Aldo Croquer - Academia.edu (original) (raw)

Papers by Aldo Croquer

Numerous studies have demonstrated the differences in bacterial communities associated with coral... more Numerous studies have demonstrated the differences in bacterial communities associated with corals versus those in their surrounding environment. However, these environmental samples often represent vastly different microbial microenvironments with few studies having looked at the settlement and growth of bacteria on surfaces similar to corals. As a result, it is difficult to determine which bacteria are associated specifically with coral tissue surfaces. In this study, early stages of passive settlement from the water column to artificial coral surfaces (formation of a biofilm) were assessed. Changes in bacterial diversity (16S rRNA gene), were studied on artificially created resin nubbins that were modelled from the skeleton of the reef building coral Acropora muricata. These models were dip-coated in sterile agar, mounted in situ on the reef and followed over time to monitor bacterial community succession. The bacterial community forming the biofilms remained significantly differ...

The 5 countries continue collaborating to consolidate the Node of the GCRMN for Southern Tropical... more The 5 countries continue collaborating to consolidate the Node of the GCRMN for Southern Tropical America (STA), covering coral reef areas of the Eastern Pacific and the Western Atlantic. The coral reefs have been limited in their growth because of the strong influence of the major continental rivers, but the biodiversity is comparable to large parts of the Caribbean and they are economically important for supplying food and a strongly developing tourism industry. The coral reefs, however, have changed radically in the last 35 years, in particular during the 1980s, due mostly to anthropogenic stresses compounded by natural disturbances. Live coral cover has dropped dramatically on many of the reefs and frequently these are now dominated by algae. There are however, still some reefs that retain high coral cover between 20-40% in the Caribbean and above 40% in the Pacific. The 1997-98 strong El Niño event in the Pacific generated only moderate bleaching and low coral mortality through...

Journal of Experimental Marine Biology and Ecology

Frontiers in Marine Science

Over the past decade, coral restoration efforts have increased as reefs continue to decline at un... more Over the past decade, coral restoration efforts have increased as reefs continue to decline at unprecedented rates. Identifying suitable coral outplanting locations to maximize coral survival continues to be one of the biggest challenges for restoration practitioners. Here, we demonstrate methods of using derivatives from imaging spectroscopy from the Global Airborne Observatory (GAO) to identify suitable coral outplant sites and report on the survival rates of restored coral at those sites. Outplant sites for a community-based, citizen science outplant event in Bávaro, Dominican Republic, were identified using expert-defined criteria applied to a suitability model from data layers derived from airborne imagery. Photo quadrat analysis of the benthic community confirmed the accuracy of airborne remote sensing maps with live coral cover averaging 3.5–4% and mean algal cover (macro algae and turf) ranging from 28 to 32%. Coral outplant sites were selected at 3–7 m depth with maximized ...

Revista De Biologia Tropical, 2002

Para comparar las caracteristicas estructurales de algunas praderas de Thalassia testudinum de la... more Para comparar las caracteristicas estructurales de algunas praderas de Thalassia testudinum de la Bahia de Mochima y su relacion con la abundancia y distribucion del erizo Lytechinus variegatus , se seleccionaron 3 praderas de T. testudinum desde la boca (oleaje intenso) hasta el interior de la bahia (aguas calmadas). En cada localidad se fijaron 5 transectos paralelos a la costa de 20 m de longitud. Se emplearon cuadratas de 1 m2 para determinar la cobertura vegetal, densidad de plantas, densidad foliar y densidad de erizos. Paralelamente se extrajeron veinticinco muestras de vegetacion con nucleadores de 15 cm de diametro para la estimacion de la biomasa seca de las diferentes fracciones de las plantas (hojas, rizomas y raices). Se realizo un analisis de varianza multivariado (Manova) y una prueba diferencia minima significativa (LSD) para contrastar las caracteristicas estructurales de las praderas entre localidades y diferentes profundidades. Un analisis de regresion multiple pa...

