Download FAR 2026/39 2025 stock assessment of gemfish (Rexea solandri) in SKI 3 and SKI 7

An assessment of the southern gemfish (SKI 3 & SKI 7) stock complex was undertaken in 2025. The assessment included characterising commercial fisheries, updating the catch-per-unit effort (CPUE) indices, and carrying out a stock assessment using an age-structured model.

The recent increase in SKI 3 and 7 commercial catches has continued with catches in 2023–24 being some of the highest on record. Because gemfish are mainly taken as bycatch in the SKI 3 & 7 fisheries, rising catches are likely to be due to increased gemfish abundance.

The recent increase in commercial CPUE was considered biologically implausible. The stock assessment modelling was unable to fit to adequately represent these CPUE indices and performed better when only the abundance information from research trawl surveys was used.

The assessment modelling suggested that the increase in the SKI 3 & 7 gemfish stock since 2017 was driven by recent above-average recruitment. There is some evidence to suggest that the recent period of above-average recruitment is due to ocean warming. If the current productivity of the SKI 3 & 7 gemfish stock is higher than the long-term average recruitment, then B0-reference sustainability measures would not be appropriate stock management.

The 2025 stock assessment Plenary recommended the use of an annual fixed proportional removal target as an alternative sustainability measure. The modelling suggests annual proportional removals of 18% or less of the standing biomass are sustainable, and current catches are below this level.

Stock biomass is expected to continue to increase for at least the next 2–3 years as the strong 2021, 2022, and 2023 year-classes grow through the fishery.