Length-weight relationship and condition factor of seven fish species of Totkabon River (southern Caspian Sea basin), Guilan, Iran

Length-weight relationship and condition factor were investigated in seven fish species, including Barbus cyri, Capoeta gracilis, Alburnoides eichwaldi, Acanthalbarnus microlepis, Ponticola cyrius, Cobitis keyvani and Oxynemacheilus bergianus from Totkabon River. A total of 570 specimens ranging from 25.90 to 146.97 mm in total length and 0.1 to 260.3 g in total weight were collected. Based on the results, growth coefficient values “b” ranged from 2.429 (A. microlpis) to 3.71 (C. keyvani). All length-weight relationships were significant (P < 0.05), with r2 greater than 0.856. The four species viz. A. microlepis, C. gracilis, P. cyrius and C. keyvani showed allometric (b < 3 < b) and three species viz. B. cyri, A. eichwaldi and O. bergianus isometric (b = 3) growth patterns. Condition factor ranged from 0.544 (O. bergianus) to 0.940 (P. cyrius). All linear regressions were highly significant (P < 0.05). The result of this study may be useful for biologists and fishery managers.