Influence of tropical seasonal changes on
oocyte diameter, responses to hormonal induction and hatching quality in two
strains of the catfish, Heterobranchus longifilis Val. (Clariidae)
D. Nguenga,
G.G Teugels, M. Legendre, F. Ollevier-2004
Aquaculture Research, 35(14): 1349-1357
Abstract:
A comparison was made between the oocyte diameter, pseudo-absolute
fecundity (PAF) and egg quality of two strains of the catfish, Heterobranchus
longifilis, maintained in outdoor ponds under a tropical highland
climate in Cameroon. The results indicated that circannual endogenous
rhythms for ovarian recrudescence and regression are absent in H.
longifilis, irrespective of breeding history, age and strain. There
appeared to be a possible slight adverse effect of climate (dry season) on
reproductive performance of both strains. Oocyte diameter and PAF increased
with increasing fish weight when data from both strains were combined,
indicating that the two strains may exhibit the same reproductive
performance. Viable eggs were obtained all year round after hormonal
induction. It is concluded that for propagation of H. longifilis in
tropical African countries, broodfish could be maintained in outdoor earthen
fish ponds with proper feeding.
(IRAD, Fishculture & Fisheries Research Unit, PO Box 255,
Foumban, Cameroon. E-mail: nguengadavid@yahoo.fr)