Minecraft wiki entry for Polar_Bear, associated text: 1–3 from player or tamed wolves kills.
There is a 3⁄4 chance of dropping 0 to 2 raw cod. The maximum amount can be increased by 1 per level of Looting, for a maximum of 0 to 5 with Looting III.
There is a 1⁄4 chance of dropping 0 to 2 raw salmon. The maximum amount can be increased by 1 per level of Looting, for a maximum of 0 to 5 with Looting III.