The National Park Service's four units on Lake Superior are joining with an American Indian tribe in an effort to keep a deadly fish virus out of the lake.

Viral hemorrhagic septicemia, or VHS, has caused large fish kills in the other Great Lakes and some inland waterways but has not been spotted in Lake Superior.

The plan announced Monday was developed by Apostle Islands National Lakeshore, Grand Portage National Monument, Isle Royale National Park, Pictured Rocks National Lakeshore and the Grand Portage Band of the Lake Superior Chippewa.

It outlines 16 steps to prevent VHS from entering Lake Superior. They include educating the public, restricting use within park waters of fish bait that could carry the virus, and prohibiting exchange of ballast water within park waters.