Beverton-Holt yield-per-recruit example 1

This is an example of Beverton and Holt (1964) yield-per-recruit (YPR) analysis. The species used for this model is an Asian Navodon modestus from Park (1985). The isopleth diagram (up, x-axis is F, y-axis is tc) and 3D graph (down) on the right show the relationship between YPR, F and tc.

The lines and the surface on the pictures present the values of YPR. If the present tc is 1.77, the optimal YPR meets at F is 0.72. If the strength of fishing at this point goes higher (F value goes higher), YPR decreases, and if wants to increase YPR at the same F, the best age of catch (tc) is around 3.

The diagrams are produced by Mathematica.


F : instantaneous rate of fishing mortality
tc : age of capture

M = 0.26 // instantaneous rate of natural mortality
tr = 0.38 // age of recruit
tL = 10.0 //maximum age in fishery
t0 = -2.262 // theoretical age of 0
Winf = 654.2 g // maximum weight


revised Apr.1 2007
by Yeongha Jung