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Seasonal variations in abundance and sex ratio of the freshwater crayfish Procambarus clarkii from four freshwater localities, River Nile, Egypt

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Last updated: 03 Jan 2025

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Abstract

A total of 693 specimens of the freshwater crayfish, Procambarus clarkii were collected from four sites  chosen along the River Nile, at Helwan (Site #1), El Warraq (site #2), El Rahawy (Site #3) and El Rayah El Mounofy (Site#4) during the period from summer 2014 to the following spring 2015. Most individuals of the collected specimens were characterized by hard-rigid outer exoskeleton, with dark-red, or deep brownish color carapace. But some specimens had old green or grey color carapace with scars and epibiotes. The collected specimens showed spatial and temporal variations, recorded 242 specimens (34.92% of all) from El Rayah El Mounofy, declined gradually into 173 (24.96%), 163 (23.52% ) and 115 (16.59%) at El Warraq, El Rahawy and Helwan, respectively. Seasonally, the highest number of individuals was 266 (29.4%), collected in spring, of them 115 were obtained from El Warraq, but declined gradually into 193 (28.9%) in summer, and 183 (24.3%) in autumn and reached the minimum number (51 individuals, 17.3%) in winter. The present results also showed that, no specimens were collected from Helwan during winter, and only 3 individuals were obtained from El Warraq, compared with 17 and 31 specimens collected from El Rahawy and El Rayah El Mounofy, respectively. In contrast, during summer, only 11 specimens were collected from El Rayah El Mounofy. The fluctuations in number of collected individuals of this species were greatly correlated with increasing in water temperature and water level after winter enclosure. The general sex ratio was 1:0.47 males: females and showed significant statistical variations between sites and seasons, recorded 1:0.40, 1:49, 1:0.63 and 1:0.40, males to females at Helwan, El Warraq, El Rayah El Mounofy and El Rahaway, respectively. The present data showed that, the whole populations of this species were varied from 6.6 to 14.3 cm in total length, from 26.84 ±14.42 at Helwan to 34.48±22.5g at El Rahawy.

DOI

10.21608/eajbsz.2018.13426

Keywords

Abundance, River Nile, Crayfish, sex ratio, body weight, total length, Egypt

Authors

First Name

El-Sayed

Last Name

M.

MiddleName

A. A.

Affiliation

Faculty of Science (Boys), Al-Azhar University, Cairo, Egypt,

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First Name

Shaaban

Last Name

A.

MiddleName

E.

Affiliation

National Institute of Oceanography and Fisheries, Al Kanater, Egypt

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First Name

El Feky

Last Name

A.

MiddleName

F.A.

Affiliation

Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt

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First Name

Abd El Gawad

Last Name

S.

MiddleName

S.

Affiliation

National Institute of Oceanography and Fisheries, Al Kanater, Egypt,

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First Name

Mohamoud

Last Name

H.

MiddleName

N.

Affiliation

Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt.

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Volume

10

Article Issue

1

Related Issue

2587

Issue Date

2018-06-01

Receive Date

2018-09-12

Publish Date

2018-06-01

Page Start

19

Page End

28

Print ISSN

2090-0759

Online ISSN

2090-0821

Link

https://eajbsz.journals.ekb.eg/article_13426.html

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https://eajbsz.journals.ekb.eg/service?article_code=13426

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2

Type

Original Article

Type Code

672

Publication Type

Journal

Publication Title

Egyptian Academic Journal of Biological Sciences, B. Zoology

Publication Link

https://eajbsz.journals.ekb.eg/

MainTitle

Seasonal variations in abundance and sex ratio of the freshwater crayfish Procambarus clarkii from four freshwater localities, River Nile, Egypt

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Article

Created At

22 Jan 2023