摘要
Length-weight relationships （LWRs） were determined for fish species Diplodus vulgaris from the Benghazi coast along the eastern Mediterranean Sea coast of Libya. Samples were collected using trammel nets. The parameters a and b from the LWR formula W = aLb were estimated. The values of the exponent b of the length-weight relationships in all categories range between 2.295 in September to 3.208 in August. The total number of fish samples investigated were 290, from which 179 were males, 41 females and 70 fishes immature. The sex ratio male to female were 4.3：1. In January, August and Females the slope ＂b＂ close to equal 3, were the categories exhibited isometric relationship, in September, October and November were slope ＂b＂ not equal 3, which the categories exhibited negative allometric relationship. The mean observed length of male was 18.29 cm at mean observed weight 114.8 g, and mean observed length of female was 19.15 cm at mean observed weight 133.97 g.The general equation for the length-weight relationship for both sex was： W = 0.03835L277, for male was： W = 0.036 L274, for female, W = 0.016 L302.
