REPRODUCTIVE CYCLE, FECUNDITY, AND SEX RATIOS OF 

 THE RED PORGY, PAGRUS PAGRUS (PISCES: SPARIDAE) 



IN NORTH CAROLINA 



Charles S. Manooch, IIP 



ABSTRACT 



Macroscopic examination of gonads and gonad indices demonstrated that March and April were the 

 peak spawning months in Raleigh and Onslow bays, N.C. Ripe fish were collected over irregular bottom 

 from January to April in water ranging from 21 to 100 m in depth. Bottom temperatures during the 

 spawning period ranged from 16.4° to 21.5°C. Three predictors of fecundity, total length, weight, and 

 age were evaluated and regression equations derived. Fish weight proved to be the most precise 

 predictor of fecundity: In fecundity = 1.7369 + 1.5178 (In weight of the fish) where fecundity is the 

 total number of eggs in both ovaries. Fecundity estimates ranged from 48,660 for a 304-mm (390-g) red 

 porgy to 488,600 for a 516-mm (1,783-g) fish. Although some individuals reached sexual maturity at age 

 II, most spawn for the first time at age III. Chi-square tests revealed a significant departure from the 

 expected 1:1 sex ratio when data were stratified by month, year, and size. Females were encountered 

 more frequently each month for all 3 yr, and in the smaller size intervals. 



The red porgy, Pagrus pagrns Linnaeus, is one of 

 the most important demersal marine fishes taken 

 by recreational anglers fishing from headboats- 

 between Cape Hatteras, N.C, and Charleston, S.C. 

 In 1972 and 1973, 513,700 red porgy weighing 1.3 

 million pounds were taken by this sport fishery 

 (Sekavec and Huntsman 1972; Huntsman 1976). In 

 spite of the importance of the species, published 

 information on the red porgy in the western 

 Atlantic is scarce. Dias et al. (1972) described the 

 length-weight relationship for Pagrus collected off" 

 South Carolina; Ciechomski and Weiss (1973) 

 reported on egg, embryo, and larval development 

 of red porgy from the Argentine Sea; and Man- 

 ooch et al. (in press); Manooch (in press), discussed 

 the taxonomic status and the food habits of P. 

 pagrus, respectively. 



This study investigated reproduction of red 

 porgy in North Carolina to determine: 1) spawning 

 season, 2) size and age of females at sexual matu- 

 rity, 3) prediction equations for estimating fecun- 

 dity, 4) sex ratios by month and size, 5) spawning 

 ecology, and 6) a description of the eggs and 

 young. This research is part of a National Marine 

 Fisheries Service project which is studying the 

 bottom fishes of the outer continental shelf of the 

 Carolinas. 



'Atlantic Estuarine Fisheries Center, National Marine Fish- 

 eries Service, NOAA, Beaufort, NC 28516. 



-Headboats are those that charge for a day's fishing on a per 

 person basis. 



MATERIALS AND METHODS 



Length, weight, sex, stage of gonad develop- 

 ment, and gonad length and weight were recorded 

 for fish sampled from North Carolina headboats 

 and by experimental fishing aboard the RV 0ns- 

 lotv Bay from 1972 to 1974. Gonads were preserved 

 in 10% Formalin-^ and macroscopically examined to 

 determine maturity using modified criteria from 

 Orange (1961): Stage 1-S: infantile, gonads small 

 and ribbonlike (sex determination by gross ex- 

 amination not possible); Stage 1: immature, go- 

 nads elongated, slender, but sex discernible by gross 

 examination; Stage 2: early maturing, gonads 

 slightly enlarged, individual ova not visible to 

 naked eye; Stage 3: late maturing, gonads en- 

 larged, individual ova visible to naked eye; Stage 4: 

 ripe, ovary greatly enlarged, many ova trans- 

 lucent and easily dislodged from follicles or loose 

 in lumen of ovary; and Stage 5: spawned, includes 

 recently spawned fish with mature ova occurring 

 as remnants in various stages of reabsorption. 



Time of spawning based on 243 females was 

 determined by using: 1) the gonad index (G.I.) of 

 Schaefer and Orange (1956), and 2) the index: 

 lOOG.W./F.W., where G.W. is the fresh gonad 

 weight to the nearest 0.01 g and F.W. is the body 

 weight of the fish to the nearest 1.0 g. Mean values 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



Manuscript accepted April 1976. 



FISHERY BULLETIN: VOL. 74, NO. 4, 1976. 



775 



