• Amongst all freshwater organisms, Brown trout Salmo trutta and Atlantic salmon Salmo salar are particularly vulnerable to extreme temperatures in both winter and summer, and potentially also to extreme flows. The geographical location of Wales at the South West edge of the European range for these two species means that populations here could be among the first to be seriously impacted or even extirpated should climatic tipping points be reached.ÊÊ
  • Apparently widespread impairment to salmonid spawning and/or recruitment occurred in Welsh rivers in 2015/16, manifest as dramatically reduced fry numbers during juvenile surveys during summer 2016. In some rivers, parr numbers were also reduced markedly. These patterns imply potential effects on two year classes and followed unusually high temperatures during periods critical to spawning (December 2015) as well as exceedingly high flows during December 2015.ÊÊ