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Measuring the Performance of Marine Protected Areas: The Case of Little Cayman and Cayman Brac, Cayman Islands

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Cayman Brac and Little Cayman are small remote islands (< 30 km²) centrally located in the northwest Caribbean. These islands have no commercial fisheries to date, low fishing pressure and a relatively low population. Their Marine Protected Areas (MPAs) were established in 1986 and have never been assessed to determine their performances on coral reef fish assemblages after 24 years of conservation and active enforcement of no-take zones. With no commercial fisheries to date, this study targeted 53 species of fish considered important for reef health status and ecological function including the species most commonly targeted by fishers. For the targeted species, their biomass, size and density were investigated for comparisons between protected areas and non-protected fished areas. An Underwater Visual Census (UVC) was carried out around both islands during the months from January through to April 2009. Analysis of data collected showed no clear MPA effect concerning their efficiency, effectiveness and performance on their fish assemblages. Cayman Brac in particular only showed a significant difference (p < 0.01) in the north MPA when total mean fish size per transect were compared. Little Cayman's north MPA showed significant differences in total mean biomass per transect (p < 0.001) and total mean biomass per family (p < 0.05). In the south MPA of Little Cayman, significant differences were found in total mean biomass per transect (p < 0.001), and per family (p < 0.05), mean fish size per transect (p < 0.001), mean size classes per species (p < 0.001), including mean density per transect (p < 0.01) of MPA vs. non-MPA. Additionally , the ratios of herbivore to carnivore biomass were investigated for each MPA to determine trophic structure of each MPA. Overall, the MPAs of Cayman Brac showed no reserve effect on their fish assemblages; however the MPAs of Little Cayman exhibited a more effective MPA system, demonstrating a " reserve effect " in the southern MPA, but also indicating a vulnerability to over fishing.
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Proceedings of the 63rd Gulf and Caribbean Fisheries Institute November 1 - 5, 2010 San Juan, Puerto Rico
Measuring the Performance of Marine Protected Areas:
The Case of Little Cayman and Cayman Brac, Cayman Islands
CHARLOTTE R. DROMARD1*, CROY M.R. MCCOY2,3 and JOHN R. TURNER3
1 Laboratoire de Biologie Marine (DYNECAR), Université des Antilles-Guyane, BP 592, 97159 Point à Pitre Cedex,
Guadeloupe, *cdromard@univ-ag.fr. 2 Department of Environment, 580 North Sound Road, P.O. Box 486, Grand
Cayman KY1-1106, Cayman Islands. 3 Bangor University, School of Ocean Sciences, Menai Bridge Anglesey, LL59 5AB,
UK.
ABSTRACT
Cayman Brac and Little Cayman are small remote islands (< 30 km²) centrally located in the northwest Caribbean. These
islands have no commercial fisheries to date, low fishing pressure and a relatively low population. Their Marine Protected Areas
(MPAs) were established in 1986 and have never been assessed to determine their performances on coral reef fish assemblages after
24 years of conservation and active enforcement of no-take zones. With no commercial fisheries to date, this study targeted 53
species of fish considered important for reef health status and ecological function including the species most commonly targeted by
fishers. For the targeted species, their biomass, size and density were investigated for comparisons between protected areas and non-
protected fished areas. An Underwater Visual Census (UVC) was carried out around both islands during the months from January
through to April 2009. Analysis of data collected showed no clear MPA effect concerning their efficiency, effectiveness and
performance on their fish assemblages. Cayman Brac in particular only showed a significant difference (p < 0.01) in the north MPA
when total mean fish size per transect were compared. Little Cayman’s north MPA showed significant differences in total mean
biomass per transect (p < 0.001) and total mean biomass per family (p < 0.05). In the south MPA of Little Cayman, significant
differences were found in total mean biomass per transect (p < 0.001), and per family (p < 0.05), mean fish size per transect (p <
0.001), mean size classes per species (p < 0.001), including mean density per transect (p < 0.01) of MPA vs. non-MPA. Additional-
ly, the ratios of herbivore to carnivore biomass were investigated for each MPA to determine trophic structure of each MPA.
