An AI-based Atlantic cod detection in an Arctic fjord: Linking Atlantic water intrusions to the cod (Gadus morhua) incursions
Vol.16,No.1(2026)
The Arctic Ocean is undergoing unprecedented environmental transformation, characterized by accelerated warming, reduction in sea ice cover, and altered oceanic circulation. These shifts are facilitating the poleward migration of boreal species, a process termed ’borealization’, which is fundamentally restructuring Arctic marine ecosystems. Kongsfjorden, a high-latitude glacial fjord in Svalbard, serves as a critical natural laboratory for observing these changes due to its position at the confluence of Arctic and Atlantic water masses. Historically dominated by the endemic polar cod (Boreogadus saida), the fjord is now witnessing an increasing presence of Atlantic cod (Gadus morhua). This study, conducted under the Indian Arctic Programme, deployed a novel, non-invasive, artificial intelligence (AI)-driven optical monitoring system to document the fish community. Our results reveal a direct correlation between abundance of Atlantic cod in the inner Kongsfjorden and an intense intrusion of warm, saline Atlantic Water (AW) in late summer 2024. In contrast, cod were nearly absent during in the early summer 2023 with weaker AW influence. These findings provide direct, high-resolution evidence for the oceanographic mechanism facilitating borealization in Arctic fjords and validate a new technology for sustained, long-term ecosystem monitoring in a remote and rapidly changing polar environment. The observed ecological shift signals a potential regime change that could restructure Arctic trophic interactions.
Arctic marine ecosystem; Atlantic cod; Polar cod; borealization; Atlantic water intrusion; deep learning
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Copyright © 2026 Prabhullachandran Lakshmi Devi, Felix Mattathil Philip, Divya David Thresyamma, Anupama Jims, Gipson Edappazham, Mohammed Syed Marjuk, Anil Raj