Malheur

Aquatic Health

brochure Malheur - Aquatic Health

Aquatic Health at Malheur National Wildlife Refuge (NWR) in Oregon. Published by the U.S. Fish & Wildlife Service (USFWS).

Refuge • - In Common carp have negatively impacted the aquatic health ofMalheur National Wildlife Refuge - we need your help to bring the birds back. alheur National Wildlife Refuge is one of the jewels of the National Wildlife Refuge System. It is a premier site for birds and birding as it provides invaluable migratory stopover and breeding habitat along the Pacifi c Flyway. Over the last 60 years, these habitats have been significantly altered by a non-native species, the common carp. As a result, refuge waters can produce only a fraction of the waterfowl and waterbirds they once did. u. s. Fi5h c~ IVj ldl!fo Savicei Duvl! Mmh! Malheur National Wildlife Refuge supports a good number of migratory ruddy ducks on the Pa cific Flyway. Ruddy and other diving ducks rely on sago p ondweed - an abundant subm erged aquatic p lant found on healthy lakes. Malheur, M ud and Harney Lakes are m agnets for colonial nesting waterbirds, or birds that gather in large assemblages during nesting season. Ref uge waters support white-faced ibis, as well as grebes, pelicans and egrets. A Disastrous e The common carp is a member oJ the minnow family with resilient characteristics: it can resist wide temperature ranges, low water clarity and high water turbidity, and has {{ wide-ranging diel and breeds prolifically. Tn the Hamey basin, common carp eat all the same foods as birds and native fish. us. Fish &J VildIife Service ~ ommon carp were introduced in the 1920s ~ as a desirable sustenance fish in many places across North America, and in the 1950s carp became established in Malheur National Wildlife Refuge waters. Since then, carp have severely depleted migratory bird food resources and diminished water quality. With over 7,2 million pounds of carp currently in refuge waters, bird productions numbers will remain dramatically decreased. Why are Carp a Problem? The greatest impact of carp is their bottom feeding behavior: carp eat invertebrates, uproot vegetation and disturb the muddy bottom. As carp populations explode, food staples for waterfowl and waterbirds disappear. The damaging impacts of common carp have seriously handicapped the refuge and its ability to fulfill its mission to provide feeding, nesting and rearing habitat for migratory birds. Currently, the ecological collapse caused by carp has reduced waterfowl production to about 2-7% of its former capability, Malhear is one of the largest lake systems west ofthe Rockies. [t is a very dynamic system with water levels changing every year. The interconnectivity of the lakes and wate/ways makes carp control an on-going battle. For the Birds Historically, Malheur Lake was home to large colonies of nesting waterbi rds, host to tens of thousands of nesting waterfowl and a resting stop for migratory shorebirds. In 1908, President Theodore Roosevelt established the Lake Malheur Reservation "as a preserve and breeding ground for native birds." The reservation encompassed over 80,000 acres around Malheur, Mud and Harney Lakes for migratory waterfowl. Today, it is known as Malheur National Wildlife Refuge, and protects over 187,000 acres of habitat, including wetlands, riparian areas, meadows and uplands. Hi'lOrically, abolll 35% oJ the Pacific Flyway's canvasback duck population used Malhellr Lake. In Jact, the lake produced approximately 400, 000 ducks, 75,000 geese and 3,500 swans, and ranked as One of the most productive waterfowl areas in NOl1h A merica. us.Fjsh &.. IVild/{e Service In 1908, William Finley photographed a white pelican breeding colony on Maiheur Lake. Finley - and his photos - were instrumental in early recognition of the importance of the lakes, riparian streams and marshes in the Hamey basin to shorebirds, warerbirds and wateifowl. A refuge fish biologist and a University of Minnesota researcher place a radio telemetry tag in a carp specimen. With tagging, scielllists can develop population estimates as well as locate carp willlering and spawning areas. u. s. Fish &,. Wildlifi: Serl'ice A Goal for the u ure ~Challenge of carp control is not insurmountable. { National Wildlife Refuge is working to restore the basin's aquatic health in order to fulfill its mission of providing feeding, nesting, and rearing habitat for migratory birds. This will be accomplished by working with partners to develop an efficient and sustainable carp control program for the entire basin using the best available science. ;:;~lheur Current Carp Control Techniques Refuge staff have been conducting carp control treatments since 1955. Since then, ongoing efforts to improve aquatic health on Malheur National Wildlife Refuge have included the use of chemicals, fishscreens, traps and barriers, and water draw downs. While all of these treatments have been effective, carp populations rebound within a few years without a basin-wide solution. In order for carp control to be a success, continuing studies on carp populations and their effect on aquatic food supplies will need to be completed. Complete eradication of common carp will not be possible in all waterways, but huge strides can be made in control. u.s. FISH & WILDLIFE SERVICE A juvenile pied-hilled grehe swims alone on a wetland. Grebes feed heavily on insects, small fish and crustaceans hy diving below the surface.

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