MERRINER: REPRODUCTIVE BIOLOGY OF THE WEAKFISH 



Table 7. — Relationship of age-group and standard length to percent sexually mature by sex for weakfish from Pamlico Sound, 



N.C. (1967-69). 



'Midpoint of lengtfi interval. 



were mature at a length of 190 mm (n = 25, 52% 

 mature) (Table 7). 



Average estimated fecundity increased with 

 age from 45,000 eggs for age females to 

 1,726,000 eggs for age IV females. The increases 

 in fecundity with age were significant (F = 15.64, 

 df = 17.4; P < 0.01; Table 8). Variation within 

 individual age groups was great with the stan- 

 dard deviation approaching one-third of the mean 

 estimated fecundity. Relative fecundity, the 

 number of eggs per gram of ovary, decreased from 

 37,650 at age to 14,867 at age IV. 



Regression analysis indicated significant rela- 

 tionships between fecundity and fish length and 

 weight. The equations describing the relation- 

 ships and coefficients of determination are: 



F -- 

 F -- 

 F -- 



Table 8. 



0.116SL2"55^^2 = 0.85; 



0.152 TL2-64i8^ ^2 = 0.86 (Figure 4); 



21,198 + 1,279 W, r2 = 0.88. 



DISCUSSION 



Weakfish spawn in or near the various inlets 

 along the coast of North Carolina (Welsh and 

 Breder 1923; Higgins and Pearson 1928; Hilde- 

 brand and Cable 1934) and also in Pamlico 

 Sound. Earlier authors did not include sounds 

 and bays as probable spawning sites since no 

 female weakfish in spawning condition had been 

 taken from inshore waters of North Carolina 

 (Roelofs 1951). Higgins and Pearson (1928) re- 

 ported a few weakfish with "free running ripe 

 eggs" in Pamlico Sound. Twenty-four female 

 weakfish in the ripe running condition were ob- 

 tained from Pamlico Sound, and this indicates 

 weakfish may also spawn in sounds and bays. 

 These areas may be at the edge of the spawning 

 zone, however. 



Spawning activity in coastal waters north of 

 North Carolina is cited by Hildebrand and 



-Fecundity estimates and relative fecundity for 22 weakfish from North Carolina and analysis of variance results for 



age versus fecundity. 



"Probability less than 0.01. 



23 



