Managing pest animals in the Isaac region

Queensland’s two species of Tilapia (Oreochromis mossambicus and Tilapia mariae) were introduced to Australia in the 1970’s as ornamental pet species and have since become one of the most threatening species to Australia’s native biodiversity. Tilapia can live in a variety of temperatures ranging from 8⁰c - 42⁰c and can reach sexual maturity from very young ages. With their exceptional adaptations Tilapia can quickly outnumber native fish species in both fresh and estuarine waterways. Other threats they pose include competition behaviours, disturbing aquatic plant beds and reducing native fish populations for fisheries. Under the Biosecurity Act 2014, Tilapia is a restricted noxious fish and can NOT be moved, fed, kept, given away, sold or released into the environment. If Tilapia is caught that it must be humanely killed and disposed of away from the location from where it was caught.  

Yellow Crazy Ants (Anoplolepis gracilipes) originated from Africa and are in the top 100 invasive alien species in the world. The species is yellow or brown in colour and grows to approximately 5mm in length. They are most typically found in forests but can also survive and thrive in much harsher dry environmental conditions. Large infestations of colonies can threaten both native plants and animals and have already had a large impact on Red Crab populations on Christmas Island. The ant is also a health risk to domestic animals, livestock and humans as it can spit formic acid which causes irritations to the skin. Yellow Crazy Ant is classified as a category 3 restricted tramp ant under the Biosecurity Act 2014 and is not to be sold, given away or distributed. All land holders have a GBO to undertake all practical measures to reduce the spread of yellow crazy ant populations on their property.  

Deer were introduced during the 19th century from Europe and Asia as game animals and are continued to be farmed today. In Queensland there is 4 feral deer species that are classified as restricted under the Biosecurity Act 2014. These are the Feral fallow deer (Dama dama), the Feral red deer (Cervus elaphus), the Feral rusa deer (Cervus timorensis), and the Feral chital deer (Axis axis). Deer species are very susceptible to the introduction of livestock diseases and because of which they can risk translocating diseases between properties. They also pose threats to crops, pastures, forestry’s, soil erosion and can create traffic hazards. For game farmers keeping deer, they must hold a permit and have a deer containment fence around the deer paddock. To move deer, farmers must meet all requirements outlined by Business Queensland.  

The European Red fox (Vulpes vulpes) was first introduced by Europeans for hunting in the 1870’s and quickly got out of hand as they colonised rapidly through Victoria and South Australia. The fox is a canine predator that has litter sizes of 4-10 pups per year. They have a mortality rate of ~65% but even so because of their vocal behaviours they are highly social and can locate other easily during mating season. Foxes are aggressive hunters and will go for a large range of native animals and birds. They are also well known for their predation on livestock of chickens and lambs. Foxes can be common in dry arid areas, coastal areas, farms, forests and in urban communities where they will scavenge for left out food and small birds. The European Red Fox has been listed as a restricted invasive animal under the Biosecurity Act 2014, and can not be moved, sold, fed, given away, released or kept as pets.  

The early settlers first introduced Feral pigs (Sus scrofa) both deliberately and accidentally and they are now found all over Australia in close distances to fresh water. Pigs can breed all times of the year and sows can produce litters of 4-10 piglets twice annually. Even though they have low mortality rates, they have been successful in developing a widespread population. Pigs are omnivores and opportune feeders which means they have a largely varied diet of plant matter, insects and small animals. Their diet range is what makes them such a pest species as they eat native fauna, native flora, crops and young farmed animals. They also carry livestock diseases and at least 5 human transmitted diseases. Feral pigs are declared as an invasive restricted animal (feral) but they may be kept as a registerable biosecurity entity if they are a persons declared designated animal. All other feral pigs must be maintained as a GBO by baiting, trapping or excluding the species on private properties. Isaac regional Council offer assistance to all Isaac regional landowners once a year during the 1080 baiting program. To find out more about this program please click here.

Rabbits (Oryctolagus cuniculus) were introduced to Australia in the mid 1800’s to be used for sport hunting, but because they can have litters of up to 8 kittens, every 30 days of the year, they became quickly invasive across the country. Feral rabbits are one of Australia’s most expensive pest animals costing the country between $600 million and $1 Billion annually in crop damage, vegetation damage, erosion, landscape destruction and the competition they pose to native fauna. In Queensland, they are a restricted invasive animal, and it is illegal to keep a pet rabbit domestically under any circumstance. All landowners have a GBO for the control of rabbits on their property and can do so by either poisoning, trapping, shooting, excluding, fumigating or releasing biological controls. It is also best practice to destroy rabbit warrens if they are on the property by ripping the warrens.  

Cats (Felis catus) are strongly independent and can easily adapt to a Feral cat state if they are released or dumped after domestication. There are two classifications of feral cats in Queensland; the first is semi-feral cats which still predominately live in urban environments as scavengers, and the second is true feral cats (normally wild born) which don’t need any human intervention for food or shelter. Felines are carnivores and are meticulous hunters. They mostly hunt at night and true feral cats tend to migrate to areas where the colour of its fur matches its surroundings for camouflage. They are also playful and opportunistic predators with an extremely high kill rate. One study on Macquarie Island showed that 375 recorded cats would consume 58,000 sea birds and 56,000 rabbits per year. Because of their predatory behaviours they are a large threat to small native animals, and they further pose a risk to marsupials through the translocation of the toxoplasmosis parasite found in cat droppings. Under the Biosecurity Act 2014, the Feral cat is a restricted invasive animal and cannot be taken as a pet, fed, sold or given away. It is important to manage feral populations on your property and it is recommended to spray or neuter your domestic cat to control feral cat populations and keep them safe when on heat.  

Wild dog’s (canis familaris) is a mixed group of dogs that can be either escaped domestic dogs, dingo hybrids, or true bred dingoes. Although the dingo is a native animal and is protected under the Nature Conservation Act 1992 in all Queensland national parks, everywhere else in Queensland they are declared a restricted invasive animal under the Biosecurity Act 2014. In protected states, dingoes can function as a beneficial apex predator by reducing feral animal populations. They are however considered a pest to property owners and farmers by eating livestock and can threaten already endangered species. Isaac Regional Council supports landholders in managing the wild dog population by running the annual 1080 baiting program for feral pigs and wild dogs and offers local citizens to take part in a monthly dingo bounty.