Growth parameters and age estimates of the mouthless crab, Cardisoma crassum Smith, 1870 (Brachyura: Gecarcinidae) from the Montijo Gulf, Pacific coast of Panama

The asymptotic carapace width (L ∞ ) and growth coefficient (k) parameters of the mouthless crab, Cardisoma crassum, were estimated, and the von Bertalanffy growth function was fitted to predict mean crab carapace width at different ages. From November 2014 to September 2015 and January 2021 to February 2024, a total of 967 crabs were sampled from five mangrove sites within the Montijo Gulf, Pacific coast of Panama. The modal decomposition method was applied to identify age groups, where the best model fit was obtained with eight age classes and the parameters: L ∞ = 91.51 mm, k = 0.24 year-1, and L 1 = 17.14 mm. Mean carapace width was 60.89 ± 7.70 mm with corresponding ages between 4.69-4.82 years. The estimated t max was 12.81 years, corresponding to a carapace width of 86.96 mm, while the age at first maturity was estimated at 4.77 years, with a corresponding carapace width of 61.01 mm. The L ∞ exceeded the maximum observed carapace width (88.30 mm), suggesting that crabs can attain larger sizes than those observed. This is the first systematic estimate of growth parameters and age in C. crassum from the Montijo Gulf, providing valuable information for future management of this fishery resource.