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Fishing in the dark-local knowledge, night spearfishing and spawning aggregations in the Western Solomon Islands

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Within the marine conservation community there is considerable interest in combining local knowledge and science to achieve management objectives. Yet there remain few studies which have examined the merits and caveats of local knowledge, or shown how combining both knowledge systems has resulted in better management outcomes. This study outlines collaborative efforts to conserve fish spawning aggregations (FSAs) in Roviana Lagoon, Western Solomon Islands. Baseline information on FSAs was obtained through local knowledge and spearfishing creel surveys. This information provided the starting point for establishing a 2-year community-based underwater monitoring program at the largest known FSA in Roviana Lagoon, where the brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) co-aggregate. This participatory research shows that local knowledge on FSAs is utilised to maximise returns from fishing, with spearfishermen targeting aggregations at night during the lunar periods when abundances peak. Because of its shallow distribution P. areolatus is the most vulnerable of the three groupers to nighttime spearfishing, with two fishermen capable of removing 15–30% of the total spawning biomass in two nights. Underwater monitoring demonstrates that while fishermen provided accurate information on many aspects of FSAs, their knowledge on spawning seasons was inaccurate for the FSA reported on here. Peak aggregations occurred from December to April each year, which differs from the traditionally recognised grouper season of October to January. A combination of local knowledge and science was used to develop appropriate management measures for this FSA, with the aggregation declared a community-based marine protected area (MPA) in 2006.
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Fishing in the dark-local knowledge, night spearfishing and spawning
aggregations in the Western Solomon Islands
R.J. Hamilton
a,
, M. Giningele
b
, S. Aswani
c
, J.L. Ecochard
d
a
The Nature Conservancy, Indo Pacific Resource Center, 51 Edmondstone, South Brisbane, QLD 4101, Australia
b
Dunde Community, Munda, Western Province, Solomon Islands
c
Department of Anthropology and Interdepartmental Graduate Program in Marine Science, University of California, Santa Barbara, CA 93106-3210, USA
d
Technology and Information Systems, The Nature Conservancy, Arlington, VA, USA
article info
Article history:
Received 30 May 2011
Received in revised form 21 November 2011
Accepted 26 November 2011
Available online 19 December 2011
Keywords:
Fish spawning aggregation
Local ecological knowledge
Groupers
Community-based monitoring
Marine protected area
Coral Triangle
abstract
Within the marine conservation community there is considerable interest in combining local knowledge
and science to achieve management objectives. Yet there remain few studies which have examined the
merits and caveats of local knowledge, or shown how combining both knowledge systems has resulted in
better management outcomes. This study outlines collaborative efforts to conserve fish spawning aggre-
gations (FSAs) in Roviana Lagoon, Western Solomon Islands. Baseline information on FSAs was obtained
through local knowledge and spearfishing creel surveys. This information provided the starting point for
establishing a 2-year community-based underwater monitoring program at the largest known FSA in
Roviana Lagoon, where the brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper
(Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) co-aggregate. This par-
ticipatory research shows that local knowledge on FSAs is utilised to maximise returns from fishing, with
spearfishermen targeting aggregations at night during the lunar periods when abundances peak. Because
of its shallow distribution P. areolatus is the most vulnerable of the three groupers to nighttime spearf-
ishing, with two fishermen capable of removing 15–30% of the total spawning biomass in two nights.
Underwater monitoring demonstrates that while fishermen provided accurate information on many
aspects of FSAs, their knowledge on spawning seasons was inaccurate for the FSA reported on here. Peak
aggregations occurred from December to April each year, which differs from the traditionally recognised
grouper season of October to January. A combination of local knowledge and science was used to develop
appropriate management measures for this FSA, with the aggregation declared a community-based mar-
ine protected area (MPA) in 2006.
Ó2011 Elsevier Ltd. All rights reserved.
1. Introduction
Within the marine conservation community there is consider-
able interest in understanding how local knowledge of fishers
can be utilised to advance both management and conservation
agendas (e.g. Drew, 2005; Johannes and Neis, 2007). Fishers can
provide important information on such things as inter-annual, sea-
sonal, lunar, diel, tide- and habitat-related differences in species
distributions and abundance, as well as providing a historical per-
spective on the state of fisheries (Johannes et al., 2000). To date
marine scientists and conservation practitioners have incorporated
fishers’ local knowledge into research programs, fisheries assess-
ments, species evaluations and conservation planning processes
(e.g. Sadovy and Cheung, 2003; Aswani and Hamilton, 2004; Dulvy
and Polunin, 2004; Saénz-Arroyo et al., 2005; Silvano et al., 2006;
Aswani et al., 2007; Almany et al., 2010; Game et al., 2011; Taylor
et al., 2011). One of the most widely applied uses of fishers local
knowledge is in the research and conservation of fish spawning
aggregations (FSAs) (Hamilton et al., 2012). In many locations, fish-
ers have known of FSAs for generations, or have experienced sea-
sonal gluts in landings subsequently identified as FSAs (Johannes,
1978; Colin et al., 2003). In recognition of this, and because of
the practical difficulties of discovering FSAs that typically form at
highly localised areas for brief periods of time, scientists that study
FSAs have often drawn on local knowledge in the initial stages of
their research (e.g. Johannes et al., 1999; Robinson et al., 2008;
Sadovy de Mitcheson et al., 2008).
Three large-bodied aggregating reef fishes that have received
considerable attention in the past decade are the brown-marbled
grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephe-
lus polyphekadion) and squaretail coralgrouper (Plectropomus
areolatus). In the Indo-Pacific these three groupers frequently
co-aggregate to spawn at predictable sites and times around the
0006-3207/$ - see front matter Ó2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.biocon.2011.11.020
Corresponding author. Tel.: +61 7 3214 6913; fax: +61 7 3214 6999.
E-mail address: rhamilton@tnc.org (R.J. Hamilton).
Biological Conservation 145 (2012) 246–257
Contents lists available at SciVerse ScienceDirect
Biological Conservation
journal homepage: www.elsevier.com/locate/biocon
Author's personal copy
new or full moon (e.g. Johannes et al., 1999; Rhodes and Sadovy,
2002; Pet et al., 2005; Hamilton et al., 2011). These groupers make
up important components of many small-scale commercial fisher-
ies in the Pacific (e.g. Rhodes and Tupper, 2007) and they are three
of the most economically valuable species in the Southeast Asia-
based live reef food fish trade (LRFFT) (Sadovy et al., 2003). As a re-
sult of their predictable aggregating behaviour, all are highly sus-
ceptible to overexploitation, with E. fuscoguttatus and E.
polyphekadion listed as near threatened (Cornish, 2004; Russell
et al., 2006, respectively) and P. areolatus listed as vulnerable (Thi-
erry et al., 2008) in the 2008 IUCN Red List.
Globally there are numerous examples of where targeted fish-
ing of FSAs has resulted in aggregation decline or loss (e.g. Sadovy
and Domeier, 2005; Hamilton and Matawai, 2006; Rhodes et al.,
2011), which has negative implications for local fisheries and the
communities that depend on them (Sadovy and Domeier, 2005).
Fisheries managers and conservation practitioners are increasingly
recognising that FSAs need protection, with marine protected areas
(MPAs) and closed seasons being the most commonly imple-
mented conservation measures (e.g. Beets and Friedlander, 1999;
Sadovy de Mitcheson et al., 2008; Rhodes et al., 2011). In some in-
stances management measures for FSAs have been designed solely
on local knowledge (e.g. Hamilton et al., 2012). In other cases, long-
term underwater monitoring has helped to establish a more com-
plete picture of FSAs than local knowledge alone, while building lo-
cal capacity and support for management (e.g. Hamilton et al.,
2011).
The multi-species FSA reported on in this paper is the largest
known grouper aggregation in Roviana Lagoon, Western Solomon
Islands. A Roviana spearfisherman discovered this FSA in 1995,
and between 1995 and 2006 it was exploited by nighttime spear-
fishermen. By 2004 Roviana spearfishermen perceived catches at
this FSA to be in steep decline, and when a non-government organi-
sation (NGO) raised community awareness on the importance of
conserving FSAs, the customary owners of this FSA agreed to estab-
lish a science-based, community-led underwater monitoring pro-
gram at the aggregation site (Hamilton and Kama, 2004). The
purpose of this monitoring was to obtain scientific information on
aggregation seasons and status, with a view that this information
could be utilised to develop appropriate community-based man-
agement strategies for the FSA. Feedback on the scientific findings
resulted in the FSA being declared a no-take community-based
MPA in June 2006. While compliance with this MPA has generally
been good, a limited amount of poaching by nighttime spearfisher-
men has occurred since 2006. The aims of this paper are to (1)
establish the temporal and spatial trends of E. fuscoguttatus,E.
polyphekadion and P. areolatus at this site, (2) determine if small-
scale commercial nighttime spear fisheries pose a significant threat
to spawning aggregations of E. fuscoguttatus,E. polyphekadion and P.
areolatus, and (3) evaluate whether or not local knowledge needs to
be independently validated before being used as the basis for
management.
