Technical ReportPDF Available
Coral Reef Status
Arrecife de Puerto Morelos National Park, México
Warning System on the Ecological Condition of Coastal Marine Ecosystems (EcoSAT)
Arrecife de Puerto Morelos National Park, Mexico. 2019. CONABIO
Coral Reef Status
Arrecife de Puerto Morelos National Park, México, 2019
Hansel Caballero-Aragón
Susana Perera-Valderrama
Sergio Cerdeira-Estrada
Raúl Martell-Dubois
Laura Rosique-de la Cruz
Lorenzo Álvarez-Filip
Esmeralda Pérez-Cervantes
Nuria Estrada-Saldívar
Rainer Ressl
Editorial coordination, design and illustrations
Yesmany Marrero Martínez
Cubierta:Jerónimo Avilés Olguín
Contra cubierta: Hansel Caballero-Aragón
First edition, November 2020
DR © Comisión Nacional para el Conocimiento y Uso
de la Biodiversidad
Liga Periférico-Insurgentes Sur 4903,
Parques del Pedregal, Tlalpan, 14010, Ciudad de México •
How to cite: Hansel Caballero-Aragón, Susana Perera-
Valderrama, Sergio Cerdeira-Estrada, Raúl Martell-Dubois, Laura
Rosique-de la Cruz, Lorenzo Álvarez-Filip, Esmeralda Pérez
Cervantes, Nuria Estrada Zaldívar, Rainer Ressl. CONABIO. 2020.
Coral Reef Report Card Arrecife de Puerto Morelos National Park,
México, 2019. Warning System on the Ecological Condition of
Coastal Marine Ecosystems (EcoSAT), from Marine-Coastal
Information and Analysis System (SIMAR).
Acknowledgments: The logistical support provided by CONABIO,
the Institute of Marine Sciences and Limnology of UNAM and
the Moon Palace Hotel through Antonio Ortiz, corporate environ-
mental manager. We also thank María del Carmen García Rivas,
director of the Arrecife de Puerto Morelos National Park.
Coral Reef Condition Indices
Arrecife de Puerto Morelos
National Park
Integral Reef
Condition Index (RCII)
Reef promoter index (RPI)
Reef detractors index (RDI)
Coral condition index (CCI)
Coral Recruit Index (CRI)
Rugosity index (RI)
Key herbivorous sh
biomass index (KHFB)
Key commercial sh
biomass index (KCFB)
Ecological condition assessment for the marine protected
areas of the Mexican Caribbean. Based on the protocols
for marine biodiversity monitoring, CONABIO
Seven indices are proposed to evaluate the condi-
tion of coral reefs from biological indicators obtained
from the CONABIO coral reef monitoring protocol
(Perera-Valderrama et al. 2020) . The indices are
proposed according to the authors’ criteria, based on
studies of Alcolado and Durán (2011) , Dahlgren et al.
(2016) , Lang et al. (2016) and McField et al. (2018) .
Each index assigns a value to the reef according
to the rank associated with its condition. The aver-
age of these seven indices leads to an integral index.
Classication and score appear in Table 1.
Table 1. Coral reefs condition indices.
i Perera-Valderrama, S., H. Caballero-Aragón, E. Santamaría-del Ángel, L. Álvarez-Filip, H. ReyesBonilla, S. Cerdeira-Estrada, R. Martell-Dubois, L.O.
Rosique-de la Cruz, J.C. Alva-Basurto, V. Francisco-Ramos, R. Ressl. 2020. Capítulo II. Arrecifes coralinos. En: Perera-Valderrama, S., S. Cerdeira-
Estrada, R. Martell-Dubois, L.O. Rosique-de la Cruz, H. Caballero-Aragón, R. Ressl (coords.). Protocolos de monitoreo de la biodiversidad marina en
áreas naturales protegidas del Caribe mexicano. Conabio. México, pp. 31-81.
ii Alcolado, P.M., A. Duran. 2011. Sistema de escalas para la clasicación y puntaje de condición del bentos e ictiofauna de arrecifes coralinos de Cuba
y del Gran Caribe. Serie Oceanológica 8, 25-29.
iii Dahlgren C., K. Sherman, J. Lang, P. R. Kramer, K. Marks. 2016. Bahamas Coral Reef Report Card. Volume 1: 2011–2013. Accesible desde: http://
iv Lang, J.C., P.A. Kramer, K.W. Marks. 2016. Fleshy Macroalgae Share Dominance with Other Organisms on Degraded Coral Reefs. Abstract, 13th
International Coral Reef Symposium. Accesible desde:
v McField M, P. Kramer, L. Álvarez-Filip, I. Drysdale, M. Rueda-Flores, A. Giró-Petersen, M. Soto. 2018. 2018 Report Card for the Mesoamerican Reef.
