Pacific lampreys are seeing returns 170% higher than the 10-year average at Bonneville Lock and Dam this year, according to the U.S. Army Corps of Engineers.
Lamprey numbers are also 252% higher than the four-year average, per biologists who report the number of fish counted as they migrate upstream past mainstem Columbia and Snake river dams.
Fish counters tallied 63,863 lampreys moving through the fish ladders during the daytime at Bonneville as of Sept. 18. The 10-year average daytime fish ladder count total is 41,414.
“We have seen some improvements in lamprey passage success at some dams, thanks to ongoing efforts to modify fishways to make them more ‘lamprey friendly,’” said Sean Tackley, a Northwestern Division Fish Policy and Program manager. “Our Tribal and federal partners have been critical in helping us make these improvements, and the Tribes continue to lead lamprey restoration efforts throughout the Columbia Basin.”
Many now recognize Pacific lamprey for their ecological and cultural significance in the Columbia River Basin. The Columbia River Inter-Tribal Commission (CRITFC) notes that the fish “provided an important source of food for the tribes of the Columbia River Basin, who prized them for their rich, fatty meat. They were served alongside salmon at tribal feasts and celebrations.”
Lampreys are also very active at night and pass via ramp-like lamprey passage structures, so daytime counts are just minimum estimates. Additionally, tribal biologists collect many lampreys at Bonneville for upstream transport to tributaries such as the Umatilla, Clearwater and Yakama rivers. USACE staff estimate the actual total number of lampreys passing the dam this year is probably closer to 165,314.
“Although we’re encouraged by this year’s numbers, we know a lot of this is driven by ocean conditions and food availability in the Pacific Ocean,” stated Tackley. “These kinds of years motivate us all to continue to do what we can to help these important fish.”
Since the 1990s, USACE has used funding to study lamprey passage behavior, develop new and effective passage structures, and modify fish ladders at the eight lower Columbia and lower Snake river dams so they work for both salmon and lampreys. These efforts have included Tribes and several other federal agencies. For instance:
CRITFC conducts translocations, genetic monitoring, Hood River natural recolonization, artificial propagation and contaminant accumulation;
The Bonneville Power Administration funds translocation programs for Tribal partners; lamprey specific passage improvements; artificial propagation research; and other research, monitoring and evaluation programs; and
The U.S. Fish and Wildlife Service (USFWS) works with Tribal, state and federal partners through the Pacific Lamprey Conservation Initiative by assessing population status and threats; conducting and funding research, monitoring and restoration actions; facilitating and participating in technical, management and policy forums; and advocating for Pacific lampreys as a cultural and ecologically critical species through outreach and education.
So far, most of the USACE work has focused on fixing adult lamprey passage at the dams, but agency biologists are also studying downstream passage of juvenile and larval lampreys at the dams so they can better understand how operations and structures may affect passage and survival of these life stages.
