HALES: ROUND SCAD IN THE SOUTH ATLANTIC BIGHT 

 60n RESTING 



40- 



20- 



UJ 30H 



a. 



< 20H 



UJ 



> 

 o 

 o 

 o 



u. 

 o 



10- 



20- 



10- 



60- 



40- 



20- 



DEVELOPING 



RIPE 



SPENT 



I ' I ' I ' I — I — i — I — I — I — r 



155 235 315 395 475 



OOCYTE DIAMETER(ijm) 



Figure 3.— Frequency distributions of oocyte diameters from four 

 randomly selected ovaries of Decapterus punctatus in each matur- 

 ity stage. The total number of oocytes measured in each ovary was 

 306 (oocytes from 3 sections within the anterior, central, and 

 posterior regions of each ovary). 



mined, and it was unknown if these individuals had 

 spawned. The regression equations of fecundity on 

 length and weight for 33 specimens were as follows: 

 logio fee = -10.9 + 5.63 logjo FL {r^ = 0.46); and 

 logio fee = -1.14 + 1.56 logio wt (r- = 0.55). 



Feeding Habits 



Approximately 91% of round scad (39-189 mm FL) 

 contained identifiable prey. The highest indices of 

 relative importance for all specimens were for cope- 

 pods (0.37), mollusk larvae (0.19), amphipods (0.06), 

 and ostracods (0.04). The most numerous prey 

 groups were mollusk larvae (29%, predominantly 

 gastropod and pelecypod veligers), copepods (25%), 

 barnacle cyprids (14%), and ostracods (10%). Chae- 

 tognaths (35%), copepods (28%), mollusk larvae 



MALES 



FEMALES 



JAN - FEB 

 N=43 



MAR -APR 

 N=67 



MAY-JUN 

 N=50 



JUL -AUG 

 N=93 



NOV -DEC 

 N=28 





JAN - FEB 

 N=51 



MAR -APR 

 N=43 



MAY-JUN 

 N=60 



JUL-AUG 

 N = 44 



NOV- DEC 

 N=22 



GONAD STAGES 



DEVELOPING 



RIPE 



SPENT 



RESTING 



Figure 4.— Seasonal occurrence of maturity stages of gonads of 

 Decapterus punctatus. N is sample size for each bimonthly period. 

 No gonads were examined from specimens collected in Septem- 

 ber and October 1980-81. 



CO 



70- 

 50- 

 30- 

 10- 



§ 70- 

 Q 



-z. 



L. 30- 



o 



(7) 10- 



QC 



LiJ 



GQ 



3 180- 



-z. 



120- 



60- 



FEMALE 



JZl 



MALE 



IMMATURE 



35 55 75 95 115 135 



155 175 



FORK LENGTH (mm) 



Figure 5.— Frequency distributions of fork length of Decapterus 

 punctatus by sex. Both sexes mature at approximately 110 mm FL. 



257 



