Is ageing an otolith like counting tree rings?
It is similar to counting tree rings, because the otolith also forms annual marks. However, the annual marks are not always clearly visible on the entire otolith. Environmental factors such as water temperature, food supply, salinity, water chemistry, and population density can cause stress on the fish, and marks other than those that are annual can form on the otolith. This can cause a complicated pattern that the biologist must interpret. Try your hand at ageing with the interactive Age Reading Demonstration (ARD).