Overall, the MPAs of Cayman Brac showed no reserve effect on their fish assemblages; however the MPAs of Little Cayman
exhibited a more effective MPA system, demonstrating a “reserve effect” in the southern MPA, but also indicating a vulnerability to
over fishing.
KEY WORDS: Marine Protected Areas, coral reef fish, reserve effect
Evaluación de los Rendimientos de las Áreas Marinas Protegidas:
El Caso de Little Caimán and Caimán Brac, Caimán Islandés
Cayman Brac y Little Cayman son islas pequeñas y remotas (< 30 km²) localizadas en el nor-oeste del Caribe. Estas islas
tienen baja población, poca presíón de pesquería artesanal y ninguna pesquería commercial activa. Las Area Marinas Protegidas
(AMP) se establecieron en 1986 y nunca han sido monitoreadas para determinear su efecto sobre las poblaciones de peces arrecifales
luego de 24 años de activa conservación y prohibición de pesquerias comerciales. Este studio se enfocó en 54 especies de peces
consideradas importantes para la salud del arrecife y función ecológica, incluyendo species preferidas por los pecadores locales. Se
midieron la biomasa, tamaño y densidades de las poblaciones para compararlas con áreas no protegidas. Se llevó a cabo un sen so
submarino (SSU) alrededor de las dos islas desde enero hasta abril de 2009. El análisis de los datos colectados mostró pocas
diferencias en la efectividad de los AMPs comparado con las zonas no protegidas. En Cayman Brac, solo se encontró diferencia
significativa (p < 0.01) en el AMP del norte cuando se compararon los promedios de tamaño de los peces por transecta. El AMP
del norte an Little Cayman’s AMP mostró un biomasa total por transecta significativamnte mayor (p < 0.001) y una biomasa (p <
0.05) por familia mayor que en áreas no protegidas. En le AMP del sur en Little Cayman se consiguieron diferencias significativas
en la biomasa total promedio por trnasecta (p < 0.001) y promedio de tamaño por familia (p < 0.0.001), promedio de las classes de
tamaño por species (p < 0.001), incluyendo promedio de densidades por transecta ( p < 0.01), comparadas con áreas no protegidas.
Adicionalmente la relación de biomasa entre peces herbívoros y carnivoros se investigó para cada AMP para determiner la
estructura trófica dentro de cada AMP. En general, los AMPs de Cayman Brac no mostraron ningún efecto reversible en las
agregaciones de peces. Los AMPs de Little Cayman por otro lado si mostraron un efecto de proteccion más efectivo y además, una
vulnerabilidad a la sobrepesca.
PALABRAS CLAVE: Area Marina Protegida, peces arrecifales, efecto reversible
Evaluation des Performances des Aires Marines Protegées:
Le Cas de Little Cayman et Cayman Brac, Cayman Islands
MOTS CLÉS: Aires Marines Protegées, poissons coralliens, evaluation des performances
Dromard, C.R. et al. GCFI:63 (2011) Page 247
INTRODUCTION
Marine environments, such as coral reef ecosystems
are of vital importance to coastal communities in the
tropics whom rely on them as a food source and income by
exploiting their fisheries (Roberts 1995, Jennings and
Polunin 1996), but are vulnerable to anthropogenic threats
such as climate change, disease, pollution and overfishing
(Jackson, et al. 2001, Hughes et al. 2003 Gardner et al.
2003, Wilkinson 2008, Hughes et al. 2010). Additionally
natural perturbations including recurrent hurricanes in
particular the Caribbean region has had damaging long
term effect on coral reef habitat and function (Nyström et
al. 2000., Wilkinson 2008). Marine parks have become
popular new tools for conservation and fisheries manage-
ment, providing refuge coral reefs and their associated
organisms. Actually, no-take Marine Protected Areas
(MPAs) preserve the fish assemblages mainly from all
kinds of fishing and extractions, whereby allowing a “build
-up” of fish biomass (Polunin and Roberts 1993., Roberts
1995b., Gell and Roberts 2003)
Studies have shown that strict no-take zones allow fish
stocks to be restored to their natural population numbers
over time in addition to providing fish and larvae to
outlying fished area by Spillover effect (Roberts and
Hawkins 2000, McCoy et al. 2009). In the last decade, an
increasing number of studies have investigated “reserve
effect” based on comparison of fish biomass, abundance,
density and individual fish size distribution between
protected areas and unprotected openly fished areas
(Dugan and David 1993, Polunin and Roberts 1993,
Roberts 1995, Wantiez et al. 1997, Harmelin-Vivien et al.
