Malheur Lake, the largest freshwater marsh in the arid west and a critical stop along the Pacific Flyway for migrating birds, has been plagued with an over-abundance of invasive common carp.

These non-native fish feed on and uproot the aquatic plants that once made Malheur Lake an immensely productive freshwater marsh for birds and other wildlife. Adding to the decline of aquatic vegetation, powerful persistent winds resuspend sediment making it difficult for aquatic plants to re-root or grow in Malheur Lake because the muddy water keeps sunlight from reaching them. In summary, major stresses for Malheur Lake include:

• Invasive common carp in Malheur Lake and tributary streams that disrupt submerged and emerged wetland vegetation establishment.
• High levels of turbidity in Malheur Lake from both internal and external sources which prevent light penetration to allow emergent and submergent plant growth.