Read this and answer the following questions. [Note that the reading in the next section may also be helpful for some of these questions.]

  1. Describe what an “age sample” is.
  2. Describe two ways in which fish in the age sample can be selected. Which way is more common in practice? Why?
  3. 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 rows sum to, what do columns sum to?
  4. Describe what a “length sample” is.
  5. Describe how fish are selected for the length sample.
  6. Describe the Isermann and Knight (2005) method for assigning ages to individual fish in the length sample.

Read Sections 5.1-5.4 in Ogle (2016)1 and answer the following questions.

  1. Which R functions are used to construct the age-length key. What are the arguments to these functions?
  2. Which R function is used to visualize an age-length key. What are the arguments to this function?
  3. 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?

  1. Don’t spend much time with the R code or statistics in Section 5.2.3, just try to get the idea of what a smoothed ALK is trying to accomplish. ↩