Revista de biologia tropical, 2002

In this study, the rates of tissue regeneration and recovery from injuries that emulated the bite... more In this study, the rates of tissue regeneration and recovery from injuries that emulated the bites of either butterfly or parrotfish on colonies of Montastraea annularis exposed to different sedimentation regimesp were determined. Two small reef patches were chosen close to key Dos Mosquises, north of the Venezuclan mainland. Sixteen colonies (8 treatments + a single replicate) were artificially damaged at each patch and their recovery was monitored for three months by photographic means. The lesions were inflicted using two different techniques: scratching the polyps with a hard-nylon brush to resemble parrotfish (Scaridae) damages (Lesions Type 1) or jetting out the tissue with a syringe to simulate butterflyfish (Chaetondontidae) bites (Lesions Type 2). The diameter of the wounds ranged from 5 (small lesion) to 8 cm (large lesions) and both kinds were inflicted on the top and bottom of the colonies, with a single replicate for each treatment. The main factors affecting the recove...

PeerJ

Estimating variability across spatial scales has been a major issue in ecology because the descri... more Estimating variability across spatial scales has been a major issue in ecology because the description of patterns in space is extremely valuable to propose specific hypotheses to unveil key processes behind these patterns. This paper aims to estimate the variability of the coral assemblage structure at different spatial scales in order to determine which scales explain the largest variability on β-diversity. For this, a fully-nested design including a series of hierarchical-random factors encompassing three spatial scales: (1) regions, (2) localities and (3) reefs sites across the Venezuelan territory. The variability among spatial scales was tested with a permutation-based analysis of variance (Permanova) based on Bray-Curtis index. Dispersion in species presence/absence across scales (i.e., β-diversity) was tested with a PermDisp analysis based on Jaccard’s index. We found the highest variability in the coral assemblage structure between sites within localities (Pseudo-F = 5.34; ...

Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roqu... more Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roques because the actual status of this species at Los Roques was unclear in this archipelago after its regional collapse. In that opportunity we aimed to produce a baseline study for this species in Los Roques combining population genetics with demographic data. At that time, our results suggested that this species had the potential to come back at least in 6 out of 10 surveyed sites. This conclusion was based upon high abundance, low disease prevalence, high genetic diversity and a dominance of sexual reproduction in these populations. However, we recognized that the potential of recovery could be hindered depending on local and regional threats. In 2014, the status of this species was re-evaluated by increasing the number of sites from 12 to 106 and by identifying and targeting local and global threats that may affect population recovery. The results from this new survey showed that A. p...

Coral disease research encompasses five decades of undeniable progress. Since the first descripti... more Coral disease research encompasses five decades of undeniable progress. Since the first descriptions of anomalous signs, we have come to understand multiple processes and environmental drivers that interact with coral pathologies. In order to gain a better insight into the knowledge we already have, we explored how key topics in coral disease research have been related to each other using network analysis. We reviewed 719 papers and conference proceedings published from 1965 to 2017. From each study, four elements determined our network nodes: 1) studied disease(s); 2) host genus; 3) marine ecoregion(s) associated with the study site; and 4) research objectives. Basic properties of this network confirmed that there is a set of specific topics comprising the majority of research. The top five diseases, genera, and ecoregions studied accounted for over 48% of the research effort in all cases. The community structure analysis identified 15 clusters of topics with different degrees of o...

PloS one, 2017

Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global ... more Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest monitoring program in the wider Caribbean, to evidence local-scale (decreases in water quality) and global-scale (increases in temperature) stressors across the basin. Trend analyses showed that visibility decreased at 42% of the stations, indicating that local-scale chronic stressors are widespread. On the other hand, only 18% of the stations showed increases in water temperature that would be expected from global warming, partially reflecting the limits in detecting trends due to inherent natural variability of temperature data. Decreases in visibility were associated with increased human density. However, this link can be decoupled by environmental factors, with conditions that increase the flush of water, dampening the effects of human influence. Besi...

