Ultrastructure of saccular epithelium sensory cells of four sculpin fish species (Cottoidei) of Lake Baikal in relation to their way of life

Abstract

Various structural elements of the apical region of hair cells and their location in the saccular macula of four sculpin fish species (Cottoidei) of Lake Baikal—two oilfish species (big golomyanka Comephorus baicalensis and small golomyanka C. dybowski), Severobaikalsk yellowfin Cottocomephorus alexandrae, and stone sculpin Paracottus knerii—were studied by scanning electron microscopy. In stone sculpin Paracottus knerii, which inhabits the coastal areas and leads a benthic lifestyle, the diversity of hair cells (in terms of the height of kinocilium and stereocilia) is big than that in the secondary pelagic species big and small golomyankas and in Severobaikalsk yellowfin, which inhabits the near-slope areas. Stereocilia of hair cells of stone sculpin and Severobaikalsk yellowfin are shorter than in the other species studied. The presence of such cells in the macula can ensure the sensitivity to more high-frequency acoustic signals and facilitate their perception by fish against the background of low-frequency noises characteristic of the coastal zone of the lake.