The most abundant marine fungi encountered in various regions of the Sea of Japan belong to the genera Penicillium, Aspergillus, Wardomyces, Trichoderma, Chrysosporium, and Chaetomium. Facultative marine fungi of the genera Scytalidium, Verticillium, and Oidiodendron and obligate marine fungi of the genus Dendryphiella are much less abundant. The composition of marine sediments and the anthropogenic load on them were found to influence the abundance and species diversity of fungi, as well as the occurrence of fungal strains producing hemolytically active substances. The biodiversity of mycobiota and the abundance of hemotoxin-producing fungi in marine sediments may be used to evaluate the anthropogenic load on marine biocenoses. Hemolytic compounds were produced by 57% of the fungi isolated from marine sediments. The hemolytic activity of Chaetomium spiculipilium was revealed in the fraction of the culture liquid containing extracellular fatty acids and pigments. The fatty acid composition of this marine fungus was determined.