2008, McCoy et al. 2009).
A recent study (McCoy et al. 2009) in Grand Cayman
was carried out testing the performances of the MPA on the
fish assemblages with surprising results. Though there are
no commercial fisheries, and relatively low human impacts
in Grand Cayman, fish biomass and size of individuals was
significantly higher inside the Marine Parks. Moreover,
the “occurrence” of species and the ratio between herbivo-
rous and carnivorous fishes was more balanced inside the
MPAs. This study suggest that recreational fishing,
primarily using lines and spears, can have a severe negative
effect because of the inherent selective nature toward
certain fish species (McCoy et al. 2009), though few
studies have ever examined the impact of this kind of
fishing on fish assemblage in coral reef habitats (Westera
et al. 2003).
In the Cayman Islands, many studies have been carried
out on coral communities but few involved fish assemblag-
es (Burgess 1978, 1994, Pattengill-Semmens and Semmens
2003). The previous cited study (McCoy et al. 2009) was
the first article focused on the response of fish community
to the establishment of the MPA in Grand Cayman, after
24 years of protection. However, no studies, to date, have
been done on MPAs performances in Little Cayman and
Cayman Brac, considered the “Sister Islands”. This
present study represents the first analysis of Little Cayman
and Cayman Brac fish assemblages and will constitute a
baseline for future studies.
These two islands are small, geographically remote
and protected from extreme anthropogenic impacts due to a
limited number of inhabitants (Cayman Brac <1 ,500, Little
Cayman < 200).
The aim of this present study is to assess effects of the
Little Cayman MPAs and Cayman Brac MPAs system on
coral reef fish assemblages by comparing fish populations
between protected and non-protected areas Reserve effect
was tested by comparisons of six variables: mean fish
biomass and size per transect and per species, mean density
of fish per transect and the ratio between the biomass of
herbivorous fishes to carnivorous fishes.
Identified hypotheses for this study are as follows:
i) There are no differences between the different
variables measured on protected and non-protected
sites, and
ii) These biological values are high and balanced around
the two islands.
METHODS
Study Site
The Cayman Islands consist of three islands, Grand
Cayman, Little Cayman and Cayman Brac, located
between 19°15' and 19°45' N latitude and between 79°44'
and 81°27' W longitude. They are the peaks of a sub-
merged ridge, which runs westwards from the Sierra
Maestra mountain range of Cuba. These three Overseas
Territories of the United Kingdom are the most arid and
isolated of West Indian islands unusually flat and formed
entirely from calcareous marine deposits (Logan, 1988).
The study was carried out in Little Cayman and
Cayman Brac, respectively located at 105 km and 130 km
north east from Grand Cayman (Figure 1), the largest and
most populated (197 km², 60,000 inhabitants). In compari-
son, these two islands are considered small, and undevel-
oped (26 km² for Little Cayman and 36 km² for Cayman
Brac) with a population of < 300 and <1500 respectively.
They are positioned close together, separated by a stretch
of just 7 km (with abyssal depths of >1000 m between
them).
There are two distinct reef terraces in Cayman Brac,
the north east coast and the southern coast of Little
Cayman: the shallow terrace reef (5 - 12 m), comprised of
two environments, lagoons and a fringing-reef complex,
and the deep terrace reef (12 - 25 m), plunging vertically to
abyssal depths. In the northwestern side of Little Cayman,
within the Bloody Bay / Jackson Point Marine Park, the
deep terrace is absent and the shallow terrace extends out
to 300 m from the coast before plummeting vertically to
abyssal depths (Fenner 1993). The narrow insular reef-
shelf measure ranges from 200 m in width at some
locations along the north and south coast extending to 1.5
Page 248 63rd Gulf and Caribbean Fisheries Institute
km maximum in width at the east and west ends of each
island. The structure of the reefs, principally constituted by
“spur and groove” formations, greatly differ according to
the exposure of the coast. The north to north easterly
approach of storms in the winter and the predominantly
south to south easterly approach of weather system in the
Summer, including tropical storms and hurricanes results in
two margin types: a high energy exposed-windward margin
(south coast) and a moderate energy protected-windward
margin (north coast).
