Rhodes and Topper: The vulnerability of Plectropomus areolatus to fishing 
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commercially important serranids ( P . areolatus , Epi- 
nephelus fuscoguttatus [brown-marbled grouper], and 
E. polyphekadion [camouflage grouper]) during repro- 
ductive periods (Rhodes and Sadovy, 2002). Temporary 
community-based MPAs are used elsewhere, such as at 
the Solomon Islands and Papua New Guinea, whereby 
fishing is allowed at FSAs after periods of build-up 
within the aggregating population. For Pohnpei, where 
the current study was focused, management protocols 
include a small-scale MPA that protects P. areolatus, 
E. polyphekadion, and E. fuscoguttatus at a common 
FSA site (Kehpara Marine Sanctuary [KMS]) and a 
seasonal serranid sales ban that coincides with peak 
reproductive periods for these species (March-April). 
However, these measures fall short of fully protecting 
these and other FSA-forming serranids because 1) some 
unprotected FSAs continue to be fished (e.g., at nearby 
Ant Atoll and Palikir Pass); 2) sales bans do not cover 
entire spawning seasons for the aforementioned species; 
and 3) some serranids appear to reproduce outside the 
sales ban period (Rhodes and Tupper, 2007). Migratory 
corridors have not been investigated locally, including 
around the KMS, and thus reproductively active indi- 
viduals possibly exist outside current MPA boundaries 
and are, therefore, vulnerable to exploitation. Finally, 
subsistence catch for aggregating serranids, shown to 
lead to overexploitation elsewhere (e.g., Olsen and La- 
Place, 1979), remains open year round, including during 
the sales ban period. 
In Pohnpei, P. areolatus is a favored target of lo- 
cal subsistence fishermen and small-scale commercial 
fishermen, representing approximately 12% of the com- 
bined-gear commercial coral reef grouper fishery that 
includes 24 species (Rhodes and Tupper, 2007). The 
species is taken year-round largely as juveniles and 
small adults from inner reef areas during nighttime 
spearfishing activities, but is also known to be targeted 
at FSA sites, including at least three known unpro- 
tected FSA sites. Anecdotal evidence indicates that 
one local P. areolatus FSA may have been extirpated 
in the 1990s after continued targeting of an annual re- 
productive migration that ceased to form around 1995. 
Gravid P. areolatus are commonly found in markets 
during reproductive months outside the March-April 
serranid sales ban period, occasionally in the hundreds 
of individuals, and there is concern that reproductively 
active P. areolatus from the KMS may be targeted along 
migratory corridors or other areas where fish congre- 
gate (i.e., staging areas) for noncommercial use during 
sales-ban periods. 
Using both conventional and acoustic tag-recapture 
techniques, we examined the vulnerability of squaretail 
coralgrouper to fishing by examining spatial and tem- 
poral trends of tagged individuals at a single protected 
spawning aggregation site. The study objectives were 
1) to determine potential sexual differences in behavior 
(within reproductive periods) that may facilitate capture 
and impact reproduction; 2) to examine the potential 
catchment area(s) (determined from recaptures) from 
which reproductive populations of P. areolatus at KMS 
may be drawn; 3) to assess the direction and distance 
of movement of fish in relation to the FSA to improve 
MPA design; 4) to identify potential migratory corridors 
of spawners in relation to KMS where fishermen may 
concentrate fishing activities; 5) to determine if the ex- 
isting MPA at KMS adequately protects reproductively 
active individuals; and 6) to assess whether current 
fisheries management could be improved to reduce the 
capture of reproductive fishes during spawning periods, 
particularly at the FSA site. Estimates of overall fish- 
ing mortality and fisheries sustainability for squaretail 
coralgrouper in Pohnpei are outside the scope of the 
current study because information on stock character- 
istics and the fishery (particularly subsistence) remain 
incomplete and, therefore, statements concerning these 
indices would be premature. 
Material and methods 
Site description 
The tagging study was conducted at the Kehpara Marine 
Sanctuary, a known protected FSA site in Pohnpei, Fed- 
erated States of Micronesia (6°55'N, 158°15'E), where P. 
areolatus, E. polyphekadion, and E. fuscoguttatus aggre- 
gate seasonally to spawn (Fig. 1). Plectropomus areolatus 
forms aggregations annually from ca. January-May at 
KMS, seaward of the barrier reef along approximately 
0.5 km of the reef flat and wall at -10-30 m depth (first 
author, unpubl. data). During the aggregation period, 
individuals seek shelter and remain in relatively close 
proximity (<5 m) to the low-relief coral that covers much 
of the site. During daytime, individuals can be observed 
meandering among large high-relief stands of coral in 
shallower portions of the reef flat and over the inter- 
mittent sand patches and rubble piles that are found 
throughout the area. Although P. areolatus aggrega- 
tions have been monitored at the site over a 7-yr period, 
spawning has never been observed within aggregation 
months. Histological analyses of gonads have recently 
confirmed a seasonal and lunar periodicity of spawning 
for this species (first author, unpubl. data). 
Fish capture, catch per unit of effort, and tagging 
To capture fish for tagging, two locally hired fishermen 
used live bait ( Myripristis sp.), hook-and-line, and mask 
and snorkel to target P. areolatus from the surface 
within the FSA site. Fishing was conducted daily over 
5 days in January and 7 days monthly from February 
through May just before and including the full moon, 
for a total of 33 fishing days. Target depths for fishing 
ranged from -15-30 m where fish aggregate within the 
FSA site. To estimate catch-per-unit-of-effort (CPUE), 
daily soak times and catch volumes were recorded from 
February to May. No CPUE estimates were made in Jan- 
uary, although fishing methods and times were similar 
among months. Following capture and before processing, 
fish were brought onboard and anesthetized in a 0.75 g/L 
