INTER-SPECIFIC VARIATION

INTER-SPECIFIC VARIATION median process and their greatest width in the middle reaching from one and
half to two and half of the premaxillary band.
There is no published information regarding the type differences in the
shape of vomerine teeth of this species i.e., category having vomerine teeth
without a posterior median process, which was designated as type A or with
posterior median process as type B (Fig. 1) . Teugels (1982, 1984) have given a
new systematic revision ofthe African catfish species ofthe genus Clarias, he
reported that C. lazera is a strain of C. gariepinus, who introduced the
synonymy, of African catfish species. As a result of the synonymy, the name
Clarias gariepinus for African catfish is at present generally accepted.
The purpose of the present study is to detennine the differences between
type A and type B of the African catfish using biometric characters and egg size
to find the best characters can be used to distinguish type A fish from type B .
Also this paper presents the results of the investigation on some biological
aspect of these two types in Lake Edku.