Fish Population Dynamic and Stock Assessment

3.2.4.2.  Ford – Walford plot & Chapman’s method

This method was introduced by Ford (1933) and Walford (1946). Without calculation, $$L_\infty$$ and K could be estimated quickly. The input data for Ford and Walford plot are L(t) as ‘x’ and $$L (t + \triangle t )$$ as ‘y’. ‘$$L_\infty$$ ’ can be estimated graphically from the intersection point of the 45º diagonal where $$L(t) = L (t + \triangle t)$$