Stock assessment of Australian east coast sea mullet (Mugil cephalus), with data to December 2024

Abstract

Australian east coast sea mullet (Mugil cephalus) form a single stock extending from southern Queensland to New South Wales. The species supports one of Australia’s largest commercial finfish fisheries and is primarily harvested using estuarine gill nets and ocean beach nets.
This is the fourth stock assessment of the Australian east coast stock. Stock status was assessed using a two-sex, age-structured Stock Synthesis model that incorporated catch, standardised catch rates, age composition and length composition data. An ensemble modelling approach combined 24 scenarios representing alternative assumptions about catch-rate trends, fish availability and longevity.
Results estimated that spawning biomass at the start of 2025 was at 39% of unfished levels, with a 95% credible interval of 25–76%. Biomass declined from the 1980s to the mid-2010s but has increased in recent years, coinciding with lower catches and reduced fishing pressure. The assessment concluded that the stock remains above the biomass limit reference point of 20%, although it is likely below the 40–60% range often associated with target biomass levels.