Katarzyna Ługowska, Joanna Jankowska
ABSTRACT. The aim of the study was to describe the embryonic development of ide. Eggs fertilized with the in vitro method were incubated under controlled laboratory conditions in continually aerated water at a temperature of 16°C. The study indicated that ide eggs swell a maximum of 2 h after fertilization (80.5%). The eggs are entirely opaque in the early stages of development up to the formation of small-celled blastulas. This is a transitional stage, and the egg chorions become fairly transparent from the moment embryos formed on the yolk spheres. The first embryonic movements inside the egg are observed 75 h after fertilization. Embryo survival decreased gradually throughout development and 85% hatched. The larvae began hatching after 114 h of development and finished after 135 h. The ide larvae broke through the egg envelope with their tails, which were the first parts of the embryos to emerge from the eggs, followed by the rest of the bodies. Properly developed larvae comprised 92% of the hatchlings. Two types of morphological anomalies were observed: spinal curvatures (A) and bodies bent in the shape of the letter C. One day after hatching, the larvae were an average of 8.59 mm long, the surface area of the body was 6.6 mm2 while that of the yolk sac was approximately 1.6 mm2.
Key words: ide, embryonic development, rheophilic fish
Przyjęto po recenzji 24.10.2013 r.