Assessment of relationship between Kutum fingerling release (Rutilus kutum) and its catch (in a period of 29 years: 1989-2017)

Kutum (R. kutum) is one of commercial fishes in the southern Caspian Sea that plays an important role in economy of people who live in the coastal areas of the sea. In spite of economic value of this species, there is no accurate assessment on effect of artificial propagation and releasing of fingerlings on stock enhancement. This study aimed assessment this effect using release and catch data in a period of 1989-2017. During the period, catch of kutum showed a significant fluctuation, but the overall trend was positive linear. Fishing effort increased with time (years), the rate of fishing effort increase was higher than that of total catch. Analysis of slope of relationship of catch-time and fishing effort-time revealed that with increase of fishing effort, there was little increase in total catch. Furthermore, analysis of relationship between total catch and CPUE showed that the rate of total catch was higher than that of CPUE, indicating a decrease in catch with increase in CPUE. As an overall, a trend in total catch and total number of fingerling release was observed during the study period, but increase in total number of fingerlings hadn't significant effect in increase of total catch. The same was observed in fingerling release and CPUE.