2. Methods
2.1. Environmental setting
The current study was conducted in Roviana Lagoon, Western
Solomon Islands (Fig. 1) in the Solomon Sea, which forms the most
eastern part of the Coral Triangle (Veron et al., 2009). Roviana La-
goon is a body of shallow water approximately 50 km long en-
closed between the New Georgia mainland and a series of
uplifted coral reef islands lying 2–3 km offshore. In Roviana fishing
practices are strongly influenced by local knowledge of the lagoon
environment. Knowledge of the tides, lunar stages and seasons in-
form fishers when, where and for what they should fish (e.g. Ham-
ilton and Walter, 1999; Aswani and Hamilton, 2004; Aswani and
Vaccaro, 2008). October to the end of January is widely known as
the ‘pazara’ season, when groupers such as E. fuscoguttatus,E.
polyphekadion,P. areolatus and the white-streaked grouper (Epi-
nephelus ongus) are said to aggregate at a minimum of 14 FSAs in
Roviana Lagoon, in the 10 days leading up to and including the
new moon (Hamilton and Kama, 2004). In Roviana Lagoon spawn-
ing aggregations are targeted by subsistence and small-scale com-
mercial fisheries, and in several cases it appears that FSAs have
been fished almost to the point of extirpation (Hamilton and Kama,
2004).
2.2. Site description
The studied FSA is located on a seaward facing reef promontory
within the western region of Roviana Lagoon (Fig. 1). In order to
protect this FSA from further exploitation by outside entities, the
exact location is not shown. The reef flat of the promontory is
3 m deep, with the reef slope dropping steeply to below 200 m.
Aggregations of all three species overlap over a linear reef distance
of ca. 300 m and between depths of 3–50 m (Fig. 2). P. areolatus are
most abundant between depths of 3–15 m, whereas E. fuscogutta-
tus and E. polyphekadion are most abundant in the middle section
of the FSA between depths of 5–50 m (Fig. 2).
This FSA is predominantly fished by nighttime spearfishermen
although daytime spearfishing occasionally occurs here. Hook
and line fishing is not practiced. Nighttime spearfishermen free
dive with the aid of fins, mask, snorkel, a rubber powered spear
and an underwater flashlight with a maximum 4-h battery life.
Spearfishermen prefer to fish this site at night, as this method pro-
duces higher catch rates than daytime spearfishing (authors, per-
sonal observations), a pattern that is common in many parts of
the Pacific (Gillett and Moy, 2006). Local spearfishermen reported
that in the first 2 years that they exploited this site (1995–1996)
the maximum catch of two spearfishermen exceeded 200 P. areol-
atus a night (Hamilton and Kama, 2004). Fishermen noted declines
in maximum catches from 1997 onwards, and in 2001 the maxi-
mum catch of two spearfishermen was 71 P. areolatus in a night
(see Table 3). Commercial spearfishermen sell their catches at fish-
eries centres in the Munda Township (Fig. 1). In 2004 approxi-
mately ten spearfishermen were known to periodically fish this
FSA.
2.3. Creel survey
Between the 23rd of January 2001 and the 20th of April 2001
one of the authors (MG) led 41 nighttime spearfishing trips over
all of the outer reefs shown in Fig. 1. Twenty-seven percent
(n= 11) of these fishing trips occurred at the FSA site and 73%
(n= 30) occurred on outer reefs 1–12 km from the FSA. After each
fishing trip MG recorded the date, fisher name(s), location, time
spent travelling and fishing, species caught and their frequency
and weight. In some instances species were clumped at the genus
level. Fish names were recorded in Roviana and translated to scien-
tific names by the senior author, who participated in several of
these fishing trips. On two occasions in 2005 and one occasion in
2010 one of the authors (MG) documented additional information
on three nighttime spearfishing trips at the FSA that he did not par-
ticipate in. He did this through informal discussions with the
spearfishermen who led these trips, and by recording the total
weights of gutted P. areolatus that were purchased from these fish-
ermen at local fisheries centres in Munda. Since 2005 and 2010
data represent gutted catches, these total weights were raised by
a factor of 1.15 to represent the ungutted condition (Grandcourt,
2005). Catch per unit effort (CPUE) for the 2005 and 2010 trips
R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257 247
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were estimated by assigning 4 h of effort to each spearfishermen,
based on the authors knowledge of the maximum battery life of
the underwater flashlights used in Roviana Lagoon.
2.4. Community-based underwater monitoring program
In March 2004 four Roviana spearfishermen who exploited FSAs
(free diving) and were also experienced SCUBA divers received
training in monitoring spawning aggregations (Rhodes, 2004). Fol-
lowing this training community approval was sought and given to
establish a 2 year community-based monitoring program at the
FSA reported on here (Hamilton and Kama, 2004). A monitoring
team and protocols were established, and over the next 2 years
the senior author provided scientific advice, mentoring, logistical
and field support to Roviana community monitors.
To determine the seasonality with which aggregations form a
250 m by 10 m wide (2500 m
2
), 20 m deep belt transect was placed
at the FSA in April 2004, and a second 200 m by 10 m wide
(2000 m
2
), 10 m deep belt transect placed at the FSA in March
2005 (Fig. 2). The upper and lower boundaries of transects were
marked by inserting 1 m long re-bar stakes into the reef at 10 m
(horizontal) intervals, and white PVC pipe sleeves were placed over
each re-bar stake to increase visibility. The two transects covered
12% of the total FSA area, exceeding the 10% minimum area that
is recommended in order to ensure sufficient precision (Pet et al.,
2006). A HOBO
Ò
data logger (Water Temp Pro H2O-001, Onset,
Southern MA, USA) was placed at the start of the deep transect
(20 m) in October 2004 and recorded water temperatures hourly
until it was recovered in June 2006.
Transects were monitored by underwater visual census (UVC)
in the early afternoon on 100 days between the 19th April 2004
and the 12th June 2006 (Table 1). Initially monitoring occurred
once a month on the new moon. The decision to monitor on the
new moon was based on local knowledge and UVC surveys con-
ducted at this site in March 2004, which showed peak FSAs abun-
dances persisted several days after the new moon had passed. It
was expected that sampling on the new moon would provide a
‘snapshot’ of the peak aggregation density. We became aware of
full moon P. areolatus aggregations in October 2004 and began reg-
ular full moon monitoring in March 2005.
To verify that new moon monitoring conformed to periods of
peak density and abundance, intensive (daily) UVC surveys were
conducted just before and just after the new moon in February
and March 2005 (6 and 5 days respectively) and February 2006
(7 days). To better understand daily aggregating patterns intensive
surveys were also conducted over all lunar phases between March
and April 2006. One of the authors (MG) led all 100 UVC surveys,
accompanied by another trained monitor. During monitoring, di-
vers swam side-by-side along the midpoint of a transect, maintain-
ing a position several metres above the aggregated fish. Monitors
recorded the total number of each of the three species sighted
within transect boundaries.
2.5. Calculation of FSA area
In order to estimate maximum FSA abundances the total aggre-
gation area was estimated in March 2005 and 2006. In both years
we placed permanent markers at the aggregation boundaries
where densities declined rapidly and neared non-reproductive val-
Fig. 1. The lagoon and reef habitat at the western end of Roviana Lagoon. The location of the provincial centre Munda is shown.
248 R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257
Author's personal copy
ues (Pet et al., 2006). Float lines were then attached to each marker
and sent to the surface, and a handheld GPS was used to mark
aggregation boundaries from the surface (Rhodes and Sadovy,
2002). The start and ends of both transects were marked using
the same method. In June 2006 we made a 3-D bathymetric map
of the FSA using a low cost bathymetric mapping method (Fig. 2).
The method converts echosound data collected in sparse geometry
over the reef by a Lowrance brand fishfinder (LCX-15 MT, Lowrance
Electronics Inc., Oklahoma, USA) into a three dimensional map
suitable for analysis with ARCGIS 9 (ESRI
Ò
California, USA) soft-
ware (see Zurk et al., 2006; Heyman et al., 2007 for details). We cal-
culated total FSA area in 2005 and 2006 by importing GPS points
onto the bathymetric map using ArcView. We subdivided the total
FSA area into a shallow (high density P. areolatus) stratum (3–
15 m) and a deep (low density P. areolatus) stratum (15.1–50 m)
(Fig. 2). Estimates of total population size per month were calcu-
lated by extrapolating mean transects counts for each depth stra-
tum using the formula: No. fish in transect total aggregation
stratum area/transect area. Total estimates are the sum of the esti-
mated abundances in the shallow and deep stratum (Nemeth,
2005).
2.6. Statistical analysis
The mean weights of P. areolatus speared outside of the FSA and
at the FSA, and the mean CPUE of P. areolatus and Epinephelus spp.
speared outside of the FSA (all lunar periods) and at the FSA during
the second lunar quarter (the period when FSAs peak) were com-
pared using Mann–Whitney rank sum tests as data were nonpara-
metric. Mann–Whitney rank sum tests were also used to compare
the mean densities of P. areolatus on new and full moons. Wilcoxon
Signed rank tests were used to compare mean densities of E. fusco-
guttatus,E. polyphekadion and P. areolatus on shallow and deep
transects as these data were paired and nonparametric. All statis-
tical tests were conducted in SigmaStat 3.5 (Systat Software, San
Jose, California, USA).
