Assessing the sustainability of bait harvests supporting the octopus fishery in the southeastern Gulf of Mexico

A Length-Based Spawning Potential Ratio (LB-SPR) approach was applied to conduct a data-limited sustainability assessment of two key bait species supporting the octopus fishery in the Gulf of Mexico: the mangrove crab, Ucides cordatus , and the spider crab, Libinia dubia . Growth, mortality, size at 50% maturity (CW 50 ), and exploitation rates were derived from monthly measurements of carapace width (CW), total weight (TW), and sexual maturity, based on bait loads landed at Celestún and Progreso. Two fishing scenarios were evaluated: (1) species-specific parameters derived from local data, applied under both current and precautionary fishing mortality levels, and (2) median parameters compiled from the literature, applied under current fishing mortality. U. cordatus exhibited slower growth (K = 0.19 y⁻¹) and a larger asymptotic size (CW∞ = 81.39 mm; mean CW = 60.5 ± 8.5 mm) than L. dubia (K = 0.27 y⁻¹; CW∞ = 70.3 mm; mean CW = 56.0 ± 7.0 mm). Males accounted for approximately 61% of the sampled individuals, and ovigerous females were observed in both species. CW 50 was estimated at 58.9 mm for U. cordatus and 53.4 mm for L. dubia ; however, these estimates should be interpreted cautiously, as maturity proxies may overestimate physiological maturity. Across the ranges explored, SPR values were consistently lower for U. cordatus , whereas L. dubia generally retained higher reproductive potential. Under precautionary fishing mortality, SPR remained high for both species ( U. cordatus = 0.66; L. dubia = 0.70), indicating sustainable conditions under reduced fishing pressure. In contrast, when locally derived parameters were combined with F > M, the SPR of U. cordatus declined to 0.37, suggesting reduced reproductive buffering rather than imminent collapse. These findings underscore the need to explicitly prioritize technical measures and management frameworks, particularly improved gear selectivity and size-based controls informed by updated maturity estimates, to strengthen long-term resilience. • Ucides cordatus and Libinia dubia are essential to the Yucatán octopus fishery. • Sustainability assessed using Length-Based Spawning Potential Ratio (LB-SPR). • U. cordatus grows slower and matures at larger sizes than L. dubia . • Both species are sustainable under F = 0.5 M; U. cordatus is overfished under current pressure (F > M). • Urgent need for enhance gear selectivity to protect juveniles and maintain sustainability.