Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

Injury and Mortality of Two Mekong River Species to Turbulent Shear Forces (#97)

Alison Colotelo 1 , Robert Mueller 1 , Ryan Harnish 1 , Jayson Martinez 1 , Thonglom Phommavong 2 , Khamla Phommachanh 3 , Garry Thorncraft 2 , Lee Baumgartner 4 , Joshua Hubbard 1 , Briana Rhode 1 , Zhiqun (Daniel) Deng 1
  1. Pacific Northwest National Laboratory, Richland, WA, United States
  2. National University of Laos, Vientiane
  3. Living Aquatic Resources Research Center, Vientiane
  4. Charles Sturt University, Albury

Global hydropower development is one solution proposed to address an increase in energy needs. However, hydropower-related impacts on riverine ecology systems is not well understood. The Mekong River Basin (MRB) is one of the world’s largest waterways and is presently experiencing significant hydropower expansion. It is also one of the most biodiverse rivers; serving as home to many species that are blocked or hindered by the development of dams. One source of injury and mortality for downstream moving fishes is passage through the turbine environment where fishes may be exposed to a number of physical stressors (e.g., shear forces, rapid decompression, blade strike and turbulence). The current study sought to understand the susceptibility of blue gourami (Trichopodus trichopterus) and iridescent shark (Pangasianodon hypophthalmus) to shear forces. Fishes were exposed to an underwater jet with velocities up to 21.3 m/s (equating to strain rates of up to 1,185 s-1). Fish were assessed for behavioral effects, injuries, and mortality. Overall, it was determined that both species were susceptible to shear forces and the effects were more pronounced at higher strain rates. Gouramis were more susceptible than sharks. To minimize impacts on these species, shear forces within turbines should not exceed critical limits.