Fig. 2. Bathymetric map of the FSA. The red line represents the midpoint of the shallow 200 m long transect and green line represents the midpoint of the deep 250 m long
transect. The green area shows the shallow (3–15 m) stratum and the purple area shows the deep (15.1–50 m) stratum of the FSA. The yellow dashed line shows the region
where the highest densities of E. fuscoguttatus and E. polyphekadion are found.
Table 1
The number of days that transects were surveyed during new moon, 1st 1/4, full
moon and 2nd 1/4 in the months of April 2004–June 2006.
Date New moon 1st 1/4 Full moon 2nd 1/4
April 2004 1 0 0 0
May 2004 1 0 0 0
June 2004 1 0 0 0
July 2004 1 0 0 0
August 2004 1 0 0 0
September 2004 1 0 0 0
October 2004 1 0 1 0
November 2004 1 0 0 0
December 2004 1 0 0 0
January 2005 1 0 0 0
February 2005 3 0 1 3
March 2005 4 0 1 1
April 2005 1 0 1 0
May 2005 1 0 1 0
June 2005 1 0 1 0
July 2005 1 0 1 0
August 2005 1 0 1 0
September 2005 1 0 1 0
October 2005 1 0 1 0
November 2005 1 0 1 1
December 2005 1 0 1 1
January 2006 2 0 1 2
February 2006 2 0 1 3
March 2006 6 0 3 6
April 2006 7 6 7 7
May 2006 1 0 1 0
June 2006 0 0 1 0
Total 44 6 26 24
R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257 249
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3. Results
3.1. Creel survey
The weight (kg) and proportion of total catch (%) of different
species captured in the 2001 creel survey are presented in Table 2.
Serranids made up 23.6% of the nighttime catch, with P. areolatus
representing 76% of the total serranid catch. A detailed breakdown
of the P. areolatus and Epinephelus spp. creel data is presented in
Table 3. Seventy-nine percentage of P. areolatus caught (244/308)
[representing 87% (295.9 kg/345.3 kg) of the P. areolatus catch by
weight] were taken at the FSA over five nights in January and
March 2001 (12% of total sample days). All of these large catches
were made during the second lunar quarter, with the highest
catches by number, weight and CPUE made 1 day before the new
moon in January and March 2001 (Table 3). The mean CPUE of P.
areolatus obtained from the FSA during the second lunar quarter
was significantly greater than the mean CPUE of P. areolatus ob-
tained on reefs outside of the FSA (all lunar periods) (9.107 kg/fish-
er/h ± SE 2.59 kg (n= 6 trips) and 0.318 kg/fisher/h ± SE 0.07 kg
(n= 30 trips), respectively; P< 0.001). The mean weight of P. areol-
atus speared from within the FSA was significantly greater than
outside the FSA (1.253 kg (SE = 0.06 kg) and 0.827 kg (SE = 0.10 kg),
respectively; P= 0.032).
E. fuscoguttatus and E. polyphekadion also aggregate at this FSA
in large numbers from December to April during the second lunar
quarter (see below), however the mean CPUE of Epinephelus spp.
captured on reefs outside of the FSA (all lunar periods) and at the
FSA (during the second lunar quarter) [0.51 kg/fisher/h ± SE
0.18 kg (n= 30 trips) and 0.68 kg/fisher/h ± SE 0.28 kg (n= 6 trips),
respectively] were not significantly different at
a
= 0.05.
The total weights and CPUE for P. areolatus captured at the FSA
during the second lunar quarter in December 2005 and April 2010
were very similar to the maximum weights and CPUE obtained at
the FSA in the 2001 creel survey (Table 3).
3.2. UVC surveys
3.2.1. Inter-annual and lunar seasonality
At the FSA E. fuscoguttatus aggregated on the new moon 4 or
5 months annually between December and April. The E. polypheka-
dion reproductive season was briefer, with aggregations forming
on the new moon in March 2005 and February and March 2006.
In contrast, P. areolatus aggregations formed throughout the year
on both new and full moons (Fig. 3). On the shallow transect signif-
icantly higher densities of P. areolatus were sighted on the new
moons (P= 0.004), but on the deep transect the mean densities of
P. areolatus sighted on new and full moons were not significantly
different at
a
= 0.05. The largest new moon aggregations of P. areol-
atus coincided with periods when E. fuscoguttatus and E. polypheka-
dion aggregations peaked.
3.2.2. Influence of depth on species distributions
On the new moon E. fuscoguttatus densities were higher in deep
water (P= 0.014), whereas E. polyphekadion densities did not differ
significantly between depths at
a
= 0.05. On both the new and full
moon the densities of P. areolatus were significantly higher in shal-
low water (P< 0.001 and P= 0.008 respectively).
3.2.3. Daily aggregation patterns
Intensive daily monitoring that was conducted on 39 days be-
tween 14th March and 30th April 2006 allowed a close examina-
tion of the build-up of FSAs (Fig. 4). In March 2006 E.
fuscoguttatus began to arrive at the FSA 6 days prior to the new
moon, with peak densities occurring 1–4 days prior to the new
moon. In the same month E. polyphekadion began to aggregate at
least 7 days prior to the new moon, with peak densities 1–3 days
Table 2
Weight (kg) and proportion of total catch (%) of different species caught in the night
time creel survey conducted between the 23rd of January and 20th April 2001. Data is
summed across 41 separate spearfishing trips during this period. Eleven trips targeted
the fish spawning aggregation (FSA) and 30 trips targeted outer reefs outside the FSA
but within 12 km of the FSA (see Section 2.3).
Species kg %
Ancanthuridae
Acanthurus lineatus 14.8 0.77
Acanthurus nigricauda 97.8 5.06
Acanthurus spp. (not listed above) 151.4 7.84
Ctenochaetus striatus 1.2 0.06
Naso lituratus 101.7 5.27
Naso spp. (not listed above) 107.8 5.58
Balistidae
Balistoides viridescens 7.8 0.40
Pseudobalistes flavimarginatus 31.7 1.64
Carangidae
Caranx spp. 9.8 0.51
Cheloniidae
Chelonia mydas 40.6 2.10
Eretmochelys imbricata 20.7 1.07
Diodontidae
Diodon hystrix 6.1 0.32
Ephippidae
Platax teira 1.8 0.09
Haemulidae
Plectorhinchus spp. 18.2 0.94
Holocentridae
Myripristis spp. 1.3 0.07
Sargocentron spp. 1.9 0.10
Labridae
Cheilinus undulatus 23.8 1.23
Lethrinidae
Lethrinus erythracanthus 8.1 0.42
Lethrinus hypselopterus 16.9 0.87
Lethrinus spp. (not listed above) 29.6 1.53
Monotaxis grandoculis 10.6 0.55
Lutjanidae
Lutjanus gibbis 6.7 0.35
Lutjanus rivulatus 4.5 0.23
Lutjanus spp. (not listed above) 25.3 1.31
Macolor macularis 16.9 0.87
Mullidae
Parupeneus spp. 24.1 1.25
Muraenidae
Gymnothorax spp. 2.5 0.13
Ostraciidae
Ostracion cubicus 9.1 0.47
Palinuridae
Panulirus penicillatus 14.1 0.73
Panulirus vesicolor 10 0.52
Scaridae
Bolbometopon muricatum 512.1 26.51
Scarus spp. 110.2 5.71
Sepiidae
Sepia spp. 10.5 0.54
Serranidae
Epinephelus spp. 110.6 5.73
Plectropomus areolatus 345.3 17.88
Siganidae
Siganus lineatus 0.4 0.02
Siganus puellus 10.8 0.56
Sphyraenidae
Sphyraena barracuda 14.8 0.77
Total 1931.5 100.00
250 R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257
Author's personal copy
prior to the new moon. For these two species no clear aggregating
pattern was obvious in April 2006, as by then the spawning season
for that year had ended. In March 2006 P. areolatus were already
aggregated on the full moon, with peak densities sighted 1–5 days
prior to the new moon. In April 2006 the P. areolatus aggregation
was smaller and the pattern of FSA formation differed somewhat,
with P. areolatus beginning to aggregate just after the full moon,
and peak densities occurring 1–6 days prior to the new moon.
Additional intensive surveys that were conducted around the
new moon period in February and March 2005 and February
2006 reveal that the lunar day on which FSAs begin to decline after
presumed spawning can vary, with FSAs declining on the new
moon or 1 or 2 days after new moon (Fig. 5).
3.2.4. Temperature
The onset of the E. fuscoguttatus reproductive season began
shortly after sea temperatures had begun to rise from their annual
lows, with peak spawning months occurring during periods of
maximum sea temperatures (Fig. 3). E. polyphekadion FSAs also oc-
curred during periods when sea temperatures were near their
maximum. Mean monthly sea temperatures had no clear associa-
tion on the formation of P. areolatus FSAs (Fig. 3). There was no cor-
relation between daily water temperatures and the pattern of
monthly aggregation formation for E. fuscoguttatus,E. polyphekadi-
on or P. areolatus (Fig. 4).
