As the mercury climbs this weekend, water temperatures are also expected to increase. Warmer waters can spell bad news for salmon, especially if the temperatures stay warm for long periods of time.

For salmon, temps above 68 degrees Fahrenheit can be dangerously warm. The fish will often take refuge in cooler areas, like tributaries.

“As we see river temperatures warm, fish might have less access to those types of habitats that they would be seeking out. That’s the risk, is that everything is warming up, and they’re not going to find those nice, cool places where they can hang out and do their thing,” said Alison Colotelo, a fisheries biologist at Pacific Northwest National Laboratory.

Source: Heat Brings Concern For Northwest Salmon And Water Temps, As Memory Of 2015 Die-Off Looms | Northwest Public Broadcasting