Biological Aspects on the Blue Crab, Callinectes sapidus (Rathbun, 1896) Inhabiting the Bardawil Lagoon, Northern Sinai, Egypt

A, Rady; S., Sallam W.; I., Abdou N. E.; M, El-Sayed A. A.

doi:10.21608/eajbsz.2018.24696

Biological Aspects on the Blue Crab, Callinectes sapidus (Rathbun, 1896) Inhabiting the Bardawil Lagoon, Northern Sinai, Egypt

Document Type : Original Article

Authors

¹ Biology and Geology Dept., Faculty of Education, Ain Shams University, Cairo, Egypt

² Marine Science Dept., Faculty of Science, Suez Canal University, Ismailia, Egypt

³ Biology and Geology Dept., Faculty of Education, Ain Shams University, Cairo, Egypt,

⁴ Zoology Dept., Faculty of Science, Al-Azhar University, Cairo, Egypt.

10.21608/eajbsz.2018.24696

Abstract

A total of 161 specimens of C. sapidus were collected during the fishing season from November 2016 to July 2017, of the 100 specimens were males (62.1%) and 61 were females (37.9%). The number of obtained specimens has seasonally fluctuated. The highest number of individuals was 67 (41.6%) obtained during spring, compared with the minimum number of 28 individuals (17.4%) collected in summer. The present results showed that 87.3% of the population fell within 75 and 124.9 mm CW and was represented by two modes comprising the sub adults and adults. There were seasonal changes in the size frequency distribution of pooled samples of this species. Males over-dominated females and were represented by the general sex ratio of 1:0.61 males: females. This ratio was tested using the Chi-square (X²) Test for Goodness (P<0.05, df=1) and recorded significant differences in autumn and winter (X² = 20.82 and 9.32, respectively),where males outnumbered females, but not significant in spring and summer. These results showed also that five maturity stages of females were determined based on morphological shapes called immature, maturing, mature, ripe and spent,but no ovigerous females were detected among the seasonally obtained specimens. The estimated size for 50% sexually mature females was 96 mm CW. There were seasonal changes in the percentage of females with regard to the different maturation stages. Gonad index indicated that males had the highest average in spring and exceeded females which had the highest in summer.

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