Abstract
Significant differences (ANOVA) in three out of six meristic characters and in 16 out of 18 morphometric characters were found among Syngnathus abaster caught in the River Danube at sites 900 km upwards from the mouth of the Black Sea, the fresh waters of Ukraine, the Black Sea and the Azov Sea. The Danube populations showed significantly greater values for antedorsal (aD) and anteanal (aA) distances, but considerably smaller values for postdorsal (pD) distance and head length (L H ) than other populations analysed (Tukey‐Kramer's test). The relation of total length (L T ) to standard length ( Ls ) for the Danube populations was L s = 0–97. L t , the length‐mass relationship was M=4.122. L T 3.63 and the mean ± S.D. of Fulton condition factor was 0.34 ± 0.08.