During the period from January 2010 to December 2010, the biometric studies of 669 (both sexes-12:39 centimeters) the whipfin, silver biddy, Gerres filamentosus (Cuvier,1829) have been described to clarify the identity of the fish population in the Hurghada Red Sea, Egypt. The straight lines of the regression equations of twenty one morphometric measurements relative to the total length or the head length indicate the linear relationships of the different body parts. Significant curvilinear

more »

... tionship existed between total length and other morphometric characters and between head length and other characters of the head. Relationships between total length and various body measurements of the fish were highly significant (p < 0.01) except the relationship between total length and 2 nd spine dorsal fin length of fish (p < 0.05). The Meristic characters including the number of fin rays, lateral line scales and gill rakers were found to be more or less similar except slight differences. The length-weight relationships respect to the total or the gutted weight were also investigated. It is obvious that, the value of the exponent (n=2.9475) indicates the negative allometric growth of this species. The values of condition factors (k c ) in the total length body-weight relationships for female , male and combined sexes were found to be 1.49 , 1.47 and 1.51, respectively. The mean values of relative condition factors (k n ) were 1.03 , 0.97 and 1.00 for female , male and combined sexes, respectively. However, relative condition factor (K n ) of Gerres filamentosus computed for July was 1.116 ± 0.24 and for January was .934 ± 0.012, which suggest the specimens were healthy and in good condition due to spawning cycle or other physiological activities or environmental factors. In searching of new potential aquaculture marine species, Gerres filamentosus may play role for enhancement of fish production as well as upliftment of socioeconomic condition in Egypt.