)

    Abstract

    Environmental flows are applied to regulated rivers, predominantly with the aim of benefiting native fauna. However, the outcomes for biodiversity and the mechanisms that underpin changes due to these manipulations are poorly understood. We examined the effects of elevated water release, of the magnitude used for riffle maintenance, on the movement and habitat use of the locally-threatened two-spined blackfish, Gadopsis bispinosus, in the Cotter River, a regulated upland stream in south-eastern Australia. We compared the behaviour of radio-tagged individuals during baseline flow conditions (0.12 m3 s-1) and during elevated flow releases (1.74 m3 s-1). Eight individuals (196 ± 8 mm TL) were radio-tracked at one site over 22 days, and six individuals (180 ± 5 mm TL) were monitored by fixed telemetry stations at a second site for 1 month. At both the sites, two-spined blackfish were nocturnal and occupied small linear ranges (23 ± 6 m). They preferentially used pools, but also used runs and riffles. Elevated discharge did not significantly affect movement, activity or dispersal of two-spined blackfish. Two individuals utilised inundated vegetation during high flow. Despite a small number of behavioural changes, there was no response to elevated flow at the population level. It is likely that the benthic nature of this species precludes its behaviour being affected by a 15-fold increase in-stream discharge. However, the indirect effects of flows of this magnitude on two-spined blackfish, and their responses to discharges of greater magnitude, remain to be investigated.
    Original languageEnglish
    Pages (from-to)63-77
    Number of pages15
    JournalHydrobiologia
    Volume673
    DOIs
    Publication statusPublished - 2011

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    highlands
    riffle
    radio
    radio frequency identification
    Gadopsis
    fauna
    vegetation
    rivers
    river
    water

    Cite this

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    title = "Response of two-spined blackfish Gadopsis bispinosus to short-term flow fluctuations in an upland Australian stream",
    abstract = "Environmental flows are applied to regulated rivers, predominantly with the aim of benefiting native fauna. However, the outcomes for biodiversity and the mechanisms that underpin changes due to these manipulations are poorly understood. We examined the effects of elevated water release, of the magnitude used for riffle maintenance, on the movement and habitat use of the locally-threatened two-spined blackfish, Gadopsis bispinosus, in the Cotter River, a regulated upland stream in south-eastern Australia. We compared the behaviour of radio-tagged individuals during baseline flow conditions (0.12 m3 s-1) and during elevated flow releases (1.74 m3 s-1). Eight individuals (196 {\^A}± 8 mm TL) were radio-tracked at one site over 22 days, and six individuals (180 {\^A}± 5 mm TL) were monitored by fixed telemetry stations at a second site for 1 month. At both the sites, two-spined blackfish were nocturnal and occupied small linear ranges (23 {\^A}± 6 m). They preferentially used pools, but also used runs and riffles. Elevated discharge did not significantly affect movement, activity or dispersal of two-spined blackfish. Two individuals utilised inundated vegetation during high flow. Despite a small number of behavioural changes, there was no response to elevated flow at the population level. It is likely that the benthic nature of this species precludes its behaviour being affected by a 15-fold increase in-stream discharge. However, the indirect effects of flows of this magnitude on two-spined blackfish, and their responses to discharges of greater magnitude, remain to be investigated.",
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    Response of two-spined blackfish Gadopsis bispinosus to short-term flow fluctuations in an upland Australian stream. / Broadhurst, Ben; Dyer, J. G.; Thiem, Jason; Pridmore, Peter.

    In: Hydrobiologia, Vol. 673, 2011, p. 63-77.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Response of two-spined blackfish Gadopsis bispinosus to short-term flow fluctuations in an upland Australian stream

    AU - Broadhurst, Ben

    AU - Dyer, J. G.

    AU - Thiem, Jason

    AU - Pridmore, Peter

    PY - 2011

    Y1 - 2011

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    AB - Environmental flows are applied to regulated rivers, predominantly with the aim of benefiting native fauna. However, the outcomes for biodiversity and the mechanisms that underpin changes due to these manipulations are poorly understood. We examined the effects of elevated water release, of the magnitude used for riffle maintenance, on the movement and habitat use of the locally-threatened two-spined blackfish, Gadopsis bispinosus, in the Cotter River, a regulated upland stream in south-eastern Australia. We compared the behaviour of radio-tagged individuals during baseline flow conditions (0.12 m3 s-1) and during elevated flow releases (1.74 m3 s-1). Eight individuals (196 ± 8 mm TL) were radio-tracked at one site over 22 days, and six individuals (180 ± 5 mm TL) were monitored by fixed telemetry stations at a second site for 1 month. At both the sites, two-spined blackfish were nocturnal and occupied small linear ranges (23 ± 6 m). They preferentially used pools, but also used runs and riffles. Elevated discharge did not significantly affect movement, activity or dispersal of two-spined blackfish. Two individuals utilised inundated vegetation during high flow. Despite a small number of behavioural changes, there was no response to elevated flow at the population level. It is likely that the benthic nature of this species precludes its behaviour being affected by a 15-fold increase in-stream discharge. However, the indirect effects of flows of this magnitude on two-spined blackfish, and their responses to discharges of greater magnitude, remain to be investigated.

    KW - Environmental flows

    KW - Flow response

    KW - Gadopsis bispinosus

    KW - Radio-telemetry

    KW - Home-range

    KW - Diel activity

    U2 - 10.1007/s10750-011-0750-0

    DO - 10.1007/s10750-011-0750-0

    M3 - Article

    VL - 673

    SP - 63

    EP - 77

    JO - Hydrobiologia

    JF - Hydrobiologia

    SN - 0018-8158

    ER -