NOTE Matlock et al : Validation of Pogonias cromis ages 



561 



(187 ± 7 mm) than on those from fish at release (147 

 ± 4 mm). The difference was due largely to small 

 sample size; a third annulus occurred at 133 mm on 

 one fish (B71764) at release but at 183 mm at recap- 

 ture (Table 1). The same tagging procedures we used 

 for black drum were used for red drum without af- 

 fecting scale growth or annulus formation (Matlock 

 et al., 1987). Annuli on black drum scales were 

 formed at mean distances from scale focus (± 1 SE) 

 of 73 ± 3 mm, 143 ± 5 mm, 179 ± 8 mm, 192 ± 20 mm, 

 and 201mm (Table 3). 



The assumption that fishermen reported TL accu- 

 rately appears valid, but they apparently reported TL 

 less precisely than did TPWD personnel. 

 Evidence for this is that the 95%. confi- 

 dence interval associated with the scale 

 radius-TL relationship was wider for re- 

 capture data than for release data (Table 

 2), but the regressions were not signifi- 

 cantly different from each other. Ferguson 

 et al. (1984) demonstrated that anglers 

 in Texas generally report accurate length 

 of recaptured tagged fish, although length 

 measurement reported by anglers were 

 less precise than TPWD measurements 

 for the same fish. 



The life history of black drum and an- 

 nulus formation in related sciaenids fur- 

 ther support that black drum scale an- 

 nulus formation is completed during April 



and May. Adult black drum spawn dur- 

 ing January through April; peak spawn- 

 ing is in March or April (Murphy and 

 Taylor, 1989). Growth in TL is continu- 

 ous until water temperature cools in win- 

 ter (December through February) when 

 growth slows substantially (Doerzbacher 

 et al., 1988). Growth increases in spring. 

 If scale growth follows a similar pattern, 

 circuli are closer to each other as growth 

 increases after winter (i.e., annulus for- 

 mation is completed in spring). Red drum 

 (>l-year-old) growth pattern is similar to 

 black drum and circuli deposition on red 

 drum scales (annulus formation) occurs 

 as expected (Colura et al., 1984; Matlock 

 et al., 1987; Doerzbacher et al., 1988; 

 Green et al., 1990; Bumgaurdner, 1991). 

 If annulus formation in all black drum 

 bony structures (e.g., scales and otoliths) 

 occurs at the same time, then indirect 

 evidence of annulus formation in black 

 drum otoliths also supports the forma- 

 tion of annuli between April and June 

 (Bechman et al., 1990). Additional research is needed 

 to validate annulus formation on scales with four or 

 more annuli. 



Acknowledgments 



We thank the staff of the Texas Parks and Wildlife 

 Department, Coastal Fisheries Branch, who removed 

 scales from black drum at tagging and David Pina for 

 preparing the final drawing of a black drum scale. We 

 also appreciate two anonymous reviewers and Ronald 

 Hardy who provided constructive comments and sug- 

 gestions that improved the clarity of the manuscript. 



