ROSS: REPRODUCTION OF BANDED DRUM 



TABLE 2. — Mean monthly ova diameters of Larimus 

 fasciatus from March through September 1976. 



females continued spawning later (September) (Fig. 

 5). Most of the smallest reproductively active 

 females (between 120 and 130mmSL) matured from 

 June to August (Fig. 5). 



Using age-length relationships of Ross (1978), 

 Larimus fasciatus reached maturity shortly after 

 turning 1-yr-old. They continued spawning through- 

 out life until age 3, which was the maximum age 

 encountered. 



Fecundity 



TABLE 3. — Number and percentage of mature and 

 immature female banded drum by 10 mm size cate- 

 gories off North Carolina, April-September 1976. 

 Maturity was judged by gonad index (GI) value. 



130 mm SL and predicted fecundity in this size range 

 is 31,088-65,038 ova. Body weight (BW) minus the 

 gonad weight (GW) was regressed onto fecundity 

 yielding the equation: 



Number of ova increased with increasing fish size, 

 ranging from 12,750 ova in a 118 mm SL female to 

 320,819 in a 179 mm female. The relationship be- 

 tween fecundity (F) and SL for 86 females was linear 

 and expressed by the equation: 



F = -376,312 + 3,395 (SL), r = 0.76 

 (Fig. 6). Length at first spawning is between 120 and 



F = -52,741 + 1,887 (BW), r = 0.76, n = 85. 



Gonad weight varies seasonally and is closely related 

 to fecundity; therefore, eliminating it from body 

 weight reduced the possibility of autocorrelation. 

 Even without the gonad weight, body weight varies 

 seasonally and to some extent daily as a function of 

 diet; therefore, body weight is not the best predictor 

 of fecundity. The fecundity to ovary weight (0 W) 



7- 



6- 



5- 



X 



LU 



Q 



4- 



Q 



I 3 



O 



o 



1- 



6 7 63 4 ^ *** 



88 

 8 



4 9 



9 



8 8 



7 6 



4 8 8 



7 4 

 6 9 9 9 8 8 8 



'788 8 8 



9 6 8 4 



9 9 8 6 «8> 



9 6 9 



89 9 99 9 9 8 9 4 « 



6 ^ ' 



6 9 7 

 7 



6 6 



6 

 6 6 6 



7 8 



4 4 

 4 



— r~ 

 90 



100 110 120 130 140 150 160 170 180 



STANDARD LENGTH(mm) 



FIGURE 5. — Relationship between famale gonad index and standard length by month 

 for banded drum during January (l)-September (9) 1976 (n = 124). 



231 



