Because of their prolific and predatory nature, laws have been enacted in some places to help stop the spread of northern pike outside of their native range. For instance, in California, anglers are required by law to remove the head from a pike once it has been caught. In Alaska, pike are native north and west of the Alaska Range, but have been illegally introduced to south-central Alaska by game fishermen. In south-central Alaska, no limit is imposed in most areas. Pike are seen as a threat to native wild stocks of salmon by some fishery managers.