Population dynamics and fishery benefits of a large legal size of a pelagic sportfish, the Talang queenfish, Scomberoides commersonnianus, in northern Australia

The life history of an increasingly important pelagic commercial and sport fish, the Talang queenfish, Scomberoides commersonnianus, was studied in northern Australia to investigate the stock status and assess current management of the species using minimum legal lengths (MLL). Estimated von Bertalanffy growth parameters were L∞ = 1404 mm FL, K = 0.10 year−1 and t0 = −1.21 year−1. There was no significant difference in growth between sexes. Ages ranged from 1 to 11 years with age composition differing between the commercial (mainly 6–7 years) and sport fishery (mainly 2–4 years). Females matured (L50) at 635 mm FL and 4–5 years. Spawning occurred between August and March when mature females were estimated to produce 259,488–2,859,935 eggs per spawning. Natural mortality (M) was estimated as 0.16–0.26 year−1, while the combined fishing mortality (Fcurrent) from commercial and sport fisheries was 0.38–0.48 year−1. Yield-per-recruit analyses revealed that under current MLL limits (no MLL or 45 cm TL) and natural mortality (M = 0.16, 0.2 and 0.26 year−1), Fcurrent exceeded the reference points Fmax (0.15–0.22 year−1) and F0.1 (0.10–0.15 year−1), suggesting the stock may be growth overfished if the current situation remains unchanged. Although a stock–recruitment relationship is unknown, spawning stock biomass-per-recruit analysis indicates the stock may also be recruitment overfished since Fcurrent exceeded the reference points F25% (0.19–0.24 year−1) and F40% (0.11–0.15 year−1). Increasing the MLL corresponding to L50 of females (70 cm TL) will greatly improve the yield and long-term sustainability of the stock, and also enhance the sport fishery by increasing the number of larger trophy fish.