Hydrology and water temperature influence recruitment dynamics of the threatened silver perch Bidyanus bidyanus in a regulated lowland river

Zeb Tonkin, Ivor Stuart, Adrian Kitchingman, Jason D. Thiem, Brenton Zampatti, Graeme Hackett, Wayne Koster, John Koehn, John Morrongiello, Martin Mallen-Cooper, Jarod Lyon

    Research output: Contribution to journalArticlepeer-review

    18 Citations (Scopus)

    Abstract

    Understanding the influence of extrinsic factors such as hydrology and hydraulics on recruitment provides essential insight to inform management of fish populations. The critically endangered silver perch Bidyanus bidyanus is a long-lived, potamodromous pelagophil endemic to Australia’s Murray–Darling Basin. Declines of this species are often attributed to river regulation, although quantitative studies linking hydrology and hydraulics to key aspects of its life cycle are sparse. We used a multidecadal age-structured dataset collected from a locally abundant population of silver perch to quantify the relative importance of different abiotic drivers on year-class strength (recruitment). Silver perch recruited across highly variable hydrological conditions. The strongest year classes were associated with a combination of low to average river discharge (i.e. within channel) and high water temperatures over the peak spawning period, followed in the next year by extended high flows and widespread flooding that promoted survival of age-1+ juvenile fish. We suggest that conditions affecting the growth and dispersal of juvenile fish, in addition to the spawning period, are critical in governing recruitment dynamics. This highlights the need for multiyear flow plans for freshwater fish populations.
    Original languageEnglish
    Pages (from-to)1333-1344
    Number of pages12
    JournalMarine and Freshwater Research
    Volume70
    Issue number9
    DOIs
    Publication statusPublished - 16 Apr 2019

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