Migrations Of Arctic Char, Most Northerly Freshwater Fish, Slow Or Stop As Water Warms
Arctic char, the most northerly freshwater fish on the planet, may struggle to survive as the polar climate warms, five years of research in western Nunavut suggests. Even shorter-term exposure to higher water temperatures could prove deadly to Arctic char, said Matt Gilbert in his PhD thesis, called “Thermal limits to the cardiorespiratory performance of Arctic char (salvelinus alpinus) in a rapidly warming North.”
During their lives, Arctic char are exposed to dramatic temperature changes from -1 C to 21 C. This means many Arctic char already encounter temperatures that are hard on their hearts and make it more difficult for them to recover from the vigorous exercise of upriver migration, said Gilbert, who studied Arctic char at Palik (Byron Bay), Halokvik (30-mile), Ekalluktok, Freshwater Creek, and Jayko River near Cambridge Bay.
“In general, when these fish are too hot, they can get lethargic, slow down, and possibly turn back during their migration to seek cooler water. When the water gets really warm they can even lose their ability to stay upright,” he told Nunatsiaq News.
Gilbert’s thesis detailed how Arctic char health declines when the fish are in water ranging in temperature from 14 C to 18 C. Consistently higher temperatures could even stop char from making their return migration to the lakes they spawned in, Gilbert said.
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https://nunatsiaq.com/stories/article/rising-water-temperatures-pose-risks-to-arctic-char-new-research/