 More than 400 diatom species, both benthic and planktonic, are found in the lake, and about half of these are endemic to Baikal; however, significant taxonomic uncertainties remain for this group.The Baikal seal or "nerpa" ("Pusa sibirica") is found throughout Lake Baikal.It is one of only three entirely freshwater seal populations in the world, the other two being subspecies of ringed seals.