3.3. Aggregation areas and total population size estimates
In March 2005 the total FSA area was 36,503 m
2
(shallow stra-
tum = 8698 m
2
, deep stratum = 27,805 m
2
). In March 2006 FSAs oc-
curred over a slightly larger horizontal reef area, and as such, the
total FSA was 38,462 m
2
(shallow stratum = 9157 m
2
, deep stra-
tum = 29,269 m
2
). Estimates of the total number of E. fuscoguttatus,
E. polyphekadion and P. areolatus present at the FSA on the new
moon from March 2005 to May 2006 are presented in Table 4.
4. Discussion
4.1. Aggregation seasons
Between 100 and 700 E. fuscoguttatus aggregated at the study
site in the week leading up to the new moon during the months
of December–April, and 200–300 E. polyphekadion aggregated in
the week leading up to the new moon in the months of February
Table 3
Detailed breakdown of the 2001 creel data presented in Table 2 for P. areolatus and Epinephelus spp. Data for several P. areolatus catches that were made at the FSA in 2005 and
2010 is also shown.
Date Location Lunar stage No. fishers Effort (h) Plectropomus areolatus Epinephelus fuscoguttatus
Weight (kg) No. CPUE (kg/h
1
) Weight (kg) No. CPUE (kg/h
1
)
23.1.01 FSA 2nd 1/4 2 5 84 70 16.80 1.2 1 0.24
24.1.01 Outside 2nd 1/4 2 6 0 0 0 0 0 0
26.01.01 FSA New moon 2 9 0.8 1 0.09 2 2 0.33
30.1.01 Outside New moon 1 2.5 2.4 5 0.96 0 0 0
31.01.01 Outside New moon 1 3 3.1 4 1.03 0 0 0
2.2.01 Outside 1st 1/4 1 3.5 0 0 0 0.5 1 0.14
3.2.01 Outside 1st 1/4 1 2.5 1.3 5 0.52 1.6 1 0.64
18.2.01 Outside 2nd 1/4 2 4 4.1 5 1.03 5.2 1 1.3
21.2.01 Outside 2nd 1/4 2 8 0.2 1 0.03 3.2 3 0.4
3.3.01 Outside New moon 2 6.5 0 0 0 0.6 1 0.09
4.3.01 FSA 1st 1/4 2 6 2.9 4 0.48 4.5 1 0.75
5.3.01 Outside 1st 1/4 2 6 1.7 3 0.28 3.7 3 0.63
6.3.01 Outside 1st 1/4 1 4 0 0 0 0 0 0
8.3.01 Outside 1st 1/4 2 6 0 0 0 2 2 0.33
11.3.01 Outside Full moon 2 5.5 3.2 3 0.58 2.5 3 0.45
12.3.01 Outside Full moon 2 8 3.1 2 0.39 4.9 3 0.39
13.3.01 FSA Full moon 1 4 1.5 2 0.38 6.1 1 1.53
14.3.01 Outside Full moon 2 6 1.5 2 0.25 1.7 2 0.28
15.3.01 Outside Full moon 2 6.5 3.8 3 0.58 1.8 1 0.28
16.3.01 Outside 2nd 1/4 2 6 0.5 1 0.08 21.5 6 3.58
17.3.01 Outside 2nd 1/4 1 3 0 0 0 0 0 0
18.3.01 Outside 2nd 1/4 2 4 0 0 0 0.7 1 0.18
19.3.01 FSA 2nd 1/4 2 4 4 3 1.00 4 1 1
21.3.01 FSA 2nd 1/4 2 6 26.8 18 4.47 0 0 0
22.3.01 FSA 2nd 1/4 2 5.5 29.2 24 5.31 8.5 3 1.55
22.3.01 Outside 2nd 1/4 2 6.5 0 0 0 0 0 0
23.3.01 FSA 2nd 1/4 2 5.5 70.6 61 12.84 0 0 0
24.03.01 FSA 2nd 1/4 2 6 85.3 71 14.22 7.6 4 1.27
25.03.01 Outside New moon 1 3 0 0 0 1.3 1 0.43
26.03.01 FSA New moon 2 6 1.4 2 0.23 9.5 5 1.58
29.3.01 Outside New moon 1 2.5 0 0 0 0 0 0
30.3.01 Outside New moon 1 3 0 0 0 11.4 4 3.8
31.3.01 Outside New moon 1 3 1.9 1 0.63 1.2 1 0.4
1.4.01 FSA New moon 2 5.5 2.4 3 0.44 0 0 0
7.4.01 Outside 1st 1/4 2 6 3.4 5 0.57 0 0 0
8.4.01 Outside Full moon 1 3 3.2 5 1.07 0 0 0
11.4.01 Outside Full moon 1 2.5 1.7 1 0.68 3.1 3 1.24
12.4.01 Outside Full moon 1 2.5 1.3 3 0.53 0.3 1 0.23
18.4.01 Outside 2nd 1/4 1 3 0 0 0 0 0 0
19.4.01 Outside 2nd 1/4 1 3 0 0 0 0 0 0
20.4.01 Outside 2nd 1/4 2 7.5 0 0 0 0 0 0
26.12.05 FSA 2nd 1/4 2 8 74.5 ? 9.3 ?
28.12.05 FSA 2nd 1/4 2 8 87.1 ? 10.9 ?
9.4.10 FSA 2nd 1/4 2 8 72.5 ? 9.1 ?
R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257 251
Author's personal copy
and March. Clearly defined spawning seasons of 2–5 months have
been reported for E. fuscoguttatus and E. polyphekadion in various
other geographies (e.g. Johannes et al., 1999; Rhodes and Sadovy,
2002; Robinson et al., 2008). In Roviana Lagoon P. areolatus aggre-
gated on new and full moon in every month of the year, with abun-
dances ranging from 100 to 1000 individuals. Densities of P.
areolatus in shallow water were significantly higher on new moons.
P. areolatus has also been shown to form new moon FSAs through-
out the year in Papua New Guinea and Palau (Johannes et al., 1999;
Hamilton et al., 2011), however neither of these studies conducted
full moon monitoring. In Komodo National Park, Indonesia, P. areol-
atus aggregations occur on the full moon between September and
Fig. 3. Mean densities (±1 SE) of Epinephelus fuscoguttatus,Epinephelus polyphekadion and Plectropomus areolatus on the deep (20 m) and shallow (10 m) transects on the new
and full moons between April 2004 and June 2006. Mean monthly seawater temperature (±1 SE) is shown from October 2004–June 2006. Note that monitoring on the shallow
transect commenced in March 2005 and y-axis scale differs between panels for presentation clarity.
252 R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257
Author's personal copy
February, with occasional new moon aggregations forming be-
tween April and July (Pet et al., 2005).
We believe that in most instances the full moon aggregations
observed in our study represent the beginning of a prolonged per-
iod of FSA build up, with spawning occurring around the new
moon. The daily monitoring conducted in March and April 2006
provides evidence of this, with small full moon aggregations build-
ing rapidly approximately a week prior to the new moon. Similar
patterns have also been observed for this species in Palau (Johan-
nes et al., 1999), and this pattern was recently validated for P.
areolatus in Manus Province, Papua New Guinea, where 416 P.
areolatus were captured, sexed and released over 16 days of contin-
uous fishing at a FSA between the 29th of April (full moon) and the
14th of May 2010 (new moon). None of the captured P. areolatus
had developed oocytes or ripe sperm until the second lunar quarter
(Almany and Hamilton, unpublished data).
However, our above interpretation is complicated by the fact
that in October 2004 and October and November 2005 full moon
aggregations of P. areolatus were larger than the new moon aggre-
gations. Hence, we cannot rule out the possibility that full moon
spawning occurs in some months of the year, which in turn sug-
gests that two different populations of P. areolatus may be using
the same spawning site, with one population larger than the other.
Two alternative explanations for the large full moon aggregations
is that in some months fishing pressure may have greatly reduced
the size of the P. areolatus aggregation by the time new moon mon-
itoring occurred, or that in these months peak aggregations had be-
gan to decline by the time new moon monitoring took place.
In Melanesia, FSAs of E. fuscoguttatus,E. polyphekadion and P.
areolatus disperse around the new moon; however, the specific lu-
nar day on which aggregations disperse can vary slightly both
within and between nearby FSAs of the same species (Johannes,
1989; Hamilton et al., 2011). The intensive UVC surveys that were
conducted in February and March 2005 and February 2006 indicate
that our new moon sampling protocols captured the peak spawn-
ing periods, with peak densities of all three species persisting until
at least the new moon in these months. However in March 2006
peak aggregations of E. fuscoguttatus,E. polyphekadion and P. areol-
atus only persisted until 1 day prior to the new moon. The observed
inter-monthly and inter-annual variability in when FSAs peak and
subsequently disperse highlights the inherent difficulty in sam-
pling peak aggregations representatively between successive
months and years. While this variability did not inhibit our ability
to determine aggregation seasons, it shows that in at least 1 month
of this study the new moon UVC survey occurred after peak densi-
ties of all three species had began to decline.
Fig. 4. The daily aggregation trends of Epinephelus fuscoguttatus,Epinephelus polyphekadion and Plectropomus areolatus (±1 SE) on deep (20 m) and shallow (10 m) transects in
relation to new and full moons between the 14th March and 30th April 2006. Mean daily seawater temperature is shown. Note that y-axis scale differs between panels for
presentation clarity.
