Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

Status of the coral formations of Bajo Nuevo Reef Complex,

Western Caribbean, Colombia

Martha Catalina Gómez-Cubillos1*; https://orcid.org/0000-0003-3384-5969

Carlos Andrés Daza-Guerra1; https://orcid.org/0000-0001-6599-2328

Nelson Alejandro Lozano-Mendoza1; https://orcid.org/0000-0001-7886-777X

Sven Zea1; https://orcid.org/0000-0002-5657-4877

1. Instituto de Estudios en Ciencias del Mar (CECIMAR), Sede Caribe, Universidad Nacional de Colombia-Colombian

Marine Fauna Research Group: Biodiversity and Uses-c/o Invemar, Salguero Beach, Rodadero, Santa Marta, Colombia;

macgomezcu@unal.edu.co (*Correspondence), caadazagu@unal.edu.co, nelozanom@unal.edu.co, szeas@unal.edu.co

Received 19-I-2024. Corrected 22-XI-2024. Accepted 26-III-2025.

ABSTRACT

Introduction: Although many reefs have been disturbed by the combined effects of climatic and non-climatic

stressors, there still are regions largely free from direct human pressures such as runoff, pollution, and maritime

traffic due to their geographic remoteness. This suggests that they are replicas of “pristine reefs”, that allow the

investigation of relationships between reef communities and their environment.

Objective: To evaluate the status of the coral formations of Bajo Nuevo, Seaflower Biosphere Reserve.

Methods: The coral health and the relative cover of reef-building organisms and of their main competitors were

evaluated. In every station (11), ten photo quadrants of 0.25 m2 were evaluated along a 10 m tape measure com-

bined, along with ~3 min videos.

Results: 32 coral species were recorded, 30 of them Scleractinia and two of hydrocorals, with the highest richness

in the reef lagoon. In 2021, the reefs in Bajo Nuevo were dominated by non-reef-building organisms (61.7 ± 0.10

%), the building species represented only 23.9 ± 0.10 %; 3.2 ± 0.03 % was coral skeleton with recent and transi-

tional death less than 15 days old. Signs of diseases affected three genera, 13 species and 23.5 % of the colonies

evaluated, of which 84.9 % showed one of the four signs related to the stony coral tissue loss disease.

Conclusions: With previous expeditions (2010-2011) as a reference, this reef complex registered in 2021 a drop

in the cover of hard corals and calcareous algae, and coral richness; an increase in the cover of non-reef-building

organisms, with a high prevalence of signs of unhealthiness associated with different coral diseases. This confirms

that these reefs are in danger (EN), as suggested by the red list of marine and coastal ecosystems of Colombia.

Keywords: stony corals; diversity; epizooties; atoll; coral mortality.

RESUMEN

Estado de las formaciones coralinas del complejo arrecifal de Bajo Nuevo, Caribe Occidental, Colombia

Introducción: Aunque muchos arrecifes han sido alterados por los efectos combinados de estresores climáticos y

no climáticos, aún existen regiones en gran medida libres de presiones humanas directas, como escorrentía, con-

taminación y tráfico marítimo, debido a su lejanía geográfica. Esto permite suponer que son réplicas de “arrecifes

prístinos”, lo que facilita investigar las relaciones entre las comunidades de arrecifes y su entorno.

Objetivo: Evaluar el estado actual de las formaciones de coral de Bajo Nuevo, Reserva de la Biosfera Seaflower.

https://doi.org/10.15517/rev.biol.trop..v73i1.57590

AQUATIC ECOLOGY

2Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

INTRODUCTION

Although many reefs have been disturbed

by the combined effects of climatic and non-

climatic stressors, there are still regions largely

free from direct human pressures due to their

geographic remoteness and difficulties for

human settlement. Distance in remote ocean

environments has kept reefs out of the direct

effect of runoff, pollution and maritime trans-

port, and even until the early twentieth century,

they were thought of as pristine zones (Brain-

ard et al., 2005). This allows them to be replicas

of “pristine reefs”, allowing to investigate the

relationships between reef communities and

their environment, mainly the effect of large-

scale disturbances (Bindoff et al., 2019; Perry et

al., 2015; Williams et al., 2015).

Knowledge gaps remain on the synergistic

and cumulative effects of global (i.e. ocean

warming) and regional (i.e. epizooties) scale

disturbances in these remote environments;

and few studies have compared the effect of dis-

turbances between remote reefs and those close

to areas of human populations (Bruckner, 2002;

Díaz-Pulido et al., 2004; Woodley et al., 2003).

Hence the importance of studies in reef forma-

tions and in general in remote ecosystems as

reference points to advance in the understand-

ing of the isolated effect of pressures operating

on a large scale in a climate change scenario.

In the Caribbean, after the large decline

of coral cover between 1970 and 1983, Souter

et al. (2021) estimated, with meta-analyses, an

additional decline of 2.1 % between 1999 and

2019. From Colombia to Mexico, the decline

was between 21.6 and 22.6 %; and only in the

Greater Antilles, coral cover increased (from

5.4 to 16.1 %) (Souter et al., 2021). Bajo Nuevo

reef complex is situated in the NW Carib-

bean, at the northern end of the Seaflower

Biosphere Reserve (Seaflower BR), and the

joint regime area Colombia-Jamaica. Due to

its remote location, the area has little historical

data, all obtained in expeditions organized by

the Colombian Navy, first in 2010 (Abril-How-

ard et al., 2012) and 2011 (Vega-Sequeda et al.,

2015), through Rapid Reef Assessments (RRA)

in 400 m2 plots, and during the Seaflower 2021

Scientific Expedition, through 10 m transects.

Because of its distance from the continent,

Bajo Nuevo is a model to assess the effect of

large-scale pressures on the status of remote

coral formations.

The objective of this study was to evalu-

ate the current status of the coral formations

of Bajo Nuevo, Seaflower Biosphere Reserve.

