The influence of temperatures ranging from 25 to 36 °C on developmental rates, morphometrics and survival of freshwater prawn ( Macrobrachium rosenbergii) embryos

Abstract

An in vivo study was conducted to assess effect of incubation temperature on embryonic development and hatching period of freshwater prawn ( Macrobrachium rosenbergii) . Brooders spawned on a single day were distributed among four temperature treatments, each with six replicates, and acclimated at a rate of 1 °C/day above and below ambient water temperature (30 °C) to reach test temperatures (25, 29, 33 and 36 °C) and maintained in separate rearing conditions until hatch. Sampling of developing embryos was done at 24-h intervals until mortality/hatching and observed under a light microscope. Major half axis, minor half axis, area and perimeter were measured at 48-h intervals. Embryonic development rates increased with increasing temperatures [ y (time from early morula hatch; h) = 40.075 x (temperature; °C) + 348.75; R 2 = 0.993). A rapid increase in major half axis, larval length, and faster hatching correlated with higher temperatures. Hence this study revealed that incubation temperature significantly influences the time to and duration of hatching and survival of M. rosenbergii eggs.