Initially forecast to open in early July this year, AFANT has been assured that the Four Mile Hole Billabong in Kakadu will now open on July 22. This follows the Billabong remaining closed throughout 2020n due to a high occurrence of the noxious floating weed – salvinia. Located in the South Alligator region of Kakadu, Four Mile Hole is part of the Wildman River catchment and is popular with adventurous fishers due to its excellent barramundi fishing and quiet campground.
Kakadu staff have reported that the good wet season has seen much of the salvinia flushed out of the billabong, however the weed still persists and will be monitored and managed. The spread of the weed to other locations also needs to be mitigated, with a number of interventions, including better signage and education being planned.
Salvinia can be spread through the translocation of plant fragments by animals and birds, as well as by boats, fishing gear, trailers and vehicles. It is essential that immediately after visiting Four Mile Hole or other Kakadu billabongs, that fishers carefully inspect their boats, trailers and landing nets to ensure there is no sneaky salvinia hitching a ride.
While this floating weed is present in a number of other billabongs in Kakadu national park, it is absent from some of the most popular Top End waterways including Corroboree Billabong and Hardies Billabong. This highlights the need reduce the risk of spreading the weed, as much as is possible, while maintaining access for a range of beneficial uses including camping and fishing.
AFANT have recommended to the Kakadu Tourism Consultative Committee and Kakadu staff, that park managers investigate the feasibility of installing simple wash down facilities in the future. Such facilities are used in other places to mitigate the transfer of aquatic weeds, and they could be installed at suitable locations within Kakadu to help reduce the risk of spreading invasive salvinia to other waters in the NT.
More information about Four Mile Billabong can be found on the Kakadu National Park website
Find out about the work of the Gundjeihmi Aboriginal Corporation’s Djurrubu Rangers, and their collaboration with NT government staff and Kakadu National Park to help control salvinia through the weevil breeding biological control program.
Learn more about noxious plants, and how you can help prevent the spread of weeds from the NT Weeds Branch