Healthy Reefs Initiative Accesible desde:
Coral Reef Status REPORT CARD
Coral Reef Status REPORT CARD
Arrecife de Puerto Morelos National Park, Mexico. 2019. CONABIO
The Arrecife de Puerto Morelos National Park
(PNAPM) is a protected natural area that covers
9,066.63 ha (90.7 km2). It is located northeast of the
state of Quintana Roo, in the Yucatan Peninsula of
Mexico. Based on satellite images, the bathymetry
(Fig. 1) and the underwater relief (Fig. 2) were esti-
mated. The Park has two terrace levels and different
erosive, cumulative and organic accretion forms (Ta-
ble 1), as well as of eight classes of benthic coverage
(Table 2) (Cerdeira-Estrada 2018 a, b and c).
The area has a warm subhumid climate, with
rains that seep through the karst substrate into an
extensive network of groundwater that discharg-
es through underwater springs and ssures to the
coast. The economy in Puerto Morelos is predom-
inantly oriented towards tourism, including diving
and snorkeling tours to the reef. Fishing is another
important economic activity, where there are con-
cessions for the extraction, capture and commercial
use of lobster, bony sh species and sharks.
Shallow coral reefs extend along the coast, present-
ing crest segments and a wide reef lagoon. The la-
goon is covered by calcareous sediments, stabilized
by seagrass beds in some areas (Fig. 3). Mangroves
(Conabio 2021) extend along the coast, separated
from the reef by a narrow and continuous sand bar.
The study was carried out in eight shallow reef
sites located between 1.5 and 4.0 m depth: 1.-Lim-
ones (LIM), 2.-Bonanza (BON), 3.-Tanchacté Norte
(TCN), 4.-Tanchacté Sur (TCS), 5.-La Bocana (LBO),
6.-Radio Pirata (RPI), 7.-Jardines (JAR) and 8.-La
Pared (LPA) (Fig. 4). The area presents zones of con-
tinuous hard substrate with the presence of Acropo-
ra palmata, and zones of patch reefs surrounded by
sand, dominated by Orbicella, Pseudodiploria, Agari-
cia and octocoral species (Fig. 5).
vi Cerdeira-Estrada S., M.I. Martínez-Clorio, L.O. Rosique-De La Cruz, M. Kolb, A. M. Gonzales-Posada, A. Uribe-Martínez, R. Martell-Dubois, J.R. Garza-
Pérez, L. Alvarez-Filip, M.I. Cruz-López, R. Ressl. 2019. Cobertura bentónica de los ecosistemas marinos del Caribe mexicano: Cabo Catoche - Xcalak.
Escala 1:8000. Edición 1. CONABIO, UNAM, México. Accesible desde:
vii Cerdeira-Estrada S., L.O. Rosique-De La Cruz, P. Blanchon, A. Uribe-Martínez, R. Martell-Dubois, M.I. Martínez-Clorio, M.I. Cruz-López, R. Ressl. 2018.
Relieve submarino del Caribe mexicano: Cabo Catoche - Xcalak. Escala: 1:8,000. Edición 1. CONABIO, UNAM, México. Accesible desde: https://simar.
viii Cerdeira-Estrada S., R. Martell-Dubois, T. Heege, L.O. Rosique-De La Cruz, P. Blanchon, S, Ohlendorf, A. Müller, R. Silva-Casarín R, I.J. Mariño-Tapia,
M.I. Martínez-Clorio, L. Carillo, M.I. Cruz-López, R. Ressl. 2018. Batimetría del Caribe mexicano: Cabo Catoche - Xcalak. Escala 1:8000. Edición 2.
Table 2. Submarine relief classes with their extension and
proportion, in the satellite studied area within the APMNP.
Table 3. Coverage classes with their extension and proportion, in
the satellite studied area within the APMNP.
Figure 1 PNAPM shallow water bathymetry using WorldView-2 satellite imagery.
Coral Reef Status REPORT CARD
Arrecife de Puerto Morelos National Park, Mexico. 2019. CONABIO
Figure 3. Benthic coverage of APMNP ecosystems using WorldView-2 satellite imagery.Figure 2. APMNP underwater shallow water relief using WorldView-2 satellite imagery.
