Lateral line morphology and development and implications for the ontogeny of flow sensing in fishes

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This chapter considers the morphological diversity of lateral line canals and neuromast receptor organs among fishes and how the pattern and timing of lateral line development can inform an understanding of the ontogeny of flow sensing. The morphology (and presumably the function) of the lateral line system changes considerably as a fish develops. Morphogenesis of the lateral line system starts before hatch and continues through the larval and juvenile stages, and thus, may take up to several months to complete during which fish size increases considerably. The appropriate course and timing of the development are critical for the development of feeding, swimming, and predator avoidance behaviors, and the ability to orient to environmental flows, which all ensure survival of young fishes. It is predicted that lateral line function, and thus flow sensing, is affected by a combination of both ontogenetic changes in the morphology of the lateral line system and the nature of the changing hydrodynamic regime in which a developing fish lives. Several aspects of lateral line development are predicted to have important effects on the functional ontogeny of the system: (1) increase in neuromast number, (2) changes in the relative number of superficial and canal neuromasts (CN), (3) changes in neuromast morphology (size, shape, hair cell number), and (4) variation in the pattern and timing of canal development.

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Flow Sensing in Air and Water: Behavioral, Neural and Engineering Principles of Operation