Mortality Components

- Read Miranda and Bettolli (2006) Section 6.6 (the complete chapter) and consider the following items.
- Define Z, F, M, and μ.
- What is the relationship between Z, F, and M?
- Explain how the regression between Z and fishing effort can be used to estimate M. What are some problems with this method.
- Explain how the catch-curve methods of the last module could be used to estimate M.
- Explain how mark-recapture data can be used to estimate F (carefully explain what else must be know for this method to work).
- Explain what is meant by “meta-analysis to estimate M, F, or Z.”

- Read Section 11.4 in
*Introductory Fisheries Analyses with R*and consider the items below.- Define Z, F, M, and μ.
- What is the relationship between Z, F, and M?
- Explain what is meant by “meta-analysis to estimate M, F, or Z.”
- What are the five methods to estimate M or F according to Miranda and Bettoli?
- Explain the meta-analytic method for estimating M proposed by Then
*et al.*(2015). - What R function is used to compute the meta-analytic estimates of M? What argument is used to compute the estimate of M proposed by Then
*et al.*(2015)? - Check out this online tool that provides meta-analytic estimates of M.

- Read Allen and Hightower (2010) Mortality (most of the complete chapter) and consider the following items.
- Define A, S, Z, F, M, μ, m, and n (make sure to look at my post-it notes about the cf and cm variables).
- Explain how mortality rate changes with age from hatch through late adulthood.
- What kind of management actions can be enacted to control F?
- What is the difference between finite and instantaneous rates? Identify each of the following as a finite or instantaneous rate … A, S, Z, F, M, μ, m, and n.
- Describe what abundance (y-axis) versus time (x-axis) would look like if one followed a cohort (i.e., year-class) of fish through time.
- How is S computed from two measures of abundance separated by one year?
- How is A computed from S?
- Describe the difference between a discrete (Type I) and continuous (Type II) fishery.
- How is μ calculated in a continuous fishery?
- How is A computed from m and n in a continuous fishery? Why is the product of m and n included in this computation?

- Read Miranda and Bettolli (2006) Sections 6.8-6.10 (the complete chapter) and consider the following items.
- Define Z, F, M, and μ.
- How is “additive mortality” defined?
- How is “compensatory mortality” defined?
- What does “additive mortality” look like in a plot of A versus μ?
- What does “compensatory” look like in a plot of A versus μ?
- How might the realization that compensatory mortality exists and an understand of how it exists influence management decisions?
- Define “accuracy” and “precision.”
- What are suggested sample sizes for catch curve analyses?
- While it is not clear in the reading, what is your best guess from the context of the reading what F
_{0.1}is? - What are management tools (i.e., regulations) commonly used to modify fishing mortality?
- What is the greatest difficulty in estimating mortality?