Intrabasin variation in allometry coefficients of LenkoranCapoeta capoeta gracilis(Keyserling, 1861) in the Gorganroud basin, southeast Caspian Sea, Iran

Summary It is believed that streams of a basin may contribute to stream-specific variation in allometry coefficients related to between-habitat differences. To test intra-basin variation of the allometry coefficients of Lenkorn Capoeta capoeta gracilis (Keyserling, 1861), a total of 1731 individuals were sampled in six streams of the Gorganroud basin (southeast Caspian Sea) between April and May 2008. Values of b ranged from 2.647 for males of Chelchai to 2.964 for females of Madarsou, indicating negative allometric growth for the fish in the basin. There were variations in the allometry coefficient among the considered groups, which can be interpreted as species’ response to different habitats. To the best knowledge of the authors, this study documents the comparative reference on variation of allometry coefficient of Capoeta capoeta gracilis in southeast Caspian streams.