Distribution of the black mangrove cichlid (Tilapia mariae) in Australia The black mangrove cichlid or ‘spotted tilapia’ is a species of deep-bodied fish belonging to the family Cichlidae. Native to West Africa, its distribution extends from the The first documented Ivory Coast through Ghana and Nigeria to Cameroon1. Introduction to Australia: discovery of introduced black mangrove cichlids in Throughout this range the species is often found in the Australian waterways was in the 1970s in the Hazelwood deeper sections of larger rivers and lagoons but also pondage, Victoria. During the 1980s, a population of black moves into flowing streams during the rainy season1. mangrove cichlids was discovered in coastal rivers in the Black mangrove cichlids have become a desirable Wet Tropics World Heritage Area of north Queensland3. aquarium species as they are hardy, readily reproduce These introductions occurred despite the species being and have attractive body and fin colouration2. This on the prohibited import list since the 1960s. The precise popularity has led to the species being exported to many origin of the illegal importations is still unknown but it is countries outside Africa. The ability of black mangrove thought to have been through the ornamental fish trade. cichlids to adapt to a wide range of ecological conditions More black mangrove cichlids have since been released has enabled them to become a highly invasive pest. For into the wild, either deliberately or accidently, and have example, in the United States the black mangrove cichlid formed self-sustaining populations. has established self-sustaining populations in several states, including Florida, Arizona, California and Nevada3. Current Australian distribution and Self-sustaining populations of this species reportedly abundance: The black mangrove cichlid is present in also occur in Russia (unconfirmed) and unfortunately, in three eastern catchments draining the Wet Tropics area Australia. of north Queensland, and an isolated population persists in the Hazelwood pondage in Victoria. This population is the only known population of black mangrove cichlids The Gulf of Carpentaria outside Queensland. drainage is at serious Northeast Queensland (Wet Tropics): The distribution threat of being colonised by of black mangrove cichlids in the Wet Tropics centres on the greater Cairns region. To the north of the city, introduced tilapia black mangrove cichlids have been present in small drainages and ponds around Cairns’ northern beaches as well as in the Barron River and associated tributaries In the United States, studies have found that the species since the mid-to-late 1980s5. During the mid 1990s, black has the potential to affect other introduced and native mangrove cichlids were introduced to the upland section fishes through aggressive interactions for territories3. of the Barron River catchment and are now abundant in They have also become the most abundant species in all tributaries as well as the large impoundment, Lake canal habitats due to their wide ecological tolerances, Tinaroo6. Feeder creeks and water bodies in the Barron and compete with small native fish and invertebrates River catchment with self-sustaining populations of this for food3. In Australia, the impacts of black mangrove species include (upland section) Peterson Creek, Kenny cichlids are still being assessed, but they are likely to Creek, Severin Creek, and in the lowlands below Barron include habitat modification, spread of diseases and River Falls, Freshwater Creek, Cattana Wetlands and reductions in native biodiversity. Thomatis Creek. To the south of Cairns, black mangrove cichlids are Stopping the spread: Currently, attempts to present in the lower Johnstone River and the Russell- stop the spread of black mangrove cichlid are through Mulgrave River system. Distributions within both education and extension programs, spot eradications catchments include the main river channels to the base and installation of screens on irrigation channels and of the coastal escarpment, major tributaries, coastal pipelines. There is currently no ‘silver bullet’ option flood plain drainages and water storages. Black mangrove for their management, but ongoing research is looking cichlids were first discovered in the Johnstone River in at alternative control options8. Considering the highly the early 1990s. They have since colonised the lowland invasive nature of the species, it is likely that the portion of both the North and South Johnstone Rivers distribution will continue to expand as the species including the feeder creeks of Victory Creek, Gracey spreads into new waterways in tropical and sub-tropical Creek, Stewart Creek and Utchee Creek. In the Russell- Australia. Mulgrave River catchment, black mangrove cichlids are abundant. They occur along the length of both rivers on References the coastal plain, as well as Lake Barrine on the Atherton 1. Fishbase (2010). Tilapia mariae (Boulenger Tablelands, on the headwaters of the Mulgrave River. 1899). Fishbase species table online. See http:// Feeder streams on the coastal plain include Behana www.fishbase.org/Summary/speciesSummary. Creek, Fishery Falls Creek and Figtree Creek draining php?ID=2489 into the Mulgrave River, and Harvey Creek, Babinda 2. Bradford M, Kroon F and Russell D (2011). The Creek and the Alice River draining into the Russell River. biology and management of Tilapia mariae (Pisces: Gulf of Carpentaria drainage: In 2008, a population of Cichlidae) as a native and invasive species: a review. black mangrove cichlid was discovered in Eureka Creek, Marine and Freshwater Research 62:902–917. an upper tributary of the Mitchell River, Queensland8. 3. United States Geological Survey (2011). Tilapia This was the first time this species had been found on mariae (Boulenger 1899). Non-indigenous aquatic the western side of the Great Dividing Range. It was species table online. quickly recognised that this population had the potential 4. Cadwallader PL, Backhouse GN and Fallu R (1980). to spread throughout the Mitchell River catchment and Occurrence of exotic tropical fish in the cooling then into the greater Gulf of Carpentaria drainage. At the pondage of a power station in temperate south– time of discovery, it was found in relatively low numbers eastern Australia. Australian Journal of Marine and in an isolated section of creek. This suggested that the Freshwater Research 31:541–546. species was only recently introduced to the area. An immediate eradication operation was carried out by 5. Lear RJ (1987). Survey of Introduced Tilapia in departmental fisheries officers to prevent further spread the Cairns Region, North Queensland. Queensland of the species7. Since then, follow-up surveys have found National Parks and Wildlife Service, Cairns, no evidence of black mangrove cichlids either in Eureka Queensland. Creek or in other tributaries of the Mitchell River. 6. Webb AC (2007). Status of non-native freshwater Victoria: A population of black mangrove cichlids persists fishes in tropical northern Queensland, including in the Hazelwood cooling ponds because of heated water establishment success, rates of spread, range and being discharged by the power station. The ponds are introduction pathways. Journal and Proceedings of located on a tributary of the Morwell River in Victoria. the Royal Society of New South Wales 140:63–78. Water temperatures in the Morwell River and other 7. PestSmart Tilapia Case Study – Eureka Creek temperate areas of Australia are at the extreme lower eradication attempt using rotenone. PestSmart end of thermal tolerance for the species, and escapees publication, Invasive Animals Cooperative Research would be unlikely to survive and reproduce here. Centre, Canberra. Catchments/drainages at risk: There is potential 8. Russell DJ, Thuesen PA and Thomson FE (2009). for black mangrove cichlids to spread into other parts Development of Management Strategies for Control of tropical and sub-tropical Australia. Areas most at risk of Feral Tilapia Populations in Australia. Queensland of invasion are usually where colonised and unaffected Department of Employment, Economic Development catchments are close to each other or where there is and Innovation, Brisbane, Queensland. 55 pp. cross-drainage or cross-catchment distribution of water Invasive Animals Ltd has taken care to validate the accuracy of (eg through irrigation schemes). Some catchments in the the information at the date of publication [August 2013]. This Gulf of Carpentaria drainage meet these criteria and information has been prepared with care but it is provided are considered to be at high risk of invasion. Apart from “as is”, without warranty of any kind, to the extent permitted natural dispersal, the other major source of spread is by law. through the movement of fish between water bodies by people. Tilapia Factsheet April 2014 TILFS5.