Dermal sense organs and their significance in the feeding behaviour of the common sole Solea vulgaris

Abstract

Light microscopy and EM studies on dermal sense organs of the sole S. vulgaris reveal that the sensory buds and EM located in large numbers between the papillae, mainly on the abocular side of the fish, were free neuromasts. These papillae may serve as protectors for the sensitive neuromasts rather than as sensory organs. They may improve the perception function of the neuromasts for mechanical stimuli. Taste buds, in different distributions, were found only in oral cavity, pharynx, on gill rakers, and on lips. The lateral line system, though partly asymmetrical, is highly developed on both the ocular and abocular sides of the fish. The nasal sac of the abocular side is smaller in size and contains fewer lamellae than that of the ocular side of the fish. Ocular and abocular nasal sacs are connected via an accessory sac. Results indicate the significance of mechanoreceptors for the feeding behaviour of postmetamorphosed sole which are known to feed most actively at night and until now have been thought to detect food primarily by means of chemoreception.