Host Fish Identification and Propagation Trials for Anodonta californiensis and A. oregonensis in the Columbia River Basin, Oregon

Western freshwater mussels, formerly widespread throughout the Pacific Northwest, have experienced population reductions in recent decades. In 2005 a survey of the Umatilla River, which runs through the Confederated Tribes of the Umatilla Indian Reservation (CTUIR), indicated much of the historic mussel population had been eradicated. Because sustainable harvest of freshwater mussels remains a treaty right, and Tribal members recognize the ecological importance of mussels in their river systems, CTUIR would like to restore mussel populations to the Umatilla River. We will use propagated mussels to test the feasibility of reintroduction methods and guide our restoration efforts. However, a lack of information about western freshwater mussel life histories and how to best propagate them hampered initial restoration efforts. Since 2005 host fishes for Anodonta californiensis have been identified as longnose dace, speckled dace, redside shiner, margined sculpin, and torrent sculpin.  Host fish for A. oregonensis have been identified as speckled dace, margined sculpin, redside shiner and Chinook salmon. Recent attempts to propagate western mussels have had mixed success, and juvenile mussel survival remains low. Future efforts will include testing additional propagation methods, as well as continuing to develop a broader understanding of host fish associations for additional western mussel species.