To test the hypothesis that coral formations in

remote environments remain in good condi-

tion due to distance to direct human pressures,

comparisons of diversity, cover and coral health

were performed between Expeditions (2010,

Métodos: Se evaluaron la salud del coral y la cobertura relativa de organismos constructores de arrecifes y de sus

principales competidores. En cada estación (11), se evaluaron diez cuadrantes fotográficos de 0.25 m² a lo largo

de una cinta métrica de 10 m, junto con videos de aproximadamente 3 minutos.

Resultados: Se registraron 32 especies de coral, 30 de corales pétreos y dos de hidrocorales, presentándose la

mayor riqueza en la laguna arrecifal. En 2021, los arrecifes de Bajo Nuevo estaban dominados por organismos no

constructores de arrecifes (61.7 ± 0.10 %), mientras que las especies constructoras representaban sólo el 23.9 ±

0.10 %; y un 3.2 ± 0.03 % era esqueleto coralino con muerte reciente y transicional menor a 15 días. Los signos

de enfermedad afectaron a tres géneros, 13 especies y al 23.5 % de las colonias evaluadas, de la cuales el 84.9 %

presentaron alguno de los cuatro signos relacionados con la enfermedad de pérdida de tejido de coral duro.

Conclusiones: Con expediciones anteriores (2010-2011) como referencia, este complejo arrecifal registró en 2021

una caída en la cobertura de corales duros y algas calcáreas, y en la riqueza coralina; un aumento en la cobertura

de organismos no constructores de arrecifes y, una alta prevalencia de signos de enfermedades coralinas. Esto

confirma que los arrecifes de Bajo Nuevo están en peligro (EN), como lo sugiere la lista roja de ecosistemas

marinos y costeros de Colombia.

Palabras claves: corales pétreos; diversidad; epizootias; atolón; mortalidad coralina.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

2011 and 2021) (Abril-Howard et al., 2012;

Vega-Sequeda et al., 2015) and their relation-

ship with the variation in the sea surface tem-

perature (SST).

MATERIALS AND METHODS

Study area: Bajo Nuevo reef complex, also

known as Petrel islands, is located in the NW

Caribbean and is part of what is called the

Archipelago of San Andrés, Providencia and

Santa Catalina, belonging to Colombia. Bajo

Nuevo is located 475 km northeast of the island

of San Andrés, at coordinates 15°53’ N & 78°38’

W. It is part of the Seaflower Biosphere Reserve

declared by UNESCO in 2000. In 2005, the

Colombian Ministry of Environment, Hous-

ing and Territorial Development recognizing

that the archipelago shows high species diver-

sity and endemism (Acero & Garzón-Ferreira,

1994), created the Seaflower Marine Protected

Area, with an area of 65 000 km2 (Abril-Howard

et al. , 2011). This Reserve homes to approxi-

mately 76.5 % of the coralline areas of the

Colombian Caribbean (Díaz et al., 2000).

At Seaflower, reef complexes are a series

of isolated structures, aligned in NE direction

along the southern flank of the Nicaragua Ele-

vation (Díaz et al., 2000). These formations are

the result of volcanic activity during the early

Cenozoic, basement subsidence between the

Cenozoic-Quaternary and the accumulation of

reef limestone on shallow peaks (Díaz, 2005).

The seasonal nature of the climate in the region

governed by the migration of the intertropical

convergence zone (Guzmán et al., 2014). The

body of water that surrounds this zone has an

average surface temperature of 29.3 °C and, up

to 200 m, salinity is on average lower (36.4)

than in deep waters (37.11) (Monroy-Silvera &

Zambrano, 2017). In the Seaflower reef com-

plexes, the direction and strength of the NE

trade winds and the energy they move along the

Caribbean translate into similar geomorpho-

logical and ecological structure between atolls

(Díaz et al., 2000).

Bajo Nuevo is the northernmost reef

complex of Seaflower and is part of the

Colombia-Jamaica joint regime area (~225

km), an area of high fishery resource exploita-

tion due to its proximity to Pedro Bank (~136

km) (Abril-Howard et al., 2012). This complex

of 100 km2, is made up of two elongated atolls,

each with a barrier which is continuous to

windward and truncated to leeward and sepa-

rated from each other by a deep channel of ~90

m to (Díaz, 2005). From the Expeditions it was

demonstrated that the ecological units present

the traditional scheme of the Caribbean atolls,

with a fore-reef terrace and a barrier to wind-

ward, followed by a lagoon terrace and a lagoon

basin with anastomosed patch reefs. After the

reef slope, depths up to 1 500 meters are

reached (Díaz et al., 1996). Most of the seabed

between 5 m and 20 m is calcareous pavement

covered by an extensive layer of gravel and

coarse sand, the result of erosion of dead coral.

In the emerged area (< 20 m2) there is a light-

house and nearby are the ruins of a cargo ship.

Field work: Between November 24 and 30,

2021, during the “Seaflower Scientific Expedi-

tion: Bajo Nuevo Island Cay 2021”, aboard

the ARC Providencia, relative cover of reef-

building organisms (stony corals and coralline

algae) and their main competitors (macroalgae,

sponges and soft corals), and the coral health

were evaluated. Methods followed the recom-

mendations of the Global Coral Reef Monitor-

ing Network (GCRMN) since a combined view

of these components allows the description of

the current condition of the reef and under-

stand the possible trajectories over time (Inter-

national Coral Reef Initiative, 2016).

Sampling stations were selected using the

work grids from the 2010 expeditions (Abril-

Howard et al., 2012) and 2011 (Vega-Sequeda

et al., 2015) (Table 1, Fig. 1). At each station,

a band transect (10 x 2 m) was marked with a

measuring tape, and photographs were done

using the alternate photo-quadrat technique,

using a Canon Powershot G7 digital camera,

and a 50 x 50 cm, 1” PVC pipe reference frame.

Ten (10) 0.25 m² quadrats of were evaluated, for

a total of 2.5 m² per transect. (Gómez-Cubillos

et al., 2019). Additionally, three videos were

4Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

recorded along the transects (~3 min) at no

more than 1 m above the bottom, with GoPro

Hero 9 digital camera.

Twelve stations were evaluated in total

(two on the windward fore-reef terrace, three

on the lagoon terrace and seven on the lagoon).