Coral Reef Status REPORT CARD
Arrecife de Puerto Morelos National Park, Mexico. 2019. CONABIO
Figure 5. Shallow reef areas of the APMNP
with dominant species examples.
Fotografia: H. Caballero-Aragón.
Figure 4. Geographical location of the study sites.
Coral Reef Status REPORT CARD
Arrecife de Puerto Morelos National Park, Mexico. 2019. CONABIO
The general condition of the APMNP is evaluated as
regular (average value of 2.7) (Fig. 7). Low recruit-
ment rates of corals and biomass of key commercial
sh are influencing negatively on the reef condition
(Fig. 6). Coral recruit density was critical at three sites
(TCN, TCS, RPI), and biomass of key commercial sh
was critical at ve (BON, TCN, TCS, LBO, JAR). The av-
erage live coral cover was over 20%, a value above the
current average for the Caribbean Sea, and reef-build-
ing species dominated. Fleshy algae cover was not
high despite the dearth of black urchins and large
herbivorous sh.
It is recommended the compliance with the sh-
ing regulations established in the APMNP, including
permits for shing activities in the area, taking into
account the trends detected in sh communities,
possibly associated with overshing. In addition, it
is recommended to maintain the reef restoration pro-
gram, and evaluate the implementation of a black ur-
chin restocking program.
RCII summarizes the general condition of the reef, averaging the classication value of each individual index
(see classication and scoring table). Its nal classication is summarized as: critical (1.0-1.8), poor (1.9-
2.6), fair (2.7-3.4), good (3.5-4.2) and very good (4.3-5.0).
Figure 7. APMNP coral reef condition indices according to the criteria in Table 1. For each site, the results of the seven
indices and the average of each index for the PNAPM (large circle of seven segments) are shown.
Figure 6. Key elements of the reef: a) Small specimen of
Mycteroperca venenosa, a commercial species of the Serrani-
dae family, b) Grunts (Haemulidae family), the most abundant
carnivores in the reef, c) Very low coverage of coralline crus-
tosed algae despite the existence of substrate available for
their development. (Photo A: R. Mesa). Photo B: G. Avilés-Olguí
Photo C: H. Caballero-Aragón.
Coral Reef Status REPORT CARD
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10 11
The percentage of promoter elements of APMNP was
34.2%, and was classied as regular. The average of
living coral cover was 25%. The general composition
of corals was 48% reef-building species, 37% oppor-
tunistic species, 5% digitiform corals, 4% brain corals,
and 6% other species (Fig. 8 and 10).
Crustose coralline algae coverage was less than 10%.
Its poor coverage coincides with low density values of
black sea urchins Diadema antillarum that were only
observed during the day in three of the studied sites
(Fig. 9 and 11).
It is calculated by adding the percentages of the benthic categories that favor the growth of the reef and
the settlement of coral larvae: live coral cover + crustose coralline algae cover + bare pavement or with very
dispersed and thin turf.
Figure 8. Living coral cover and coral composition per site.
SD: standard deviation.
Figure 9. Bottom coverage by crusted coral algae and density of
the black sea urchin Diadema antillarum.
SD: standard deviation.
Figure 11. Elements that favor the condition of the coral reef:
to. Coralline crusted algae and b. Black sea urchin Diadema
antillarum. Photo: H. Caballero-Aragón.
Figure 10. Example of dominant coral species in the PNAPM,
a. Acropora palmata. Photos: G. Avilés-Olguín and b. Agari-
cia tenuifolia. Photo: H. Caballero-Aragón.
a. a.
b. b.
Coral Reef Status REPORT CARD
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12 13
The APMNP presented a percentage of detractors of
37.2%, which classies it as regular. There were three
sites in good condition and only one in poor condition.
Mean coverage of fleshy algae were not very high,
only Jardines exceeded 20%. Turf and articulated cal-
careous algae mean cover were also below 21% at all
sites (Fig. 12 and 13). Cyanobacteria and aggressive
invertebrates were not very abundant.
These general values of algal cover could be an
indicator of water quality (low levels of nitrates and
phosphates) in the coral reef area, despite the con-
centration and degradation of floating sargassum on
the coastline due to its massive influx in the summer
months. A backwash with clean ocean waters could
be helping to maintain stable levels of physicochem-
ical parameters. It is recommended to carry out tem-
porary water quality studies to corroborate this. The
observed herbivore biomass also appears to contrib-
ute to the control of macroalgae on the reef.
