Hot of the press! Fish Futures’ Angus McIntosh, Jonathan Tonkin and Nixi Boddy with former University of Canterbury MSc student Olivia Hore looked into how stream flow and predation impact native freshwater fish.
They created this easy-to-follow handout as well as an open-access manuscript.
Overall, the research came about because non-migratory galaxiids were sometimes found in streams with lower flow, but rarely found in streams with a lot of trout, and we wanted to investigate if there was an interaction between these two things.
They found that although low-flow conditions reduce predatory effects of non-native trout on populations of native galaxiids, populations of these native fish were also suppressed by the low flow.
Thus, to conserve native fish, we should aim to restore and protect natural flow regimes to maintain suitable fish habitat, as well as actively manage the harmful effects of non-natives. Removing water is likely to have net harmful effects on both types of fish.
