Morphometric trait measurements of Arctic char in foothill lakes of arctic Alaska ...

• Main Author: Klobucar, Stephen
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: Arctic; Lester; Alaska
• Online Access: https://dx.doi.org/10.5061/dryad.80gb5mkqc; https://datadryad.org/stash/dataset/doi:10.5061/dryad.80gb5mkqc

Polymorphism facilitates coexistence of divergent morphs (e.g., phenotypes) of the same species by minimizing intraspecific competition, especially when resources are limiting. Arctic char (Salvelinus sp.) are a Holarctic fish often forming morphologically, and sometimes genetically, divergent morphs. In this study, we assessed the morphological and genetic diversity and divergence of 263 individuals from seven populations of arctic char with varying length-frequency distributions across two distinct groups of lakes in northern Alaska. Despite close geographic proximity, each lake group occurs on landscapes with different glacial ages and surface water connectivity, and thus were likely colonized by fishes at different times. Across lakes, a continuum of physical (e.g., lake area, maximum depth) and biological characteristics (e.g., primary productivity, fish density) exists, likely contributing to characteristics of present-day char populations. Although some lakes exhibit bimodal size distributions, using ... : We sampled arctic char in 2016 (May-Sept) and 2017 (May) via gill nets and hook-and-line sampling. We used eight panel, experimental benthic gill nets (gill net mesh size range = 18 – 64 mm; Lester et al. 2009) set perpendicular to shore on the lake bottom, which extended from the littoral zone to bottom depths in open water areas, and checked nets every half hour to minimize mortalities. We conducted hook-and-line sampling alone through the ice (May) and concurrently with gill nets during open water periods. We used a mix of hook-and-line methods (e.g., lure size), in addition to experimental gill nets, to sample char across sizes classes. We sampled all lakes at similar time periods and used same sampling methods at each lake. Therefore, we are confident we sampled across all fish greater than approximately 115 mm (but see Finstad and Berg 2004).. For example, hook-and-line sampling was conducted both littoral and in open water habitats throughout the water column. For each arctic char captured, we ...