R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257 253
Author's personal copy
4.1.1. Temperature
Changing water temperatures have been linked to the onset and
cessation of the spawning season for aggregating groupers and
snappers in both Australia and the Caribbean (Colin, 1992; Samoi-
lys, 1997; Heyman et al., 2005). In Roviana Lagoon only E. fusco-
guttatus showed a possible correlation between temperature and
the onset of the annual spawning season, with UVC monitoring re-
sults showing that E. fuscoguttatus initiates spawning aggregation
formation 1 or 2 months after water temperatures have began to
rise from their annual lows, with peak aggregations occurring dur-
ing periods of maximum sea temperatures (30 °C). This correla-
tion contrasts with recent findings in Pohnpei, where E.
fuscoguttatus forms spawning aggregations during periods of sea-
sonally low water temperatures (28.5 °C) (Kevin Rhodes, pers.
comm.). In Roviana Lagoon none of the three grouper species stud-
ied showed any correlation between daily water temperatures and
the pattern of monthly aggregation formation. From the Roviana
and Pohnpei data, it appears that if temperature acts to stimulate
reproductive activity, it alone is not likely the overriding environ-
mental factor. Additional temperature data from other regional
spawning sites for these species may help clarify what role, if
any, temperature plays in reproduction.
4.2. Vulnerability of FSAs to spearfishing
Of the three groupers studied, P. areolatus is the most vulnera-
ble to nighttime spearfishing during aggregation periods. Night-
time spearfishermen that targeted the FSA during the second
lunar quarter obtained P. areolatus at a CPUE 29 times higher than
CPUE obtained outside the FSA. Likewise, P. areolatus captured at
the FSA were significantly larger than those captured outside.
The nighttime spearfishing trips that were conducted at the FSA
in December 2005 are insightful since they occurred during a per-
iod when UVC monitoring took place. Over two nights in December
2005 (5 and 3 days prior to the new moon) two spearfishermen
captured 161.6 kg of P. areolatus from the FSA, which represents
approximately 129 fish, based on the mean weight of P. areolatus
(1.253 kg) captured at the FSA in the 2001 creel survey. A UVC sur-
vey conducted in that same month provides an estimate of 299 P.
areolatus at the FSA on the new moon (i.e., 72 h after the last
spearfishing trip). If we account for the fish removed from this site
prior to UVC monitoring, and assume that the peak FSA persisted
until the new moon in December 2005, then we can estimate that
over two nights two spearfishermen removed 30% (129/429) of the
P. areolatus FSA in 16 h or less. A more conservative estimate is ob-
tained if we assume that the peak P. areolatus FSA only persisted
until a day prior to the new moon in December 2005. Intensive sur-
veys show that on average densities of P. areolatus sighted the day
after peak aggregation periods are 50% lower than the previous
day. Thus we can estimate that in peak periods 858 P. areolatus
were present at the site and over two nights two spearfishermen
removed approximately 15% (129/858) of the P. areolatus FSA.
Other studies have shown similar vulnerabilities of the species to
hook and line fishing. Specifically, Wilson et al. (2010) used UVC
and CPUE surveys to estimate that 20–25 hook and line fishers in
Raja Ampat, Indonesia, removed more than two-thirds of a large
P. areolatus aggregation in 6 days.
E. fuscoguttatus and E. polyphekadion also aggregate in shallow
and deep water at the FSA during the second lunar quarter be-
tween December–April, however CPUE for Epinephelus spp. at the
FSA were not significantly different from CPUE on reefs 1–12 km
away from the FSA. The dominance of P. areolatus in FSA catches
is attributable to four factors. Firstly, some Roviana spearfishermen
prefer not to spear large aggregated serranids such as E. fuscogutt-
atus, as they have to spend considerable time filleting this species
before sale, whereas P. areolatus is purchased whole at fisheries
centres in Munda. Secondly, P. areolatus is an intermediate size that
is easy for spearfishermen to catch and handle, whereas spearing
the considerably larger E. fuscoguttatus risks gear damage or loss.
Thirdly, P. areolatus is relatively inactive at night and consequently
easier to spear than E. polyphekadion and E. fuscoguttatus, which are
more active and often flee from divers (Hamilton et al., 2005). Fi-
March 2005
-3 -2 -1 0 1 2 3
0
10
20
30
40
March 2006
-3 -2 -1 0 1 2 3
0
10
20
30
40
Febuary 2005
-3 -2 -1 0 1 2 3
Per 1000 m2
0
10
20
30
40
3 days before and after the new moon. New moon = 0
Febuary 2006
-3 -2 -1 0 1 2 3
0
10
20
30
40
Plectropomus areolatus
Epinephelus fuscoguttatus
Epinephelus polyphekadion
Fig. 5. Mean densities (±1 SE) of Epinephelus fuscoguttatus,Epinephelus polyphekadion and Plectropomus areolatus on the deep (20 m) transect before, during and after new
moon in February and March 2005 and 2006.
254 R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257
Author's personal copy
nally, as revealed in the UVC data reported here, P. areolatus is the
most abundant species in shallow water and thus search time is
likely lower.
4.3. Local knowledge of FSAs
This study shows how local knowledge on FSAs is utilised to
maximise capture success, with Roviana spearfishermen predomi-
nating targeting the FSA during the second lunar quarter, when
numbers of P. areolatus are at their maximum in shallow water.
In Roviana Lagoon spearfishermen provided detailed information
on the locations of FSAs, species composition, the lunar stages
when FSAs disperse, depth distributions of aggregated fish and
their behaviours (Hamilton and Kama, 2004). This level of detail
is not surprising, as fishers from the Western Solomon Islands
are renowned for having highly detailed local knowledge (e.g.
Hviding, 1996; Johannes, 1989; Hamilton and Walter, 1999; Asw-
ani and Vaccaro, 2008).
Nevertheless, local knowledge of the October to January pazara
spawning season was incorrect for the FSA reported on here, with
UVC data demonstrating that aggregations of E. fuscoguttatus and E.
polyphekadion occurred from December to April. Furthermore, P.
areolatus aggregations of variable size occurred in virtually every
month of the year, and often from full to new moons, information
that was absent from the Roviana local knowledge base. We do not
know why local knowledge on the pazara season did not prove to
be correct in this instance. One possible explanation is that the
FSA reported on here has a different spawning season from other
well known FSAs in central and eastern Roviana Lagoon that have
been exploited for generations (Hamilton and Kama, 2004), and
Roviana fishermen may have simply assumed that this recently
discovered FSA had the same spawning seasons.
This finding highlights that while local knowledge can be of
great value, it will often only provide part of the picture and at
times may be inconsistent with scientific findings (e.g. Daw
et al., 2011; Ruddle and Davis, 2011). As a result, local knowledge
should be independently validated before it is used as the basis for
management or conservation (Usher, 2000), especially when it re-
lates to the management of vulnerable species and critical habitats.
Indeed, when we held the initial meeting with local leaders in
Roviana that claim ownership of the FSA reported on here, they ex-
pressed interest in placing a closed season at this FSA from Octo-
ber–January based on their traditional knowledge of the Roviana
pazara season (Hamilton and Kama, 2004). However, when UVC
data were presented back to local leaders they realised that a
closed season from October to January would offer limited protec-
tion to E. fuscoguttatus and E. polyphekadion, and very little protec-
tion to P. areolatus. Consequently they declared this FSA as a year-
round no-take MPA in 2006.
4.4. Success and challenges of running a community-based monitoring
program
In Roviana Lagoon the decision to train local spearfishermen in
monitoring was pivotal to both the success of the UVC program
and the conservation of this FSA. With sufficient training and men-
toring, spearfishermen who had limited formal education became
competent FSA monitors, due to their acute underwater observa-
tional skills. As their awareness on the importance of maintaining
FSAs grew they advocated for this FSA to be protected, and since
monitoring ceased in 2006 have not returned to fish at the FSA. De-
spite these benefits, monitoring is expensive and it is unrealistic to
think that communities (or even provincial fisheries departments)
in Melanesia could fund ongoing FSA monitoring programs. The di-
rect cost of running the Roviana FSA monitoring program for
2 years was USD $25,000. This included salaries for FSA monitors,
boat hire, SCUBA equipment and insurance. This amount does
not include the indirect costs of having the senior author support
this program. We suggest that in the short to medium term, FSA
monitoring programs should be co-funded by environmental NGOs
and national government agencies until a long-term sustainable
funding solution is achieved.
4.5. Current status of the FSA
Low levels of nighttime spearfishing (2–6 incidents a year) have
continued to occur at the FSA since it was declared a community-
based MPA in 2006 (MG personal observations). Incidents of
poaching at the FSA appear to relate to three factors. Firstly, multi-
ple communities claim customary rights to fish this FSA, making
consensus on management difficult. Secondly, the FSA is situated
some distance from communities, which means poachers are unli-
kely to be seen and thirdly, local leaders and provincial fisheries
officers have limited capacity to enforce the closure. Despite some
poaching, respect for this closure is generally good, and anecdotal
observations of the FSA indicate no changes in the abundances of E.
fuscoguttatus and E. polyphekadion and only slight reductions in the
abundances of P. areolatus since 2006 (MG personal observations).
