Effects of latency period on aspects of the reproductive biology of Hetrobranchus longifilis

Abstract

Heterobranchus longifilis broodstock were procured, acclimatized and hypophycised with ovaprim. Eggs were stripped from the females between 8 and17 hrs. After hypophysation, while milt was obtained from the males by dissection. Proliferation and ease of flow of eggs were observed as the latency period increased. Lowest mean value of 32,750 eggs was obtained at the 8th hour while the highest value of 97,000 eggs was obtained at the 17th hour of latency period. Similarly, percentage fertility ranged between 71.68 and 27.67, percentage hatchability had no regular pattern, ranging between 77 and 70 while fry survival rate ranged between 78.33 and 18.5. Latency period correlated positively with relative fecundity (r = 0.96); negatively with percentage fertility (r = - 0.85); slightly negative with percentage hatchability (r = - 0.36) and highly negative with fry survival rate (r = - 0.895). The ideal optimal latency period (OLP) for H. longifilis therefore is 11 hours post – hypophysation at a temperature of 28 0 c. Keywords : Fish, Heterobranchus longifilis , latency period, ovaprim, reproductive biology > Animal Production Research Advances Vol. 2 (4) 2006: pp. 221-227