Stock assessment of Queensland east coast red emperor (Lutjanus sebae), Australia, with data to June 2021

Abstract

Red emperor (Lutjanus sebae) is a species of tropical snapper that inhabits Queensland waters. Research suggests a single Australian genetic population, with a panmictic population structure throughout northern Australia. They are gonochoristic (born male or female and do not change sex) and spawn primarily during the summer months. On Queensland’s east coast, they can attain lengths of at least 100 cm (total length) and live for up to 43 years.

This is the first stock assessment of Queensland east coast red emperor.

The stock assessment was conducted on financial years and included input data through to June 2021. The assessment used a two-sex, age-structured population model, fit to age and length data, constructed within the Stock Synthesis modelling framework.

Twenty-four model scenarios were run, covering a range of modelling assumptions and sensitivity tests. Base case (most plausible) scenario results suggested that the Queensland east coast red emperor stock experienced a decline in the period 1953–2005 to reach 55% of unfished spawning biomass. This was followed by a period of fluctuation between 55% and 60% of unfished spawning biomass from 2005 to present. At the beginning of 2022, the stock level was estimated to be 58% (56–65% range across scenarios) of the unfished spawning biomass.