The MPAs in Cayman Islands were established in
1986. Little Cayman has two Marine Parks, with one
distributed on each side of the island. Bloody Bay /
Jackson Point Marine Park, on the northern side covers
1.72 km² of the island shelf and the Preston Bay Marine
Park, on the southern side covers 1 km² (Figure 1).
Combined, the parks represent 14.5 % of the total shelf
area of Little Cayman. Three Marine Parks are located
around Cayman Brac: two in the south covering 2.86 km²
and 0.38 km² of the shelf area, the third one, located on the
northern side, covers 0.45 km². These three parks com-
bines gives a total shelf area protection of 17.8 % of the
island. The locations of different MPAs around the islands
are presented in Figure 1. In the Cayman Islands, residents
are permitted to fish within protected areas provided that
they do so from the shore or beyond the 25m depth contour
of the deep terrace reef.
Method of Visual Census
Sampling was carried out during the months of
January through to April 2009, between 0900 hours and
1500 hours. In order to study potential reserve effect, 16
comparable reef sites were randomly selected around Little
Cayman and 12 sites around Cayman Brac. Half of the
studied sites around each island were located inside the
Marine Park, which represent eight protected sites at Little
Cayman and six protected sites at Cayman Brac (Figure 1).
Fish counts were made at two depths; the shallow terrace
reef (10 - 12 m) and the deep terrace reef (16 - 18 m),
except the north side of Little Cayman where the deep
terrace is missing and the shelf edge rarely exceeds 10 m
within the Marine Park, forcing all surveys to be done
within the 10 - 12 metre depth contour to be comparable
(Table 1).
Figure 1: Location of Cayman Islands in the Caribbean and location of the studied sites
around Little Cayman and Cayman Brac. Hatched zone corresponds to the Marine Protected
Area.
Table 1. Little cayman Cayman Brac
North South North South
Protected sites
Shallow
terrace 4 2 2 2
Deep
terrace 2 1 1
Non-protected sites
Shallow
terrace 4 2 2 2
Deep
terrace 2 1 1
All sites Total 8 8 6 6
Dromard, C.R. et al. GCFI:63 (2011) Page 249
Data were collected by Underwater Visual Census
(UVC), using belt transects, (Samoilys and Carlos 2000).
At each site, fish were censused along three transects (50
m x 5 m) with a 10 m gap in between transects, sampling
750 m² of reef area per site. The diver swam along
transects with a graduated PVC T-bar and recorded the
number of individuals, species and total length of fish (in 9
size classes of 5 centimeter increments), within 2.5 m on
either side of the transect line and 5m above it. Pre-
determined target fish identified within the transect belt
were identified and counted, with 53 coral reef species,
belonging to 16 fish families, constituting the list of
targeted fish species (Table 2). However, six species were
not observed during our censuses in Little Cayman:
Epinephelus itajara, Caranx latus, Lutjanus jocu, Lachno-
laimus maximus, Pomacanthus arcuatus and Aluterus
scriptus). Similarly five species were absent during
censuses at Cayman Brac: Epinephelus itajara, Lutjanus
jocu, caranx latus, Haemulon plumieri and Aluterus
scriptus.
In order to standardize counts and sampling effort,
census began at least 15 minutes after deploying each
transect and the time of census was limited to a maximum
of 15 minutes for consistency. The collection of data
began after a training period to familiarize species
recognition. Fish replicas of different shapes and sizes
were used to estimate size classes and mean standard error
of size estimates was -1.09 cm.
