408 
Fishery Bulletin 96(3), 1998 
0 10 20 30 40 
Maximum age (years) 
Figure 5 
Relationship between the population dynamic parameters maximum size 
L x and maximum age t k for three economically important Florida Keys reef 
fish taxa: groupers, Epinephelinae (■); snappers, Lutjanidae (A); and grunts, 
Haemulidae (•). 
also noted similarities in key relations within vari- 
ous taxa that separated out into somewhat discrete 
clusters when maximum size versus maximum age 
by species is plotted (Fig. 5). This pattern of species 
clusters suggests that species within the various taxa 
groupings will likely respond to exploitation in a simi- 
lar manner. The sensitivity to exploitation is high- 
est for groupers, followed by snappers, and then 
grunts. 
Overfishing and community shifts 
Despite conservative assumptions, the estimated 
fishery exploitation rates suggest that many Florida 
Keys reef fish stocks are overfished according to defi- 
nitions for U.S. fisheries (Rosenberg et al., 1996) 
(Figs. 7 and 9). Many desirable grouper and snapper 
stocks have low spawning potential ratios (SPRs). 
Inverse relationships between increased fishing ef- 
fort (particularly by the recreational sector) (Fig. 3) 
and the long-term decreased average size and stock 
biomass (e.g. Fig. 60 of the most desirable species 
(e.g. groupers and snappers) are particular concerns. 
The Florida Keys reef fishery shows the classic 
pattern of serial overfishing, in which the more vul- 
nerable species are progressively depleted (Munro 
and Williams, 1985; Russ and Alcala, 1989). The long- 
est-lived, latest-maturing, and lowest mortality (M) 
stocks [i.e. groupers] are those first to experience sig- 
nificant declines in population biomass, followed in 
sequence by intermediate-lived stocks [snappers], 
and finally by short-lived stocks [grunts] [Fig. 7]). 
Within families, the inverse relations between the 
spawning potential ratio and exvessel market price 
(Fig. 8) are consistent with serial overfishing. As ex- 
pected, the most valuable snapper and grouper also 
tend to have the lowest spawning potentials. During 
the time frame of this study, numerous measures 
were taken to reduce fishing mortality in state and 
federal waters. Fish traps were progressively elimi- 
nated between 1980 and 1992, and numerous bag 
limits and minimum size limits were imposed. Fish- 
eries were closed for queen conch ( Strombus gigas), 
jewfish ( Epinephelus itajara), and Nassau grouper 
( E . striatus). These actions are evidence of trends re- 
ported in this study. 
Our data suggest that there may have been sub- 
stantial changes in the composition of the biomass 
and abundance of the reef fish community over the 
past several decades. Although many groupers and 
snappers have declined, apparently in response to 
growing fishing effort, some grunts have increased 
in relative abundance. Claro (1991) noted a similar 
process in the Golfo de Batabano, Cuba, and hypoth- 
esized that chronic overharvesting of snappers re- 
sulted in shifts in community composition in favor 