It is calculated by adding the percentages of benthic categories that affect corals or discourage the settle-
ment of their larvae: fleshy algae + articulated calcareous algae + turf (thick) + cyanobacteria + aggressive
invertebrates (encrusting sponges, sea squirts and other bioeroding invertebrates).
Figure 12. Substrate coverage by fleshy algae, articulated
calcareous algae and turf. SD: standard deviation.
Figure 13. Reef detractors: a) Fleshy algae, b) Articulated calcareous algae and c), d) Turf (Photos H. Caballero-Aragón).
a. c.
b. d.
Coral Reef Status REPORT CARD
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14 15
Mean old coral mortality per site did not exceed 40%.
Two sites presented values below 10%. Old mortal-
ity is the result of the accumulation of the effect of
stressors that caused mortality in the past (more than
a year), such as diseases, bleaching, storms, sedi-
mentation, among others. If young colonies predom-
inate on the reef, the average values per site may not
be high, as old mortality is better reflected in larger,
long-lived massive colonies. Also, in branched colo-
nies that are usually split by wave action, these old
mortality percentages are less reflected. Recent mor-
tality in APMNP did not exceed 4% (Fig. 14). The main
cause of recent death in corals was microbial diseas-
es (mostly SCTLD and black band disease).
The CCI evaluation for APMNP was good given the
average percentage of live coral tissue per colony ob-
served (88%). Two sites (LIM, RPI) presented a large
number of healthy A. palmata colonies with high per-
centages of living tissue. Two sites (TCN, LPA) pre-
sented a very good index condition, observing Orbi-
cella colonies of more than 1 m in diameter with few
dead tissue. In one of the sites (BON), although the
average mortality of the corals barely reached 20%,
a very deteriorated reef was observed, with colonies
100% dead, very eroded and covered by other organ-
isms, which no longer were identied as corals, there-
fore, they did not contribute to the site’s average mor-
tality percentages (Fig. 15).
This index analyzes the average percentage of living coral tissue from each coral larger than 5 cm in diame-
ter. It is calculated from the estimated values of percentage of old mortality (OM) and recent mortality (RM)
for each colony: CCI = 100 - (OM + RM). The average of the index values for the site is then calculated.
Figure 14. Coral mortality percentages for each APMNP site.
SD: standard deviation.
Figure 15. Examples of corals with old (a) and recent mortality (b) from APMNP. Healthy colony of Acropora palmata (c). Site
with great coral deterioration (d) (Photos: H. Caballero-Aragón).
a. c.
b. d.
Coral Reef Status REPORT CARD
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16 17
Stony coral tissue loss disease (SCTLD), known in the
Mexican Caribbean as white syndrome, is a new le-
thal disease affecting corals, that was reported for the
rst time in Florida in 2014, and outbreaks have sub-
sequently appeared throughout the Caribbean (FDEP
2019)IX. Its cause is unknown and it is spreading rap-
idly. It affects more than 20 species, especially mas-
sive corals (brain, column, star, among others). Dis-
eased colonies show multiple lesions and die quickly.
The disease was reported for the Mesoamerican Reef
in 2018, and it has caused signicant damage to coral
communities (Alvarez-Filip et al. 2019)X.
Within the sample of our study, the percentages of
affected colonies were not high. The disease was no
longer found in a high incidence phase, at least in the
sampled sites, where species such as A. palmata, A.
tenuifolia, and P. astreroides predominated, which
have not been affected by this disease (Tables 4 and
4). In turn, in near patch coral areas out of the sam-
pling, closer to the reef lagoon of the APMNP, with a
greater predominance of Orbicella and brain corals,
numerous partially or totally dead colonies were ob-
served, apparently affected in recent periods. In ad-
dition, active black band disease was observed in
many colonies, some apparently previously affected
by SCTLD (Fig. 16).
Stony Coral Tissue Loss Disease (SCTLD)
Table 4. Percentage of coral colonies affected by the different diseases by site within the study sample in the APMNP.
Table 5. List of diseases and percentage of colonies by affected species, within the study sample in the APMNP.
Figure 16. Massive corals affected with SCTLD and black band disease in patch reef areas of the APMNP
(Photos H. Caballero-Aragón).