Data Analysis
Length estimates of observed were used to estimate
biomass (weight) per unit area of reef by using the
allometric length-weight conversion (Bonhsack 1988) and
expressed in (g/m²) using surface area sampled:
W=aTLb
Where W is weight in grams, parameters a and b are
constants obtained from the literature (Froese and Pauly
2005) and TL is total length in centimeters. The diet of the
different trophic groups has been listed (Table 1), accord-
ing to data from Randall (1967) and species were classed
into five trophic groups:
i) herbivores (HB),
ii) omnivores (OM),
iii) piscivores (fish feeders) (Predators: P),
iv) invertebrates feeders (Carnivores 1: C1),
v) fish and invertebrates feeders (Carnivores 2: C2).
Fish density, size and biomass were tested for
normality (Shapiro-Wilks test). Data from within the
MPAs was compared to data outside the MPAs using a
student’s t-test when level of replication allowed and the
data met the test’s assumptions of normality. Otherwise,
non parametric test (Wilcoxon-Mann-Whitney) was used
for comparisons. Since paired MPAs are located on
opposing sides of each island and subjected to contrasting
environmental conditions, comparisons between MPA and
non-MPA sites were separated and analyzed according to
aspect (northern and southern).
Conservation Values
In this study, conservation values were adapted to
allow us to characterize the efficiency of the MPAs in
Little Cayman and Cayman Brac. We considered six
biotic variables: mean fish biomass per transect, mean fish
biomass per fish families, mean fish density per transect,
mean size of individuals per transect, mean size of
individuals per fish species and proportions between
herbivores-omnivores and carnivores. By doing this, it
was possible to give a value to each Marine Park according
to their effect on fish assemblages, in allocating one point
for each variable that was significantly higher inside the
evaluated MPA.
Page 250 63rd Gulf and Caribbean Fisheries Institute
MPA (p < 0.05). In the south MPA of Little Cayman,
Kyphosidae, Lutjanidae and Scaridae participate actively
to increase the biomass inside the MPA, with a biomass
respectively six, two, and one and half times higher inside
the MPA (p < 0.05).
Around Cayman Brac, no significant difference in fish
biomass was found between protected and non-protected
sites. With an average of 47.13 g/m² inside MPAs and
48.36 g/m² outside MPAs, both north and south MPAs,
these values are very low and correspond to the mean
biomass we found in non-protected sites around Grand
Cayman: 44.66 g/m².
Ratio Between Herbivorous and Carnivorous Fish
Biomasses
Ratios between two groups of fish (carnivores and
herbivores-omnivores) allowed us to investigate the
distribution of trophic groups inside and outside the MPA.
The first group was comprised by the herbivores and
omnivores (HB-OM), the second grouped carnivores
together: P (Predators), C1 (invertebrates feeders) and C2
(fish and invertebrates feeders) (CA). We compared the
ratio R between biomass of these two trophic groups. A
ratio equal to one (1) will show a balanced fish communi-
ty, with the same proportion between carnivores and
herbivores. Results are presented in Figure 3.
On the southern side of Little Cayman, significant
difference were found between ratio measured on protected
sites (R= 0.38) and ratio measured on non-protected sites
(R= 0.27). Additionally, the mean biomass of carnivores
represented 28% of the total fish biomass inside the MPA
and 21% outside the MPA (p < 0.05). Although these
values were more pronounced at Grand Cayman (20% of
the total mean biomass outside the MPA versus 39% inside
the MPA for carnivorous fishes), this difference between
RESULTS
A summary of the different mean values measured at
Little Cayman and Cayman Brac, on protected and non-
protected sites is presented in Table 3 (mean biomass, mean
density and mean size of individuals). Significant differ-
ences between MPA and comparative non-MPA sites were
noted. Data from Grand Cayman, originally from McCoy et
al. (2009) were added to the table for comparison.
Fish Biomass
Mean fish biomasses, in g/m², was calculated for each
transect covered during the census and are presented in Table
3. Comparisons of mean fish biomass calculated on
protected and non protected sites showed a biomass signifi-
cantly higher inside MPAs at Little Cayman (p = 0.01).
These values of fish biomass were two times higher inside
Marine Parks than out (Little Cayman:72.46 g/m² and 30.41
g/m² in the south respectively; 90.49 g/m² and 46.78 g/m² in
the north respectively) and were similar to the mean fish
biomass measured on Grand Cayman MPA: 71.78 g/m²
inside MPA and 44.66 g/m² outside MPA.
