The Australian bass (Percalates novemaculeata)[2] is a small-to-medium-sized species of primarily freshwater (but estuarine spawning) ray-finned fish found in coastal rivers and streams along the east coast of Australia.

[4][5] The species was simply called perch in most coastal rivers where it was caught until the 1960s, when the name "Australian bass" started to gain popularity.

[10] More recent studies have found Percalates to be the earliest-diverging genus within the order Centrarchiformes, being only distantly related to Macquaria and other percichthyids.

[11] Steindachner does not explicitly state the reasons behind the surprisingly ambiguous specific name novemaculeata that he created for Australian bass.

It may be a Latin rendering of "new" (novem) and "spotted" (maculeata) and refer to the distinct black blotches juvenile bass are temporarily marked with when very small (i.e. <6–7 cm).

The opercula or gill covers on Australian bass carry extremely sharp flat spines that can cut fishermens' fingers deeply.

Australian bass stocked in man-made impoundments (where they cannot breed) grow to greater average and maximum weights than this.

Although the system is extensive, it terminates in a sequence of coastal lakes and lagoons and has only one shallow and changeable entrance to the Southern Ocean — features that appear to be incompatible with the estuarine breeding habits of Australian bass and other aspects of their life cycle.

[8] The timing of these migratory movements are also dependent on river flows, particularly freshes and floods that drown out and make larger rapids and cascades passable.

Australian bass are found at their highest altitude in the freshwater reaches of rivers during the months of December, January and February.

The distance Australia bass travel upstream appears to be limited only by flows and impassable barriers (historically, waterfalls; today, often, dams).

"In the freshwater reaches of coastal rivers in the warmer months, Australian bass require reasonable quality, unsilted habitats with adequate native riparian vegetation and in-stream cover/habitat.

Sunken timber ("snags"), undercut banks, boulders, shade under trees and bushes overhanging the water and thick weedbeds are all used as cover.

When aggregated for spawning in the broad reaches of estuaries in winter, Australian bass are less cover oriented, and generally sit in deeper water.

[14] Australian bass continue the trend present in the larger native fish species of SE Australia of being very long-lived.

Longevity is a survival strategy to ensure that most adults participate in at least one exceptional spawning and recruitment event, which are often linked to unusually wet 'La Niña' years and may only occur every one or two decades.

Dams and weirs blocking migration of Australian bass both to estuaries and to the upper freshwater reaches of coastal rivers is the most potent cause of decline.

A related issue is the myriad of other structures on coastal rivers such as poorly designed road crossings that (often needlessly) block migration of Australian bass.

Fishing for Australian bass is a summer pastime, undertaken during the warmer months in the freshwater reaches of the rivers they inhabit.

Their extraordinary speed and power is probably due to their significant, strenuous annual migrations for spawning and a life-style that is migratory in general.

Australian bass in their natural river habitats are not to be underestimated; they head straight for the nearest snags (sunken timber) when hooked, and light but powerful tackles with stiff drag settings are needed to stop them.

It pays for fishermen to remember that wild Australian bass are still highly migratory when in the freshwater reaches of rivers, and can also be an extremely wary fish in these habitats, much more so than exotic trout species.

In 2014 the NSW Fisheries Department announced an extended closed season for Australian bass and estuary perch, from 1 May to 31 August.