Anatomy and differential growth of the lateral line system of the mottled sculpin, Cottus bairdi (Scorpaeniformes: Cottidae).

Scanning electron microscopy and standard histological techniques were used to describe the basic anatomy and postembryonic growth of the lateral line system of Cottus bairdi. The gross anatomy and distribution of lateral line neuromasts in canals and superficially on the skin are similar to what has been reported for many primitive actinopterygian fishes. Both canal and superficial neuromasts showed postembryonic growth in the number of hair cells and size of neuromasts, but canal neuromasts grew more elongate whereas superficial neuromast grew symmetrically. Neuromasts in the mandibular canal grew significantly faster than any other neuromasts and superficial neuromasts on the head showed the least amount of growth. Differential growth of the sculpin lateral line system may be related to the feeding behavior of the animal and to differences in the ambient levels of water noise to which larval and adult fish are exposed.