The Composition and length frequency of Non-target fish catch using of Conical Lift Net in Babolsar and Amirabad Fishing Ports

The diameter of the ring connected to the balustrade Conical Lift Net was initially 1.5 m. But gradually the diameter of the attached ring increased Today it is about 4 meters. The seems to increase the diameter of the ring This increased the number of non-target fish in this method. The purpose of this study was length frequency and species composition of non-target fish caught in Conical Lift NetMay 1997 in two fishing ports of Babolsar and Amirabad by four fishing vessels during 33 torrents at a depth of 40-50 m. After identifying the species caught, the total length and weight of the specimens were measured. From a the total of 193 fish caught, the highest and lowest percentage of total relative frequency fish species Alosa caspia were (37.8%)and Gasterosteus aculeatu (4.7%). Relative frequency of other species caught in Babolsar and Amirabad ports Syngnathus abaster were 38.8% and 28%, Gasterosteus aculeatu 50% and 0%, Mugilidae 11.11 and 18.2%, Alosa caspia 0% and 41.7%, respectively. Rutilus frisii kutum was 0% and 12%. The results also show that the frequency of fish caught in Amirabad fishing port is higher than Babolsar fishing port and strongly dependent on area (p < 0.01). The results indicate the high pressure resulting from the production of Bycatch fishing on non-commercial species in Amirabad fishing port. Most frequency in Babolsar and Amirabad fishery ports were respectively in the length class of 4.5-5.5 cm Gasterosteus aculeatu and length class of 15.5-5.5 cm Syngnathus abaster in fish.