UCC study shows climate change impacting native trout
A study by the Environmental Research Institute at University College Cork shows that climate change is impacting the lives of native trout species.
The study found that increased water temperatures and reduced food supply strongly affect where trout decide to live — with more opting to stay in rivers as things heat up.
This could seriously decrease the sea trout population as the climate continues to change, according to the researchers, who examined how the changes influence the migration of brown trout.
They reared young wild trout for two years under conditions of reduced food and increased temperature, and then recorded the numbers of future sea-going migrants.
The study found that food reduction increased the numbers of migrating fish, but warm temperatures had the opposite effect. Fewer fish chose to migrate to sea, instead remaining resident in freshwater.
Lead author on the study, Louise Archer, said brown trout are iconic for their ability to undertake impressive migrations to sea, yet little is still known about why some fish choose to migrate, and why others remain resident in freshwater rivers and lakes.
The study noticed that fish choosing migration were smaller and in poorer condition than those that remained in freshwater, indicating sea migration occurred when the fish urgently needed to consume more food.
How will the fish balance this with the urge to remain in the ever warmer rivers was one of the questions examined.
Louis Archer said understanding how climate change will affect migratory “sea trout” is crucial to successful management and conservation of the species, particularly since many sea trout populations have shown dramatic declines across Europe in recent years.
“Our study sheds some light on this enduring question by highlighting how warming temperatures cause fewer fish to migrate to sea, with more fish remaining in freshwater to reproduce earlier.
“Worryingly, our research suggests that with climate warming, we may see further declines in sea-going trout,” she said.
The study findings by the UCC researchers was published in Global Change Biology, a monthly peer-reviewed scientific journal covering research on the interface between biological systems and all aspects of environmental change that affect a substantial part of the globe.
