Hood and Johnson Life histoi-y of Pagrus pagivs 



733 



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age that red porgy in the Flower Garden 

 Banks were fully recruited to the sampling 

 gear ( primarily hook-and-line) used by Nelson 

 ( 1988). In the SAB, the age of full recruitment 

 decreased from age 5 in 1972-83 to age 4 in 

 1984-86, probably because of higher exploi- 

 tation rates (Vaughan et al., 1992). Hunts- 

 man et al. (1983) reported that the age of 

 full recruitment to the SAB head boat fishery 

 was 4.1-4.3 years. 



Our estimates of Z ( 0.54-0.87/yr ) are within 

 the range of reported estimates for other pop- 

 ulations sustaining fishing pressure. Nelson 

 (1988) estimated Z to be 0.86/yr for fish 

 from the Flower Garden Banks off Texas in 

 1980-82. In the SAB, estimates of Z increased 

 from the early 1970s through the early 1990s: 

 Z = 0.64/yr for SAB populations from 1972 

 to 1974 (ivianooch and Huntsman, 1977) to 

 Z = 1.58/yr for 1991 (Huntsman et al.'"). 

 Recently, Vaughan'' estimated Z for the SAB 

 to be between 0.90 to 0.94/yr depending on 

 the input value of natural mortality in his 

 stock assessment model. Vassilopoulou and 

 Papaconstantinou ( 1992) reported Z = 0.34/yr 

 for a relatively unexploited red porgy stock in 

 the Mediterranean Sea and estimated natu- 

 ral mortality to be 0.28/yr. 



Reproduction 



Protogynous hermaphrodites such as red 

 porgy may be more susceptible to overfish- 

 ing than gonochoristic species if size-selec- 

 tive fishing reduces the number of males 

 available for spawning (Bannerot et al., 1987; 

 Koenig et al., 1996). This trend is not evident 

 for GOM red porgy. Our sex ratio of 1:1.6 

 had proportionally fewer females than did 

 the 1:2.8 ratio reported by Nelson (1988) for 1980-82. In 

 the SAB, the proportion of females has been increasing 

 in association with fishing pressure. Manooch ( 1976) esti- 

 mated that the sex ratio of red porgy in the SAB was 

 1:2.8 for 1972-74 and that proportionally more males were 

 landed in the fishery than during later years (1:4.9-1:6.5 

 for 1979-1994; Harris and McGovern, 1997). The sex ratio 

 of another GOM protogynous hermaphroditic reef-fish spe- 

 cies, the gag (Mycteroperca microlepis). has been affected 

 by overfishing (Koenig et al. 1996) in that there are pro- 

 portionally fewer male gag in overfished populations than 

 in less fished populations (male-to-female ratio of 1:76.6 

 for 1991-93 (Koenig et al., 1996) compared with 1:4.9 for 

 1977-80 IHood and Schleider, 1992]). Koenig et al. (1996) 

 hypothesized that because males are more aggressive in 



Female 



^=^^ 



0.05 



0.04 



0.03 



0.02 



0.01 



0.00 



—\ 1 1 1 1 1 1 r 



Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 



Male 



4-t=L 



T 1 1 1 



Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 

 Month 



Figure 7 



Monthly gonadosomatic indices iGSI) for female and male red porgy from 

 the eastern Gulf of Mexico. Median values are connected by the solid 

 line. 



'" Huntsman. G. R., D. S. Vaughn, and J. C. Potts. 1993. Trends 

 in population status of the red porgy Pagrus pagrus in the 

 Atlantic Ocean of North Carolina and South Carolina, USA, 

 1971-1992. South Atlantic Fishery Management Council, 1 

 South Park Circle, Charleston, SC 29422-1997. 



feeding, they are more likely to be captured by fishermen 

 who target gag aggregations. 



Our reported lengths at maturity ( most red porgy were 

 mature by 225 mm) were closer to lengths reported for 

 exploited populations (<275 mm; Pajuelo and Lorenzo, 

 1996; Harris and McGovern, 1997 ) than for lightly or newly 

 exploited populations (>276 mm; Manooch, 1976; Vassilo- 

 poulou and Papaconstantinou, 1992; Harris and McGov- 

 ern, 1997 ). Decreases in the size at matui'ity for red porgy 

 may be associated with increased fishing effort; Harris 

 and McGovern (1997) found 279f of red porgy females were 

 mature between 251 and 275 mm in pooled years 1979-81 

 compared with 54'; in pooled years 1991-94. 



Sexual transition occurred at smaller sizes than those 

 reported by Nelson ( 1988): our estimated length at which 

 half the population is male was 345 mm compared with 404 

 mm.'' In the SAB, Harris and McGovern (1997) reported 

 an increasing proportion of males between 351 and 400 

 mm over time, 12.13';; in 1979-81, 32.35Q in 1988-90, 

 and 49.337r in 1991-94, which they attributed to size- 

 selective fishing pressure. For most protogynous reef-fish 



