454 
Fishery Bulletin 96(3), 1998 
Age (years) 
Figure 3 
Observed weights-at-age and fitted von Bertalanffy regres- 
sion line for black drum from the Chesapeake Bay region, 
1990-92. 
between fish total length and otolith maximum 
length (OL= 2.69 + 0.20 TL), and otolith maximum 
width (OWID= 2.69 + 0.14TL), were isometric, rea- 
sonably linear, and therefore were useful for back- 
calculation of fish lengths. Other relations between 
total length and all relations on age were exponen- 
tial functions (OWT=1.72 x 10 -5 TL 2 - 66 ; OR- 6.02 x 
10 ~ 3 TL lA6 ; OL= 10.78 Age °- 256 ; OWID=8.7l Age °- 231 ; 
OWT=0.231 Age 0 025 ) OR=0. 964 Age 0 541 ). 
Annuli on black drum otoliths continue to be depos- 
ited with increasing fish size. Annuli counts were sig- 
nificantly and positively related to fish length (Fig. 2) 
and weight (Fig. 3). Fitted regression lines and data 
plots indicate counts continue to increase most clearly 
with weight. However, they also increase with length 
even though there is a leveling off at greater numbers 
of annuli. Although usually used merely to describe 
growth patterns, Figures 2 and 3 provide evidence — 
usually not stated — that otolith age is valid. 
Age and size compositions 
The Chesapeake Bay fishery generally captures old 
black drum. Mean age was 26 years (Fig. 4). Ages 
ranged from 6 to 59 years in the regularly sampled 
catch, but several juveniles were obtained from sam- 
pling pound nets. Median age in the catch was con- 
sistent from year to year (1990=25.0, 1991=23.0, 
1992=24.0; Kruskal-Wallis % 2 =4.53, P>0.05) and be- 
Age (years) 
Figure 4 
Overall age distribution of black drum in the Chesapeake 
Bay fishery, 1990-92. Juveniles were taken in the fall of 
1990 and 1992 in special sampling of the pound nets. 
tween sexes ( S = $ =24.0; Wilcoxon 2=1.01, P>0.05). 
Age at the 95 th percentile was 48 years, indicating 
that many older fish were landed. The youngest fish 
