The ontogeny of neurosensory structures in larval Atlantic halibut,Hippoglossus hippoglossus(Linnaeus, 1758)

Summary The ontogenic development of neurosensory structures in larval Atlantic halibut, Hippoglossus hippoglossus (L.) was examined using microscopy imaging techniques and analysis. Larval samples were preserved at developmental stages of 444, 486, 528, 570, 612, and 666 degree-days, respectively. Larvae were measured and photographed macroscopically. The fish were then embedded in paraffin for histological processing. 5 μm sequential sections of the anterior of the larvae were cut and stained using hematoxylin and eosin dyes. The resulting sections were examined using an Olympus BX60 compound microscope. The development of neurosensory structures such as neuromasts and sensory papillae were observed throughout all developmental stages of larvae and early development of the lateral line was observed at 666 degree-days. Neuromast frequency increased as larvae matured, suggesting that larvae were approaching their first feeding event towards the end of the sampling period. Possible implications of development on larval first feeding are discussed.