Baikalian gammarids (amphipod) collected via SCUBA from the rocky substrate at approximately 10 meters depth in the southern basin of Lake Baikal, Russia. There are 259 species of gammarids in Lake Baikal, more than in any other lake in the world, and 98% of the species are endemic to the lake. Gammarids are an essential food source for many fish in Lake Baikal, and in the littoral zone the density of gammarids can reach 30,000 individuals per square meter of the substrate (For more information, see: Kozhova, O.M. & L.R. Izmesteva. 1998. Lake Baikal: Evolution and Biodiversity. Backhuys Publishers. Leiden, The Netherlands. ). Gammarids shown here were collected by staff of the Limnological Institute, Irkutsk, Russia in August, 2001. Photo taken during the Lake Baikal course (Wellesley College).