Population estimation of Oriental River Prawn Macrobrachium nipponense (De Haan, 1849) in Anzali Wetland

Oriental River Prawn Macrobrachium nipponense, originating in Japan and China, is one of the exotic species in Anzali wetland. It has a high population in many parts of it, especially in inlet rivers. To estimate the population in Anzali Wetland, 18 traps (Opera House and Hokkaido) were used during the two periods of July and August in three parts; including western area, SiahDarvishan and Sorkhankol. The trend of catch per unit of effort has been declining in July while an increase in catching was observed in August in two regions of SiahDarvishan and Saorkhankol. The average catch was 100 and 145 per unit of daily effort in August and July, respectively. The average weight of the individuals was 3.3±0.5 gr. The population was estimated 228±178 and 194±58 gr/m2 in July and August, respectively. These estimations are greater than those provided by other natural water resources such as marine areas for different species. For a clearer conclusion for potential of species to exploit are needed more investigation.