Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p8
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 21600–24597

was found to be highly differentiated from both the Hawkesbury-Nepean and Murray-Darling Basin lineages (Pavlova et al., 2017b), supporting a long term evolutionary trajectory of the Shoalhaven lineage. Analysis of mitochondrial lineage divergence showed that the Shoalhaven Basin diverged from the common ancestor of the Murray-Darling Basin and Hawkesbury-Nepean around 1 332 000 to 419 000 years ago (Pavlova et al., 2017b).
Genetic analysis of microsatellite markers shows that, with two exceptions, all Murray-Darling Basin populations form independent genetic clusters, indicating a strong effect of genetic drift (loss of genetic diversity) due to population isolation (Pavlova et al., 2017a; 2017b), consistent with earlier studies (Faulks et al., 2011; Nguyen et al., 2012). The two exceptions were: Holland's Creek and Lake Dartmouth in one cluster, likely reflecting recent stocking of Holland's Creek with fish derived from Lake Dartmouth, and; the Lachlan and Abercrombie rivers (which are connected) in one cluster, in which there appears to be unidirectional gene flow from the Abercrombie River to the Lachlan River (Faulks et al., 2011), however the Lachlan River population appears extinct above Lake Wyangala (NSW DPI pers. comm., 2016; Pearce et al., 2017). Similar patterns of populations forming independent genetic clusters have been shown in the Hawkesbury-Nepean system (Pavlova et al., 2017a).
Given the current taxonomic status, this recovery plan remains relevant to all lineages of Macquarie perch.

    3.4 Description

The Macquarie perch is a moderate sized, elongated, oval shaped, laterally compressed fish with large silvery-white eyes, a small mouth and a rounded tail. The snout is tapered and the upper jaw slightly overhangs the lower jaw. There are conspicuous pores on the lower jaw. Macquarie perch have a concave nape similar to, but not as distinct as, golden perch (Macquaria ambigua). They are similar in appearance to golden perch, Australian bass (Macquaria novemaculeata) and estuary perch (Macquaria colonorum). Juveniles closely resemble several pygmy perch species found in eastern Australia (Nannoperca spp.) (Family Percichthyidae).
The colour of Macquarie perch within the Murray-Darling Basin varies from almost black or dark silvery-grey, dark bronze to pale bluish grey or green-brown above, with off-white below. Fins sometimes have a purplish or yellowish tinge. Coastal drainage fish often have grey-brown, buff and dark grey patches.
Size varies greatly between Murray-Darling Basin and coastal drainage populations, with Murray-Darling fish reaching up to 550 mm and 4 kg (but are uncommon today over 1.5 kg), while coastal drainage fish rarely reach over 190 mm with a maximum recorded size of 253 mm (Lake 1959; 1978; Battaglene 1988; Harris & Rowland 1996; Douglas et al., 2002; Bruce et al., 2007; Knight & Bruce 2010; Lintermans & Ebner 2010).

Figure 1: Typical adult Macquarie perch from the Murray-Darling Basin
Photo – Luke