Against all odds: Arctic squid (Cephalopoda, Oegopsida: Gonatus fabricii) reproduce under ice in the central polar Basin

Gonatus fabricii is the most abundant cephalopod in the Arctic. Its biomass equals that of commercial fishes in the Nordic Basin and supports many predators. It is the only squid that reproduces in the Arctic, where its spawning is known from several geographically confined areas. However, relevant records from the most northern part of its distribution are restricted to one spent female and one paralarva that were both caught in the early 1960s. We describe the reproductive characteristics of a spent female that was encountered at the surface (= ice mooring) in the Amundsen Basin in 2023. It confirms that G. fabricii has low potential (8800–16200 oocytes) and realised fecundity (25–28 % of potential fecundity, 2500–3000 oocytes) compared to most other studied deep-sea squids. Combining this observation with historical records (from 1960s to 2020), we show that G. fabricii might reproduce in the Central Polar Basin, and suggest a spawning area of G. fabricii that encompasses the central Amunsden Basin, eastern Lomonosov Ridge and eastern Makarov Basin. These records demonstrate that G. fabricii is the only nekton species that reproduces in the deep waters of the Central Polar Basin. The Central Polar Basin is the only spawning area of G. fabricii , where its two main whale predators (sperm whale and northern bottlenose whale) do not occur. The absence of predators’ pressure may be among the main reasons that drove G. fabricii from the warmer and more productive Nordic Basin to the colder and less productive Central Polar Basin. • G. fabricii reproduces in the deep-sea areas of the Central Polar Basin. • This squid is the only nekton species that is able to do so. • Predators potentially are among the main drives of origins of this spawning area. • Potential and realised fecundity of G. fabricii are lower than in majority of deep-sea squids.