The effect of temperature on early development of barbel Barbus barbus (L.)

The rate of swelling of barbel Barbus barbus (L.) eggs and of embryonic development increased with temperature (from 12 to 22°C). Survival of embryos decreased during the embryonic development and the highest mortality at each developmental stage occurred at 12 and 22°C. Body malformations in embryos during cleavage and organogenesis were the most frequent at 12, 14 and 22°C. During the embryogenesis, three types of embryonic body malformations were observed: yolk sac oedema, spine curvature and shortening of body. At all temperatures, most of larvae hatched with tail first but at 12 and 22°C significantly more larvae hatched with yolk sac compared to the other temperatures. The highest percentage of normal viable larvae was obtained at 14 and 18°C. Larval malformations and dead larvae were significantly most frequent at 12 and 22°C compared to the other groups. At all temperatures, spine curvatures and yolk sac deformation were the most frequent types of larval deformations.