Biosystematic study of (Clupeidae) Alosa in Mazandaran and Golestan province coastal waters

This survey is part of identification and determination of clupeidae (Genus Alosa), in southern Caspian Sea, Mazandaran and Golestan Province coastal waters during 1997-99. In this study, total of 336 fish samples were studied. The results showed that 4 species of clupeidae, belong to: Alosa brashnikowii (Borodin, 1904), A. caspia (Eichwald, 1983), A. saposchnikowii (Grimm, 1887) and A. kessleri (Grimm, 1887). For species identification two morphometric and morphomerestic factors were used. One of the important factors of morphometric is gill rakers and, A. braschnikowii had 20-40 with average of 30.93±6.11, A. caspia had 110-125 with average of 118.3±5.23, A. kessleri had 60-73 with average of 66.82±3.31 and A. saposchnikowii had 20-48 with of average of 32.83 ±4.93 percent gill rakers. Another important morphometric factors are percent ratio of eye diameter to total length. A. braschnikowii had 2.9-5.82 and average of 4.72±0.53 percent, A. caspia had 5.73-7.46 and average of 6.21±0.52, A. saposchnikowii had 6-9.33 and average of 7.3±1.8 percent and finally, A. kessleri had 4.27-6.48 and average of 5.46 ±0.71 percent