MORPHOLOGY AND POPULATION STRUCTURE OF ATHERINA BOYERI IN THE SOUTHERN CASPIAN SEA

The study of morphology and biological charactristics of A. boyeri in the southern Caspian Sea was investigated during 2000-2001. The fish samples were collected by beach seine (mesh size = 6 mm) monthly and then fixed in formalin 5%. The biometric and morphometric results are as follow:Total length = 73.82 ± 17.73, mean weigth = 3.15± 2.02, number of lateral line scale= 48± 3, number of branched rays of first dorsal fin 8; number of branched rays of second dorsal fin = 12; number of branched rays of anal fin = 13; number of branched rays of ventral fin = 5, number of vertebra = 47 and gill rakers = 34.
Also, the results of other measurments (in mm) were: head length = 23 , head depth = 14, inter orbital width = 5, post-orbital length = 7, maximum body depth= 14, minimum body depth = 5, peduncle length = 19, first dorsal fin length= 7, pectoral fin length = 14, pelvic fin length = 11, pelvic-anal fin distance= 34, pectoral-pelvic fin distance= 43, post-dorsal distance= 20 and predorsal distance= 43mm.
The comparance between males and females showed that from point of 2 meristic and one morphometric parameters, they showed significant difference. The study on population structure of Atherina boyeri indicated the range of 1 to 3 years old with average of 1.7 year. The total length and body weight equation was caclulated W=0.00000615 T.L3.02. The sex ratio of this species was estimated as M:F=0.47:0.53.