Biometric Characterization and Sexual Dimorphism in 10 Demersal Fish Species From Southern São Tomé and Príncipe

ABSTRACT This study examines key biometric parameters—length–weight relationships (LWRs), sex ratios, and Fulton's condition factor ( K )—for 10 demersal fish species in the coastal waters of southern São Tomé Island: Dentex macrophthalmus , Dentex congoensis , Pagrus caeruleostictus , Lethrinus atlanticus , Lutjanus fulgens , Lutjanus goreensis , Lutjanus agennes , Apsilus fuscus , Pomadasys rogerii , and Paranthias furcifer . The samples were collected by artisanal fishers from March 2019 to February 2020 across eight nearshore sites. Fishing occurred regularly using handlines, including horizontal and vertical longlines and single‐hook artificial lures. A total of 1417 individuals were analysed. LWR slopes ( b ) ranged from 2.122 to 3.515, with negative allometry observed in most cases. Significant sex‐based differences in growth patterns were detected in several species. Sex ratio analysis revealed male‐biased populations in D. macrophthalmus , P. rogerii , and P. furcifer , and female‐biased populations in D. congoensis , L. fulgens , and L. goreensis . Condition factor values ranged from 0.468 to 1.525, with notably low K values in A. fuscus , suggesting poorer body condition. This study provides the first baseline data for LWRs, sex ratios, and condition factors for these species in São Tomé and Príncipe and reports a new maximum body length for P. furcifer . The findings offer critical input for future stock assessments and evidence‐based fisheries management in the region.