The convict cichlid Amatitlania nigrofasciata (Cichlidae): first record of this non-native species in Western Australian waterbodies

WA Museum Records and Supplements | Updated 7 years ago

INTRODUCTION – The southwest of Western Australia is recognised as a global biodiversity hotspot (Myers et al. 2000), and although it is relatively depauperate in freshwater fish biodiversity, these species have high rates of endemicity (Morgan, Gill and Potter 1998). The South West drainage division includes the Swan Coastal Plain, a long (approximately 600 km) and narrow (30 km at its widest point) plain extending from Geraldton to Cape Leeuwin that is bordered by the Indian Ocean and the Darling Escarpment (Cummings and Hardy 2000; Thackway and Cresswell 1995).

Establishment of non-native species outside their natural range is a major threat to endemic species (Canonico et al. 2005; Courtenay and Stauffer 1990; Dudgeon et al. 2006) and has been identified as a major cause of extinctions (Reid et al. 2005). The incidence of introductions of non-native fish to freshwater environments of Australia has increased (Arthington et al. 1999; Lintermans 2004). Freshwater systems are often subject to both acute and chronic anthropogenic interactions and as a result suffer a high risk of introductions (Costanza et al. 1998; Gherardi 2007; Rahel 2007). The Swan Coastal Plain has the highest population density in the state of Western Australia (ABS 2011); therefore, freshwater systems in this area are particularly vulnerable to non-native fish introduction.

The convict cichlid, Amatitlania nigrofasciata Gunther, 1867 has a history of taxonomic confusion (Schmitter-Soto 2007a; Schmitter-Soto 2007b; Smith et al. 2008), most recently being moved from the genus Archocentrus to Amatitlania in 2007 (Schmitter-Soto 2007a; Schmitter-Soto 2007b). It is naturally found in Central American rivers and lakes on the Pacifi c slope from Rio Sucio, El Salvador to Rio Suchiate, Guatemala; and the Atlantic slope from Rio Patuca, Honduras to Rio Jutiapa, Guatemala (Schmitter-Soto 2007a). It has established wild populations in the USA (Hawaii), Mexico, Israel, Japan and Australia (Ishikawa and Tachihara 2010; Welcomme 1988).

The species is a member of the Cichlidae, a family of fish known for prolonged biparental care of offspring (Bernstein 1980; Keenleyside 1991). Due to confusion over taxonomy, the various studies of convict cichlids may not all represent the same species. However, all species are closely related, and therefore the results of behavioural studies are broadly applicable across the group. The convict cichlid group has been extensively studied in the laboratory (Wisenden 1995) but despite significant research, few studies have investigated the life history of Amatitlania nigrofasciata in natural environments. Adults were shown to reach 100 mm standard length (SL) (Kullander 2003) and mature females were found at 32 mm SL in introduced populations in Japan (Ishikawa and Tachihara 2010). This size is similar to that reported for the closely related Amatitlania siquial, whose males mature at sizes as small as 51 mm SL, and is a species which has received more intensive study (Wisenden 1995). Parental pairs are monogamous, and in the introduced population in Japan, bred throughout the year despite water temperatures of less than 20C (Ishikawa and Tachihara 2010). Amatitlania siquia excavates small caves under hard substrate and lays its eggs on the roof of these caves (Wisenden 1995). Both sexes care for the young (Noonan 1983) with adult fi sh caring for the brood by shepherding juveniles when outside the cave (Wisenden et al. 1995) and returning them to the cave at night for shelter, where adults stand guard and defend against potential predators (Gagliardi-Seeley and Itzkowitz 2009; Wisenden 1995). The non-native population in Japan exhibits rapid growth in the first year, early maturation, a long spawning period, multiple spawnings and a short life span (Ishikawa and Tachihara 2010). Although tropical, the population in Japan has survived water temperatures as low as 17.1C (Ishikawa and Tachihara 2010).

Within Australia, two populations have been reported. One population has existed in the artificially warmed waters of the Hazelwood Power Station cooling ponds in Victoria since 1978 (Allen 1989). The second population was purported to occur in Queensland by Koehn and MacKenzie (2004), however examination of the literature referenced to substantiate the presence of this population; Arthington and McKenzie (1997); Arthington and Bluhdorn (1995); and DPIQ (2001), reveals no reference to this species.

This report documents the first finding of Amatitlania nigrofasciata in a waterbody within Western Australia.