Ault et al.: A multispecies assessment of coral reef fish stocks 
405 
Year 
Figure 3 
Time series of three types of nominal fishing effort directed at Florida Keys 
reef fish from 1965 to 1993 based on numbers of recreational ( ) and com- 
mercial (sfc) vessels registered in Monroe County, Florida. Headboats ( + ) are 
considered to be a subset of the commercial fishing fleet. 
management endpoints like yield-per-recruit (YPR) 
and spawning potential ratio (SPR) are provided (Fig. 
6). These results are typical of the management in- 
formation provided for each species. 
Our analyses indicated that the average size in 
the exploitable phase for many economically impor- 
tant reef fish populations was marginally above the 
minimum size of capture regulated by fishery man- 
agement agencies (i.e. South Atlantic Fishery Man- 
agement Council and the Florida Marine Fisheries 
Commission). To assess the impact of these mortal- 
ity rates on the stock production, we performed an 
analytical yield analysis to estimate the YPR for each 
stock, and evaluated the current YPR status in rela- 
tion to “eumetric” (cf. Beverton and Holt, 1957) or 
well-balanced fishing in terms of the minimum size 
of fish captured and level of fishing effort (Fig. 6A). 
An issue of paramount concern in assessing analyti- 
cal yield models are the settings of the two dynamic 
control variables, F and L' (Fig. 6A). From the per- 
spective of optimal decision making, any transition 
of the fishery over the yield surface should minimize 
negative risks, while maximizing the economic, eco- 
logical, social, and aesthetic aspects. The YPR analy- 
sis for gray snapper suggests that the current size 
(or age) of first capture, L' at 254 mm ( = 10 in), likely 
results in “growth overfishing.” To maximize the YPR 
for the range of F operating in the fishery for the 
last two decades, L' should be increased to greater 
than 350 mm (Fig. 6B). 
Figure 6C shows progressive reductions of gray 
snapper stock biomass when F is increased to the 
estimate’s lower bound shown in Figure 6B. The like- 
lihood range of F (i.e. F=[0. 5,1.1] ) is likely also con- 
tributing to a very low SPR for gray snapper. In fact, 
it is below the Federal minimum of 30% SPR (Fig. 
6D). The minimum estimated F still reduces SPR to 
about 29% of the unexploited state, whereas the up- 
per bound estimate results in 15% SPR. The major- 
ity of the range of estimated F suggest that the gray 
snapper stock is also “recruitment overfished” as re- 
flected by reduced spawning potential. 
The summary of the SPRs for Florida Keys reef 
fish (Fig. 7) shows that a total of 13 of 16 groupers, 7 
of 13 snappers, and 2 of 5 grunts, for which there are 
data, are below the SPR that constitutes overfishing 
by Federal definitions. Overall, 63% of the 35 stocks 
that could be analyzed were overfished. Linear re- 
gressions of SPR on exvessel price showed a signifi- 
cantly negative (F 1>14 =7.55, P=0.0157) slope for grou- 
per and a marginally significant (F 1 n =4.77, P= 
0.0514) negative slope for snapper (Fig. 8). 
Discussion 
Fishery dynamics 
Our results indicate that Florida Keys reef fish popu- 
lations have been heavily fished for at least the last 