Based on these values, the highest relative mean fish
biomass in the Cayman Islands would appear to be within
the Bloody Bay / Jackson Point Marine Park (north MPA of
Little Cayman), with a mean fish biomass of 90.59 g/m².
Biomass per family was studied at Little Cayman (north
and south) in order to show which fish family contributed the
most to fish biomass inside MPAs (Figure 2). In the north
MPA of Little Cayman, three fish families participate to the
higher mean biomass: Haemulidae and Balistidae with a
mean biomass two times higher inside the MPA, and
Lutjanidae with a mean biomass four times higher inside the
Little Cayman
(south)
Little Cayman
(North)
Cayman Brac
(South)
Cayman Brac
(North)
Grand
Cayman
Density (ind/100m²)
Protected
28.13
36.67
18.18
28.4
26.17
Non protected
23.73
26.30
21.64
29.96
28.81
Statistic Test
W = 89.5
W = 108
W = 34.5
W = 41.5
T = 0.974
Difference
*
NS
NS
NS
NS
Biomass (g/m²)
Protected sites
72.46
90.59
39.23
55.02
71.78
Non protected sites
30.41
46.78
43.94
52.79
44.66
Statistic Test
W = 124
W = 108
T = -0.295
W = 26
T = 2.644
Difference
***
**
NS
NS
**
Mean Size of fish (cm)
Protected sites
21.80
22.62
20.75
21.89
22
Non protected sites
17.88
20.89
19.19
19.58
19.8
Statistic Test
W = 130
W = 95
W = 53
W = 64
W = 1159
Difference
***
NS
NS
**
***
Table 3.
Dromard, C.R. et al. GCFI:63 (2011) Page 251
the biomass of carnivores and herbivores in the southern
MPA at Little Cayman showed an unbalance and possibly
disturbance of the trophic structure by people illegally
fishing the protected sites. No significant differences
between MPA and non-MPA were found on the northern
side of Little Cayman even with a mean biomass of
carnivorous fishes corresponding to 41% (R = 0.71) of the
total mean biomass inside the MPA and 27% (R = 0.38)
outside the MPA.
At Cayman Brac, no difference was found between the
proportion of herbivores and carnivores between protected
and unprotected sites, with the same percentage of
carnivores inside and outside MPAs which represented
30% (R = 0.42) of the total mean fish biomass.
Mean Density of Fish
Mean density of fish was significantly higher inside
the MPA located in the south of Little Cayman (p < 0.05)
with 23.73 individuals/100 m² on non protected sites and
28.13 individuals/100 m² on protected sites.
No differences were found at Cayman Brac between
mean densities of fish measured inside and outside MPAs
(p > 0.05). Thus, on the different studied MPAs of
Cayman Islands, only one MPA (The Bloody Bay /
Jackson Point Marine Park) showed a mean fish density
significantly higher than the outlying fished areas.
Mean Size of Fish
The mean size of fish was estimated on each transect,
in cm, and grouped in nine size classes. We analyzed the
mean size of fish per transect and per species. The results
are presented in Table 3. Significant differences of fish
size between protected and non protected areas were found
in two cases: In the south MPA of Little Cayman, fish
were 4 cm bigger inside the MPA (p < 0.001). Mean size of
fish located inside the Marine Park was 21.80 cm and 17.88
cm outside the Marine Park. When we compared size of
fish by species, on average Nassau grouper was 15 cm
bigger, mutton snapper was 12 cm bigger, yellowtail,
Spanish hogfish and Mahogany Snapper were 5 cm bigger,
inside the MPA.
In the northern MPA at Cayman Brac, the mean size of
fish inside the MPA was 21.89 cm and 19.58 cm outside
the MPA, giving a difference of 3 cm between areas (p =
0.01). However, no differences were found when we
compared the mean size of fish species by species. Though
comparisons of mean size of fish were not significant for
all studied areas (North side of Little Cayman and south of
Cayman Brac), similar combined values of fish size were
found at the Sister Islands when compared to Grand
Cayman where mean size of fish were 22 cm within the
MPA and 19.8 cm outside the MPA, respectively.
