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Aquatic Nuisance Species

Introducing harmful, non-native organisms into New Hampshire’s waters can lead to environmental damage and declines in the aesthetic and recreational appeal of our lakes, ponds, and rivers. As of Spring 2003, the law prohibits the transport and introduction of exotic aquatic plants in New Hampshire!

Variable Milfoil is a non-native plant that has taken over many bodies of water in New Hampshire. It interferes with boating, fishing, swimming, and the ecology of the body of water. The plant is spread easily when boat propellers, fishing line, or other recreational gear cuts off pieces of the plant. These pieces then can travel to new parts of the body of water to root; or they can be trapped on boats and trailers, diving gear, and fishing equipment and moved to a new body of water. A single fragment of this plant can cause a new infestation. There are also other aquatic plants that can be as problematic, including hydrilla, Brazilian elodea, fanwort, Eurasian milfoil, and water chestnut.

Zebra Mussels are about the size of a human fingernail, or a pistachio nut, but cause hundreds of millions of dollars in damage across the U.S. They pose a serious threat to water supplies, industrial processing plants, marine engines, and recreation. Zebra mussels clog water intake pipes and can give bad odors to bodies of water. Their sharp shells also can cut the feet of swimmers.

To prevent spreading aquatic nuisance species, inspect your trailer and remove any plants and animals you see before leaving the area.

Here’s what you can do to prevent the spread of aquatic nuisance species.

  • Inspect your boat and trailer, removing all aquatic organisms (zebra mussels and any aquatic plants).
  • Drain your motor, live well, and bilge on land before leaving the area.
  • Empty bait buckets on land before leaving the area.
  • Never release live bait into a body of water or release aquatic animals from one body of water into another.
  • Rinse your boat, propeller, trailer, live well, and equipment; and remove by hand anything trapped between the boat and trailer.
  • Air dry your boat and equipment for as long as possible—five days is optimal.
  • Flush the engine’s cooling system with hot water.
  • Apply antifouling materials, such as paint and films, to boat hulls, trim tabs, water ports, transducers, and swimming platforms to discourage zebra mussel attachment.
  • Avoid boating through dense beds of aquatic plants.
  • Report any new suspicious plant growths to the NH DES at 603-271-2248.

What is New Hampshire doing to combat exotic aquatic plants?

The Lake Host Program was developed to prevent new infestations of exotic aquatic plants in New Hampshire’s lakes and ponds. Volunteers conduct quick and friendly inspections of your boat, trailer, and other recreational gear for exotic plants that may have become attached.

For more information about exotic species or to become a Weed Watcher, call the NH DES at 603-271-2248 or visit

Commonly Confused Look-Alike Aquatic Plants

Marine Sanitation Device (MSD)
Commonly confused look-alike aquatic plants.

Introducing harmful, non-native organisms into New Hampshire’s waters can lead to environmental damage and declines in the aesthetic and recreational appeal of our lakes, ponds, and rivers. The law prohibits the transport and introduction of exotic aquatic plants in New Hampshire!

Infested Bodies of Water in New Hampshire

Infested bodies of water in New Hampshire.
  1. Lake Winnipesaukee (Several Areas)
  2. Lees Pond, Moultonboro
  3. Lake Ossipee (Several Areas)
  4. Opechee Lake, Laconia
  5. Lake Winnisquam (Several Areas)
  6. Silver Lake, Tilton
  7. Crescent Lake, Wolfeboro
  8. Lake Wentworth, Wolfeboro
  9. Mascoma Lake, Enfield
  10. Sunrise Lake, Middleton
  11. Locke Lake, Barnstead
  12. Lower Suncook Lake, Barnstead
  13. St. Paul’s School Pond, Concord
  14. Little Turkey Pond, Concord
  15. Big Turkey Pond, Concord
  16. Bixby Pond, Epsom
  17. Northwood Lake, Northwood
  18. Lake Massabesic, Auburn
  19. Phillips Pond, Sandown
  20. Big Island Pond, Derry
  21. Arlington Mill Reservoir, Salem
  22. Cobbetts Pond, Windham
  23. Captain Pond, Salem
  24. Flints Pond, Hollis
  25. Cheshire Pond, Jaffrey
  26. Contoocook Lake, Jaffrey
  27. Pearly Pond, Rindge
  28. Forest Lake, Winchester
  29. Connecticut River (Several Locations)
  30. Lake Massasecum, Bradford
  31. Lake Monomonac, Rindge
  32. Hopkinton Lake/Dam, Hopkinton
  33. Nashua River, Nashua
  34. Powder Mill Pond, Hancock
  35. Ashuelot River, Winchester
  36. Little Suncook River (Several Areas)
  37. Mine Falls Pond, Nashua
  38. Winnipesaukee River (Several Areas)
  39. Cocheco River, Rochester
  40. Robinson Pond, Hudson
  41. Squam River, Ashland
  42. Squam Lakes, Ashland/Holderness
  43. Horseshoe Pond, Merrimack
  44. Gorham Pond, Dunbarton
  45. Belleau Lake, Wakefield
  46. Danforth Ponds, Freedom
  47. Rocky Pond, Gilmanton
  48. Dublin Lake, Dublin
  49. Lake Sunapee, Georges Mills
  50. Nutts Pond, Manchester
  51. Contoocook River, Jaffrey
  52. Turtle Pond, Concord
  53. Balch Lake, Wakefield
  54. Melendy Pond, Brookfield
  55. Potanipo Lake, Brookfield
  56. Brindle Pond, Barnstead
  57. Jones Pond, New Durham
  58. Scobie Pond/Haunted Lake, Francestown
  59. Mountain Pond, Brookfield
  60. Barnstead Parade Pond, Barnstead
  61. Merrimack River (Several Locations)
  62. Kimball Pond, Hopkinton
  63. Ottarnic Pond, Hudson
  64. Pemigewasset River, Sanbornton
  65. Wilson Lake, Salem
  66. Lake Pemigewasset, New Hampton
  67. Piscataquog River, Goffstown
  68. Halfmoon Pond, Barnstead
  69. Rockybound Pond, Croydon
  70. Powwow Pond, Kingston
  71. Glen Lake, Goffstown
  72. Long Pond, Danville
  73. Spaulding Pond, Milton (Salmon River)
  74. Upper Goodwin Pond, Concord
  75. Willand Pond, Dover
  76. Post Pond, Lyme
  77. Otter Lake, Greenfield
  78. Naticook Lake, Merrimack