Seasonal comparison of frequency and CPUE of sturgeon spawners caught by gillnet in the south coasts of the Caspian Sea (Case study: Golestan province)

Abstract

Introduction: The purpose of this study was to evaluate the number, catch composition, and catch per unit effort (CPUE) of sturgeon spawners by gillnet in the fishing grounds of Golestan province.
Materials &Methods: Sampling and data collection were conducted in the 4 fishing grounds according to the fishing seasons of sturgeon fish using gillnets (Polyamide) with a mesh size of 150 mm from autumn 2018 to autumn 2019. Five species of sturgeon fish including Acipenser persicus, Huso huso, Acipenser gueldenstaedtii, Acipenser nudiventris, and Acipenser stellatus were caught during the sampling period.
Result: The highest fish weight was observed in autumn 2019 (946 kg) and the lowest was in spring 2019 (242 kg). The highest total catch weight and fishing effort were obtained for matured males of A. persicus (389 kg and 0.9 g/fishing effort) and the lowest was for matured females of A. stellatus (13 kg and 0.03 g/fishing effort).
Conclusion: According to the results of the Chi-square test, the separate and simultaneous effect of sampling time and the location was significant on the number of matured Acipenser persicus (P<0.05).