July 19, 2023 — This summer is a colder, rainier, and buggier season in Bristol Bay, and across Alaska. Meanwhile, last week the world faced four straight days of the hottest temperatures on record, marking Earth’s extreme warming.
The biggest challenge of climate change for Bristol Bay salmon isn’t necessarily warming temperatures right now. It is the variability, said Bill Templin, Chief Salmon Fisheries Scientist for Alaska Department of Fish and Game.
“You know, climate change isn’t just directional. It’s not just that things are warming, it’s also that there’s greater variability in the systems,” he said.
Templin believes these cold, wet, stormy summers are a product of climate change too.
“There can be a wider swing of hot and cold or dryness, drought, flooding, excessive water in the systems,” said Templin. “That variability makes it hard for an organism to adapt to the changes which can lead to reduced productivity from systems that are otherwise healthy, with healthy habitats and low fishing pressures.”
What does that mean for salmon?
There’s some good news. Starting in freshwater, where salmon return to spawn and remain the first year of life, Bristol Bay’s deep lakes provide a natural buffer to temperature changes.
“So it seems like the lakes are really this big buffering mechanism,” said fisheries ecologist and researcher Daniel Schindler with the University of Washington’s Alaska Salmon Program. That’s critical for the salmon’s success.
Freshwater lakes are deep and stratified, meaning temperatures of the water are warmer at the surface going down to cooler at the bottom. Salmon can dive deep and escape warmer surface temperatures. According to Schindler, that means they can return to spawn earlier if ocean temperatures are too warm, like the birth ward at the hospital.