Marine Animal Forests, 2016

Octocorals (Cnidaria, Octocorallia) constitute a geographically widely distributed and common gro... more Octocorals (Cnidaria, Octocorallia) constitute a geographically widely distributed and common group of marine invertebrates commonly referred to as “soft-corals,” “sea fans,” “horny corals,” “sea feathers,” and “sea plumes.” They are found from shallow coastal habitats to mesophotic and abyssal depths. Octocorals are important members of most Atlantic-Caribbean, Indo-Pacific, and Mediterranean coastal and mesophotic reef communities; however, information about their susceptibility to diseases, predation, and competition, and their relationship with changing environmental conditions is limited. At least 19 diseases have been observed in at least 42 common octocoral species throughout their range. Twelve of these have been reported in the widerCaribbean (CA), one in Brazil (BR), two in the Mediterranean (ME), one in the Eastern Pacific (EP), and three in the western Pacific (WP). Pathogenic and/or environmental causes have been identified for eight diseases, including viruses, terrestrial fungi, protozoans, bacteria and cyanobacteria, filamentous algae, parasitic copepods, and high temperature. Only a few of the suspected pathogens have been tested with Koch’s postulates. At least eight disease outbreaks have led to extensive octocoral mortalities in the CA, ME, BR, and EP with detrimental ecological consequences. The fungal disease Aspergillosis has produced the highest mortalities in the CA and the EP. Other fungi, protozoans, and the bacterium Vibrio coralliilyticus were identified as potential causes of the death of millions of colonies in two Mediterranean disease outbreaks. Bacterial and fungal agents seemed to be responsible for the mass mortalities in Brazil and the WP. Most outbreaks in all regions were linked to high thermal anomalies associated with climate change, which seems to be the major driver. Other biological stressors such as predation and/or competition produce injuries that may contribute to the spread of infections and mortality. Overfishing of common predators could lead to population explosions of octocoral-feeding species that produced mass mortalities in some Caribbean localities. Our lack of knowledge of causes and pathogenesis of octocoral diseases parallels that of hard corals. New diseases are being described almost every year concomitant with increasing seawater temperatures. The ecological and economic consequences could be significant, with drastic changes in the seascape of shallow coral reefs and other coastal marine habitats and reduction of their ecological services. Given our limited knowledge, our best options for recovery of octocorals and coral reefs in general include sound management of coastal fisheries, development and tourism; reduction of landand sea-based pollution; and abating effects of climate change.

PeerJ, 2016

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitu... more Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms:Orbicella faveolata(massive-boulder),O. annularis(massive-columnar) andAcropora cervicornis(branching). We also compared mortality rates in colonies ofA. cervicornisbearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. InA. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI inA. cervicorniswas faster than in the massive speciesO. faveolata(0.5 ± 0.6 mm/day) andO. annularis(0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the morta...

PeerJ, 2016

This study evaluated pollution levels in water and sediments of Península de Paraguaná and relate... more This study evaluated pollution levels in water and sediments of Península de Paraguaná and related these levels with benthic macrofauna along a coastal area where the largest Venezuelan oil refineries have operated over the past 60 years. For this, the concentration of heavy metals, of hydrocarbon compounds and the community structure of the macrobenthos were examined at 20 sites distributed along 40 km of coastline for six consecutive years, which included windy and calm seasons. The spatial variability of organic and inorganic compounds showed considerably high coastal pollution along the study area, across both years and seasons. The southern sites, closest to the refineries, had consistently higher concentrations of heavy metals and organic compounds in water and sediments when compared to those in the north. The benthic community was dominated by polychaetes at all sites, seasons and years, and their abundance and distribution were significantly correlated with physical and che...

Interciencia, Sep 1, 2002

PeerJ, 2016

In the past decade, significant efforts have been made to describe fish-habitat associations. How... more In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies ofAcropora cervicornisto estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% o...

Marine Biodiversity Records, 2016

PeerJ, 2016

Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout... more Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recover...

Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout... more Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recover...

Caribbean Journal of Science, 2009

... Temporal variability and impact of coral diseases and bleaching in La Parguera, Puerto Rico f... more ... Temporal variability and impact of coral diseases and bleaching in La Parguera, Puerto Rico from 2003-2007 Ernesto Weil 1, Aldo Croquer and Isabel Urreiztieta ... 1998; Green and Bruckner 2000; Gil-Agudelo and Garzón-Ferreira 2001; Rodríguez-Martínez et al. 2001; Weil et al. ...

