The person to whom a bear tag has been issued shall carry the tag while hunting bear. Upon the killing of any bear, that person shall immediately fill out the tag completely, legibly, and permanently, and cut out or punch out and completely remove notches or punch holes for the month and the date of the kill. One part of the tag shall be immediately attached to the ear of the bear and kept attached during the open season and for 15 days thereafter. The holder of the bear tag shall immediately, upon harvesting a bear, notify the department in a manner specified by the commission. Except as otherwise provided by this code or regulations adopted pursuant to this code, it is unlawful to possess any untagged bear.