In 11 stations, transects were made with the

photo quadrant technique (27.5 m2), and for 12

stations were reviewed 2 hours of video (Table

1, Fig. 1).

Image processing: Photo quadrants were

processed using ImageJ 1.52v (Schneider et

al., 2012). Per quadrant, using at 100-point

Fig. 1. Map of the study area: A. Location of the Seaflower Reserve, B. location of the Bajo Nuevo reef complex and C.

location of the stations evaluated in Expedition 2021.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

grid, the coverage (%) of the benthic catego-

ries described by Caribbean Coastal Marine

Productivity (2001) and Garzón-Ferreira et al.

(2002) was calculated. Then, with polygons and

layers of the ROI Manager tool, by coral species,

the cover (cm2) of living tissue and skeleton

with recent (1-3 days), transitional (4-14 days)

and old (weeks to months) death, was estimated

(Bruckner, 2020).

From photos and videos, coral richness

(number of species) and abundance (number

of colonies) and the presence of signs associ-

ated with diseases were estimated. Per video,

~10 frames were selected. By image (photo-

graph and video frame), easily distinguishable

colonies were counted by species. As a colony,

any area of coral tissue growing independently

and separately from other neighboring colo-

nies was considered (Jackson et al., 1985). By

colony, the presence of signs related to coral

diseases was evaluated (Bruckner, 2020; Ray-

mundo et al., 2008; Weil et al., 2019). The signs

were selected taking as reference: a) changes

in coral tissue coloration (darkening, paleness,

bleaching), b) shape of the lesion (regular and

irregular), and c) exclusivity with the host.

The signs were tentatively assigned to one or

more coral diseases reported in the Caribbean

(Gil-Agudelo et al., 2009).

Data analysis: Data were processed using

Microsoft Excel spreadsheets. Per station, rich-

ness was estimated as the number of species;

abundance was estimated from the number

of colonies; total and relative cover (%) was

estimated from random points and polygons,

and the prevalence of signs (%) by coral species

and colonial type (# cases with signi / # total

colonies spj) (Weil & Rogers, 2011). Geomor-

phological unit, depth and level of exposure to

swell were used as analysis factors (Díaz et al.,

1996; Garzón-Ferreira et al., 2002; Zea, 2001).

The results were classified, according to the life

history types of coral species proposed by Dar-

ling et al. (2012) and Randazzo-Eisemann &

Garza-Pérez (2022), as competitive, generalist,

stress tolerant and weedy.

The representativeness of the sampling

was calculated using the estimator proposed by

Chao & Jost (2012), which is a measure of the

Table 1

Location and general characteristics of the stations evaluated in Bajo Nuevo during Expedition 2021.

Station ID Coordinates Depth Level Exposure Level Geomorphological Unit

Latitude Longitude

E1 15.922056 -78.563389 Medium 2 FT

E2 15.812750 -78.725889 Medium 1 LT

E3 15.828222 -78.699361 Shallow 1LT

E4 15.851917 -78.670611 Medium 0 L

E5 15.844583 -78.668083 Shallow 1LT

E6 15.876222 -78.638194 Medium 1 L

E7 15.857917 -78.667111 Deep 0 L

ARC 15.894500 -78.672750 Deep 2 FT

E8 15.864861 -78.678722 Medium 0 L

E9 15.863583 -78.659611 Medium 0 L

E10 15.914250 -78.581111 Medium 0 L

E11 15.911111 -78.575583 Medium 0 L

Abbreviations: Depth Level: Shallow > 7 m; Medium between 7 and 12 m; Deep > 12 m (Garzón-Ferreira et al., 2002).

Exposure Level: 0 (none); 1 (low); 2 (moderate); 3 (high), with respect to swell and depth of the water column (Zea, 2001).

Geomorphological Unit: FT (Windward fore-reef terrace); LT (Lagoon terrace); L (Lagoon with coral patches) (Díaz et al.,

1996). Metadata can be downloaded at the Marine Biodiversity Information System site (SiBM for its initials in Spanish)

(Gómez-Cubillos et al., 2023).

6Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

completeness of the sample with respect to the

size of the community. Diversity was calculated

by Chao interpolation and extrapolation analy-

sis, using Hill numbers in units of the effective

number of species (Chao et al., 2014; Hill, 1973;

Jost, 2006). The values of true diversity, 0D (spe-

cies richness), 1D (common species) and 2D

(very abundant species), with their respective

confidence intervals at 95 %, were calculated

using the iNEXT package (Hsieh et al., 2022).

Using data of presence-absence of species with

the help of the BAT package (Cardoso et al.,

2022), beta diversity (β) was calculated based

on Jaccard dissimilarity. In this, total dissimi-

larity (βcc) = replacement of species (β-3) +

differences in richness (Brich), as proposed by

Carvalho et al. (2013). These analyses were

performed using the R software version 4.3.1 (R

Development Core Team, 2017). The changes

in composition and structure of the assembly

between geomorphological units were analyzed

with the technique of non-metric multidimen-

sional scaling (nMDS) using as distance mea-

sure the binary Bray-Curtis similarity index

(Primer-E V.6), with the cover data in % previ-

ously processed with the angular transforma-

tion (arc sine √ ( x / 100)).

To catalog the species according to their

abundance (colonies), the proportion of indi-

viduals with respect to the total was calculated

in each species, ordered from highest to lowest

by the base 10 logarithm. Confidence limits

at 95 % were obtained by resampling, using a

Bootstrap with the boot package (Canty & Rip-

ley, 2022); this analysis was carried out using

the R program version 4.3.1 (R Development

Core Team, 2017). In this way, the species that

were found above the upper limit of that inter-

val were cataloged as abundant, those found

within the interval were cataloged as common,

and those below the lower limit were cataloged

as scarce (Cruz et al., 2017).

Expedition 2021 results were compared

with those obtained in previous expeditions

from 2010 (Abril-Howard et al., 2012) and 2011

(Vega-Sequeda et al., 2015). To explain trends

observed in 2021 about the health status of the

coral formations in Bajo Nuevo, the sea surface

temperature (SST) was estimated from NOAA

interactive maps (series: 2009-2021) (Nation-

al Oceanic and Atmospheric Administration

[NOAA], 2023).

