Lake trout (Salvelinus namaycush) otoliths indicate effects of climate and lake morphology on growth patterns in Arctic lakes

Climate change is occurring rapidly in the Arctic, and an improved understanding of the response of aquatic biota and ecosystems will be important for this data-limited region. Here, we applied biochronology techniques and mixed-effects modelling to assess relationships among growth increments found on lake trout (Salvelinus namaycush) otoliths (N = 49) captured from 13 lakes on the Arctic Coastal Plain of northern Alaska, observed and modelled climate patterns, and individual-level fish and lake characteristics. We found that annual growth varied by year, fish growth slowed significantly as individuals aged, and females grew faster than males. Lake trout had higher growth in flow-through lakes relative to lakes that were perennially or seasonally connected. Annual growth was positively correlated with observed air temperature measurements from a local weather station for the period 1998-2014, but no clear warming trend was evident for this period. Modelled August air temperatures from 1978-2014 predicted lake trout annual growth (root mean squared error = 0.045 mm) and indicated increasing temperatures and annual lake trout growth over the period 1950-2014. This study demonstrated that biochronology techniques can reconstruct recent climate patterns and provide a better understanding of trends in Arctic lake ecosystems under a changing climate.