Larval Lamprey Assessment at Wapato and Sunnyside Fish Screening Facilities

Larval Lamprey Assessment at the Roza Dam Forebay and Yakima River Delta Region, 2015

In 2015, Pacific Northwest National Laboratory and staff from the Yakama Nation conducted deep water larval lamprey surveys near the Roza Dam Diversion Fish Screening Facility and at the Yakima River delta region to determine lamprey occurrence and provide a general assessment of substrate composition. Results from surveys indicated that very few larval lamprey are inhabiting regions just upstream of the Roza Diversion facility although suitable substrates are present and abundant. At the Yakima River delta, larval lamprey searches were conducted at three general areas consisting of the main river channel and delta regions to the north of the mouth. Most of the substrates in this region had significant macrophyte...

Summary of Pacific Lamprey Salvage Efforts from Dryden Diversion Maintenance Operations (Wenatchee River, Dryden, WA)

Dryden Diversion is an irrigation diversion on the Wenatchee River (river km 27.8, 1.75 mm mesh-size fish screens) which entrains many thousands of larval/juvenile Pacific Lamprey each year. The Yakama Nation (YNPLP) assisted with Pacific Lamprey salvage operations 1) when the canal was dewatered (October 12 and 13, 2015) and 2) during dredging operations in the canal forebay area upstream of the headgate (March 4, 2015). Part I: Dryden Diversion was dewatered on October 12, 2015 and lamprey salvage efforts in the canal occurred on October 12, 13, and 14, 2015, by Chelan County PUD (CCPUD), the YNPLP, US Fish and Wildlife Service (USFWS), and Washington Department of Fish and Wildlife (WDFW). Through our collective...

Effects of suction dredge mining on freshwater mussels

Suction dredge mining can can affect all life stages of freshwater mussels. Mussels are harmed directly through physical injury or mortality, interference with reproduction and feeding, and inability to excavate themselves and/or regain a natural orientation in the substrate after being entrained and covered by tailings; and indirectly through habitat loss and water quality degradation. The damage to substrate used by mussels can last more than one season. These direct and indirect effects are likely to reduce the size and resiliency of freshwater mussel populations.