Aspects of the reproductive cycle of the prawn Macrobrachium nipponense (De Haan, 1849) from Al-Hammar Marsh, Southern Iraq

Abstract

The reproductive cycle of the Macrobrachium nipponense (De Haan, 1849) was studied in Al-Hammar Marsh, Southern Iraq during Dec. 2015 to Nov. 2016.The averages of total length, carapace length and weight for males were 65.7 mm, 28.8 mm and 2.9 g respectively, and for ovigerous females were 60.1 mm, 26.0 mm and 3.3 g respectively. Length-weight relationship of M. nipponense was W= 0.407 L e 0.031 (r = 0.67) for the females and W= 0.177 L e 0.043 (r = 0.90) for the males. The highest percentage of ovigerous females was 98.88 % attained in August. The maximum gonado somatic index was recorded in March (10.66) and the minimum was 5.72 recorded in July 2016. The condition factor for the males was ranging from 1.30 to 2.90 in November and August, respectively, while for the females it was between 1.11 and 2.10 at the same periods. Total number of eggs per female was from 799 to 2047 egg/ind. Minimum sex ratio (males: females) was 1:0.17 recorded in February, and the maximum 1:9.00 was recorded in June.