Question

Which among the following models do not require biological data inputs for fish stock assessment ?
(A) Surplus production model
(B) Thompson and Bell prediction model
(C) Relative response model
(D) Yield per recruit model
(E) Swept area method
Choose the correct answer from the options given below :

• A. (A), (B), (D) and (E) only.
• B. (A), (C) and (E) only.
• C. (B), (C), (D) and (E) only.
• D. (B), (D) and (E) only.

Hint:

Holistic models (Surplus production, Swept area) require only catch, effort, or area data, whereas Analytical models (Y/R, Thompson & Bell) require detailed biological inputs.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Fish stock assessment models are divided into holistic models (which treat the fish stock as a single homogenous biomass and require minimal inputs) and analytical models (which require detailed age- and size-structured biological data).

Step 2: Detailed Explanation:
Let us analyze the data requirements for each of the listed models:
1. Surplus Production Model (A): A holistic model (e.g., Schaefer and Fox models) that treats the stock as a single biomass. It requires only catch and fishing effort data, without requiring any biological parameters like age, growth, or natural mortality. Thus, it does not require biological inputs.
2. Relative Response Model (C): A simple, non-analytical empirical model used to assess the response of fish populations to changes in fishing pressure, requiring only basic catch-effort trends instead of biological datasets.
3. Swept Area Method (E): Used to estimate biomass from bottom trawl surveys. It requires only the catch per unit area, net geometry (width), and the total area swept by the trawl. No biological data (age, size, mortality) is required.
Let us evaluate the remaining options:
- Yield per Recruit Model (D) & Thompson and Bell Model (B): These are analytical, age-structured models that require detailed biological parameters, such as the growth coefficient (\(K\)), asymptotic length (\(L_{\infty}\)), natural mortality (\(M\)), and length-at-first-capture.
Therefore, models (A), (C), and (E) do not require biological inputs.

Step 4: Final Answer:
The correct option is (A), (C) and (E) only.