Certain population and reproduction characteristics of the oriental river prawn (Macrobrachium nipponese) in Anzali lagoon

Document Type : Biology(Animal)

Authors

1 Faculty of Agriculture and Natural Resources, University of Gonbad, POBox: 163

2 International Research Institute for Caspian Sea sturgeon, the research, education and extension, Rasht, Iran, POBox: 3464- 41635

3 Fisheries and Aquaculture Research, Education and Research Center for Agriculture and Natural Resources Gilan, organization, research, education and extension, Rasht, Iran, POBox: 3394- 41635

Abstract

The present research was conducted during April-October 2014 on 10645 pieces of prawn (Macrobrachium Nipponese) consisting of 5667 male, 4978 female and 68 juvenile. The male/female ratio was 1/14:1. The weight-length range among the prawns recorded were 0.01-13.69 gr and 6.5-81.5mm respectively. The average body weight-length among male prawns examined (TL= 46.6mm , W = 2.76gr) showed to be higher than those of in female (average TL = 44.5mm and W = 2.14gr). The body weight-length relationship in both male and female proved to be strong, enjoying positive allometrics (r2 = 0.99; b= 3.22 female, b= 3.33 male). The condition factor of male prawns fluctuated from 1.96 to 2.33 (average, 2.07± 0.04) while in female prawns it varied from 1.97 to 2.17 (average 2.04±0.04).The ovigerous females were observed from May to September with a peak time in July.The minimum and maximum total lengths of female spawners were 23.7 and 71.5mm respectively that occurred in July.The mean size at first maturity measured, stood at 46.1mm.The lowest fecundity rate was in Aug with a minimum 42 pieces of eggs followed by the highest fecundity in July with 5821eggs (Average, 1227± 48). There appeared to be a direct and significant relationship between egg number and the total length(r= 0.79).The reproductive output was different in various month of the year ranging from 1.6 in September to 22.4in July (average, 9.2±0.2). The results indicate that there is a favorable environmental condition for M. nipponese.

Keywords

Journal of Animal Environment
Volume 8, Issue 4
January 2017
Pages 243-254

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