Biological investigation of Macrobrachium nipponense (De Haan, 1849) in Siyadarvishan River, Guilan province

Abstract

In the present study Macrobrachium nipponense shrimp were studied of biological for the first time in Siyadarvishan River in Guilan province. The number of 813 specimens of population was examined at three stations from upstream, midstream and downstream in seasons of autumn and winter in 1390 and spring in 1391. According to Salman et al. (2006) species description, the specimens were identified as Macrobrachium nipponense and twenty two specimens were sent to Dr. De Grave in the Oxford University Museum of Natural History in the United Kingdom for further verification. The number of eggs from 501 to 3578, Sex ratio of male to female 1 to 1.4, the number of ventral rostral teeth in males and females varied from 0 to 6, dorsal rostral teeth in females 8 to 18, in males 10 to 18. Positive correlation was between total length and wet weight for males(R=0.95) and females(R=0.91).The One-Way Interaction ANOVA results showed (P<0/05) that average weight, total length, carapace length was more in males than non ovigerous females and average carpus length, merus, propodus and palm length was more in males than ovigerous and non ovigerous females.