Question

Which model is one of the age-structured models?

• A. Relative response model
• B. Surplus production model
• C. Virgin stock model
• D. Yield per recruit model

Hint:

If you see "Beverton-Holt" or "Yield per Recruit," think "Analytical" or "Age-structured." If you see "Schaefer" or "Fox," think "Surplus Production" or "Holistic."

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Fisheries models are generally divided into two types: Holistic models (surplus production) and Analytical models (age-structured or length-structured). Holistic models treat the stock as a single biomass, whereas analytical models look at the individual components (age groups) of the population.
Detailed Explanation:
1. Surplus Production Models: These (like the Schaefer or Fox models) are "black box" models that only require catch and effort data. They do not consider the age or size of the fish.
2. Yield per Recruit (YPR) Model: Developed by Beverton and Holt, this is a classic age-structured model. It follows a cohort of fish from the time they are "recruited" to the fishery throughout their lifespan. It accounts for growth (age-based length/weight) and mortality (age-based survival) to calculate the total yield. Because it specifically incorporates the age at first capture and the growth of the fish over time, it is classified as age-structured.
3. Relative Response and Virgin Stock: These are terms describing stock states or general responses rather than specific computational age-structured models.

Step 2: Final Answer:
The Yield per Recruit model is the correct answer.