We are seeing many species struggle with rising global temperatures amidst climate change. However, multiple studies have shown that the rainbow trout (Oncorhynchus mykiss) has an impressive ability to acclimate to these changes. The rainbow trout is a cool-water species native to the northern Pacific and its tributaries (National Park Service 2015).
Photo courtesy of the Ohio Department of Natural Resources.
A study by Adams et al. (2022) used a population of 3,000 hatchery trout to assess their thermal acclimation potential. The fish were separated into tanks and tested at a range of temperatures from 15-25 degrees Celsius. Despite being a cool-water species that prefers waters below 20 degrees Celsius, the results found that the fish were able to consistently acclimate to temperatures above 20 degrees.
Li et al. (2024) conducted a similar study by testing the mitochondria and livers of rainbow trout after acclimating them to warmer temperatures. They found that acclimation can greatly reduce liver damage and improve mitochondrial function when the trout are exposed to increased temperatures.
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Despite only being native to the Pacific, rainbow trout are stocked throughout the US and other countries as a valuable sport fish. Their ability to acclimate to a warming climate will be a useful tool for managing fish species in the future.
Sources:
Adams OA, Zhang Y, Gilbert MH, Lawrence CS, Snow M, Farrell AP (2022) An unusually high upper thermal acclimation potential for rainbow trout. Conservation Physiology 10(1).
Li H, Yu H, Zhang X, Huang W, Zhang C, Wang C, Gao Q, Dong S (2024) Temperature acclimation improves high temperature tolerance of rainbow trout (Oncorhynchus mykiss) by improving mitochondrial quality and inhibiting apoptosis in liver. Science of Total Environment 912.
Rainbow Trout. National Park Service. https://www.nps.gov/shen/learn/nature/rainbow-trout.htm
Rainbow Trout. Ohio Department of Natural Resources. https://ohiodnr.gov/discover-and-learn/animals/fish/rainbow-trout