Predictions of Barramundi stocks are based on:
• Numbers of fish that are spawned (born) each year and survive the first year (recruits)
• Environmental drivers being river flow and rainfall
• Natural mortality rates in the population
• Fishing mortality rates (commercial and recreational)
• Growth rates and age of fish

These factors are used to estimate the proportion of fish in each year class (based on size) and an overall estimate of stocks on a low to high scale.