Length-Weight Relationships and Condition Factor of Bonga Fish (Ethmalosa fimbriata) in the Coastal Waters of Delta State

Morphometric studies of commercially important fish species provide critical biological data for fisheries assessment and stock management. This study examined the length-weight relationships and condition factor of Bonga fish (Ethmalosa fimbriata) harvested from the coastal waters of Delta State, South South Nigeria. A total of 360 specimens were collected from landing sites at Warri, Escravos, and Sapele over a period of four months. Standard length and total length were measured to the nearest millimetre, and wet weight was recorded to the nearest 0.01 gram. The relationship between length and weight was described using the power function W equals aLb. Fulton's condition factor (K) was calculated for each specimen. Sex determination was performed through gonadal examination. Results indicated that the length-weight relationship closely conformed to the cube law, with b values ranging from 2.89 to 3.11, indicating near-isometric growth. Mean condition factor values ranged from 0.91 to 1.08 across sites and months, reflecting generally good body condition. Female specimens were slightly heavier than males at equivalent lengths. Seasonal variation in condition factor was noted, with highest values recorded during the wet season months of June and July, corresponding to peak feeding activity. Significant differences in condition factor between sites suggested habitat-level variation in food availability. The study establishes baseline growth parameters for E. fimbriata in the Delta State coastal zone, contributing data essential for sustainable harvest management of this commercially vital species. Keywords: Ethmalosa fimbriata, length-weight relationship, condition factor, Delta State, fisheries biology.