Behrooz ABTAHI
The present study describes histological aspects of the development of gills, heart, kidney, swim bladderand spleen from Day 0 up to Day 21 after hatching in Hamun mahi Schizothorax zarudnyi larvae and provides valuable information on its structural status during ontogeny. This information is particularly useful for establishing the functional systemic capabilities and physiological requirements of larvae for optimal welfare and growth. Observations described are related to main developmental stages of Hamun mahi and are defined on the basis of external morphological features. Pronephric excretory structures, a tubular heart and respiratory anlage are present at hatching but spleen and swim bladder become apparent during Stage 2. During the first two stages, Hamun mahi larvae undergo intense organogenesis particularly during Stage 2. Despite Stage 2, the next developmental stage is not characterized by the appearance of new structures but by the increase in size and complexity of the pre-existing ones.