The limited creel data that we have from 2010 supports Giningele’s
observations, with the total weight and CPUE of P. areolatus landed
on a single night in April 2010 being similar to the highest total
weight and CPUE of P. areolatus landed on single nights in 2001
and 2005.
5. Conclusions
In this paper we have shown how local knowledge and marine
science can be utilised in combination to conserve critical life
stages of vulnerable species. Specifically we were interested in
the conservation of E. fuscoguttatus,E. polyphekadion and P. areola-
tus FSAs in Roviana Lagoon. By documenting local knowledge of
FSAs and conducting a spearfishing creel survey we obtained base-
line information on the locations, species composition, seasons,
status and threats to grouper FSAs in Roviana Lagoon. To further
advance our understanding of FSAs a 2-year long community-
based monitoring program was established at the largest known
FSA in Roviana Lagoon.
The results of this cooperative NGO-community study shows
that P. areolatus is extremely vulnerable to nighttime spearfishing,
due to long residency times at FSAs, high densities in shallow
Table 4
Total population estimates of E. fuscoguttatus,E. polyphekadion and P. areolatus at the FSA on the new moon between the months of March 2005 and May 2006.
March
2005
April
2005
May
2005
June
2005
July
2005
August
2005
September
2005
October
2005
November
2005
December
2005
January
2006
February
2006
March
2006
April
2006
May
2006
E. fuscoguttatus 606 112 56 0 0 0 6 41 0 228 655 704 507 0 6
E. polyphekadion 199 18 35 0 0 0 0 0 0 0 23 299 275 6 0
P. areolatus 604 283 445 353 299 34 64 199 102 299 1089 1039 576 367 234
Total No. groupers 1409 413 536 353 299 34 70 240 102 527 1767 2042 1358 373 240
R.J. Hamilton et al. / Biological Conservation 145 (2012) 246–257 255
Author's personal copy
water and the ease with which it can be approached at night.
Clearly FSAs of P. areolatus need to be protected from nighttime
spearfishing wherever it is practiced. Conversely, the depth distri-
butions and diver avoidance behaviour of deeper-dwelling E. fusco-
guttatus and E. polyphekadion at FSAs offers them a greater degree
of protection from free diving spearfishers. However both E.
polyphekadion, and to a lesser extent E. fuscoguttatus, are highly
susceptible to hook and line fisheries (Rhodes and Sadovy, 2002;
Rhodes et al., 2011), and are therefore also deserving of protection.
In Roviana Lagoon the monitoring program served as an effec-
tive vehicle for building community support for managing the
FSA, and it also provided an independent validation of local knowl-
edge on grouper spawning seasons. Results of the monitoring
study showed that while local knowledge can be highly detailed,
like all knowledge systems, it is not infallible (Johannes et al.,
2000), with science-based underwater monitoring building a more
complete picture of FSA seasons than local knowledge alone.
Clearly, local knowledge is most useful in management and conser-
vation if it is carefully collected, evaluated and validated, and the
cultural sensitivities and confidentiality of local knowledge is re-
spected (Ruddle et al., 1992; Usher, 2000; Daw, 2008; Hamilton
et al., 2012).
In this study it was local knowledge and the scientific results of
the community-based monitoring program that led to the develop-
ment of appropriate management measures for this FSA, with the
aggregation declared a year-round community-based MPA in
2006. Finally, while we cannot prove that the conservation efforts
reported on here have assisted in the FSA remaining healthy, one
thing is clear; this site is one of the largest known multi-species
FSAs in Melanesia, and its ongoing preservation is critical for the
long-term health of grouper fisheries in Roviana Lagoon.
Acknowledgments
First and foremost we would like to thank W. Kama for assisting
with the local knowledge survey and FSA monitoring. We also
thank S. Baso, G. Gadepeta and S. Kari for assisting with FSA mon-
itoring. We are grateful to the Munda area communities who al-
lowed us to work on their reefs. We thank N. Peterson for
producing Fig. 1, and G. Almany and K. Ruddle for improving an
earlier version of this manuscript. Funding for this project was pro-
vided by Oak Foundation, The David and Lucile Packard Foundation
and The John D. and Catherine T. MacArthur Foundation.
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... IFK incorporates many terms which are used interchangeably depending on the context and sources. These include: traditional (ecological/environmental) knowledge (TK/TEK), local ecological knowledge (LEK), Indigenous and local knowledge (ILK), fisher knowledge (FK), Indigenous ecological knowledge (IEK), Indigenous skills, folk knowledge and ethnological science (Kunatuba, 1983;Berkes, 1993;Aswani and Hamilton, 2004;Veitayaki, 2005;Hamilton and Potuku, 2007;Rasalato et al., 2010;Hamilton et al., 2012;Thaman et al., 2013Thaman et al., , 2014. Pacific Islanders of Fiji and other small Pacific islands prefer the term Indigenous in place of native, ethnic and landowners and, for this reason, we used IFK to indicate the knowledge that is unique to, and owned by, Indigenous fishers, both globally and in the Pacific. ...
... The fourth and current wave (1960 -present day) delivers systematic documentation, investigation and the marriage and/or comparison of IFK with MSK, which acknowledge the local people's in-depth understanding and knowledge of their environment and resources. These reports offer better use and management approaches for the overexploited resources, and document the fast-eroding IFK of the islands (Johannes, 1981;Calamia, 1999;Johannes and Yeeting, 2000;Aswani and Hamilton, 2004;Veitayaki, 2008;Hamilton et al., 2012;Thaman et al., 2017). ...
... Fiji Wind, tidal movement, daily weather conditions, yam season, local environment conditions Kunatuba, 1983;Veitayaki, 2002 Kiribati Lunar cycle, wind, tidal movement Tebano and Tabe, 1993;Lieber, 1994;Takeda and Mad, 1996 New Caledonia Current movement, flowering or fruit bearing of selected trees, lunar cycle Teulières, 1988 Papua New Guinea Eddies, currents, driftwood, lunar cycles, seasonal periods Groves, 1936;Carrier, 1982;Hamilton et al., 2005 Samoa, Cook Islands Lunar cycle, tidal movement, wind movement (speed and direction) Mokoroa, 1981;Kramer, 1994;Herdrich and Armstrong, 2008;Solomona and Vuki, 2012;Levine and Sauafea-Le'au, 2013 Solomon Islands Lunar cycle; wind patterns; flowering, shedding and the re-growth of leaves of certain plants, wind and tidal movement, wet and dry seasons Akimichi, 1978;Gina-Whewell, 1992;Takekawa, 2000;Atu, 2005;Sabetian and Foale, 2006a Tokelau Lunar cycle Ono and Addison, 2009 Tonga Tidal movement Vaea and Straatmans, 1954;Kronen, 2002b Tuvalu Celestial movements, lunar cycle, tidal movement Kennedy, 1929;Turbott, 1950 Vanuatu Solar cycle, lunar cycle, wind, tidal patterns, cold and warm seasons, yam planting season Mondragón, 2004;Hickey, 2006 spawning aggregations of three grouper species (Hamilton et al., 2012); and in the Caroline Islands and Kiribati in Micronesia, fishers believed that an overcast sky and light rain during the day signaled good conditions for cast netting (Takeda and Mad, 1996). Indigenous fishing culture also extends to seabirds, which are important indicators for environmental conditions suitable for fishing, and show where schools of fish are present. ...
Article
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The time-tested Indigenous fishing knowledge (IFK) of Fiji and the Pacific Islands is seriously threatened due to the commercialization of fishing, breakdown of traditional communal leadership and oral knowledge transmission systems, modern education, and the movement of the younger generations to urban areas for work and/or study. Consequently, IFK, which has been orally transmitted for generations, has either been lost, not learned by the current generation, or remains undocumented. This study focuses on the critical need to conserve and include IFK as a basis for assessing the conservation status of ecologically and culturally keystone fisheries species as a basis for planning site-specific management of marine and freshwater fisheries in Fiji and the Pacific Islands. The study reviews studies of the last two and a half centuries on IFK from Fiji and elsewhere in the small oceanic islands of the Pacific, as a basis for the conservation, documentation and intergenerational transfer of this knowledge as the foundation for sustainable fisheries management. The study also reviews: the nature and conservation status of IFK, itself; and the conservation status of species considered to be of particular ecological and cultural importance; reasons for the loss of species/taxa and associated knowledge and practices; and actions that can be taken to address this loss.
... The fishers' ecological knowledge (FEK) is a kind of traditional knowledge that has been extensively studied in recent decades by a multidisciplinary science known as ethnobiology, which includes the study of knowledge and concepts developed by human societies regarding biology and ecology (Posey, 1992;Berkes, 1999;Hanazaki, 2015). Studies based on FEK have contributed with important information on the distribution, reproduction and migration of fish and benthic invertebrates, besides supporting fisheries management and delimitation of protected areas (Aswani and Lauer, 2006;Le fur et al., 2011;Silvano et al., 2006;Herbst and Hanazaki, 2014;Hamilton et al., 2012;Silvano and Begossi, 2012;Morado et al., 2021). Especially in cases where data are not available, the fishers' knowledge is often the only source of information on fishery resources, changes in fishing stocks, species composition and about environmental changes that influence the biology of resources (Johannes et al., 2000;Azzurro et al., 2011;Tesfamichael et al., 2014;Hallwass et al., 2013Hallwass et al., , 2020Ribeiro et al., 2021). ...
