Determining the age of fish has been historically difficult, primarily involving lethal methods. A new DNA test solves this problem.
Fish must be released into good quality water, with suitable habitat and lots of food. These conditions have been quite rare in Murray Darling rivers in recent years.
Crises in the Darling River have raised questions about cotton and rice farming in the Murray Darling Basin.
As the health of the Murray Darling Basin is in decline, fish ear bones recovered from ancient Aboriginal camp sites can provide vital data about river health in the past.