How did dams affect length-weight and length-length relationships of Capoeta razii (Cyprinidae) in Sefid River, the southern Caspian Sea basin?

Abstract

Fish populations are affected by dams in terms of morphology, reproduction, migration, growth rate and etc. To examine the hypothesis; how dams can affect the length-weight and length-length relationships in cyprinids, four Capoeta razii segregated populations (by dams) were studied. The length-weight (LWR) and length-length (LLRs) relationships were calculated for three populations from upstream, dam lakes and downstream of Manjil and Tarik dams in Sefid River, in the southern Caspian Sea basin. Also, one independent population from the damming impacts was considered as the control, to examine other possible annual effects on LWR. The b values in the LWR ranged from 2.893 to 3.586 in downstream and dam lakes populations, respectively. The r 2 value ranged from 0.966 to 0.988. The averages of recorded length and weight in dam lake population were up to two and six times (respectively) more than the ranges in up and downstream populations. Monthly LWR is presented for the control population. The sex and maturity were found as effective factors on LWR in the control population. No significant differences were observed in LWR by seasons. All LLRs were highly significant ( r 2 > 0.95). This study presents that the dams and the sex and maturity can be considered as effective non-biological and biological factors (respectively) affecting growth patterns as expressed by length and weight relationships in cyprinid ( C. razii ) populations. The results may be helpful in future fisheries studies and conservation programs.