Rhodes and Tupper: The vulnerability of Plectropomus areolatus to fishing 
201 
tation (Coleman et al., 1999). Similarly, the removal of 
larger individuals (males in protogynous species) may 
lead to reductions in the mean size of both males and 
females (from compensated sex change) to reduce overall 
fecundity (Vincent and Sadovy, 1998) and, in the case of 
extreme operational sex ratios, may adversely affect re- 
productive behavior. At the KMS FSA, males appeared 
to be more vulnerable to line fishing than were females, 
comprising 79% of the catch during tagging operations 
and representing all recaptures within the KMS. Males 
also dominated recaptures by the fishery among spear- 
caught individuals. Interestingly, females and juvenile 
squaretail coralgrouper dominated marketed catch of 
squaretail coralgrouper overall, and 97% of the mar- 
keted catch in 2006 was smaller than the mean size 
of sexually mature males (Rhodes and Tupper, 2007). 
Thus, in Pohnpei, the potential currently exists for both 
growth overfishing and recruitment overfishing and 
there is an urgent need for a thorough examination of 
island-wide stock levels and sustainability within the 
squaretail coralgrouper fishery, as well as the sustain- 
ability of both the subsistence and other fisheries tar- 
geting FSAs. One possible explanation for the paucity 
of females in catch is that recaptured females went 
unreported or that fishermen targeted larger individu- 
als (i.e., males) to benefit from the combined higher fish 
value and reward. An improvement to our study would 
be to perform real-time observations of the fishery at 
heavily fished locations, such as Peleng Channel, to 
verify the sex ratio of the catch. 
Among acoustically tagged individuals, the data 
showed a high degree of variation in the seasonal pat- 
tern and duration of stay for individuals that frequent 
the FSA site. Although these results could be explained 
in part by mortality (natural, fishing, and tag-induced, 
particularly acoustic) or a failure of receivers to detect 
all fish present, similar variability has been shown 
elsewhere for serranids with the use of these and other 
tagging methods (e.g., Zeller, 1998; Starr et al., 2007). 
In Pohnpei, a gradual reduction in the number of acous- 
tically tagged individuals returning to the FSA was 
observed within a reproductive year; only 50% of tagged 
individuals returned in the month after initial tagging. 
Similar findings were found for acoustically tagged 
Nassau grouper in Belize, where no more than 50% of 
tagged E. striatus males and 52% of tagged females 
were present during any reproductive month following 
tagging (Starr et al., 2007). Nassau grouper returning 
to the FSA after having been tagged showed a similar 
sequential decrease in numbers. On the Great Barrier 
Reef, only 31% of tagged mature leopard coralgrouper 
participated in spawning aggregation activities within 
a reproductive year; this percentage may indicate that 
individuals do not spawn annually (Zeller, 1998). Al- 
though Zeller (1998) suggested that tagged individuals 
may reproduce outside FSAs, spawning outside aggre- 
gations for FSA-forming species has not been shown. 
Likewise, high site fidelity has been shown for a num- 
ber of serranids, with individuals observed moving past 
an active conspecific FSA to return to the site where 
they previously spawned. Sequential reductions in the 
number of conventionally tagged red hind have also 
been shown in the U.S. Virgin Islands (Nemeth et al., 
2007). Although it is possible that the observed find- 
ings could be explained by natural or fisheries-related 
mortality, it seems more likely that some adults do not 
participate in all potential spawning months within 
the reproductive season and that some may not spawn 
in consecutive years. Although more investigations are 
needed, if these implications are correct, individual 
(monthly) FSAs represent subsets of the reproductive 
population, and these subsets complicate monitoring 
programs that solely use FSAs to estimate reproductive 
population abundance and changes therein. Regardless, 
these results indicate that the relationship between a 
FSA and the adult population is complex and additional 
work is needed on serranid reproductive dynamics for 
designing effective monitoring and management strate- 
gies for adult populations and in understanding impacts 
on these populations through FSA-targeted fishing. 
The assessment of catchment areas for aggregating 
serranids by using tagging methods is relatively new, 
yet necessary to complete our understanding of repro- 
ductive population dynamics and to determine sustain- 
ability when fishing efforts are unevenly distributed. In 
Pohnpei, support for a catchment area of -200-300 km 2 
for the KMS-based squaretail coralgrouper FSA is pro- 
vided from recapture data that indicates short-scale 
(10-12 km) movement of individuals in relation to the 
FSA after spawning. The observed recapture patterns 
do not appear to be strictly tied to area-specific fishing 
effort because Kitti municipality receives only 50% of 
fishing efforts statewide, yet >95% of recaptures oc- 
curred within a relatively small area of the municipal- 
ity (Rhodes et al., 2007). Although it is possible that 
fishing effort during spawning months (and full moon 
periods) is more concentrated in Kitti than at other 
municipalities, such a pattern was not borne out from 
over 1000 interviews (2006) of fishermen participating 
in commercial fishing activities. Thus, for squaretail 
coralgrouper in Pohnpei, the reproductive population in 
relation to the KMS spawning aggregation appears to 
be highly localized and thus management could be ap- 
plied to individual aggregations, in addition to combined 
aggregations within Pohnpei. Similar to sex-specific 
residency patterns, other studies of FSA-forming ser- 
ranids also indicate that adults are concentrated within 
relatively small areas in relation to their respective 
FSA. For example, evidence exists for confined catch- 
ment areas for red hind determined from two FSAs in 
the U.S. Virgin Islands: 1) 500 km 2 for the St. Thomas 
FSA and 2) 90 km 2 for the St. Croix site FSA (Nemeth 
et al., 2007). The catchment area for Nassau grouper 
at the Glover’s Reef Atoll FSA (Belize) appears to be no 
more than 384 km 2 (Starr et al., 2007). For P. leopardus 
along the Great Barrier Reef, Zeller (1998) estimated a 
catchment (migration) area of ca. 80 km 2 . For these spe- 
cies, data clearly indicate limited movement by (most) 
individuals after spawning and highlight the potential 
for localized extinction and associated impacts to fish 
