Effects of environmental variables on a nearshore arctic fish community, 2001–2018

Nearshore fish communities comprise a fundamental component of Arctic marine ecosystems and serve as an important subsistence resource. As changing climate conditions affect Arctic waters, nearshore fish communities may also shift; however, how these communities will respond to climate change is not well understood. This study summarizes trends from a long-term (2001–2018) nearshore fish sampling program near Prudhoe Bay, Alaska, in the central Beaufort Sea. Abundance data ( n = 1.78 million fish) from daily sampling (July–August) at four fixed sampling locations showed distinct shifts in fish community metrics. Since 2001, annual species richness has significantly increased by approximately one species per decade ( p = 0.0167) while water temperature has warmed by approximately 1.4 °C. Results from non-metric multidimensional scaling (nMDS) and Permutational Analysis of Variance (PERMANOVA) models indicated that species composition based on biweekly catch data has significantly changed across years with distinct variations among sample locations and throughout the season. Salinity and water temperature were significantly related to multivariate species composition; specifically, the abundances of five species changed significantly over time. The species that increased in response to observed changes in the aquatic environment appear to be eurythermic and/or euryhaline generalist species such as Broad Whitefish Coregonus nasus and Saffron Cod Eleginus gracilis . Such patterns of altered species compositions demonstrate that continued long-term changes in environmental conditions will likely favor generalist species, potentially causing substantial shifts within the Arctic nearshore ecosystem with impacts on important subsistence resources.