First juvenile Chum Salmon confirms successful reproduction for Pacific salmon in the North American Arctic

The distributional extent of Pacific salmon Oncorhynchus spp. in the North American Arctic is unresolved. While adult Pacific salmon have a recurring presence across the Alaskan North Slope and into the Canadian Arctic, it is uncertain if these fish are part of established Arctic populations, vagrants from outside sources reproducing unsuccessfully, or both. Here we present the first confirmed record of a juvenile Chum Salmon O. keta captured in the nearshore marine ecosystem in the North American Arctic. This provides the first scientific evidence of successful spawning and early marine survival of Pacific salmon in the North American Arctic. It was caught near Kaktovik, Alaska in August 2017 with a group of similarly sized age-0 Mackenzie River Arctic Cisco Coregonus autumnalis. Stable isotope and otolith microchemistry analyses are consistent with use of the nearshore estuarine corridor from the Mackenzie River west along the northern coast. This contributes critical information needed to identify, manage, and conserve biodiversity at the northern range edge, and will help to clarify the status of Pacific salmon as potentially emerging fisheries develop in the North American Arctic due to climate warming.