Meeting Abstract
Fish forage in the dark by using the lateral line system to detect water flow generated by prey. Upon hatching, the lateral line includes one type of receptor, the superficial neuromast (SN), and this is joined by a second type, the canal neuromast (CN), by the time a fish has grown into an adult. Although CNs are known to have superior sensitivity to high-frequency stimuli, it is unclear if their development endows a fish with a superior ability to forage in the dark. We investigated this subject by comparing foraging behavior in darkness in zebrafish (Danio rerio) at 30 day-post-fertilization (dpf), which have only SNs and at 90-dpf fish, which have both receptor types. In order to examine the flow regimes that stimulates feeding at these stages, we found that we could provoke feeding in the dark with a vibrating sphere over a range of frequencies. Sphere detection was determined by unconditioned eye motion directed at the sphere. By this measure, the older fish sensed the sphere at about twice the distance of the younger fish. Therefore, the development of of CNs is correlated with enhanced flow sensitivity. Therefore, the development of receptors in the lateral line system appears to equip fish with the ability to exploit habitats with limited or no light.
