Background. Like in most salmonids, females of Artic charr dig nests, while spawning, to deposit their eggs, while the role of males is most often limited to the territorial defence. The aim of this study was to examine the histological structure of skin in both sexes, in the body parts which are particularly exposed to mechanical damage during spawning. Materials and methods. Based on material representing three forms (anadromous, land-locked (lake), and dwarf/riverine), collected in the pre-spawning and spawning periods, histological structure of the skin was analysed for three body areas: dorsum (back), side, and venter (belly). Results. In females of all the forms the skin in analysed body areas was thicker and contained more mucous cells, compared to males. In the ventral region it was the thickest, on the dorsum-the thinnest. A comparison of the skin structure in the three forms showed that, in the land-locked form (both sexes), the skin in all the body parts was thicker and richer in mucous cells, compared to the anadromous form. Conclusion. The skin of Arctic charr females plays a protective role, preventing mechanical damage during nest digging and egg burying, because of its substantial thickness and the abundance of mucous cells especially in the ventral region.

fish, salmonids, Arctic charr, lithophiles, nest digging, skin