The Department of Natural Resources built Lake Julius in 1976 on the Leichhardt River.
The dam has a storage capacity of 107,500 Ml and a surface area of 12.55km2. Julius has an average depth of 8.9m and a maximum depth of 25.2m. Currently Lake Julius is in use as a water supply for Mount Isa, Cloncurry and regional mines.
Lake Julius is an excellent Sooty Grunter fishery and is the primary source of Sooty brood stock for the MIFSG breeding program. Sooty’s breed prolifically in Julius due to the regular flooding of waterways that flow into the impoundment. Sooty’s need to swim upstream during water flow events to spawn. The two main feed rivers (the Paroo and the Leichhardt) also have long sandy stretches which are desirable as breeding grounds for the species.
Apart from a small number of Saratoga released in 1988/89, stocking of Barramundi and Sooty Grunter by the group has been limited due accessibility and supply issues.
Due to the ability of Barramundi to travel from the impoundment during flood events there is a recognised need for re-stocking programs to maintain a sustainable fishery (fingerlings for release in the "Gulf Catchment areas" must come from South Eastern Gulf genetic stock).