... The increase in accessibility of information technologies, such as methods based on Geographic Information System (GIS) has been used to integrate fishers' knowledge with scientific knowledge (Anuchiracheeva et al., 2003;Hall and Close, 2007;Gerhardinger et al., 2009;Selgrath et al., 2016). GIS techniques also have been used to delimit Marine Protected Areas in Oceania (Aswani and Lauer, 2006;Hamilton et al., 2012) and North America (Scholz et al., 2004). Based on the protocol developed by Close and Hall (2006), several studies have applied GIS to access the FEK, mostly addressing the spatial distribution of use of fishing resources or catches per unit of effort (CPUE) in artisanal coastal fisheries (Hall and Close, 2007;de Freitas and Tagliani, 2009;Moreno-Báez et al., 2010. ...
... However, these management strategies especially in the case of the implementation of marine protected areas, should be properly discussed with local fishers, besides incorporating their FEK, to avoid potential conflicts that can undermine the efficacy of these conservation strategies . Indeed, FEK has been used to delimit or propose marine protected areas with several examples in which GIS tools were applied to increase the participation of fishers' communities in this process (Scholz et al., 2004;Aswani and Lauer, 2006;Hamilton et al., 2012;de Oliveira Leis et al., 2019). ...
Article
Fishers’ ecological knowledge (FEK) has contributed to studies on the reproduction and migration of fish and marine invertebrates. With increasing accessibility to information technologies, several surveys have begun to use Geographic Information Systems (GIS) to access FEK through participatory mapping. Scientific knowledge on migration of fishery resources is fundamental to properly support initiatives for fisheries management. However, the technologies available to study migration are usually expensive and require several years of sampling. Our objective was to use GIS to access FEK and to identify the migration patterns of five fishery resources in a subtropical coastal ecosystem of the Southern Atlantic Ocean: the white catfish - Genidens barbus, the fat snook - Centropomus parallelus, the common snook - Centropomus undecimalis, the Atlantic spadefish - Chaetodipterus faber and the white shrimp - Litopenaeus schmitti. We interviewed 132 fishers in the Paranaguá estuarine complex and its adjacent coastal zone, Brazil. Of these fishers, 39 participated in the participatory mapping process. Our results based on FEK indicated that the migration of fishery resources is reproductive and occurs mainly in the later spring and summer when the species enter or exit the estuarine complex from coastal zone. The participatory mapping results indicated that G. barbus and C. faber migrate from the coastal zone to the estuary, while Centropomus species and the shrimp L. schmitti exit the estuary towards the coastal zone. The information generated by FEK and the methods used should be considered in future studies on ethno ecological research and to understand reproductive migration of these species. Furthermore, these observations could support fisheries management and environmental impact assessment of infrastructure projects.
... Convergence on the other hand mainly seems to occur together with community-inclusive resource management and a good dialogue between scientists, policy makers and communities. It may also indicate successful existing policies and conservation initiatives [96,97]. ...
... We can see a relationship between programmes involving local communities, stakeholders as well as scientists, such as those in Vietnam, Palawan and TMP, and high levels of convergence between what the natural sciences measure and what communities perceive (figure 2). This could be a supportive argument for the co-development of resource management plans as this might create a level of understanding between all involved actors and encourage ownership and responsibility [96,98]. Marine conservation programmes of non-governmental organizations (NGOs), for example, often include end-of-project evaluations that consider ecological changes compared to a baseline. ...
Article
Despite a growing interest in interdisciplinary research, systematic ways of how to integrate data from different disciplines are still scarce. We argue that successful resource management relies on two key data sources: natural science data, which represents ecosystem structure and processes, and social science data, which describes people’s perceptions and understanding. Both are vital, mutually complementing information sources that can underpin the development of feasible and effective policies and management interventions. To harvest the added value of combined knowledge, a uniform scaling system is needed. In this paper, we propose a standardized methodology to connect and explore different types of quantitative data from the natural and social sciences reflecting temporal trends in ecosystem quality. We demonstrate this methodology with different types of data such as fisheries stocks and mangrove cover on the one hand and community’s perceptions on the other. The example data are collected from three United Nations Educational Scientific and Cultural Organization (UNESCO) Biosphere reserves and one marine park in Southeast Asia. To easily identify patterns of convergence or divergence among the datasets, we propose heat maps using colour codes and icons for language- and education-independent understandability. Finally, we discuss the limitations as well as potential implications for resource management and the accompanying communication strategies.
... Convergence on the other hand mainly seems to occur together with community-inclusive resource management and a good dialogue between scientists, policy makers and communities. It may also indicate successful existing policies and conservation initiatives [96,97]. ...
... We can see a relationship between programmes involving local communities, stakeholders as well as scientists, such as those in Vietnam, Palawan and TMP, and high levels of convergence between what the natural sciences measure and what communities perceive (figure 2). This could be a supportive argument for the co-development of resource management plans as this might create a level of understanding between all involved actors and encourage ownership and responsibility [96,98]. Marine conservation programmes of non-governmental organizations (NGOs), for example, often include end-of-project evaluations that consider ecological changes compared to a baseline. ...
Article
Despite a growing interest in interdisciplinary research, systematic ways of how to integrate data from different disciplines are still scarce. We argue that successful resource management relies on two key data sources: natural science data, which represents ecosystem structure and processes, and social science data, which describes people's perceptions and understanding. Both are vital, mutually complementing information sources that can underpin the development of feasible and effective policies and management interventions. To harvest the added value of combined knowledge, a uniform scaling system is needed. In this paper, we propose a standardized methodology to connect and explore different types of quantitative data from the natural and social sciences reflecting temporal trends in ecosystem quality. We demonstrate this methodology with different types of data such as fisheries stocks and mangrove cover on the one hand and community's perceptions on the other. The example data are collected from three United Nations Educational Scientific and Cultural Organization (UNESCO) Biosphere reserves and one marine park in Southeast Asia. To easily identify patterns of convergence or divergence among the datasets, we propose heat maps using colour codes and icons for language- and education-independent understandability. Finally, we discuss the limitations as well as potential implications for resource management and the accompanying communication strategies. This article is part of the theme issue ‘Nurturing resilient marine ecosystems’.
... Local knowledge can help the decision makers to develop locally feasible solutions (Leite and Gasalla, 2013). Integrating local knowledge in resource management planning seems to promote co-management schemes between resource users and managers (Silvano and Begossi, 2005;Silvano et al., 2006;Hamilton et al., 2012;Abecasis et al., 2013;Leite and Gasalla, 2013;Bulengela et al., 2019). This is because of information on issues, such as fish populations (Aswani and Hamilton, 2004), fish diet (Silvano and Begossi, 2010) and fish reproduction (Silvano et al., 2006), and freshwater cetacean population (Leite and Gasalla, 2013), which were commonly gathered using methods from the natural sciences, can also be gathered through local knowledge. ...
... Local ecological knowledge is a prerequisite for local, context-specific solutions that help to cope with changing environments and facilitate climate change mitigation and adaptation (Mistry and Berardi, 2016). If these two types of information are cross-verified and combined, we could create a comprehensive knowledgebase for more adaptive and effective resource management (Silvano et al., 2006;Butler et al., 2012;Hamilton et al., 2012). ...
Article
Full-text available
Despite the potentially huge contributions that coastal communities might make in marine resource management and sustainability, their participation in such efforts have only been recognized recently, particularly in Southeast Asia. Involving community perceptions can offer new insights for policy makers and resource managers and can elicit strong commitment and support from the communities themselves. This article aims to understand the perceptions of coastal communities of local environmental issues, specifically how these have developed over time, to understand the expectations and perceptions of trends. Sixteen marine environmental issues were identified during stakeholder meetings in Palawan, Philippines. A co-developed survey was administered to 431 respondents from coastal communities in two municipalities (Taytay and Aborlan) and in the city of Puerto Princesa in Palawan. The results show variation in the perceptions and expectations across issues. We find that communities expect positive trends for mangrove coverage, beach tree cover, and seagrass coverage as well as for seaweed farming and quality of drinking water. The amount of plastic litter, wild fish and shellfish, and the severity of sewage pollution are perceived to get slightly worse. The aquaculture sector is expected to remain unchanged in the future as it had been in the past. We also find significant differences in how people from different areas of residence perceive their marine environment. In the discussion, we mapped these different community perceptions on existing policies and their implementation. We further recommend how community perceptions can be integrated into resource management and policy making in the future.
... The species had been very abundant around Yaeyama Islands half a century ago but the population declined drastically due to harvesting spawning aggregations. The magnitude of the spawning aggregation is known to be very large for this species among the genus (Rhodes and Tupper, 2008;Frisch et al., 2016) and the population decline is rapid (Hamilton et al., 2012;Hughes et al., 2020). Fast growth and early maturation of P. areolatus (Rhodes et al., 2013) implies that the population might recover if the fishery of this species could be effectively managed. ...
