Laboratory of Hydrobiology, Institute of Biology and Soil Sciences, FEB RAS (first Director V.Ya. Levanidov, Dr. of Biology, present Director Ye. A. Makarchenko, Cand. of Biology) was ogranized in 1971 to study algae, water invertebrates, ecology of aquatic organisms and their classification. The major area the lab is working in is spatial distribution of species and communities in water basins and reservoirs and the related problems of fresh water pollution. The geography of its interests embraces Primorye at large and the adjacent territories. The recent studies of the lab deal with the biota of Lake Khanka, the major fresh water reservoir in the Russian Far East, including:
- species composition of fresh water biota;
- regularities of structural organization and functioning of fresh water communities;
- anthropogenic impact on fresh water species and communities, determination of  trends and character of structural-functional reconstruction in communities;
- working out water quality assessment criteria (accounting regional flora and fauna) and optimal exploitation strategy for fresh water reservoirs.
    Lake Khanka and the adjacent bogs is a unique natural complex, the nest and rest area for various birds, the habitat of rare meadow and bog plants. The fauna of the lake includes diverse fish and invertebrate populations, with many rare and endemic species. In 1971 in accordance with Ramsar Convention this territory was awarded with the status of international significance. In 1990 the basin of Lake Khanka was organized into the Khankaisky State Preserve. In April 1996 Russian Federation and the People's Republic of China signed an agreement establishing on its basis the Russia-PRC Preserve "Lake Khanka".
    The main landscape elements of the territory are meadows, bogs, cane thickets, shallow lakes. Total square area of the preserve makes over 110 000 hectares. The square area of the Khanka proper at a mean water level is 4 070 km2, mean depth is 7.5m, maximal depth is 10m. It is noteworthy that the water level in the lake changes each 26 years, the difference between maximal and minimal levels comes up to 210cm, the difference of square area - to 17%, of water volume - to 39%. Sixteen rivers flow into the lake, the major among them are Melgunovka, Ilistaya, Spasovka, Komissarovka.
    The Sungach is the only river flowing out of the Khanka. Through the River Ussuri it links the lake with the River Amur. The basin of the River Razdolnaya that now flows into the Sea of Japan historically belonged to the Khanka basin. All rivers flowing into the lake are of plain type with meandering riverbeds, slow stream, and marshy banks. All are born in the surrounding hills and bogs.
    The Khankaisky Preserve and its surroundings are the habitat for 300 species of birds, with many of them to be at the brink of extinction. 44 species are enrolled into the Red Book of Russia, 12 - into the Red Book of the World. In number of bird species the preserve ranks first (among the preserves of similar size) not only in Russia, but also in the area of moderate European and Asian latitudes. Two mammals from the 43 registered in the preserve are in the Red Book of the World, 2 -in the Red Book of Russia. One reptile and two fish species are enrolled in the Red Book of Russia. The preserve is rich in aquatic, bog and meadow flora with many rare and extinct endemic plants, nine vascular species are enrolled into the Red Book of Russia.

    Algae and invertebrates of the Khanka basin, unlike fish population, are not completely studied. Alga diversity accounts 356 varieties and forms from 7 sections  (Tabl. 1), invertebrates - 550 species from 280 genera and 130 families (Tabl.2).
    These are preliminary numbers, detailed studies of the Khanka flora and fauna have been launched just recently. Each year field expeditions yield new data on species diversity. Invertebrates are basically amphibiotic insects making 60% of the total. Some classes, such as flies and dragonflies are not completely studied. Bank undergrowth is abundant in the insects belonging to the class of May and caddis flies.

 The abundance of May, caddis, and stone flies in streams and rivers around Lake Khanka indicates their water purity.
 Fish diversity includes 000 species.

    Eight invertebrates mostly of Mollusca type are enrolled into the Red Book of Russia:

• Dahurinaia daurica;
• Dahurinaia tiunovae;
• Lanceolaria maacki;
• Lanceolaria chankensis;
• Lanceolaria ussuriensis;
• Lanceolaria bogatovi; and
• Cristaria tuberculata.

 T. VSHIVKOVA, Institute of Biology and Soil Sciences, Far Eastern Branch, Russian Academy of Science

Yu.  SUSHITSKY, Institute of Biology and Soil Sciences, Far Eastern Branch, Russian Academy of Science