RESULTS

In the windward fore-reef terrace (depth: 7

m), an environment very exposed to swell, the

structural complexity was low, fleshy macroal-

gae (Turbinaria spp.) dominated, and the corals

were small, scabby and scattered. In the lagoon

terrace (depth: 5.6-7.2 m), where the swell has

already dissipated at the barrier, patches of

reefs with variable structural complexity were

observed, consisting of Orbicella spp. and very

old skeletons of Acropora palmata. Finally, in

the reef lagoon (depth: 7.3-14 m), a relatively

calm water habitat increased the structural

complexity in the form of anastomosed patches

of Orbicella spp. and giant standing skeletons of

brain corals (Colpophyllia natans, Diploria laby-

rinthiformis and Pseudodiploria strigosa) and of

Siderastrea siderea.

Richness of coral species: In November

2021, 32 species of hard corals were recorded,

30 of which were scleractinian and two hydro-

corals (Fig. 2). The greatest richness was pres-

ent in the reef lagoon with 32 species, seven of

them exclusive to the lagoon. In contrast, on

the windward fore-reef terrace, 20 species were

observed (Fig. 2). In general, the lowest rich-

ness (17 spp.) was recorded at the stations most

exposed to swell and increased as the degree

of exposure decreased. All species were found

at medium depth (7-12 m; 32 spp.), while in

deeper (> 12 m; 25 spp.) and shallow (< 7 m; 20

spp.) waters the diversity decreased (Table 2).

The richness observed in Expedition 2021

(32 spp.) was lower than the records of 2010

(36 spp.) and 2011 (37 spp.) (Abril-Howard

et al., 2012; Vega-Sequeda et al., 2015) (Fig. 2;

Table 1). When comparing beta (β) diversity

between Expeditions, a dissimilarity (βcc) of

48.9 % was estimated with what was recorded

for April 2010 by Abril-Howard et al. (2012).

This value was mainly attributed to species

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

Table 2

Species of hard corals recorded in Bajo Nuevo during the 2010 (Abril-Howard et al., 2012), 2011 (Vega-Sequeda et al., 2015)

and 2021 expeditions.

Species Type Total 2010 Total 2011 2021

Total FT LT L

Acropora cervicornis C x x+x+x*

Acropora palmata C x x+x++ x x x

Agaricia agaricites W x x++ x+++ x x x

Agaricia fragilis W x x+x+++ x x x

Agaricia grahamae W x+++ x x

Agaricia humilis W x++ x x x

Agaricia lamarcki W x x+

Agaricia tenuifolia W x+x++ x x

Cladocora arbuscula NC x+x

Colpophyllia natans ST x x+x++ x x

Colpophyllia breviserialis NC x+x*

Dendrogyra cylindrus C x x+

Dichocoenia stokesii ST x x+

Diploria labyrinthiformis ST x x+x++ x x x

Eusmilia fastigiata NC x x+

Favia fragum W x x+x++ x x x

Helioseris cucullata W x x+x++ x x x

Isophyllia rigida W x x+x+x x

Isophyllia sinuosa W x x+

Madracis decactis W x x+x+++ x x x

Madracis cf. myriaster NC x

Manicina areolata W x x+x+x*

Meandrina meandrites ST x x+

Millepora alcicornis NC x x++ x+++ x x x

Millepora complanata NC x x+x+x x*

Montastraea cavernosa ST x x+x+x*

Mycetophyllia aliciae W x+x+x*

Mycetophyllia danaana NC x+x*

Mussa angulosa W x

Mycetophyllia ferox W x

Mycetophyllia lamarckiana W x x+

Orbicella annularis ST x x++ x+++ x x x

Orbicella faveolata G x x++ x+++ x x x

Orbicella franksi G x x+x+++ x x

Porites astreoides W x x++ x+++ x x x

Porites divaricata W x+x+++ x x x

Porites porites W x++ x+++ x x x

Porites furcata W x

Pseudodiploria clivosa ST x x+x+x x

Pseudodiploria strigosa ST x x++ x++ x x x

Scolymia sp. W x+

Scolymia cubensis W x

Siderastrea radians W x x+x++ x x x

Siderastrea siderea ST x x++ x+++ x x x

Stephanocoenia intersepta ST x x+x+x x

Stylaster roseus NC x x+

Tubastraea coccinea NC x+

Abbreviations: Type (according to life story): C = competitive, W = weed, ST = stress tolerant, G = generalist and NC =

Not classified. FT = Windward fore-reef terrace; LT = Lagoon terrace and L = Lagoon with coral patches. x (presence); x*

(exclusive species); abundance: + (scarce), ++ (common), +++ (abundant) (Cruz et al., 2017).

8Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

replacement (β-3) (40 %) and to a lesser extent

to the difference in richness (βrich) between

expeditions (8.9 %). When comparing with the

records of Vega-Sequeda et al. (2015) of August

2011, the dissimilarity (βcc) was lower (35.7

%) and was due to species replacement (β-3)

(23.8 %) (Table 1). This species replacement

(β-3) between the 2021 expedition and the pre-

vious ones, is evidenced in new records for Bajo

Nuevo with species such as Agaricia humilis, A.

grahamae, Cladocora arbuscula, Mycetophyl-

lia danaana and Colpophyllia breviserialis, the

latter being a new record for the San Andrés

Archipelago. On the contrary, species recorded

in 2010 and 2011 expeditions, such as Agaricia

lamarcki, Dendrogyra cylindrus, Dichocoenia

stokesii, Eusmilia fastigiata, Isophyllia sinuosa,

Meandrina meandrites, Mycetophyllia lamarck-

iana and Stylaster roseus were not observed in

2021 (Table 2).

For Bajo Nuevo, the representativeness of

the sampling reached 100 % in 2021, accord-

ing to the Chao & Jost (2012) estimator. Using

diversity analysis (iNEXT), a species richness

of 0D = 32 ± 3.44 (effective species ± I.C) was

estimated. When considering all species with

a weight proportional to their abundance, a

diversity of 1D = 9.8 ± 0.31 effective species was

estimated, evidencing a low uniformity with

species with a high number of colonies and

other scarce species. Finally, by giving greater

weight to dominant species, a diversity of 2D

= 5.6 ± 0.23 was estimated. Of 7 123 colonies

counted, the most abundant species were Orbi-

cella annularis (2 415 colonies), Agaricia agar-

icites (1 191), Porites astreoides (481), Orbicella

faveolata (438) and Porites porites (356).

