Diversity, Relative Abundance and Biology of Fishes in Angereb and Sanja Rivers, Tekeze Basin, Ethiopia

Tesfaye, Genanaw (2006) Diversity, Relative Abundance and Biology of Fishes in Angereb and Sanja Rivers, Tekeze Basin, Ethiopia. Masters thesis, Addis Ababa University.

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Abstract

Diversity and relative abundance of fish species of Rivers Angereb and Sanja were studied from samples (923 specimens) collected during November 2004 to October 2005. The samples were collected in the dry season and wet season. Fish sampling was done using gill nets with various stretched mesh size, hooks and line, monofilament nets with different mesh size and cast nets. Ten fish species were identified from the two rivers and these are included in the families Cyprinidae, Cichlidae, Mormyridae, Clariidae and Bagridae. The fish species identified are East African and Nilo-Sudanic in forms. Cyprinid fish, L. forskalii, was the most dominant both in number and weight in both rivers during the two sampling seasons. Analysis of variance shows that there were significant variations both in number and weight of fish specimens between the two seasons. The three most dominant fish species in the rivers are L. forskalii, L. cf. intermedius and L. nedgia. The length-weight relationship for these species were found to be curvilinear and described by TW = 0.0715TL2.47, TW = 0.0269TL2.96 and TL = 0.0269TL2.74 respectively in Angereb River. It was TW = 0.01TL3.021, TW = 0.0057TL3.18 and TW = 0.006TL3.14 for L. forskalii, L. cf. intermedius and L. nedgia respectively in Sanja River. The mean FCF for L. forksalii, L.cf. intermedius and L. nedgia were 1.26, 1.14 and 1.18 in Angereb River and 1.09, 1.05 and 1.05 in Sanja River respectively. There was significant variation (ANOVA, P < 0.05) in mean FCF of L. forskalii and L. intermedius in the two rivers. In both rivers females were more numerous (Chi-square, P < 0.05) than males. The mean absolute fecundity of L. forskalii ranging in length from 21 to 25cm FL and mean body weight of 229 gm was 48120. The smallest count was 27094 eggs in fish with 14 gm total weight and 22.2 cm fork length. The highest was 120314 eggs in fish with 1023 gm total weight and 37 cm fork length. Fecundity of the species in the rivers was linear when related to total weight, fork length and gonad weight.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Rivers, Angereb, Sanja, fish diversity, relative abundance, length-weight relationship, Fulton Condition Factor.
Subjects: Q Science > QH Natural history
Q Science > QH Natural history > QH301 Biology
Q Science > QL Zoology
S Agriculture > SH Aquaculture. Fisheries. Angling
Divisions: Africana
Depositing User: Selom Ghislain
Date Deposited: 12 Jul 2018 11:26
Last Modified: 12 Jul 2018 11:26
URI: http://thesisbank.jhia.ac.ke/id/eprint/7426

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