straits between the Kuril Islands connecting the Sea of Okhotsk with the Pacific Ocean. There are 26 straits, most of them are submerged saddles between volcanic cones. Although the straits are short, their width ranges from 1.8 km (Second Kuril Strait) to 55 km (Kruzenshtern Strait). The prevailing depth is about 500 m, dropping to 1,764 m and 1,468 m in Kruzenshtern and Boussole straits. In some places, such as the Second Kuril Strait, the depth is only 10 m. The straits are marked by strong tidal currents with a velocity of 2 to 12 km per hour.