Field work
Physico-chemical parameters of temperature and salinity, were measured by the Hydro-lab. Juvenile fishes were collected from the mangroves of Sharm Al-Bahary, Qula’an and Hamata in winter, spring and autumn. Fishes were collected by a small beach seine that was towed horizontally creeping on the bottom for a distance of approximately 100 m (Ahmed, 1992). Fishes were removed and then frozen for further investigation. Sizes of the juvenile fishes were measured to the nearest 0.1 cm.