The study examined lakes in Wyoming’s Wind River Mountains, a region of the Rocky Mountains with historically fish-free glaciers, alpine mountains, and alpine lakes. Beginning in the early 20th century, wildlife managers began releasing trout into lakes for fishing enthusiasts, and as a result, the zooplankton that inhabited the lakes evolved into smaller ones as the larger plankton became food for fish. .
Over the summer of 2018-2021, the researchers collected hundreds of fish from 18 high-elevation lakes and collected information on lake size, depth, elevation, vegetation and history of fish stocks. . They then compared the fish they found to fish born in hatcheries in Wyoming.
It turns out that lake fish have more esophageal bone or cartilage structures called gill scrapers, allowing them to pump more plankton into their stomachs. Researchers found more and longer gill paddles in the esophagus of lake-dwelling fish that were released decades ago. They suggest that this structure evolved as a result of the need for fish to forage in zooplankton-rich lakes, and that natural selection allowed fish with body structures that allowed them to gather as much zooplankton as possible. I think that was preferred. The researchers wrote that this evolution probably occurred due to these external pressures rather than simply random genetic mutations.
The pace of change varies from lake to lake, with some fish taking 47 years to develop more gills, while others did not develop more gills 88 years after they were first released into the lake habitat. there was.
Overall, however, the researchers say, evolutionary changes occur rapidly, which may indicate that some animals can respond quickly to human-induced changes in other habitats. They call for further research on whether fish in other lakes evolved similarly, or as rapidly.
