The main feeding habitat of the western Pacific subpopulation is the shallow (5 — 15 m (16 — 49 ft) depth) shelf off northeastern Sakhalin Island, particularly off the southern portion of Piltun Lagoon, where the main prey species appear to be amphipods and isopods.
The waters off Russia's Sakhalin Island,
a main feeding habitat for them in the summer, are being targeted for oil and gas development.