Article
Body color of the coralgroupers (Serranidae, Plectropomus) is known to vary from red to brown and dark to pale, with a vivid red color is thought to be preferred in fish markets of East Asia. This study revealed quantitative effects of the body color of coralgroupers on the market value at fish market in Okinawa, Japan. Results showed that bid price of six color grades of P. leopardus are significantly different, and normal- to dark-red individuals were sold at higher auction prices than light-brown and light-red individuals. Results also showed that unit price per kg of coralgroupers increased up to 1.5 kg body weight but slightly decreased for fish larger than 4 kg. Increase of fish supply in the market greatly reduced the bid price of the coralgroupers, and condition factor (index of fatness for individual fish) influenced the bid price of individual fish. These results indicate that an effective fisheries management strategy could be available if the optimal size and color individuals were harvested for days/weeks when a shortage of wild fish catch occurred.
... Nonetheless, the uncontrolled expansion of this sector of the fishery has the potential to rapidly increase fishing mortality and cut off the supply of migrating fish that would otherwise be captured in the handline sector of the fishery. Therefore, a potential management solution is to cap the number of traps at its current level, in which trap operators with a history of involvement in the fishery are grandfathered into their concessions and additional permits are not issued until an existing permit is relinquished (Jennings et al., 2009 (Bijoux et al., 2013;Filous et al., 2020;Hamilton et al., 2012b;Hughes et al., 2020). Nevertheless, Rangiora's longnose emperor fishery is one of the largest domestic fisheries for coral reef species in French Polynesia (DRM, 2019) and given that assuming a mean rate of natural mortality its SPR is currently estimated to be just above the minimum threshold of overexploitation, small management actions taken now could make significant improvements to the sustainability of this fishery and guarantee that the resources continue to provide for the people of Rangiroa Atoll and the greater community of French Polynesia. ...
Article
Full-text available
The spawning aggregations of coral reef species support artisanal fisheries throughout the Pacific Islands, but they are vulnerable to over exploitation and need improved fisheries management. To this aim, we employed a combination of fishery methods including life history studies to estimate the age, growth, and reproductive parameters of longnose emperor (Lethrinus olivaceus), and a length-based stock assessment to provide the community of Rangiroa Atoll with an assessment of their longnose emperor spawning aggregation fishery. The von Bertalanffy growth parameters of this species were estimated to be L∞ = 80 (75-87) cm TL, K = 0.18 (0.15-0.24), t0 =-0.82 (-1.43--0.27) with a mean natural mortality rate of 0.309 ± 0.038. The sex ratios we observed in our study support the belief that this species exhibits functional protogyny with females reaching sexual maturity at 38cm TL and approximately 3 years of age, and sex change occurring at approximately 45cm TL and 4 years of age. The Spawning Potential Ratio (SPR) of the longnose emperor stock was estimated to be between 19 to 28% across the years of this study and simulations of SPR and yield per-recruit indicate that if the community wanted to conserve >30% of the stock's SPR, the ideal minimum size limit for this species is 50cm TL. Our results provide the baseline life history information that is required to evaluate the fisheries for this species in the South Pacific region and support community-led management actions for this spawning aggregation fishery on Rangiroa Atoll. This article is protected by copyright. All rights reserved.
... This may sometimes be the only data source available, may complement biological data, and be more accurate than interviews (Daw, Robinson & Graham, 2011;O'Donnell, Molloy & Vincent, 2012;. The participatory approach adopted here can be widely applied elsewhere and has been successfully adopted in small-scale coastal fisheries (Hamilton et al., 2012;O'Donnell, Molloy & Vincent, 2012;Begossi, Salivonchyk & Silvano, 2016;Schemmel et al., 2016), recreational freshwater fisheries (Zukowski, Curtis & Watts, 2011) and for monitoring terrestrial mammals (Luzar et al., 2011). This study thus reinforces the importance of including local populations and their local knowledge in ecological studies and management plans (Danielsen et al., 2010), especially in complex socioecological systems such as tropical smallscale fisheries (Begossi, 2008). ...
Article
• Frugivorous fish provide often conflicting ecosystem services of seed dispersal and food provisioning in tropical rivers. Fishing may reduce the size and abundance of frugivorous fish, thus affecting their potential as seed dispersers, which could affect the conservation of these fish and of floodplain forests. • The goal of this study was to assess the influence of co-managed protected areas in the form of extractive reserves (RESEX) and small-scale fisheries on frugivorous fish in the Tapajós and Negro rivers, in the Brazilian Amazon. The study examined whether: (i) frugivorous fish are important for fisheries and selectively caught; and (ii) frugivorous fish abundance, size and fisheries catch per unit of effort are higher inside the RESEX than outside. • The analyses included fisheries-dependent data (3,753 fish landings) and independent data (12,730 sampled fish) collected in 16 fishing communities (eight for each river). In both rivers, frugivorous fish are among the 10 species caught the most and frugivorous biomass was proportionately higher in landings than in samplings, indicating fisheries selectivity towards these fishes. • In both rivers, catches of frugivorous fish were higher outside the RESEX than inside. Catch per unit effort and the proportion of frugivores in the catch were higher outside the RESEX in the Tapajós River but did not vary between sites inside and outside the RESEX in the Negro River. Frugivorous fish were larger inside the RESEX in the Negro, but smaller inside the RESEX in the Tapajós. • The results indicated that the ecosystem services of seed dispersal and food source provided by frugivorous fish are not in conflict in the tropical rivers studied. Therefore, these clearwater and blackwater rivers in the Brazilian Amazon show a balance between fisheries and conservation of frugivorous fish, which play an essential role in the functioning of tropical floodplain forest ecosystems.
... There are many examples in the literature of local knowledge and citizen science data being used to identify priority sites, patterns of ecological connectivity and fish nursery areas (Berkström et al., 2019). For example, identifying important coral reefs with help from fishers and SCUBA divers' extensive local knowledge(Hamilton et al., 2012;. In addition, crowdsourced online digital images and communication on social media platforms are being used to address data gaps in marine species distributions(Noble et al., 2020). ...
Technical Report
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PS 6 seeks to ensure that project studies take account of all of these factors in an approach that is driven by the understanding of ecological patterns and processes and not project impacts. Once biodiversity value has been defined at an ecologically appropriate scale then AoI can be used to define the potential direct, indirect and cumulative impacts on the biodiversity values that have been determined and quantified. However, no comprehensive guidance on how to define different spatial scales of analyses are provided. Therefore, this document seeks to provide additional guidance to support the determination of ecologically appropriates scales of analysis in order to meet the requirements of PS 6 (and aligned IFI environmental and social risk frameworks). The focus of the guidance is on defining ‘seascape’ and EAAAs, including the relationship of these areas with a project’s AoI.
Article
Local ecological knowledge provides novel, detailed and context-specific information about human and non-human use of marine ecosystems, therefore incorporating this knowledge into marine conservation planning is crucial. Participatory mapping offers an opportunity to include local knowledge in spatial planning for natural resource management. However, local knowledge presents certain challenges in the form of data inconsistencies, fuzziness, and inability to disaggregate different types and formats of knowledge. Using the case of fisheries in southern Maharashtra state, India, I demonstrate how local ecological knowledge may be used to improve the understanding of data-poor fisheries. In the context of fisheries that are globally recognised as lacking management, I examine how local ecological and spatial knowledge about species and fishing practices can be used to fill fine-scale management gaps that do not account for context-specific habitat use. I also explore how fishers’spatial knowledge is intertwined with other forms of local knowledge. The participatory mapping exercise demonstrates that although fishing communities do not profess to be interested in threatened marine species conservation, their spatial and customary fishing practices potentially align with conservation goals. Clear synergies between livelihoods and marine conservation emerge when using local ecological knowledge along with participatory mapping. This research demonstrates that successful fisheries management and marine conservation planning is possible using existing social, cultural practices, translated through geographic tools.
Article
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Many species of groupers form spawning aggregations, dramatic events where 100s to 1000s of individuals gather annually at specific locations for reproduction. Spawning aggregations are often targeted by local fishermen, making them extremely vulnerable to over fishing. The Red Hind Bank Marine Conservation District located in St. Thomas, United States Virgin Islands, was closed seasonally in 1990 and closed permanently in 1999 to protect an important red hind Epinephelus guttatus spawning site. This study provides some of the first information on the population response of a spawning aggregation located within a marine protected area. Tag-and-release fishing and fish transects were used to evaluate population characteristics and habitat utilization patterns of a red hind spawning aggregation between 1999 and 2004. Compared with studies conducted before the permanent closure, the average size of red hind increased mostly during the seasonal closure period (10 cm over 12 yr), but the maximum total length of male red hind increased by nearly 7 cm following permanent closure. Average density and biomass of spawning red hind increased by over 60 % following permanent closure whereas maximum spawning density more than doubled. Information from tag returns indicated that red hind departed the protected area following spawning and migrated 6 to 33 km to a ca. 500 km2 area. Protection of the spawning aggregation site may have also contributed to an overall increase in the size of red hind caught in the commercial fishery, thus increasing the value of the grouper fishery for local fishermen.
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