Benthic cover: In November 2021, the

reefs in Bajo Nuevo were dominated by non-

reef-building organisms (61.7 ± 0.10 %) ( ±

1 standard deviation - S.D.). The building spe-

cies (corals, hydrocorals and calcareous algae)

only accounted for 23.9 ± 0.10 %. The abiotic

substrate (14.4 ± 0.09 %) was made up of soft

bottoms of sand and debris (11.2 ± 0.10 %) and

coral skeleton with recent and transitional death

less than 15 days old (3.2 ± 0.03 %) (Fig. 3).

The highest cover of reef-building organisms

was found in the lagoon (29.1 %), habitat with

medium depth and low exposure to swell. In

general, non-reef-building communities domi-

nated in all environments (Lagoon-L = 57.1 %;

Lagoonal Terrace-LT = 65.8 %; Windward fore-

reef terrace-FT = 82.3 %) as well as in the dif-

ferent depths and levels of exposure.

When excluding the abiotic substratum to

recalculate the living cover, it was confirmed

that fleshy macroalgae have been increasing

in the last decade, becoming dominant in the

Fig. 2. Richness of hard corals recorded for the Bajo Nuevo reef complex during expeditions 2010 (Abril-Howard et al., 2012),

2011 (Vega-Sequeda et al., 2015) and 2021.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

community, as they increased from 27.3 ± 10.47

% in 2010 (Abril-Howard et al., 2012), to 37.8

% in 2011 (Vega-Sequeda et al., 2015) and to 72

± 0.10 % in 2021. The high macroalgal cover

recorded in 2021 is mainly attributed to turf

algal growth (43.2 ± 0.07 %) (Fig. 3). Corals and

hydrocorals contributed 19.8 ± 0.08 %, especial-

ly massive corals (14.5 ± 0.08 %) (Fig. 3). Hard

coral cover in 2021 was higher than what was

recorded in 2011 by Vega-Sequeda et al. (2015)

(12.1 %), but lower than what was recorded in

2010 by Abril-Howard et al. (2012) (30.2 ± 19.1

%). The contribution of other invertebrates was

8.2 ± 0.04 %, mostly soft corals (5.3 ± 0.04 %)

(Fig. 3, Table 3).

Macroalgae dominated in all stations; the

highest covers were recorded in the windward

terrace (88.4 %) and the lowest ones were

recorded in the lagoon (65.5 %). Among geo-

morphological units, turf algal cover varied

between 40.2 and 49.7 %. Erect fleshy algae

(Dictyota spp. and Turbinaria spp.) dominated

on the windward terrace (42.1 %) and crustose

and articulated calcareous algae (Halimeda spp.

and Amphiroa spp.) were more abundant in

protected environments (Lagoon-L = between

3.4 and 5.6%) than in exposed environments

(Windward fore-reef terrace-FT = between

0.7 and 0.9 %).

The highest covers of corals and hydro-

corals were recorded in the lagoon (24.8 %) and

the lowest ones were recorded in the windward

terrace (6.9 %), differences attributed mainly to

the contributions of massive corals (Lagoon-

L = 19.9 %, Lagoonal Terrace-LT = 5.6 %,

Windward fore-reef terrace-FT = 5.7 %). The

foliaceous and branched corals presented the

highest covers in the lagoon terrace (2.7-5.4%)

and the lowest ones in the windward terrace

(0-0.2 %). The highest hard coral cover record-

ed in the lagoon in 2021 coincides with what

was reported by Abril-Howard et al. (2012);

however, the records in 2010 are approximately

three times higher (70 %) than what was evi-

denced in 2021 (Table 3). In addition, in 2021,

in no transect hydrocorals exceed a 1 % cover.

The highest cover of other sessile inver-

tebrates was recorded in the lagoon (9.7 %),

followed by the lagoon terrace (5.7 %) and the

windward terrace (4.7 %). This pattern is attrib-

uted to the contribution of soft corals in the

lagoon (6.5 %) and in the lagoon terrace (4.3

%) and their absence in the windward terrace;

habitat where sponges presented the highest

cover (4.7 %).

In terms of coral cover, O. annularis was

the most abundant species (7.1 ± 0.08 %), fol-

lowed by Agaricia spp. complex (3.2 ± 0.03 %)

Fig. 3. Cover % (relative to total alive) of reef-building organisms and their main competitors (macroalgae and other sessile

invertebrates) in the Bajo Nuevo reef complex, in November 2021. (Average ± 1 S.D.).

10 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

and O. faveolata (2.9 ± 0.03 %). The individual

contributions of the other coral species (29

spp.) were less than 1 % (Table 3).

When comparing the coral cover between

stations, stations E1 (FT) and E5 (LT) were the

most extreme along axis 1 of the nMDS (Fig. 4),

due to the presence of species that were record-

ed only in these stations, such as Pseudodiploria

clivosa (4.7 %) in station E1 (total coral 6.9 %),

and A. palmata (4.7 %) and C. arbuscula (0.4 %)

in station E5 (total coral 15.7 %). In addition, in

E5 Favia fragum had its highest cover (0.7 %).

In the group comprising stations E2-E3 (Fig.

4), located on the lagoonal terrace, cover varied

between 12.2 % and 13.6 %, with Agaricia spp.

(E2 = 6.6 % and E3 = 8.6 %) being the largest

Table 3

Total and mean cover ± 1 S.D. (%) of coral species and other benthic categories recorded during the 2010 (Abril-Howard et

al., 2012), 2011 (Vega-Sequeda et al., 2015) and 2021 expeditions.

