Figure 4.

Principal component analysis on the top seven seasonal environmental variables for our 11 sampling locations based on their loadings shows a clear separation of northern and southern sites along PC1. Win, winter; Spr, spring; Sum, summer; BS, bottom salinity; BT, bottom temperature; SS, surface salinity; ST, surface temperature (top panel). Sites classified as northern, southern, or admixed, based on Jeffery, DiBacco, Wringe et al. (2017) are clearly separated based on the environment alone, with admixed sites being intermediate to the northern and southern sites (bottom panel)