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Some Aspects of the Reproductive Biology and Sex-ratio of Cirrhina Reba (hamilton) (cyprinidae : Cypriniformes)

Sarmin Akther
Department of Zoology, University of Rajshahi, Rajshahi

Shirin Akther
Department of Zoology, University of Rajshahi, Rajshahi

Abstract/ Executive Summary:

Some aspects of the reproductive biology viz. sex-ratio gonadal length index (G.L.I.), gonado somatic index (G.S.I.) and sex-ratio of Cirrhina reba were studied during September 2004 to July 2005. In present study the highest values of GLI (33.76) and GSI (0.63) were in the month of July. Total length (TL) and gonadal length (GL), total weight (TW) and gonadal weight ( GW ), standard length (SL) and gonadal length ( GL ) and gonadal weight relationships were found to be positive; and the relationships were: GL = -3.873 + 0.219 TL (r = 0.992), GW = 0.01511+0.000815 TL (r = 0.979), GL = -2.6030+0.253 SL (r = 0.990), GL = 0.01997+0.000938 SL (r= 0.976), GW = 13.2952+0.6064 TW (r = 0.958), GW = 0.0772+0.00233 TW (r = 0.979). The sex- ratio of C. reba were 1:1.62 for male and female respectively. The Chi-square test showed significant differences of sex-ratio among months and totals.

Keywords: Reproductive biology, sex- ratio of Cirrhina reba.

Location: Rajshahi

Start Date: 01-09-2004

End Date: 31-07-2005

Program Area: Resource Development and Management

Commodity:

Objectives:

The present investigations reveal that the breeding season (peak) of C. reba is April to July. The present study is aimed at providing a comprehensive account of the reproductive period and sex-ratio of C. reba in the freshwaters of Rajshahi based on reproductive system, sexual maturity, reproductive cycle etc.

Methodology:

A total of 1100 () specimens were collected for study from September 2004 to July 2005 (100 specimens in each month) from different fish landing centres of Rajshahi city. Among the total 1100 specimens collected, 673 were females and 427 males. Common experience was used identify the sex. After collection the specimens were preserved in 10% formalin solution. Gonads were dissected out and preserved in 5% formalin solution in separate vials and plastic containers. During preservation the gonads were properly labelled for subsequent studies. Excess moisture was removed by blotting the surface of the fish as well as the gonads with blotting paper before taking weights. The gonadal lengths were taken with meter scale in mm and their weights in g. To study reproductive cycle of C. reba two methods were applied. Gonadal length index (GLI) and Gonado somatic index (GSI) Co-relations between the total length of fish and gonadal length and gonadal weight, and that between standard length of fish and gonadal length and gonadal weight were calculated.

Source of Information: Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp. 21-24 ISSN 1023-6104

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Out of 1100 specimens of C. reba, 427 were males and 673 were females. The total male and female ratio was 1:1.62. This study revealed that the monthly fluctuation of male and female population occurs in the catch, and the percentage of female is higher than that of the male, throughout the year excepting the month of December. The chi-square showed significant difference among months and total male-female ratio of C. reba. From the above findings it can be concluded that the breeding season of C. reba extends from April to October with the peak in June-July. Total length, standard length, total weight, gonadal length and gonadal weight relationship were found to be linear and positively correlated. The female were predominant almost through out the year.

Knowledge Management: Journal