Between Primorsko, the road passes along the marsh lagoon Arkutino. His area of 62 hectares has been covered with rare plant species - floating water lilies, irises, creeping vines. The salinity of the lake is 0.2%.
Marsh is separated from the sea by sand dunes and the beach sand lily grows. The beach also named Arkutino. Bay is a magnificent view of the island of St. Thomas, where he met the wild cactus. The bay can often see swans and other waterfowl. Under the Protected Areas Act, which regulates the categories of protected areas, their purpose and mode of preservation and use, disclosure and governance in 1962 Arkutino marsh and flooded forest around it were declared botanical reserve.
Notable in the reserve are the dense forests, water lilies, duckweed, yellow water rose kamasha, bulrush and reed. The tourist infrastructure includes wooden bridge and playground at the east end of the lake - through them, thousands of Bulgarian and foreign tourists can enjoy the unique nature of the reserve. In addition to rare plants in the reserve can be seen insects, waterfowl, turtles, snakes and more. Reserve Arkutino enter into the composition of the reserve Ropotamo, which in turn is part of a larger protected area - "Ropotamo Ramsar site." Prez1975 on Arkutino, along with Silver Lake, was declared a Ramsar site, ie wetland of international importance. These are the first two Ramsar sites in the country. Later the scope of the protected area represents area enlarged and in 2002 the area was called "Ropotamo Ramsar site."