Interspecific differences and ecological correlations of ultraviolet radiation tolerance in low- and high-altitude fishes

Ultraviolet radiation (UVR) is a ubiquitous environmental factor and with complex diverse effects on organisms, the UVR tolerance of species varies due to selection, adaptation evolution. This study aimed improve our understanding interspecific differences in fishes. First, we compared skin histology between high-altitude fishes their low-altitude relatives. Second, assessed histological changes 22 fish after exposure quantified damage levels. Finally, factors affecting difference among were studied. Thin or absent scales was common characteristic different taxonomic groups, but other structure parameters (the thickness dermis epidermis, size number mucous club cells) did not show convergence. After exposure, cells experimental generally reduced, epidermal dermal varied species. The change rata melanin area strong negatively correlated level damage, indicating that increased helpful reduce damage. On whole, differ from those However, epidermis Gymnocypris eckloni Oncorhynchus mykiss , which had highest tolerance, nonpathologically thickened, they may contribute tolerance. There significant fishes, cold water showing stronger Interestingly, some (e.g., O. ) also showed high suggesting besides adaptation, low-temperature play an important role organismal UVR.