Species / Category 2010 2011* 2021**

Total corals and hydrocorals 30.19 ± 19.11. Up to 70 in the lagoon 12.1 19.83 ± 0.08

Orbicella annularis 4.72 ± 2.97 7.08 ± 0.08

Agaricia spp.1.67 ± 0.87 3.24 ± 0.03

Orbicella faveolata 3.45 ± 2.83 2.90 ± 0.03

Porites porites 1.00 ± 0.01

Orbicella franksi 1.16 ± 0.76 0.93 ± 0.02

Siderastrea siderea 2.04 ± 1.09 0.70 ± 0.01

Porites astreoides 0.58 ± 0.01

Madracis decactis 0.55 ± 0.01

Acropora palmata 0.43 ± 0.01

Pseudodiploria clivosa 0.42 ± 0.01

Diploria labyrinthiformis 0.65 ± 0.50 0.41 ± 0.01

Millepora spp. 0.32 ± 0.00

Porites divaricata 0.32 ± 0.01

Colpophyllia natans 0.30 ± 0.01

Siderastrea radians 0.28 ± 0.00

Pseudodiploria strigosa 1.02 ± 1.19 0.21 ± 0.01

Favia fragum 0.11 ± 0.00

Cladocora arbuscula 0.04 ± 0.00

Mycetophyllia aliciae 0.02 ± 0.00

Helioseris cucullata 0.01 ± 0.00

Meandrina meandrites 0.33 -

Eusmilia fastigiata 0.50 -

Macroalgae 27.35 ± 10.47 37.8 71.98 ± 0.10

Turfs 43.18 ± 0.07

Erect fleshy 21.02 ± 0.09

Calcareous articulated 5.10 ± 0.02

Crustose algae 2.67 ± 0.02

Other sessile invertebrates 8.19 ± 0.04

Gorgonaceans 13.5 5.26 ± 0.04

Sponges 6.7 2.70 ± 0.02

Other 0.22 ± 0.00

Soft bottoms 27.6 11.18 ± 0.10

* Average cover of coral species susceptible to SCTLD (Kramer et al., 2020), based on the results of the 2011 Expedition

(Vega-Sequeda et al., 2015). / ** Cover relative to total alive in 2021, except for the Soft Bottoms category.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

contributor. The highest cover occurred in the

lagoon groups of stations, varying between 19

and 33.2 %, excepting in station E11 (11.6 %).

In this habitat, Agaricia spp. had a lower cover

(1.3 and 6.1 %) and O. annularis had a greater

cover (0.7 and 25.4 %). The differences within

the lagoon group were given by the species spe-

cific to each station [E7 = Colpophyllia natans

(3.3 %) and Mycetophyllia aliciae (0.2 %), E10

= Helioseris cucullata (0.1 %), E11 = Diploria

labyrinthiformis (4.5 %)] (Fig. 4).

It is noteworthy that in November 2021,

45.4 ± 0.1 % of the benthic cover was ancient

coral skeleton (Bruckner, 2020), covered by

organisms with encrusting growth such as algal

turf, gorgonaceans (Erythropodium caribaeo-

rum), sponges (Chondrilla caribensis) and tuni-

cates (Trididemnum solidum). The contribution

of these organisms together in the different

geomorphological units was very homoge-

neous, varying between 42.9 and 49.1 %. The

greatest cover was found in shallow (49.1 %)

stations, compared to mid-depth (45.3 %) and

deep (39.9 %) stations. These results, together

with the proportion of coral skeleton with

recent and transitional death (3.2 ± 0.03 %),

suggest that recent pulses of coral tissue loss

have occurred in Bajo Nuevo, being more

intense in shallow waters.

Coral health: In 2021, seven signs associ-

ated with six coral diseases and health con-

ditions [White Band Disease (WBD); White

Plague Disease (WPD); Yellow Band Disease

(YBD); Dark Spots Disease (DSD); Aspergil-

losis (ASP) and bleaching] were identified (Gil-

Agudelo et al., 2009). In addition, four of these

signs can be associated with Stony Coral Tissue

Loss Disease (SCTLD) (Table 4). The highest

number of colonies with signs of disease was

found in the lagoon (76.7 %), followed by the

lagoon terrace (20.9 %) and the windward ter-

race (2.4 %).

The reported signs affected three genera,

13 species and 23.5 % (1 674) of the colo-

nies evaluated (Table 4; Fig. 5). The massive

meandroid forms (Colpophyllia natans, Diploria

labyrinthiformis and Pseudodiploria strigosa)

showed a 53.4 % sign prevalence of, followed

by the plocoid forms (Orbicella spp. complex)

Fig. 4. Non-metric multidimensional scaling analysis (nMDS), based on a Bray-Curtis similarity matrix of hard coral cover,

comparing among geomorphological units. Abbreviations: FT = Windward fore-reef terrace; LT = Lagoonal terrace and L =

Lagoon with coral patches.

12 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

Table 4

Evaluated health signs, associated diseases and host coral species.

Sign Description Associated diseases Host species

1Polyps with loss of color. Dispersed or regular

pattern.

SCTLD

Bleaching

O. annularis

O. faveolata

2Bands and/or spots of exposed skeleton (white)

in contact or not with necrotic tissue.

White Band Disease (WBD) A. cervicornis

A. palmata

Irregular patches of exposed skeleton. In contact

or not with necrotic tissue and high production

of mucus.

SCTLD

Bleaching

White Plague Disease (WPD)

Agaricia spp.

C. natans

D. labyrinthiformis

M. decactis

Millepora spp.

O. annularis

O. faveolata

P astreoides

Porites spp.

P. strigosa

S. siderea

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

Sign Description Associated diseases Host species

Patches and rings of yellow color, in contact

or not with necrotic tissue or exposed skeleton

(white).

SCTLD

Bleaching

Yellow Band (Blotch) Disease (YBD)

White Plague Disease (WPD)

Agaricia spp.

O. annularis

O. faveolata

O. franksi

P astreoides

P. strigosa

Dark spots from black to violet, with irregular

shape and size, can be depressed, low-lying

with respect to healthy tissue. Inside it can have

necrotic zones. High production of mucus.

SCTLD

Bleaching

Dark Spots Disease (DSD)

Agaricia spp.

C. natans

D. labyrinthiformis

O. faveolata

S. siderea

6Dark spots from black to violet. Small with

irregular shape.

