Reproduction and Biology
Originally temperatures of close to 24 degrees Celsius were considered necessary for golden perch to spawn (Lake, 1967) but as with all Murray-Darling fish species it has become apparent that their "required" spawning temperature is flexible and that they can and do spawn at somewhat lower temperatures (as low as 20 degrees Celsius) (Koehn & Harrington, 2005). Golden perch have a flexible breeding strategy but generally need a spring or summer flood or "fresh" to stimulate spawning. Like some other primarily lowland native fish species of the Murray–Darling river system, these floods or freshes appear to be necessary for good survival and recruitment of spawned fish. Golden perch are highly fecund, females between 2.2 to 2.4 kg producing approximately half a million eggs per spawning event with fish above 2.5 kg producing well in excess of this number. The eggs are generally planktonic, and hatch fairly quickly (24 to 36 hours) (Lake, 1967; Rowland, 1996).
Like other Macquaria species, sexual dimorphism is present, with females reaching much larger maximum sizes than males. Females also reach sexual maturity at older, larger sizes than males.
Golden perch continue the trend, among many native fish of southeast Australia, of being very long-lived. Longevity is a survival strategy in the often challenging Australian environment which ensures that most adults participate in at least one exceptional spawning and recruitment event. These events are often linked to unusually wet La Niña years and may only occur every one or two decades. Maximum recorded age is 26 years (Mallen-Cooper & Stuart, 2003).
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