Location: Princeton, Oregon

About Malheur National Wildlife Refuge was established on August 18, 1908 by President Theodore Roosevelt as the Lake Malheur Bird Reservation. Roosevelt set aside unclaimed lands encompassed by Malheur, Mud and Harney Lakes as a preserve and breeding ground for native birds. The newly established Lake Malheur Bird Reservation was the 19th of 51 wildlife refuges created by Roosevelt during his tenure as president. At the time, Malheur was the third refuge in Oregon and one of only six refuges west of the Mississippi.

Background and context

Common Carp (Cyprinus carpio) first invaded Malheur Refuge in the late nineteen thirties or early forties. The Silvies River provided them access to Malheur Lake where they became a nuisance ten years later. During the next ten years carp migrated up the Blitzen River and invaded the Blitzen Valley wetlands. Their spread to the Double-O unit of the refuge was temporarily restricted by the natural land bridge between Harney and Mud Lakes. But during the years of 1952, 1957 and 1958 the natural barrier was breached, allowing carp to invade the Double-O unit wetlands also. By the early 1960’s carp were established in large numbers throughout the refuge, and began to have an adverse impact on the aquatic habitat and production of submerged aquatic plants and aquatic invertebrates. These aquatic plants and invertebrates are important food items for native fish, waterfowl, shorebirds and other water birds.

While carp search for aquatic invertebrates they compete directly with other aquatic wildlife by consuming and uprooting submerged aquatic plants. These plants, especially sago pondweed (Potamogeton pectinatus), are important foods for other wildlife and provide a critical part of the subsurface habitat used by aquatic invertebrates and native fish. Carp alter the aquatic ecosystem when feeding by causing water turbidity. While feeding on the bottom, they vigorously roil the water in search of food which stirs up the sediment and organic material and resuspend this material in the water column. Consequently, subsurface sunlight needed for plant growth is reduced, and photosynthetic plant production and oxygen levels decrease. With high concentrations of carp, the effects of swimming and spawning also contribute to increased turbidity. Eventually carp can change the physical environment of an entire aquatic ecosystem to a turbid water state. (This background is from Vetter 1995)

More information

See the following links for output from this project:

Colvin, M.E. Application of carp control strategies into a model for Malheur NWR. Malheur National Wildlife Refuge Invasive Carp Control Workshop. Burns, OR. (Invited) PDF, Model (Stella) Colvin, M.E., S. Grummer, J. Wahl, T. Stewart, and C. Pierce. Carp and water quality research, a midwest case study. Malheur National Wildlife Refuge Invasive Carp Control Workshop. Burns, OR. (Invited) PDF