332 
Fishery Bulletin 99(2) 
K= 0.105 
Figure 1 
Beverton-Holt yield per recruit curves on F for black drum, estimated t c = 5-25 and M=0.02-0.12 
under A'=0.105. The dotted line ( ) in each panel (t =25) represents the estimated current level 
oft for black drum in the Chesapeake Bay region. F UIV is represented bv the symbol • and F„ ; is 
represented by the symbol O. 
Estimated values of P n were also low for black drum 
caught in Chesapeake Bay. For L^=117 cm, and the cur- 
rent estimated / . ( 1 10 cm, corresponding to f =25), P =0.06, 
i.e. on average, only 6% of their potential growth still re- 
mains when black drum in Chesapeake Bay enter the ex- 
ploited phase at age 25. For alternative values of t r equal 
to 5, 10, 15, 20, and 30 years, values of P„ are 0.46, 0.27, 
0.16, 0.09, and 0.03, respectively. 
Modeling with /C=0.124 
Yield modeling was also done to encompass an alterna- 
tive estimate of growth based on the Brody coefficient ( K ) 
determined from the northeast Florida fishery (Murphy 
and Taylor, 1989). Because Chesapeake Bay region catches 
did not include fish aged 1-5, the estimate of K (0.105; 
Jones and Wells, 1998) differed slightly from that esti- 
