Why are there less and less salmon?

In October, I visited a local stream to observe the seasonal salmon run, where salmon swim upstream to lay their eggs. However, the guide explained that both the number and variety of salmon have declined significantly compared to previous years due to rising water temperatures and habitat loss. Salmon are highly sensitive to temperature changes and cannot survive beyond a critical threshold. As global warming continues, fewer salmon may be able to migrate and reproduce. This experience was a reminder of how climate change disrupts entire ecosystems, affecting not just one species but the delicate balance of nature itself.