2.3 | Environmental Data
We collected temporal, hydrological, and thermal conditions associated
with each ichthyoplankton sample. We used Julian date to account for
temporal variation in larval fish presence based on seasonal variation
in spawning for each taxon, regardless of environmental conditions.
Next, we acquired hydrological data from United States Geological Survey
and United States Army Corps of Engineers gauging stations nearest each
site (Supplemental data). We calculated average weekly river discharge
(m3/s) and coefficient of variation (CV) of each
sample to estimate the magnitude and variability in hydrological
conditions prior to sampling. Finally, we calculated average and CV of
weekly river temperature (°C) using linear regression for each tributary
based on field water temperature observations compared to gauging
station values (Supplemental data).