Fish Population Dynamic and Stock Assessment

4.1.4.4.3.  Powell – Wetherall method

In this method, plotting of$$\overline{Lc}$$ – L' against L’ gives a linear equation from which ‘a’ and ‘b’ can be estimated, L$$\infty$$ = -a/b; and slope b = -K / (Z+K) slope. This method is more suitable for situations where little or nothing is known about the fish stock in question.

Input data needed.

1. LFD data

2. The number caught for each length interval are to be recorded

(For calculation of Z by this method, refer to practical section.