WALTZ ET AL.: BIOLOGY OF THE WHITEBONE PORGY 



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T I i | i I I i | I I r i i — i — i — i — r 

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SIZE CLASS (cm) 



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AGE 



Figure 7.— Percent of all Calamus leucosteus that were fe- 

 males or functional females and the percent occurrence of 

 transitional fish only by size and age. 



Table 5.— Otolith age-mean fecundity values for 

 Calamus leucosteus. The Bliss (1967) approximation 

 was used in transforming the mean from logarithmic to 

 arithmetic units. 



Age 



Number of 

 individuals 



Mean fecundity 



Range 



log fecundity = 4.501(log TL) - 5.742 

 n = 62 r 2 = 0.64 



log fecundity = 1.656(log W) + 1.013 

 n = 63 r 2 = 0.66 



where FL, SL, and TL are in mm and Win g. 



South Carolina Commercial Landings 



Regional catch and landing data for C. 

 leucosteus are available only as the combined 

 values of C. leucosteus and Stenotomus sp. from 

 the offshore trawl fishery (Table 6). Whitebone 

 porgy represent approximately 98% of these 

 values (Ulrich 4 ). The mean size of random sub- 

 samples of the trawl catch (1979: FL = 27 cm; 

 1980: FL = 26 cm) was very similar for both years 

 (Fig. 8). 



this decreased to 79% in April, whereas the high- 

 est percentage of ripe fish were observed in May 

 (32%). No ripe fish were encountered before 

 April or after August. Fish undergoing transi- 

 tion were more frequently encountered after 

 spawning (Table 4). The highest percentages of 

 transitional fish were observed in August (1 1.7%) 

 and September (13.6%). Both sexes may mature 

 at age 1 and females as small as 179 mm FL have 

 been observed with hydrated eggs. 



Fecundity ranged from 30,400 to 1,587,400 

 eggs and generally increased with age (Table 5). 

 It was significantly related to length and weight. 

 The functional regressions for fecundity verses 

 length and weight are 



log fecundity = 4.463(log FL) - 5.347 

 w = 63 r 2 = 0.64 



log fecundity =4.475(logSL) - 5.093 

 n = 63 r 2 = 0.66 



4 G. Ulrich, Finfish Management Section, Division of Marine 

 Resources, South Carolina Wildlife and Marine Resources 

 Department, P.O. Box 12559, Charleston, SC 29412, pers. com- 

 mun. 19 May 1980. 



Table 6.— Reported landings of Calamus leucosteus 

 and Stenotomus sp. from the South Carolina offshore 

 trawl fishery 1979 and 1980. Values for November and 

 December 1980 are low because of incomplete land- 

 ings data from one Charleston, S.C. dock. 



871 



