Effects of temperature on hatchability and egg yolk consumption of climbing perch Anabas testudineus

Abstract

This study investigated the effect of temperature on hatchability and egg yolk consumption of Climbing Perch Anabas testudineus larvae, obtained from artificial insemnation and held at five different temperatures (23 °C, 25 °C, 31 °C, 33 °C and ambient). Each treatment consisted of three replicates in which a total of2600 eggs were placed inside each replicate. During embryonic period, eggs development was observed at three hours interval. The hatching rate calculated showed significant difference between temperatures and that higher temperature (31 °C and ambient) resulted in higher hatchability (81.59 % and 82.12%) while lower temperature (23 °C) was likewise (73.59 %). During yolk-sac phase, yolk consumption was observed at six hours interval. Egg yolk volume was also observed and calculated until yolk reserves had been fully consumed. Statistical analysis showed that initial mean yolk volume was not significantly different, however, mean yolk volume from the sixth hour onwards displayed significant difference until yolk exhaustion. At 33 °C, yolk reserves was the quickest to be fully consumed at 120 hours while at 23 °C yolk reserves was the slowest to be fully consumed at 168 hours. It is certain that high temperature resulted in higher hatchability and yolk consumption rate while lower temperature demonstrated low hatchability and yolk consumption rate