Pacific lamprey, an ancient, eel-like fish species, are seeing returns 170 percent higher than the 10-year average at Bonneville Lock and Dam this year.  U.S. Army Corps of Engineers biologists say Lamprey numbers are also 252 percent higher than the four-year average.  So far, fish counters have tallied 63,863 lampreys moving through the fish ladders during the daytime at Bonneville as of last Monday.  The 10-year average daytime fish ladder count total is 41,414.  Corps biologists are optimistic about the numbers they’re seeing, crediting ongoing efforts to modify fishways to make them more “lamprey friendly.”  Lamprey are also very active at night and pass via special ramp-like lamprey passage structures, so daytime counts are just minimum estimates, and tribal biologists collect many lampreys at Bonneville for upstream transport to tributaries such as the Umatilla, Clearwater and Yakama rivers.  So far, most of the Corps’ work has focused on fixing adult lamprey passage at the dams, but agency biologists are also now studying downstream passage of juvenile and larval lamprey at the dams so they can better understand how operations and structures may affect passage and survival of these life stages.