Spatiotemporal variation of environmental conditions and prey availability that drive Arctic nearshore fish community structure in the Point Barrow, Alaska, region

Abstract

The Arctic nearshore surrounding Point Barrow, Alaska, is a dynamic system with complex oceanographic and meteorological processes that drive community composition to change rapidly in space and time. Nearshore fish and zooplankton communities were sampled in the summers of 2013–2015. Spatial, temporal, environmental, and biological drivers of fish community structure in the Arctic nearshore surrounding Point Barrow were investigated using multivariate canonical correspondence analysis (CCA). A CCA model using the 13 most explanatory variables (three environmental, one spatial, four temporal, and five zooplankton abundances) explained 73% of the variance in community structure in this region. Distinct fish communities were identified within the three waterbodies that were studied (Chukchi Sea, Beaufort Sea, and Elson Lagoon), and these distinctions were largely driven by salinity. Species move into the nearshore at various times after landfast ice breaks up, creating an annual succession of species that can be found in these nearshore habitats. Low-latitude species tend to become abundant later in the summer season, whereas true Arctic species are present under the ice or move in shortly after breakup. Arctic species are also more abundant in colder years, whereas low-latitude species dominate during warmer years. The increasing abundance of low-latitude species in the Arctic nearshore may have serious implications for the food webs in these ecosystems as climate change continues.