PCWA-L 480.pdf - PCWA Middle Fork American River Project ...

Creating a Summary - Analyzing Multiple
Cohorts
You might be interested in the overall characteristics of a fish that passes through more than one
life stage, or maybe you would like to determine the predation of a particular prey Item by more
than one cohort. Creating a summary allows you to combine the calculations of more than one
cohort into one file.
Why create a summary? To understand why a summary provides useful information about your
analysis, you must first recall the definition of a cohort. A cohort file represents a single species of
fish at a single life stage, such as an adult perch. The cohort can represent one fish or many fish.
But let's say that your anaiysis includes the same species of fish at two different life stages, ·and
you're interested in the total prey consumption by both life stages. You could create two separate
cohort files, generate consumption output for each cohort, and add the outputs manually. A
summary file makes this process easier.