Temperature, latency and incubation time of Clarias gariepinus, Heterobranchus longifilis and their hybrids

Abstract

Latency and incubation periods of Clarias gariepinus, Heterobranchus longifilis and the incubation period of C. gariepinuseggs fertilized with sperm of H. longifiliswere studied. There was a negative correlation between the water temperature, latency and incubation periods for the two species and their hybrids.
The latency time for C. gariepinus changed (dropped) at the rate of 1.30 hours for every 1°C raise/increase in water temperature, and for H. longifilis the rate was 1.50 hours for every 1°C. However, the incubation periods showed the rate of change for C. gariepinus to be 3.33 hours; and H. longifilis4.02 hours for every 1°C increase in water temperature.
For the hybrid, the incubation period dropped at the rate of 3.57 hours for every 1°C increases in water temperature.


Tropical Freshwater Biology VOL. 8 1999, pp. 49-54



KEY WORDS:

Latency – incubation - Clarias gariepinu - Heterobranchus longifilis – Hybrid - Brood fish.