Dark Spots Disease (DSD) S. siderea

7Violet spots of irregular size and shape. In contact

or not with necrotic tissue.

Aspergillosis (ASP)

Predation

G. ventolina1

G. flabellum

14 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

with 30 %. Of the total affected colonies, 84.9 %

showed one of the four signs related to SCTLD.

Among massive corals, S. siderea (63.9 %)

showed the highest prevalence of unhealthy

signs (Fig. 5).

Of the total cases, signs three and four,

described for four diseases (Table 4), presented

the highest occurrence (30.6 and 30 %, respec-

tively). Then, sign seven, exclusive to the genus

Gorgonia, represented 13.5 % of the cases, with

a prevalence of 54.1 %. Sign five was present in

13 % of all the affected colonies, with a higher

prevalence in S. siderea (49.8 %) and D. labyrin-

thiformis (19.4 %). Sign one represented 10.5 %,

while sign two, exclusive to the genus Acropora,

was present in 1.6 % of the affected colonies;

but its prevalence in Acropora cervicornis was of

72.7 % and in A. palmata was of 26 %. Finally,

sign six was present exclusively in S. siderea

with a prevalence of 5.9 % (Fig. 5).

Sea surface temperature (SST): According

to the NOAA interactive portal, in the South

Atlantic region, where Bajo Nuevo is located,

the annual cycle of the SST begins with the

progressive warming of the waters at the end of

June (28-29 ºC), reaching the maximum values

(31 ºC) during the height of the rainy season

(September-October) and decreasing to 27 ºC

between January and February. In the analyzed

series (2009-2021), during the rainy seasons of

2010, 2015 and 2017, the maximum sustained

SST was ~32 ºC and in 2019 it recorded ~33 ºC,

values above the physiological optimum upper

limit estimated for corals and zooxanthellae (>

31.5 ºC) (Baumann et al., 2016; Fitt et al., 2000;

Kleypas et al., 1999) (Fig. 6).

DISCUSSION

In 2021, coral richness was lower than

that recorded in previous expeditions (Abril-

Howard et al., 2012; Vega-Sequeda et al., 2015).

Between expeditions, species replacement pre-

sented greater importance in terms of beta

diversity (β); process that generates a homog-

enization in the types of life history and a

tendency to favor species considered weeds,

which opportunistically colonize recently dis-

turbed habitats (Randazzo-Eisemann & Garza-

Pérez, 2022). Darling et al. (2013) suggest that

thermal bleaching and other anthropogenic

stressors overfishing may drive changes in the

composition of reef communities. Moreover,

during these transitions, surviving corals have

stress-tolerant, and these changes in commu-

nity structure affect reef ecosystem functions

and services essential to human well-being

(Randazzo-Eisemann & Garza-Pérez, 2022).

Fig. 5. Prevalence (%) total and by signs of deterioration and coral species for the Bajo Nuevo reef complex, in November

2021. For more details, see Table 2. The diamonds indicate the total number of colonies.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

In the last decade, in Bajo Nuevo, the low

cover and abundance of competitive species

such as Acropora spp. and the absence of D.

cylindrus during 2021, in part, may be related

to large-scale disturbances that caused a sig-

nificant reduction of Acroporidae populations

in the Caribbean since the late 1980s, and the

documented low recovery rates for the Carib-

bean (García-Ureña et al., 2020; Gardner et

al., 2003; Souter et al., 2021). Furthermore,

several authors agree that competitive species

only dominate in “ideal” environments, so that

a decrease in their cover and in the structural

complexity of the reef is to be expected with the

increase of these disturbances, due to its high

sensitivity to breakage and dislodgment during

storms, low tolerance of stress and high mortal-

ity after bleaching from thermal anomalies and

epizooties (WBD and serratiosis) (Baumann

et al., 2016; Darling et al., 2012; Madin, 2005;

McClanahan et al., 2007).

Conversely, in the last decade, the areas

with the greatest coral development in Bajo

Nuevo have been dominated by the Orbicella

spp. complex, both in cover and abundance.

This is because O. annularis is more tolerant to

stress, has higher fecundity, episodic spawning

events and large corallites. These characteristics

allow it to store energy and resist sustained

recruitment failure for decades, increasing its

long-term survival in stressful environments

(Hughes & Tanner, 2000; van Woesik et al.,

2012). In addition, O. faveolata and O. franksi

are generalist and more competitive species

(Baumann et al., 2016; Darling et al., 2012).

However, a high prevalence of unhealthy signs

(30 %) in 2021 suggests that these species

have been affected by bleaching and other

diseases, causing pulses of massive loss of tis-

sue, as has been recorded in other Carib-

bean reefs (Álvarez-Filip et al., 2011); events

that may recur as temperature stress increases

(Buglass et al., 2016; Gardner et al., 2003;

Greenstein et al., 1998).

Despite differences in coral richness and

cover between expeditions, probably influenced

by the methodologies used in each of them, the

results indicate that the reefs of Bajo Nuevo are

experiencing a change from the dominance of

corals to the dominance of macroalgae, mainly

of algal turfs, a trajectory already described for

other Caribbean reefs (Souter et al., 2021).

Coral diseases are one of the main causes

of degradation in reefs and the estimation

of their prevalence is an approximation to

recognize the potential degradation of a reef

Fig. 6. Average values of Sea Surface Temperature – SST (°C) in the South Atlantic region, between 2009-2021 (NOAA, 2023).

Red line marks limits of physiological stress for corals and zooxanthellae.

16 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

area (Gil-Agudelo et al., 2009). Although dis-

eases are a natural process, they are problematic

when outbreaks negatively affect populations,

leading them to vulnerable or near-extinction

states (Raymundo et al., 2008). In this regard,

the Caribbean is considered a hot spot of epi-

zooties, due to the high number of pathologies,

high virulence rates and number of species

affected (~75 %) (Raymundo et al., 2005). Like-

wise, the islands of San Andrés and Providencia,

in Seaflower, are classified as a center of high

prevalence of diseases, especially WBD and

DSD (Navas-Camacho et al., 2010), although

there is no clarity of the factors that contribute

to it (Weil et al., 2002). However, in 2021 there

were no signs associated with Black Band Dis-

ease, considered one of the infectious diseases

that has most influenced the deterioration of

many reefs worldwide (Ainsworth et al., 2007).

