Fisheries exploitation and management of the narrow-barred Spanish mackerel, Scomberomorus commerson (Lacepède, 1800), in the eastern Red Sea

The narrow-barred Spanish mackerel, Scomberomorus commerson, is a highly valuable commercial species in the Red Sea. Annual landings along the Saudi Arabian Red Sea coast average approximately 2, 380 tonnes, generating nearly 35 million USD in revenue. Given this economic importance, effective fishery management is essential. This study assessed the growth, maturity, and mortality of S. commerson using fishery-dependent samples collected from the eastern Red Sea between 2022 and 2024. Total length (L, n = 4, 432) ranged from 10.0 to 151.0 cm, and total weight (W, n = 1, 683) varied from 9 to 17, 694 g. L–W relationships were W = 0.0088 × L2.90 for females and W = 0.0143 × L2.78 for males. The von Bertalanffy growth parameters, estimated via otolith reading, were L∞ = 151.55 cm, K = 0.18 year−1, and t0 = −0.83 years. Median length at first maturity was 39.71 cm, with no significant difference between sexes. Mean natural mortality rate, averaged across three empirical models, was 0.27 year−1. Total mortality rate, derived from a linearized decay model, was 0.58 year−1, giving a calculated fishing mortality rate of 0.31 year−1. Virtual population analysis provided age-specific fishing mortality rates as input for yield-per-recruit and spawning potential ratio (SPR) analyses. SPR analysis revealed that the current fishing pattern has reduced the spawning stock biomass to approximately 25% of its unfished level. The exploitation rate was 0.53, exceeding the limit reference point of 0.5. The fishery, dominated by handlines and gillnets, captures individuals across a broad size range, with immature fish comprising 17% of total landings. Most juveniles are taken incidentally as bycatch in the shrimp-trawl fishery. To promote stock recovery and long-term sustainability, management measures are recommended, including a 40% reduction in fishing effort, seasonal closures during spawning periods, and improvements in gear selectivity to minimize juvenile catch.