Effect of salinity on growth of juvenile Yarra pygmy perch (Nannoperca obscura: Percichthyidae)

Hillary C. Mahon, Michael P. Hammer, James O. Harris

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    2 Citations (Scopus)


    The threatened Yarra pygmy perch (Nannoperca obscura) is an obligate freshwater fish endemic to the south-eastern coast of mainland Australia, where a majority of river systems have been heavily modified since European settlement. The purpose of this garden study was to explore any relationship between the growth rate of juvenile N. obscura with respect to salinity. Trials were conducted encompassing perceived and potential ranges within the species’ environment, through five salinity treatments and recorded growth after 8 weeks. Two brood-groups were trialed simultaneously to observe any intrapopulation variance in phenotypic response potentially linked to genetic variance. The salinity trials found a clear model indicating increasing growth for moderate salinities (i.e. 2.5–7.5 ppt), therefore identifying the ideal salinity range for N. obscura juveniles. Phenotypic response between brood-groups was varied and inconsistent, potentially reflecting low genetic variability. With a limited genetic variance restricting adaptability, tolerance to a changing environment would be reduced. Therefore increased salinization and subsequent flushing events within habitats may be key threats to the species’ survival.

    Original languageEnglish
    Pages (from-to)1491-1500
    Number of pages10
    JournalEnvironmental Biology of Fishes
    Issue number6
    Early online date2014
    Publication statusPublished - 1 Jun 2015


    • Freshwater fish
    • Growth
    • Nannoperca obscura
    • Pygmy perch
    • Salinity


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