ONTOGENIC DEVELOPMENT AND COMPOSITION OF THE MUCOUS CELLS AND THE OCCURRENCE OF SACCULAR CELLS IN THE EPIDERMIS OF ATLANTIC HALIBUT

An increase in the number of mucous cells of the epidermis, as well as qualitative changes of the mucus composition from predominantly neutr al to a mixture of neutral and sulphated glycoproteins occurred during the development from a pelagic larva to a bottom-dwelling flatfish. N umerous saccular cells were observed in the epidermis of the yolk-sac larvae that disappeared simultaneously as the mucous cells increased i n number in the epidermis of the metamorphosed halibut. These findings may help to understand the protective role of the mucus layer of Atla ntic halibut during development as compared to other fish species in a quaculture. (C) 1997 The Fisheries Society of the British Isles.