Thermal dependence of embryonic development and hatching rate in Labeo rohita (Hamilton, 1822)

The present study was designed to assess the embryonic development of Labeo rohita fertilized eggs incubated at four different temperatures (26, 31, 33 and 36 C) until hatching. Fertilization was carried out at ambient temperature (26 C) and was considered as Oh of embryonic development. Developmental stages were monitored by sampling embryos in different temperatures at particular intervals. Highest hatching percentage and least time for attaining each ontogenic stage were observed at 31 > 33 > 26 > 36 degrees C and were significantly different (p < 0.05). The lowest hatching percentage and maximum time duration for attaining a given ontogenic stage were observed at 36 degrees C; this treatment also resulted in malformed embryos. Our study demonstrated that incubation temperature significantly (p < 0.05) influences hatching duration, hatching rate and survival of L. rohita eggs. (c) 2006 Elsevier B.V. All rights reserved.