Title
Life history patterns of Arctic Alaska Inconnu elucidated through Strontium otolith microchemistry
Author(s)
Kevin M. Fraley; Jason C. Leppi; Randy J. Brown; Martin D. Robards
Published
2023
Abstract
In Northwest Alaska, Inconnu (Stenodus leucichthys; Iñupiaq: Sii) are an important subsistence harvest species for rural and Indigenous Alaskans in both coastal and inland communities. For example, over 25,000 Inconnu are harvested annually in Kotzebue Sound. The migratory patterns and preferred habitats of these fish are well-documented for the freshwater spawning stage of their life cycle, but their estuarine and coastal movement patterns and habitat use are largely unknown. Observations of inconnu captured more than 200 km away from their normal range of Hotham Inlet (e.g., Ikpek Lagoon in Bering Land Bridge National Preserve and Cape Thompson in Alaska Maritime National Wildlife Refuge) have amplified calls to characterize life history patterns, in part to describe how the species may be responding to climate change and anthropogenic effects such as longer ice-free seasons and coastal industrial development. To ascertain this, we collected sagittal otoliths from fourteen adult inconnu from coastal lagoons within Cape Krusenstern National Monument. Using laser ablation isotope microchemistry, we analyzed strontium isotope ratios across each otolith core-to-edge chronology to infer stock of origin (by comparing with seven spawning stock reference samples) and habitat use during the lives of each fish. Preliminary results indicate that inconnu in the lagoons originate from both Kobuk (50%) and Selawik (29%) River spawning stocks, though some fish were unable to be assigned (21%). Otolith microchemistry chronology indicates that these fish spend the majority of their early lives in brackish environments, returning to freshwaters to spawn multiple times after reaching maturity. However, several distinct life history strategies were identified, including putative saltwater occupancy. Analyses are ongoing for these inconnu, as well as for other Coregoninae species collected from coastal lagoons, but these data represent novel information about the life history patterns of this important subsistence-harvested fish.

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