Towards sustainable management of the Cunene horse mackerel (

This study assessed the status of the Cunene horse mackerel (Trachurus trecae) stock in Guinea-Bissau (2018–2023) using fishery-dependent and independent data. Catches ranged from 29.1 kt (kilotones) in 2020 to 10.2 kt in 2023, dominated by Chinese (57.2%) and Guinean (22.6%) fleets. Fishing was concentrated between January and May, mainly in the 10–12°N and 16–18°W area, with demersal trawl accounting for 52.1% of catches. Biological parameters revealed negative allometry with b = 2.80 [2.75–2.84], L50 = 20.0 [19.6–20.3] cm for grouped sexes, L∞ of 48.8 [46.4–52.2] cm, K of 0.55 [0.34–0.74] yr−1, and M of 0.67 [0.47–0.87] yr−1, indicating a “fast” life history. Length-based indicators show reduced yields and loss of large spawners, suggesting current exploitation patterns might be unsustainable, but results were considerably sensitive to life history parameter values, particularly L∞ and L50, which warrants continued data collection. These findings call for immediate science-based management, which might include seasonal closures, reduced fishing effort, improved gear selectivity, and enhanced monitoring. Enhanced institutional capacity and regional cooperation are critical to strengthening monitoring efforts.