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|Title: ||DIVERSITY, RELATIVE ABUNDANCE AND BIOLOGY OF FISHES IN ANGEREB AND SANJA RIVERS, TEKEZE BASIN, ETHIOPIA|
|Authors: ||Genanaw, Tesfaye|
|Date Added: ||31-Aug-2007 |
|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.|
|Description: ||A THESIS SUBMITTED TO THE SCHOOL OF GRADUATE
STUDIES, ADDIS ABABA UNIVERSITY IN PARTIAL FULFILLMENT
FOR THE DEGREE OF MASTER IN BIOLOGY|
|Appears in:||Thesis - Biology|
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