Subspecies and Distribution. P. h. hispida Schreber, 1775 — Arctic Ocean. P h. botnica Gmelin, 1788 — Baltic Sea. P. h. ladogensis Nordqvist, 1889 — Lake Ladoga (W Russia). Ph. ochotensis Pallas, 1811 — Sea of Okhotsk and N Japan (Hokkaido). P. h. saimensis Nordqvist, 1889 — Lake Saimaa (S Finland).