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

Predicting barotrauma susceptibility for downstream passage at river infrastructure (#96)

Brett Pflugrath 1 2 3 , Craig Boys 4 , Bruce Cathers 2
  1. Pacific Northwest National Laboratory, Richland, WA, United States
  2. Water Research Laboratory, University of New South Wales, Manly Vale, Sydney, New South Wales, Australia
  3. Fisheries , New South Wales Department of Industry, Taylors Beach, New South Wales, Australia
  4. Institute of Land Water and Society, Charles Sturt University, Albury, New South Wales, Australia

When fish pass downstream through river infrastructure, such as dams and weirs, barotrauma may
occur due to a rapid decrease in pressure. In severe cases, barotrauma may lead to mortality.
Different species are likely to respond very different to these rapid decreases in pressure. Therefore,
to predict barotrauma for a specific species, surrogate species may not be a valid approach, and it
may be necessary to examine each species individually. For this study, Australian bass and carp
gudgeon were exposed to a range of rapid decompressions using hyper/hypobaric hydro-chambers
and examined for injuries and mortality. Rapid decompression data from these two species, in
addition to previously examined Murray cod and silver perch were evaluated to determine which
injuries were highly associated with and likely to predict mortality. Dose-response logistic
regressions models were developed for each species to predict injury and mortality over a range of
rapid decompressions. These models are a valuable tool for estimating injury and mortality rates for
fish passing though river infrastructure and can be applied to specific sites where pressure profiles
have been developed. Applying these models to current and future infrastructure can provide
important insight into what measures or design alterations may be necessary to directly reduce the
negative impacts of river infrastructure on fish populations.