Otolith

The otolith is a small calcareous structure found in the inner ear of fish (and other vertebrates) which helps to sense body orientation and movement. It works by the displacement of the otolith, which is connected to the hair cells within the inner ear, that senses the displacement, then produces a nerve signal which is interpreted and passed onto the brain, allowing the fish to sense its orientation and motion. The otolith is an important sensory structure, as it allows organisms to sense the orientation of their body and thus helps to stabilise their movements as they move through their environment. The sensitivity of the otolith has allowed it to be used in research, by monitoring the movement of fish to better understand their behaviour, and in aquaculture, by providing a non-invasive way to monitor fish health. By understanding the structure of the otolith and its uses, aquaculture farmers can ensure their fish are healthy and the environment is suitable for fish health.