Baikal endemic sponge disease and anthropogenic factor

This article presents the results of observations of the state of the Baikal endemic sponge fauna (Fam. Lubomirskiidae) in the five-year dynamics against the background of their mass mortality. We indicate the change in the projective bottom cover with healthy and diseased sponges at two sites that are radically different from each other in the level of anthropogenic pressure. We also analyse the types of diseases and sponge species exposed to these at the study sites. We observe a significant decrease in the area of the projective bottom cover with healthy sponges both at the site experiencing heavy anthropogenic pressure and at the site where it is almost absent. However, our data have indicated great influence of the anthropogenic factor on the course of the disease and death of sponges. Degradation of sponges at the anthropogenically unfavourable site began much earlier than that at the site with the minimum anthropogenic impact. The most common species are the most susceptible to all types of diseases. At the same time, there is a catastrophic decrease in the abundance of the only branching species in Lake Baikal, Lubomirskia baikalensis.