Read Sections 7.1-7.4 in Ogle (2016) and answer the following questions.

  1. What are five things that weight-length relationships are used for?
  2. Which are more precise – length or weight measurements? Explain.
  3. What is the difference between a common and natural logarithm?
  4. Why is linear regression inappropriate to model weight-length data?
  5. Weight-length data follows what kind of function for most fish species?
  6. Demonstrate how this function is transformed to a linear function?
  7. What parameter does the slope of the transformed model represent?
  8. What R function is used to fit a linear regression?
  9. What R function is used to extract the regression parameter estimates?
  10. What R function is used to extract the regression parameter confidence intervals?
  11. What R function is used to determine if there is a significant relationship between weight and length (or their transformed values)?
  12. How does one check whether the assumptions of a linear regression have been met or not?
  13. What does it mean about fish shape over time if the slope parameter is equal to 3? If it is not equal to 3?

Read Pope and Kruse (2007) pages 424-425 and answer the following questions

  1. What are the two things the weight-length relationships have historically been used for?
  2. Weight-length data follows what kind of function for most fish species?
  3. Demonstrate how this function is transformed to a linear function?
  4. What type of values does the b parameter usually take?
  5. What value of b is indicative of allometric growth?
  6. Define allometric growth?
  7. What kinds of “things” can impart a bias in the weight-length relationship?

  1. Read Chapter 8 in Ogle (2016) and these notes and answer the following questions.

  2. What are the three most common condition indices?
  3. What is the formula for Fulton’s condition factor?
  4. What fundamental assumption about fish “growth” does Fulton’s condition factor make? Why does this make this metric largely useless?
  5. What is the formula for the relative condition factor of LeCren?
  6. What is the primary limitation for using the relative condition factor?
  7. What is the formula for a relative weight?
  8. What possible relationship with condition should be checked for before computing an overall measure of condition for a stock of fish?
  9. What R function is used to find the coefficients of the standard weight equation for a given fish species? What are the arguments to this function?
  10. What statistical test can be used to compare mean relative weights among Gabelhouse length categories?

Read Pope and Kruse (2007) Sections 10.1, 10.3, 10.6, & 10.7 (the complete chapter is here) and answer the following questions.

  1. What is “condition” a measure of?
  2. Condition indices must control for what confounding effect? Put this into your own words.
  3. Why is measuring fish condition important to a fisheries scientist?
  4. What are the three most common condition indices?
  5. What is the formula for Fulton’s condition factor?
  6. What fundamental assumption about fish “growth” does Fulton’s condition factor make? Why does this make this metric largely useless?
  7. What is the formula for the relative condition factor of LeCren?
  8. What is the primary limitation for using the relative condition factor?
  9. What is the formula for a relative weight?
  10. What value of Wr represents fish in “good condition”?
  11. What abiotic and biotic factors have been found to be related to fish condition?