Sea Lamprey Control Planned for Paw Paw River

The U.S. Fish and Wildlife Service will be treating sections of the Paw Paw River in Berrien and Van Buren Counties between September 23 and October 2, 2025. The goal is to reduce invasive sea lampreys, which can harm fish in the Great Lakes.

Sea lampreys are parasites that attach to fish and feed on their blood and body fluids. Without control efforts, they can cause serious damage to the Great Lakes fishery.

How treatment works

• Special treatments called lampricides will be added to the river for about 12 hours.
• These lampricides are designed to target sea lampreys but may also affect some fish, insects, or plants.
• The process is closely monitored to keep people and the environment safe.
• The U.S. Environmental Protection Agency and Health Canada have reviewed the treatment and found it safe when used at proper levels.

What residents should know

• River water may look red or green during testing.
• Avoid unnecessary contact with the water during treatment.
• Do not use river water for irrigation during and for 24 hours after treatment.
• Bait fish or other aquatic organisms kept in river water may be affected.

Sea lamprey control has been in place since 1958 and is an important part of protecting the $7 billion Great Lakes fishery. Read U.S. Fish and Wildlife Service press release here.

View Paw Paw River map of treatment here.

For more information, call:

• Marquette Biological Station: 906-226-6571
• Ludington Biological Station: 231-843-7000