Characterizing phenotypic diversity in marine populations of the threespine stickleback

The threespine stickleback (Gasterosteus aculeatus) is an important model for studying the evolution of vertebrate morphology. Sticklebacks inhabit freshwater, brackish, and marine northern hemisphere waters. Anadromous and marine populations (hereafter marine) are assumed to have remained unchanged morphologically from ancestral marine sticklebacks, despite marine environments varying on regional and local scales. Recent studies suggest that genetic and phenotypic structure exists in marine populations, yet the scale of this variation, and its ecological causes remain unclear. Our goal was to assess morphological trait variation in marine stickleback populations around Southern British Columbia (BC) and determine if oceanographic and habitat characteristics were associated with this variation. Between May-July 2019, we sampled 534 sticklebacks from 15 sites around Vancouver Island, a region characterized by a large diversity of oceanographic and habitat features. We characterized trait..., General Methodology of the Project
Between May – July 2019, a total of 534 fish were collected from 15 sites around Vancouver Island and Southern BC, Canada. At each site, sticklebacks were caught with beach seines at 1–2m depth and 2–3m offshore, or with un-baited minnow traps. We sampled in all four oceanographic regions of Vancouver Island: the Strait of Georgia, the Juan de Fuca Strait, and the western and northern coasts of Vancouver Island. Within each region, we sampled from three different coastal habitat types: tidal flats, salt marshes, and lagoons.
Stickleback Head and Body Photograph Files
The original image files were converted into tps format using the software tps.Util version 1.61, and then organized into files for superimposition. The tps images were uploaded into tps.Dig version 2.05 to digitize landmarks on the head and body photographs. The TPS files are included as well, labelled as “All_Body_Fraser_El-Sabaawi.TPS” and “All_Head_Fraser_El-Sabaawi.TPS”. For the head ..., Programs: tps.Util version 1.61 and tps.Dig version 2.05. 
In R, we used the landvR package and the geomorph package.