On the southern and eastern coasts of the lake, many round tumuli and stone circles built of undressed stones were found. The structures are sometimes arranged in series parallel to the coastline with equal intervals between them. The tumuli are 1 to 4 m in diameter, and are at elevations of -212 to-215 m. below Mediterranean sea level. The function and the dating of these structures are yet unclear. The big ones (on the southern coast) may have served as artificial fish nurseries. The small ones, which are arranged in a straight line (at Ein-Gophra), could have supported wooden poles of a fishing fence-weir.