Survival and divergence of Arctic endemic cod species during 50,000 years of climate change.

Two Arctic endemic cod species, Arctogadus glacialis and Boreogadus saida, lived at 87-89°N during 48,000-35,000 years ago and reappeared at 12,000 years ago.

• Why it matters: Understanding how Arctic fish species survived past climate variability addresses gaps in knowledge about ecosystem resilience and adaptation during glacial periods.
• What they did: Researchers analyzed fish otoliths preserved in deep-sea sediments, revealing the presence of these species at high latitudes during specific periods of the last 50,000 years.
• The result: Findings suggest the glacial Arctic Ocean was a breeding ground for cold adaptation, indicating refugia enabled survival and divergence of these species under extreme climate conditions.