Jones and Wells: Yield modeling for Pogonias cromis 
335 
K= 0.124 
Figure 4 
Beverton-Holt yield per recruit curves on F for black drum, estimated t= 5-25 and M=0.02-0.12 
under A'=0.124. The dotted line ( ) in each panel U c = 25) represents the estimated current level 
of t r for black drum in the Chesapeake Bay region. F MAX is represented by the symbol • and F t) , 
is represented by the symbol O. 
for M< 0.04. Yield values were slightly higher than for 
K- 0.105 for all levels of M (Fig. 4; Table 2), and the bench- 
marks, F max and F 0 1 , fell at higher values of F. Hence, 
the reasoning that was used to discount growth overfish- 
ing previously can also be used here. When M=0.02-0.04, 
yield-per-recruit curves peaked at t c =5-15 yr and were 
asymptotic or rising at older ages. Both scenarios indi- 
cated that growth overfishing is possible but improbable 
because of the unlikely maximum ages that such low val- 
ues of M imply and because curves peaked at values of t c 
lower than those experienced in this fishery. At higher lev- 
els of M (0.10; 0. 12), growth overfishing was even less like- 
ly than at slower growth levels. Yield-per-recruit curves 
peaked only at t =5 and for F>0.28. Likewise, this t c was 
too young for the fishery, and Z and F CUR were consider- 
ably smaller than the lowest values of F MAX or F 0 l Hence, 
