Operationalizing Mud Crab (Scylla spp.) Length–Weight in a Micro-Site Data-Limited Ecotourism Fishery

Urban mangrove fisheries and ecotourism need micro-site, data-limited baselines to guide low-cost gear management. This study establishes the size structure and length–weight scaling (Carapace Width–weight Relationship (CWR) and Carapace Length-weight Relationship (LWR)) of mud crabs (Scylla serrata, S. olivacea) as practical inputs for monitoring and trap guidance. Foldable traps (3 stations × 3 traps) were deployed during September and November of 2024 and 15 individuals (5 females, 10 males) were measured for Carapace Width (CW, mm) and body weight (W, g). We summarized CW distributions and fitted W = αL^b in log–log space by OLS to assess association strength and test isometry (b=3). CW spanned from 49.00 to 85.00 mm and mass from 15.81 to 102.47 g. CW–W relationships were strong, and growth was positively allometric (females, males, pooled), indicating mass increases faster than width. Results should be interpreted cautiously, given the narrow spatial scope, sampling dates, and small female sample. The findings provide a reproducible baseline for cross-estuary comparison and can be operationalized without additional analyses into an auditable workflow for ecotourism co-management, consisting of publishing a site-specific minimum-size concept, recording CW at landings, tuning entrances/mesh so smaller crabs escape, and monthly auditing using the existing indicators.