Conservation Values
In Little Cayman, a notation of 6/6 was given to the
MPA located in the south and a notation of 2/6 for the
MPA located in the north (Bloody Bay / Jackson Point
MPA). For the case of Cayman Brac, only one point was
accorded to the MPA located on the northern side, this was
due to the size of fish significantly bigger inside the Marine
Figure 2. Mean biomass (g/m²) of Scaridae (Sca), Lutjani-
dae (Lut), Carangidae (Car), Sphyraenidae (Sph), Mullidae
(Mul), Balistidae (Bal), Pomacanthidae (Pom), Acanthuri-
dae (Aca), Serranidae (Ser), Haemulidae (Hae), Labridae
(Lab), Chaetodontidae (Cha), Kyphosidae (Kyp) and
Muraenidae (Mur) on protected sites (gray) and non
protected sites (black); on the northern sites (N) and on the
southern sites (S) of Little Cayman.
Figure 3. Proportions of Herbivores-Omnivores (HB-OM)
and of Carnivores (CA), on protected and non protected
sites, at Little Cayman northern side (N) and Little Cayman
southern side (S).
Page 252 63rd Gulf and Caribbean Fisheries Institute
Protected Area when compared to outside the Marine
Protected Area. There were no differences for the five
other variables between the protected and the non
protected sites.
DISCUSSION
Due to the remote location of Little Cayman and
Cayman Brac and the lack of any significant infrastructur-
al development on either island, mixed results were
surprising. The southern side of Little Cayman showed an
efficient MPA, with differences on fish community,
whereas the MPA located in the south of Cayman Brac did
not have any impact on the fish community. In our
hypothesis, a lack of differences between protected and
non protected sites was expected due to the absence of
fishing pressure within the MPAs. However, the MPA
located in the south of Little Cayman showed a strong
reserve effect, possibly indicative that it is being effective,
or that protection has maintained a healthier reef area and
fish assemblages as had been there prior to designation as
an MPA.
In the north of Little Cayman, we found some
differences between the biological variables we measured
inside and outside of the MPA, though all were not
significant, they did indicated a small reserve effect and a
vulnerability of this MPA to modifications on the fish
assemblage structure.
The impacts of artisanal and recreational fishing
practices have been given little or no attention and have
been largely overlooked for a long time (Cooke and Cowx
2004, 2006, Hawkins and Roberts 2004, Morales-Nin et al.
2005). However, given the fact that there are no commer-
cial fisheries in the Cayman Islands and according to the
results published on Grand Cayman (McCoy et al. 2009),
these kind of fishing practices can have damaging effects
on fish communities leading to differences between the
fish assemblage structure inside and outside of MPAs.
In Cayman Brac, no reserve effect was found around
the island, which could possibly be indicative of an
environment naturally protected by an absence of anthro-
pogenic pressure. But around this island, biological
variables such as fish biomass, size of individuals and fish
density are especially low. For example, the lack of
significant differences between fish biomass inside and
outside the MPA located in the south of Cayman Brac
should be the result of a low level of fishing pressure
along this coast and should foster and promote a high
value of fish biomass. However, the mean biomass
measured along this coast was 41.58 g/m², approximately
the same biomass measured on non-protected fished sites
at Grand Cayman.
The size and location of MPAs has often been used to
explain the mixed results obtained at the Sister Islands
(Cayman Brac and Little Cayman), since contrarily to
Grand Cayman, the different marine parks at the Sister
Islands represent small areas and their locations were
chosen by the public, not for the high biological values
(Petrie and Bush 1991). Indeed, all studied MPAs at Sister
Islands were less than 3 km², while the MPA of Grand
Cayman, demonstrating effectiveness and efficiency was
more than three times bigger. The optimum size of a MPA
has been debated for decades (Aswani and Hamilton 2004)
and a recent review showed that any sized marine reserve
increases fish density and diversity, although larger one
would be more effective (Claudet et al. 2008). An
interesting study from Halpern (2003) has showed that the
effect of a reserve on biological measure appears to be
independent of reserve size demonstrating that the St.
