Temperature sensitivity of skeletal development in Oreochromis niloticus (Teleostei: Cichlidae)

The development of cartilaginous and osteological structures of the dorsal, anal and caudal fins, and axial skeleton in Nile tilapia ( Oreochromis niloticus ) was studied under three temperature treatments (22, 28 and 34oC). Fish samples were collected periodically during the developmental stage from hatching up to 39 days post hatching. Bone and cartilage development were evaluated. The results showed that the pattern and sequence of development and appearance of these elements in the three treatments are similar, and the difference is in timing of appearance and ossification of skeletal elements. Samples from 34oC started and ended bone formation earlier, but these process in 22oC treatment was very late. The temperature on the onset and end of chondrogenesis and ossification had a profound effect; these effects on 22oC treatment were severe than other treatments. The sequences of the chondrogenesis and ossification process was well conserved at all temperature treatments.