1. Read Sections 11.1 and 11.2 (skip Section 11.2.2) in Introductory Fisheries Analyses with R and these notes and consider the items below.
• Define A, Ct, Ct+1, and Z.
• What is the formula for computing annual mortality from catches that are separated by a single year?
• Describe the difference between longitudinal and cross-sectional catch-at-age data.
• What must be true for a vector of consecutive catches-at-age to be equal when extracted from longitudinal and cross-sectional data.
• What is the equation for the “catch-curve” model (that shows how catch is related to time)? Show how this equation can be linearized.
• How is Z estimated from catch-curve data?
• How is A estimated from Z?
• What is the characteristic shape of catch curve data? Specifically, identify three regions on the curve.
• Why does the catch curve have the shape described in the previous question?
• What are the assumptions of a catch curve model for estimating Z?
• What R function can be used to efficiently perform a catch curve estimate of Z?
• What R function is used to extract the estimates of Z and A from this function?
• What R function is used to extract confidence intervals for Z and A from this function?
2. Read Miranda and Bettolli (2006) Sections 6.1-6.3 (the complete reading) and consider the items below.
• What is “mortality”?
• What is the characteristic shape of catch curve data? Specifically, identify three regions on the curve.
• Why does the catch curve have the shape described in the previous question?
• What are the assumptions of a catch curve model for estimating Z?
• What assumption about recruitment is made for a catch curve? Is this a realistic assumption? How do modest violations of this assumption affect the estimates of Z?
• How large of a sample is needed for a catch curve analysis?
• What is a weighted catch-curve analysis?