نوع مقاله : مقاله پژوهشی
1 گروه شیلات، دانشکده شیلات و محیط زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
2 اداره کل شیلات مازندران، بابلسر، ایران.
3 گروه آمار، دانشکده علوم، دانشگاه گلستان، گرگان، ایران.
4 پژوهشکده اکولوژی دریای خزر، ساری، ایران.
عنوان مقاله [English]
This study aimed to investigate the lenght frequency and species composition of fish caught in conical lift-netin May 2018 in two fishing ports of Babolsar and Amirabad by four fishing vessels during 33 torrents at a depth of 50-40 m. After identification, the total length and weight of the specimens were measured. Of the 27967 fish samples examined, the highest relative abundance belonged to Clupeonella caspia (98.98%) and the lowest one Gasterosteus aculeatu (0.032%). Number of fish caught in the Babolsar and Amirabad ports were 27610 and 357, respectively. Out of 193 fishes, the highest and lowest percentage of relative frequency fish specieswere for Alosa caspia (37.8%) for G. aculeatu (4.7%). The relative abundance of other species in the ports of Babolsar and Amirabad are Syngnathus caspius was 38.8 and 28%, G. aculeatu 50 and 0%, Mulets 11.11 and 18.2%, A. caspia 0 and 41.7%, Rutilus kutum 0% and 12%, respectively. The results show that the maximum and minimum frequencies in Babolsar port was 99.86% for Clupeonella caspia and 0.03% for C.engrauliformis and in Amirabad were 65.38% and 6.04%, respectively, for C. caspia and C.grimmi. Among the Kilka fish caught in the two zones, the abundance of C. caspia and C.engrauliformis were highly dependent on the fishing region (p < /em><0.01). The results show that maximum lenght abundance of conical lift net in Babolsar and Amirabad fishing ports are 11.5-12.5 cm.