Tilapia pest program reaches 10 year milestone QLD
Rod Cheetham
2021 marks a significant 10-year milestone for the Tilapia Exclusion Strategy. For 10 years this program has successfully aided in keeping the Murray Darling Basin tilapia free. The Murray-Darling Basin Authority (MDBA) Demonstration Reach Program began the Tilapia Exclusion Strategy in 2011 and continues to fund an education program, which aims to keep the basin free of the pest fish Tilapia or Mozambique Mouth Brooder. So far, despite tilapia infestations in catchments close by, the Basin has remained tilapia
translocate tilapia 3. Monitoring by training the community to identify and report tilapia should an incursion occur. This has been facilitated through the distribution of tilapia education material and identification resources. Pre-Covid, tilapia experts made regional visits to high risk areas. High risk areas are usually those with populations of tilapia already in the regional waterways, and geographically close by to the northern reaches of the Murray Darling Basin. Typically these are in Queensland. The same experts would visit and present at regional shows, schools, fishing clubs and Landcare groups within the Northern Murray
catchments that is definitely not a welcome addition to the fish community in the basin. Covid unfortunately has severely reduced face-to-face educational opportunities, and so this year the project is trying a more media focused approach, with more articles such as this one and on line education. The tilapia has already been implicated in the rapid demise of native fish in many other parts of the world, such as the pacific islands and now even in parts of Australia. There are real fears by Fisheries Authorities that if tilapia become established within the MDB an already stressed native fish and aquatic community will be changed
Nicole Whysall doing her bit by removing a large tilapia from the waterways. Photo courtesy of Jason of Pest Fishing Adventures. free, and this is great news. If Covid has taught us anything, it’s definitely prevention is a far more desirable outcome than infection. The same applies to the pest fish tilapia. The program has three parts: 1. To raise awareness through education. 2. Prevention by educating the community not to
darling Basin itself, such is the risk of tilapia becoming established in the Murray Darling Basin. For many decades now the aquatic ecosystem as well as anglers, stocking groups and clubs within the MDB have been impacted by the pest fish carp. Tilapia is another, possibly more sinister pest fish already established in adjacent
irreparably, particularly the smaller fish species. Tilapia also impact on the water quality, cause blue green algae and eat native fish. The invasive tilapia or Mozambique Mouth Brooder, (Oreochromis mossambicus) is a native to Africa, and has unfortunately become established and continues to spread in a number
A tilapia with typical red fins suggesting breeding is about to occur. Photo courtesy of Jason of Pest Fishing Adventures.
of Queensland and NSW coastal river systems. It is even present in a catchment in Western Australia. Invasive pests of all kinds have had huge and often devastating effects on Australia’s unique ecosystems, particularly throughout the Murray Darling Basin (MDB). This great country has seen the devastating impacts, both economic and environmental of rabbits, feral pigs, feral cats, blackberry, lantana and carp just to name a few. All pests are not helpful for agricultural production or ecosystem preservation. The Mozambique Mouth Brooder has a number of enhanced breeding and living strategies to enable reproduction under stressed environmental conditions that may provide a significant survival advantage over Australian native fish. In particular breeding rapidly in drought refuge waterholes when stressed, pushing out native fish. In large numbers they are capable of re-suspending nutrients creating blue green algae blooms which can become toxic to native fish and impact on people’s health. As the name suggests it is a mouth brooder. The female provides a safe haven for its eggs and young within the mouth, leading to high survival of young.
As stated earlier, this tilapia pest species has already been implicated in the rapid demise of native fish in other parts of the world, such as the Pacific Islands and within Australia. At this 10-year anniversary, of successfully keeping the basin tilapia free can I encourage you all to spare a thought about the risk tilapia pose to our largest and unique river system that drains around 15% of mainland Australia. Many of you would have heard of Fisheries Scientist, Dr Stuart Rowland and the huge volume of work he has done for and on behalf of the native fish of the MDB. In retirement Stu is still battling for the native fish within the Murray Darling Basin. In Stuart’s recently published book, “The Codfather” he suggests in the chapter titled ‘Goodbye Darling’ that the Darling River ecosystem as a whole is already extinct. Stuart suggests that given the existing degradation of the Darling River in particular, and given the present management systems in place, the system is more likely to experience periods of low to no flow. It is conditions like these that tilapia will most likely thrive in. If this is so, imagine what an infestation of tilapia would do. Or any
other aquatic pest for that matter. Dr Rowlands book is well worth a read by anyone interested in the history of the unique Murray Darling river system and the iconic native fish such as the Murray cod and golden perch that we have all come to know, respect and even love. At the very least, we as a community can remain vigilant and alert. Please report any suspected tilapia sightings in the MDB to the relevant authorities. In NSW, pest fish sightings can be reported on the DPI 24-hour Hotline: 1800 675 888. Or online complete the form or Email: aquatic.biosecurity@dpi. nsw.gov.au. In Queensland, report suspected infestations to the Department of Agriculture and Fisheries (DAF) Biosecurity section on 132523 or get on the DAF website and follow the pest fish prompts. Those of you who live, fish, travel and camp anywhere within and along the Murray-Darling Basin, watch out for potential infestations. Check on any unusual and dead fish you observe or catch in rivers and waterways. Know what tilapia look like. Many of us in Queensland unfortunately are already familiar with this pest. Even so I have included a few illustrations with this article to make identification a bit easier. Don’t let our politicians and civic fathers off the hook either. Let them know the community values our unique natural systems. 10 years tilapia free is a great result. Let us all keep tilapia out of the Murray Darling Basin! If there is anyone out there who would like further information on tilapia or pest fish identification material, you can contact Rod Cheetham on 0427514704. – Rod Cheetham, Fisheries Aquaculture & Wildlife Developments
Physical differences between tilapia and Australian native fish: the tilapia (right) has a continuous dorsal fin but a typical native fish has a dent or gap in the dorsal fin. 16
OCTOBER 2021
