The impact of ghost fishing on catch rate and composition in the southern Caspian Sea

Highlights: • Despite the sharp decline in sturgeon stocks, they caught by ghost fishing below the length at first maturity. • A significant difference shows between fall and winter. • Species catches composition are more homogeneous for winter than fall. - Abstract: The catch rates and the catch composition of lost nets were investigated during two seasons (fall and winter) in the southern Caspian Sea. A total of 167 surveys were conducted using anchor to retrieve ghost nets, which led to recover a total of 515 monofilaments gillnet. The most abundant caught species in during both seasons was belonged to Alosa caspia (52.1–43.9%). At both seasons, individuals of Huso huso, and Acipenser stellatus were substantially caught below the length at first maturity. The highest mean of catch rates was discovered at 0–10 m depth (2.79 kg), while the depth of 10–20 m provided the lowest amount of catch (2.0 kg). The Spearman correlation test showed that an increase in depth is reflected in lower values of the retrieved ghost nets. Overall, this study revealed that ghost gillnets is widely distributed in the southern Caspian Sea, mainly at the shallow waters.