Study of Some Biological Aspects of the Nile Carp, Labeo niloticus (Pisces, Cyprinidae) from Khashm El-Girba Reservoir and Atbara River, Sudan: I Abundance; Sex Ratio; Gonado-somatic Index and Breeding Season
Mutasim Yousif Mohamed Abdalla *
Khashm El-Girba Fisheries Research Station, Fish and Aquatics Research Centre, Animals Resources Research Corporation, Sudan.
Abuelgasim Ibrahim Abdelhalim
Department of Zoology, Faculty of Science, University of Khartoum, Sudan.
Ahmed El Bedawi Adam
Fisheries and Aquaculture Consultant, Ministry of Animal Resources and Fisheries, Khartoum State, Sudan.
*Author to whom correspondence should be addressed.
Abstract
The aim of this study is to investigate some biological aspects of the Nile carp, Labeo niloticus, in Khashm El-Girba reservoir and Atbara River, Sudan. The study was conducted during December 2015 to November 2016. Samples were collected bi-monthly from three localities, namely; Um Aswad (Atbara River), El-Remila and El-Monaba (Khashm El-Girba reservoir), using beach seine nets of 1.2 cm 4.0 cm and 7.0 cm stretched mesh. A total number of 1,190 specimens of L. niloticus were collected from the three sampling sites. Two peaks of abundance were observed for L. niloticus at all sampling sites (February- March and September- October). Sex ratio was 1:1, except in downstream areas, where females were more dominant than males. Gonado-somatic index showed one peak of increase, and ranged from 1.28 - 1.79 and 0.50 – 1.701 for females and males respectively, indicating one spawning season.
Keywords: Abundance, Gonado-somatic index, Labeo niloticus, sex ratio, spawning season