Lucia reserve, with 0.0026 km² is associated with signifi-
cantly larger values in the biomass and size of the organ-
isms within the reserve.
Marine parks have in general a positive impact on
fish community by increasing biomass and abundance.
However, this impact is often less important and less
obvious on coral reef community (Coelho and Manfrino
2007) because they cannot prevent corals disease and
bleaching events. Cayman Brac has been repeatedly
effected by hurricanes of Category 3 or higher over the past
few decades, with the most recent being a direct hit by
Hurricane Paloma in November 2008, a strong Category 4
storm devastating the small island ( Croy McCoy, pers.
Comm.), which could explain why its reefs are in worse
condition than those of Little Cayman, where despite their
proximity, damages were much lower. In a recent study
(Gall 2009) it was demonstrated that reefs at Cayman Brac
were not different inside and outside the MPA, but were
badly damaged. The lack of contrast between protected and
non protected areas in Cayman Brac is unknown but further
studies should reveal wither it is due to size of MPA,
degraded habitat quality, high fishing pressure in adjacent
waters or a combination of these factors. Similar findings
in the US Virgin islands (Rogers and Beets 2001) also
showed no significant differences in number of species,
biomass or mean size of fishes possibly due to habitat
degradation and high fishing pressure in addition to stresses
outside the control of the park managers (e.g. hurricanes).
Furthermore Monaco et al. (2007) compared the fish
community inside and outside of the same Marine Park in
the US Virgin Islands and concluded that due to degraded
habitat and the lack of structural complexity within the
Marine Park, the potential for reef fish to increase in
numbers and biomass maybe compromised.
Low levels of fish biomass around Cayman Brac can
equally explain the fishing pressure in Little Cayman.
Further to the habitat degradation and the decline of fish,
Little Cayman waters are more plentiful in term of fish and
very attractive to the residents of Cayman Brac.
The case described here is an example of the marine
ecosystem fragility in a very small scale. In view of
natural or anthropogenic pressures, small impacts can have
grave consequences on biological communities in upsetting
the delicate balance of marine environments and their
ecological functions.
Dromard, C.R. et al. GCFI:63 (2011) Page 253
ACKNOWLEDGEMENTS
Many thank to Mrs. Gina Ebanks-Petrie, Director of the Dept. of
Environment, and Mr. Timothy Austin, Deputy Director, Cayman Islands
Government for their support of this study. Additional thanks to all the
staff whom contributed to the field work including Dr. Janice Blumenthal,
Mr. John Bothwell, Mr. Jeremy Olynik, Mr. Phillippe Bush, Mr. James
Gibbs, Mr. Keith Neil, and Mr. Robert Walton Logistical support for this
project was provided by the DOE.
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... Grand Cayman has three types; the south and east coasts of the island are the highenergy exposed windward aspect, the north is the moderate energy protected-windward aspect and the west is the low energy leeward aspect (McCoy et al. 2010 ). The northeast to southwest orientation of the Sister Islands results in only two energy zone; high-energy exposed windward aspects in the south and moderate energy protected-windward aspects in the north (Dromard et al. 2011 ). Development of spur-and-groove on all three islands depends upon the exposure of the coastline to winter storms from the north and north-east and summer storms and hurricanes from the south to southeast. ...
... Development of spur-and-groove on all three islands depends upon the exposure of the coastline to winter storms from the north and north-east and summer storms and hurricanes from the south to southeast. The south and east coasts of all three islands have the highest energy zones overall and therefore the greatest development of spur-and-groove structure (McCoy et al. 2010 ;Dromard et al. 2011 ). Coral cover values for the Cayman Islands as a whole were 25% in 1997 and declined to 18% by 1999. ...
... More than half of the shallow reefs have been designated as protected areas (e.g. marine parks, replenishment zones) since 1986 [2]. Little Cayman has a small resident population (<200 people) and lacks agriculture, freshwater input rivers or streams, commercial fishing, industry, and ports; providing a rare opportunity to decouple the impacts that anthropogenic stressors (e.g. ...
Chapter
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