IXFDEP (Florida Department Environmental Protection). 2019. Florida Reef Tract Coral Disease Outbreak (2014 – Present).
coral/content/florida-reef-tract-coral- disease-outbreak
XAlvarez-Filip L., N. Estrada-Saldívar, E. Pérez-Cervantes, A. Molina-Hernández, F.J. González-Barrios. 2019. A rapid spread of the stony coral tissue
loss disease outbreak in the Mexican Caribbean. PeerJ 7: e8069
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18 19
The density of coral recruits in the APMNP was low,
with the mean values ranged from 0.8 to 3.6 colonies
m-2. Eight genera of recruited corals were identied,
of which Agaricia, Siderastrea and Porites were the
dominant (Fig. 17). The CRI evaluation for the reef
was poor due to its average value (2.2 colonies m-2).
Coral recruitment processes in the Caribbean show
a declining trend in recent years, and a predominance
of brooder and opportunistic species. Recruitment
rates depend on the condition of the adult corals,
the survival of the larvae during their life cycle, and
the condition of the habitat. Stress factors on adult
corals (eg, bleaching events and diseases), and un-
suitable conditions for larval settlement, discourage
the establishment of new coral recruits. The poor cor-
al recruitment in the APMNP coincides with the low
cover of crustose coralline algae. The presence of this
type of algae favors the settlement and survival of the
recruits given its chemical and biological properties,
together with the microlm of diatoms and bacteria
associated to them.
Figure 17. Density and predominance of coral recruit species
on the reef. SD: standard deviation.
The reef structure created by the stony corals favors
the increase in the abundance and diversity of sever-
al groups of species in this ecosystem. The different
forms of coral growth provide a complex three-di-
mensional structure ideal for housing a variety of
sh and invertebrates. Reefs with a greater number
of large corals provide greater structural complexity.
Two sites (LIM, LPA) had the highest coral den-
sity, with average values of more than 10 colonies
10 m-1, while in another (LBO) the 5 colonies 10 m-1
were not reached. Two sites (LBO, RPI) had the high-
est colony diameter averages (above 100 cm), while
another two had averages below 50 cm. The great-
est rugosity was found in LBO, RPI and LIM (Fig. 18).
In general, the index for the APMNP is evaluated as
regular (1.62), and this is influenced by the lower val-
ues found in the sites that presented lower density of
A. palmata and Orbicella colonies (Fig. 19).
Figure 18. Density and size of corals, and general reef rugosity.
SD: standard deviation.
Figure 19. Variability in the reef structural complexity
(Photos: H. Caballero-Aragón).
Coral recruitment refers to the incorporation of new individuals into the population and is considered a fun-
damental process in coral reefs, because it directly determines the structure and function of their popula-
tions. To calculate this index, we work with the values of average density of recruits (colonies <5 cm) per site,
obtained from the number of colonies per square frame (25 cm on each side), multiplied by 16.
The structural complexity of coral reefs (rugosity) has a marked influence on the diversity, composition and
abundance of various reef groups, which is why it is considered an important ecological indicator. For its cal-
culation, the chain method was applied: RI = Dimension of the stretched chain / Dimension of the contoured
chain on the hard substrate. An average index per site was then calculated from the number of replicas.
Coral Reef Status REPORT CARD
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20 21
The KHFB classication for Puerto Morelos was
good (average biomass of 66.5 g m-2) with a great
variability observed between sites (Fig. 20). The
mean biomass of the Scaridae family ranged from
9.9 to 68.2 g m-2, while that of Acanthuridae ranged
from 1.6 to 93.2 g m-2. The mean density of the for-
mer was 0.11 to 0.24 individuals m-2, and that of the
latter 0.05 and 0.28 individuals m-2. The average
size of the sh of both species did not reach more
than 23 cm.
Although the biomass of key herbivorous sh
at some sites (2.6) was very good, not many large
specimens (> 40 cm) were observed. Of the two
largest parrotsh species in the Caribbean, Scarus
guacamaia was absent, and S. coelestinus was rare.
The dominant parrotsh species was Sparisoma vir-
ide, which was abundant at all sites, but its individ-
uals did not exceed 35 cm. On the other hand, large
schools of surgeonsh were observed, mainly Acan-
thurus coeruleus, which were the ones who contrib-
uted the most to the biomass averages in most of
the sites (Fig. 21).
The condition of the KCFB for Puerto Morelos was
evaluated as poor (average biomass of 12.4 g m-2),
where except for one site (LPA), the biomass did not
exceed 20 g m-2 (Fig. 19). The density of key com-
mercial sh was not high and in seven of the sites
(except in LPA), the average did not exceed 0.12 indi-
viduals m-2.
