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 r 2 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.