Aquatic Health - It's for the Birds!

Commercial fisherman harvest invasive carp from Malheur Lake as part of research to reduce carp numbers in wetlands

The Refuge's mission is to conserve wildlife and habitat for the American public and generations to come. The primary focus of the Refuge has been the management of habitat for birds and mammals; however, fish habitat has become an increasingly important aspect of the habitat management program. The Refuge is now placing special emphasis on the management of native fish species found within the Blitzen River watershed.

To develop an effective aquatic health program for the Refuge, staff must understand: how fish use Refuge waterways; the timing of migration of redband trout and other native fish; identify all native fish spawning areas; understand population dynamics; and determine fish densities. The biggest challenge for the program will be to understand the impacts that invasive common carp (Cyprinus carpio) have on aquatic health and how this relates to bird use on the Refuge and impacts to wetlands and ponds.

Invasive Common Carp

Common carp were first introduced into Harney Basin in the 1920s as a sustainable food source. Over the last 60 years, increasing numbers of carp have severely depleted migratory bird food resources and caused poor water quality. Carp impacts have reduced migratory bird productivity at the Refuge to 2-7% of its former production capability. Restoration of the productivity of refuge wetlands will directly benefit waterfowl production on the Pacific Flyway and is a priority for Malheur Refuge.

The greatest impact of invasive carp on wetlands is their feeding behavior. Carp are bottom feeders and sift through mud searching for aquatic insects and plants. Feeding activities not only uproot aquatic vegetation, but also produce silt plumes in the water column which make it difficult for plant synthesis and insect production, and in turn limits food for migratory waterfowl. The Refuge has developed a brochure about the impacts that common carp have on the Refuge to help spread the word.

The Refuge has partnered with a number of Federal and State agencies, NGO’s, private citizens and Tribal participants to address the impact of carp on aquatic habitat on the refuge and elsewhere in the Harney Basin. Their first task was to develop a white paper identifying how to address the issue of invasive carp. Researchers are working with the Refuge on carp control research and educational outreach.

If you would like to follow research efforts and the control of carp on the refuge join our list serve at Malheur Carp Coalition.

New Video about the impact of Invasive Common Carp in Malheur Lake

The Oregon Wildlife Heritage Foundation and the Refuge have funded the production of a new video about the impacts of invasive common carp in Malheur Lake and efforts to restore the productivity of Malheur Lake for the benefit of wildlife. The Oregon Wildlife Heritage Foundation is also an important partner in the basin-wide Harney Basin Wetlands Initiative, which is working to implement basin-wide carp control strategies and work with private landowners to maintain flood-irrigation and haying practices that sustain important bird habitats.