The Serranidae family was practically absent,
only a small individual of Mycteroperca venenosa
was observed. Individuals of Lutjanidae larger than
40 cm were very scarce. The most abundant com-
mercial species was Lutjanus mahogoni, which in
some places formed schools of specimens that did
not exceed 30 cm in length. The species with the
highest biomass was L. analis (Fig. 20).
The lack of the main predatory sh could influ-
ence the trophic web of the reef. Key commercial sh
condition indicators suggest a possible overshing
effect. This could be the consequence of a region-
al effect, which is also manifested in the APMNP.
However, to make any conclusive criteria regarding
Herbivorous sh are a key indicator group due to their ecological role as controllers of algae on the reef. They
biomass per site (weight of sh / unit area) was calculated from the sum of the estimated weight values of
each individual, which is obtained by introducing their estimated size (size range classes) in an equation
of length - weight. Only Achanturidae (surgeonsh) and Scaridae (parrotsh) families are included as key
herbivorous shes.
The most important shery species on coral reefs (commercial sh) play an important ecological role as
predators, controlling populations of species that damage corals. The calculation of the KCFB is done in the
same way as for the key herbivorous sh. Only the families Serranidae (groupers) and Lutjanidae (snappers)
are included within the category of key commercial sh.
Figure 20. Biomass of key herbivorous sh of the APMNP. Figure 21. Reef herbivores sh: a. Parrotsh Sparisoma viride, key
herbivore most in the APMNP (Photo: S. Perera-Valderrama), b.
School of surgeonsh (Acanthurus coerulus), key herbivore with the
highest biomass (Photo: G. Avilés -Olguín).
Figure 22. Biomass of key commercial sh in the APMNP. Figure 23. Reef commercial sh: a. Lutjanus mahogoni, key com-
mercial species with the highest density in the APMNP (Photo:
J. Hernández) and b. L. analis, key commercial species with the
highest biomass (Photo: H. Caballero-Aragón).
the general condition of this group of sh, its natu-
ral variability and seasonality must be considered.
Many commercial species live in wide areas and
have a high mobility, so sampling must be done
more frequently to obtain results more representa-
tive of the actual status of this indicator in the park.
Full-text available
Casitas, low-lying artificial shelters that mimic large crevices, are used in some fisheries for Caribbean spiny lobsters ( Panulirus argus ). These lobsters are highly gregarious and express communal defense of the shelter. Scaled-down casitas have been shown to increase survival, persistence, and foraging ranges of juveniles. Therefore, the use of casitas has been suggested to help enhance local populations of juvenile P. argus in Caribbean seagrass habitats, poor in natural crevice shelters, in marine protected areas. Following the emergence of Panulirus argus virus 1 (PaV1), which is lethal to juveniles of P. argus , concern was raised about the potential increase in PaV1 transmission with the use of casitas. It was then discovered that lobsters tend to avoid shelters harboring diseased conspecifics, a behavior which, alone or in conjunction with predatory culling of diseased lobsters, has been proposed as a mechanism reducing the spread of PaV1. However, this behavior may depend on the ecological context (i.e., availability of alternative shelter and immediacy of predation risk). We conducted an experiment in a lobster nursery area to examine the effect of the use of casitas on the dynamics of the PaV1 disease. We deployed 10 scaled-down casitas per site on five 1-ha sites over a reef lagoon (casita sites) and left five additional sites with no casitas (control sites). All sites were sampled 10 times every 3–4 months. Within each site, all lobsters found were counted, measured, and examined for clinical signs of the PaV1 disease. Mean density and size of lobsters significantly increased on casita sites relative to control sites, but overall prevalence levels remained similar. There was no relationship between lobster density and disease prevalence. Dispersion parameters ( m and k of the negative binomial distribution) revealed that lobsters tended to avoid sharing natural crevices, but not casitas, with diseased conspecifics. These results confirm that casitas provide much needed shelter in seagrass habitats and that their large refuge area may allow distancing between healthy and diseased lobsters. On eight additional sampling times over two years, we culled all diseased lobsters observed on casita sites. During this period, disease prevalence did not decrease but rather increased and varied with site, suggesting that other factors ( e.g. , environmental) may be influencing the disease dynamics. Using scaled-down casitas in shelter-poor habitats may help efforts to enhance juvenile lobsters for conservation purposes, but monitoring PaV1 prevalence at least once a year during the first few years would be advisable.
ResearchGate has not been able to resolve any references for this publication.