Some biological aspects of the African Catfish Clarias gariepinus and the Nile Carp Labeo niloticus

Dissertant

Nasur, Fathiyah Ali

Thesis advisor

Ali, Sayyid Muhammad

University

Omdurman Islamic University

Faculty

Faculty of Sciences and Technology

Department

Department of Zoology

University Country

Sudan

Degree

Master

Degree Date

2009

English Abstract

Some aspects of the biology Clarias gariepinus (Clariidae, Burchell) and labeo niloticus (cyprinidae, forskal) from the White Nile (Jebel Aulia, Kawa and kosti) were studied during March 2006 to March 2008.

C.

gariepinus was abundant all throtgh the year, especially during March to July (summer season).

L.

niloticus was very scarce.

610 C.

gariepinus and 30 L.

niloticus (mostly juveniles) were collected during the study period for establishing length weight relationship, growth, exploitation, feeding and breeding. C.

gariepinus: Length weight relationship was Y= 2.4136 X-2.341 R2= 0.81.

Where Y= weight (gm), X= standard length (cm). Growth according to Vonpertalanffy equation (1987) was: Lt = 123 (1-e) -0.1(t+1.01).

Lt= length at age t0 , L∞= 123, k = 0.1 and to = -1.01 Length of first exploitation = 30.5cm. Length at first maturity = 30 cm.

Exploitation should be delayed until these fishes reach a reasonably larger size so as to adequately contribute to recruitment.

The breeding season was March to September.

Absolute fecundity ±STD = 95363.56± 92615.91.

Relative fecundity based on fish standard length = 1897.91 ±1203.34, and on weight = 83.57 ± 28.51.

The relationship between the absolute fecundity and standard length Y =1.5291 X+4.6576, R2 = 0.38. Y= absolute fecundity, X = standard length.

C.

gariepinus is a carnivore that feed on fish and gastropods.

The mouth gape extended from 3.8 to 5.9 cm in 30 cm and 70 cm long fishes.

This allows predation on small fishes.

The relationship between the gape of the mouth and the standard length was Y= 0.6595 X -0.904, R2= 0.53 where : Y= gape of mouth, X = standard length.

The intestine ranged from 11 to 105 cm in 22 and 53 cm long fishes.

The increase in mouth gape, with the increase of fish length shows that larger fishes rely on larger preys with increasing age.

The relationship between the weight of food in the stomach and the stander length Y= 1.4919 X-1.1711, R2= 0.

21.

The Y= weight of food (gm), X= standard length (cm).

The relationship between the length of the stomach plus the intestine and the standard length was: Y = 1.6773 X -1.9835, R2 = 0.63 Y= length of intestine, X= standard length L.

niloticus : The length weight relationship was : Y = 2.5855 X -2.8591, R2= 0.9 Where Y= weigh, X = length.

The breeding season extended from March to October.

Absolute fecundity = 823639.5 ± 135015.11, relative fecundity based on standard length= 14075.8 ± 2145.56.

Relative fecundity based on weight 38.11 ± 4924789.

The relationship between absolute fecundity and standard length Y = 6.247 X-5.3514, R2= 0.9 Y = absolute fecundity, X = standard length.

L.

niloticus is a herbivore that feed on blue green algae, diatoms, small plants and mud with small mouth gape extending from 1.5 to 3.5 cm in 30 and 70 cm long fishes.

The relationship between the gape of mouth and the standard length was : Y = 1.032 X-2.8438, R2= 0.9 Y = gape of month, X standard length. The intestine plus the stomach was very long ranging from 204 to 868 cm in 19 and 63 cm long fishes.

This reflects that this fish is highly herbivorous.

The relationship between the length of the intestine and the standard length was : Y = 1.0427 X-2.2518, R2 = 0.82 Y = length of intestine, X = Standard length.

The relationship between weight of gut and standard length Y = 1.5291 X-4.6576, R2= 0.14

Main Subjects

Zoology

Topics

• Physiology
• Sudan

No. of Pages

54

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-362577