368 



Fisher/ Bulletin 100(2) 



Q. 



w 



1970 



1980 



1985 



1990 



I Total -♦-Female -s-Eggs 



-Male 



1(10 



50 



B 



1970 



1975 



1980 



1985 



Year 



1990 



1995 



Total 



- Female 



- Eggs 



- Male 



Figure 7 



Static spawning potential ratio for total biomass, female biomass, 

 egg production, and male biomass for red porgy off the southeast- 

 ern United States from calibrated VPA based on (A) primary catch 

 matrix, and (B) alternate catch matrix. 



the two matrices (and. indeed, in all sensitivity runs) were 

 similar, depicting much higher population size and spawn- 

 ing biomass during the 1970s and severe decline through 

 the 1980s and 1990s. This pattern was independent of the 

 large retrospective pattern in the terminal year. Declining 

 trends in CPE from headboats and in fishery-independent 

 sampling (Fig. 3), combined with the observed decline in 

 recruitment (Fig. 4B), also depict an increasingly deplet- 

 ed population. Additional evidence is provided by the sur- 

 plus-production model, which estimated that the popula- 

 tion was at high levels during the 1970s, but that since the 

 mid 1980s it has been far below the level capable of pro- 

 ducing MSY (Fig. 11). Implementation of a 12-inch mini- 

 mum size limit in 1992 (amendment 4 ISAFMC''! ) appears 

 to have reduced F only on ages 1-3, but F on fully recruit- 

 ed ages (4-I-) has increased (Table 5). 



Static SPR (in total mature biomass) is estimated for 

 the recent period at 42*^?^ and 27'? from the primary and 

 alternate catch matrices, respectively (Table 6). Mean SPR 

 estimated from the primary catch matrix for all three pe- 

 riods is above SPR=35'7f . the value used by the South At- 

 lantic Fishery Management Council to define overfishing 

 for red porgy (amendment 12 |SAFMC-'| i. Estimated SPR 

 from the alternate catch matrix is below SS"? in the recent 

 period (Table 6). 



Coleman et al. (1999), in a discussion of reef fish man- 

 agement, pointed out that SPR as usually estimated from 

 female biomass or egg production has proven less effec- 

 tive for protogynous reef fishes than for fishes that do 

 not change sex. With the loss of the largest size classes, 

 predominantly male, remaining males may not be able to 

 increase harem size sufficiently to fertilize all available 

 females. Thus, determining SPR solely on female repro- 

 ductive contribution may not capture the true decline in 

 reproduction caused by fishing. For that reason, Vaughan 

 et al. (1992, 1995) recommended calculating static SPR 

 from total mature biomass, broadening the concept of stat- 

 ic SPR for protogynous species. Vaughan et al. (1995) cal- 

 culated reduction in the proportion of males for black sea 

 bass due to changes in fishing mortality and under the as- 

 sumption that transition rate does not change with pop- 

 ulation abundance. They estimated a reduction of about 

 40'/f due to recent fishing mortality, a reduction similar to 

 the ~2>Q% we estimated for red porgy. 



Whether males are currently limiting, or the degree to 

 which increased fishing mortality can cause them to be- 

 come limiting, is unknown. Regardless, increased fishing 

 mortality on all ages would be expected to reduce the pro- 

 portion of males in the mature population. The rate at 

 which the imposition of fishing mortality may alter the av- 



