Tilapia (Oreochromis mossambicus or the Mozambique mouthbrooder) is an invasive species in Australia, posing a significant threat to the endemic native fish and aquatic ecosystems. Traditionally found in Southern Africa, this species is incredibly adaptive and fast-growing, guaranteeing its spot in the top 100 of the world’s worst introduced species (NSW DPI). The fish was originally introduced to Australia in the 1970’s as an ornamental pet, however, it is now illegal to own, sell or move tilapia under the Biosecurity Act 2015. In 2022, Australia reported the greatest number of new invasions of Tilapia globally, with new populations identified in Queensland and NSW. To better understand the risks Tilapia pose to Australian fresh water systems, and learn to identify, check out this video!
Tilapia competes with native fish for food and space, often preying upon native fish eggs. Tilapia is also known to exhibit aggressive behaviour, increasing higher infection and mortality rates among native fish. The female fish carry eggs in their mouths, which can survive and hatch after the adult host dies. Therefore, placing these fish back into waterways can cause new infestations. Additionally, the nest building habits of male Tilapia can damage aquatic habitats through increased turbidity and destruction of aquatic plants.
However, the species is a widely-used source of protein in many other countries. The practice of farming Tilapia is believed to have originated more than 4, 000 years ago in Egypt. The 2020 FAO State of World Fisheries and Aquaculture Report stated that between 0.7-0.85 tons of Tilapia and other cichlids are caught every year. It is the fourth most commonly consumed seafood in the world. It is budget friendly, nutritious, and mild tasting, making it widely accessible.
In the aquaculture industry, the Tilapia market has expanded, making it a heavily traded fish globally. It is an ideal farming fish as it can survive mass farming and can grow fast on a vegetarian diet, making it cheap to produce. China has the largest Tilapia industry globally, producing approximately 1.9 million tons of Tilapia per year. In Pacific nations, such as Fiji, the farming of the species is being explored as a potential area for economic growth, food security and self-sufficiency.
What about Australia?
Although many countries consider this a popular table fish, in Australia, consumers are less likely to incorporate known invasive species into their diets. There are also certain rules and regulations about catching Tilapia to eat, discouraging their consumption in order to reduce the risk of new infestations. If Tilapia are allowed to be kept and consumed for profit, it inadvertently promotes their spread through the creation of illegitimate fisheries. There are strict laws outlining the prohibition of catching or growing tilapia in Australian aquaculture.
So, what do I do if I catch one?
The spread of Tilapia is usually caused by people moving the fish between water systems. Here’s some guidelines from the NSW DPI to follow:
- Don’t release fish into waters or allow fish to escape into waterways. It is illegal to return any recreationally caught Tilapia to the water. If caught whilst recreational angling they must be humanely dispatched and utilised or disposed of in a bin going to landfill.
- Don’t use suspected pest species as bait (whether dead or alive). Even dead Tilapia may still have eggs or young in their mouths.
- Obtain a permit from NSW DPI prior to any fish stocking activities and stock fish from a reputable local supplier rather than another region or interstate (to minimise risks of introducing species not native to your local area). Note – it is illegal to release fish into waters without a permit and heavy penalties apply.
- Give unwanted aquarium fish to a friend or a pet shop. If a suitable home cannot be found, please see the recommended guidelines for humane destruction of fish.
- Learn how to identify Tilapia.
- Be on the lookout for new species of fish in your area.
- Report sightings of suspected Tilapia, take good quality photographs and freeze the whole fish where possible.
- Clean your gear (e.g. landing nets, boots) and check for signs of eggs or young Tilapia. If found, ensure these eggs and young are not able to re-enter any Australian waters.
Main photo: Mozambique tilapia.
Source: Townsville Bulletin