1. Read Sections 5.1-5.4 (skip 5.4.1-5.4.3 unless you plan to do the XC homework) in Introductory Fisheries Analyses with R and these notes and consider the items below.
    • Describe what an “age sample” is.
    • Describe two ways in which fish in the age sample can be selected. Which way is more common in practice? Why?
    • Describe the age-length key … specifically what type of data forms the rows, what type of data forms the columns, what is the meaning of a value in a cell, what do the rows sum to, what to columns sum to?
    • Describe what a “length sample” is.
    • Describe how fish are selected for the length sample.
    • Describe the Isermann and Knight (2005) method for assigning ages to individual fish in the length sample.
    • Which R functions are used to construct the age-length key. What are the arguments to these functions?
    • Which R function is used to visualize an age-length key. What are the arguments to this function?
    • Which R function is used to assign ages (as prescribed by a age-length key) to individual fish in the length sample. What are the arguments to this function?