In 2021, 3.2 % of the Bajo Nuevo hard ben-

thos was coral skeleton with recent and transi-

tional death less than 15 days old. In addition,

23.5 % of the colonies showed signs associated

with bleaching and epizooties. According to

Lirman et al. (2014), values > 2 % of recent

mortality reflect significantly stressful condi-

tions. So, the high prevalence of signs un

unhealthy, the number of affected species and

the proportion of recently dead coral skeleton,

show that this reef complex was going through a

pulse of mortality caused by outbreak of mixed

epizooties, with similar signs but different eti-

ologies. Besides, the evaluated signs suggest

the presence of at least six different epizooties,

including SCTLD. This disease represents an

important threat to the Caribbean reefs due to

its wide geographic range, extended duration,

high mortality rates (weeks to months) and the

large number of coral species affected (Reefre-

silience, 2023).

Mixed epizooties outbreaks have already

been previously documented in coral reef, as

well as their significant relationship with ther-

mal anomalies (Bruno et al., 2007). It is recog-

nized that host density (coral cover) acts as a

threshold in the incidence of these outbreaks

(Bruno et al., 2007) and that horizontal trans-

fer due to the proximity between healthy and

unhealthy colonies, together with the presence

of vectors (fish and invertebrates) determines

the severity of each outbreak (Jones et al., 2004;

Kuta & Richardson, 2002). different studies

have shown that anomalies in SST linked to

the climate change increases the occurrence

of coral diseases (Jaap, 2000; Patterson et al.,

2002), because induce bleaching episodes and

outbreaks of YBD, DSD and ASP (Gil-Agudelo

et al., 2009), which can be more aggressive in

reefs with high coral cover (e.g. Bajo Nuevo

in 2010). These findings indicate that, in Bajo

Nuevo, a probable cause of this mixed outbreak

in 2021 is the thermal stress generated by

anomalies in SST, which increase stress in cor-

als and favor the proliferation of certain groups

of pathogens associated with these diseases

(Bruno et al., 2007; Francini-Filho et al., 2010;

Kuta & Richardson, 2002).

Another important finding was the pro-

portion of standing ancient skeletons of giant

colonies of S. siderea and meandroid corals

(C. natans, D. labyrinthiformis and P. strigosa),

without evidence of physical or mechanical

damage. Although storms have drastic effects

on the composition, stability, and structure of

communities, and Seaflower is located within

the Caribbean hurricane belt (Díaz et al., 2000),

in 2021 there was no evidence of recent coral

damage caused by storms. These skeletons,

with varying degrees of erosion, were occu-

pied by communities with irregular shapes

and encrusting growth such as algal turf, gor-

gonaceans, sponges and tunicates. In 2021 this

portion of the benthos accounted for approxi-

mately half of the monitored benthic cover.

These indicate that Bajo Nuevo has experienced

different pulses of coral death in the last decade.

In addition, the historical decrease in the cover

of meandroid corals and the absence of other

species such as Eusmilia fastigiata and Meandri-

na meandrites, which were previously abundant

(2010-2011), are evidence of the occurrence

of different mortality pulses and that some of

them could be related to SCTLD, because this

disease is lethal for these species (advance rate

of 3-4 cm/day; Weil et al., 2019).

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 73: e57590, enero-diciembre 2025 (Publicado Abr. 28, 2025)

Climatic and oceanographic conditions

modify a wide variety of ecological processes

and thermal anomalies influence the sever-

ity and dynamics of epizooties (Bruno et al.,

2007). Experimental studies have shown that

thermal stress significantly affects the photo-

synthetic efficiency, growth and survival of cor-

als, although the specific responses depend on

the species and age of the coral (Kuanui et al.,

2015), thus positioning itself as a critical factor

in the structuring of reef communities (Bau-

mann et al., 2016). Therefore, the anomalies in

the SST between 2009 and 2021 partly explain

the causes of coral deterioration (mixed epizo-

oties) and the consequences of these changes

on the structure of reef communities in Bajo

Nuevo (replacement of coral species and chang-

es towards the dominance of fleshy macroalgae,

particularly alga turf).

With this study, it is concluded that the

hypothesis that remote ocean reefs experience

less deterioration due to their remoteness from

direct human disturbances, is ruled out for Bajo

Nuevo. Taking as reference the results of previ-

ous expeditions (2010-2011), this reef complex

registered in 2021 an evident drop in the cover

of hard corals and calcareous algae; a decrease

in coral richness and increase in the cover of

non-reef-building organisms (macroalgae) and

high prevalence of signs unhealth associated

with different coral diseases. This condition

may be a response of the communities to large-

scale pressures, such as anomalies in sea surface

temperature (SST). The results on the current

status of Bajo Nuevo confirm that these reefs

are endangered (EN), as suggested in the red

list of marine and coastal ecosystems of Colom-

bia (Uribe et al., 2020).

Ethical statement: The authors declare

that they all agree with this publication and

made significant contributions; that there is no

conflict of interest of any kind; and that we fol-

lowed all pertinent ethical and legal procedures

and requirements. All financial sources are fully

and clearly stated in the acknowledgments sec-

tion. A signed document has been filed in the

journal archives.

ACKNOWLEDGMENTS

We recognize the invaluable contributions

of the crew of the ship ARC Providencia,

the staff of the Colombian Ocean Commis-

sion–CCO [for its Spanish initials], especially

Juliana Acero and David Barrios, coordinators

of the Seaflower Scientific Expedition 2021

- II Bajo Nuevo Cay Islands, and each one of

the 19 expedition participants. We appreciate

the financial support of the Ministry of Sci-

ence, Technology and Innovation through the

Colombia Bio Program and of the Universidad

Nacional de Colombia, Caribbean Headquar-

ters. Undoubtedly. “This Expedition was quite

a voyage to the heart of the great Caribbean”.

Contribution # 571 of CECIMAR.

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