Length-frequency data on grey mullet (Mugil cephalus) from the Cross River Estuary

Title: Length-frequency data of Mugil cephalus (grey mullet) from Cross River Estuary, Nigeria (2023–2024) Description: This dataset contains length-frequency measurements of 2,146 Mugil cephalus specimens collected monthly from artisanal fishery landings in the Cross River Estuary (4°24′–5°24′N, 7°48′–8°30′E), Nigeria, between January 2023 and December 2024. Data collected: Total length (TL, cm, nearest 1 cm): 6–35 cm range Sampling date (monthly resolution) Season (Dry: Dec–Mar, Wet: Apr–Nov) Fishing gear (cast nets, gill nets, beach seines) Landing site (upper, mid, lower estuary) Usage: Primary data for FiSAT II length-based stock assessment (ELEFAN, VPA, yield-per-recruit) supporting length-based biomass modeling and GAM analyses of fishing mortality-biomass relationships. Gear selectivity corrections applied (see supplementary Table S1). Methods summary: Fish measured from freshly landed catches using calibrated ichthyometer. Data grouped into 1 cm classes per standard FiSAT protocols (Pauly & Morgan, 1987). Keywords: Mugil cephalus, length-frequency, artisanal fishery, Cross River Estuary, Nigeria, FiSAT, stock assessment, tropical fisheries