<![CDATA[The Bombay duck (Harpadon nehereus), a common bycatch species found in various coastal fisheries, has experienced a global population decline. Studies on its reproductive biology, distinguishing between males and females, are still limited, particularly in the Strait of Malacca. This study aimed to investigate sexual dimorphism in the reproductive biology of H. nehereus, including body length distribution, length-weight relationship, growth pattern and coefficient, condition factor (K), hepatosomatic index (HSI), sex ratio, and gonadal maturity stage (GMS). Each specimen was morphometrically measured and dissected to collect data on total length, body weight, growth pattern, condition factor (K), hepatosomatic index (HSI), and gonadal maturity stage (GMS). Linear regression analysis was performed to examine the length frequency distribution, length-weight relationship, and growth pattern, as well as to evaluate the condition factor, hepatosomatic index, sex ratio, and gonadal maturity stage. The results showed that the total length of males ranged from 150 to 309 mm, and that of females from 198 to 309 mm. The length-weight relationship of both sexes showed a positive correlation, indicating positive allometric growth. The condition factor (K₁=3.2753% and K₂=2.9142%) and hepatosomatic index (HSI= 0.00717%) indicated that the physiological status of H. nehereus was generally healthy, with a condition factor value of 1-3. The sex ratio showed a higher number of males than females, with an average ratio of approximately 2.10:1. Analysis of gonadal maturity stages showed that most males were at stage I (immature), while most females were at stage IV (mature). Keywords: bombay duck, condition factors, hepatosomatic, length-weight]]>