Numerous studies have demonstrated the differences in bacterial communities associated with coral... more Numerous studies have demonstrated the differences in bacterial communities associated with corals versus those in their surrounding environment. However, these environmental samples often represent vastly different microbial microenvironments with few studies having looked at the settlement and growth of bacteria on surfaces similar to corals. As a result, it is difficult to determine which bacteria are associated specifically with coral tissue surfaces. In this study, early stages of passive settlement from the water column to artificial coral surfaces (formation of a biofilm) were assessed. Changes in bacterial diversity (16S rRNA gene), were studied on artificially created resin nubbins that were modelled from the skeleton of the reef building coral Acropora muricata. These models were dip-coated in sterile agar, mounted in situ on the reef and followed over time to monitor bacterial community succession. The bacterial community forming the biofilms remained significantly differ...

The 5 countries continue collaborating to consolidate the Node of the GCRMN for Southern Tropical... more The 5 countries continue collaborating to consolidate the Node of the GCRMN for Southern Tropical America (STA), covering coral reef areas of the Eastern Pacific and the Western Atlantic. The coral reefs have been limited in their growth because of the strong influence of the major continental rivers, but the biodiversity is comparable to large parts of the Caribbean and they are economically important for supplying food and a strongly developing tourism industry. The coral reefs, however, have changed radically in the last 35 years, in particular during the 1980s, due mostly to anthropogenic stresses compounded by natural disturbances. Live coral cover has dropped dramatically on many of the reefs and frequently these are now dominated by algae. There are however, still some reefs that retain high coral cover between 20-40% in the Caribbean and above 40% in the Pacific. The 1997-98 strong El Niño event in the Pacific generated only moderate bleaching and low coral mortality through...

Journal of Experimental Marine Biology and Ecology

Frontiers in Marine Science

Over the past decade, coral restoration efforts have increased as reefs continue to decline at un... more Over the past decade, coral restoration efforts have increased as reefs continue to decline at unprecedented rates. Identifying suitable coral outplanting locations to maximize coral survival continues to be one of the biggest challenges for restoration practitioners. Here, we demonstrate methods of using derivatives from imaging spectroscopy from the Global Airborne Observatory (GAO) to identify suitable coral outplant sites and report on the survival rates of restored coral at those sites. Outplant sites for a community-based, citizen science outplant event in Bávaro, Dominican Republic, were identified using expert-defined criteria applied to a suitability model from data layers derived from airborne imagery. Photo quadrat analysis of the benthic community confirmed the accuracy of airborne remote sensing maps with live coral cover averaging 3.5–4% and mean algal cover (macro algae and turf) ranging from 28 to 32%. Coral outplant sites were selected at 3–7 m depth with maximized ...

Revista De Biologia Tropical, 2002

Para comparar las caracteristicas estructurales de algunas praderas de Thalassia testudinum de la... more Para comparar las caracteristicas estructurales de algunas praderas de Thalassia testudinum de la Bahia de Mochima y su relacion con la abundancia y distribucion del erizo Lytechinus variegatus , se seleccionaron 3 praderas de T. testudinum desde la boca (oleaje intenso) hasta el interior de la bahia (aguas calmadas). En cada localidad se fijaron 5 transectos paralelos a la costa de 20 m de longitud. Se emplearon cuadratas de 1 m2 para determinar la cobertura vegetal, densidad de plantas, densidad foliar y densidad de erizos. Paralelamente se extrajeron veinticinco muestras de vegetacion con nucleadores de 15 cm de diametro para la estimacion de la biomasa seca de las diferentes fracciones de las plantas (hojas, rizomas y raices). Se realizo un analisis de varianza multivariado (Manova) y una prueba diferencia minima significativa (LSD) para contrastar las caracteristicas estructurales de las praderas entre localidades y diferentes profundidades. Un analisis de regresion multiple pa...

Revista de biologia tropical, 2002

In this study, the rates of tissue regeneration and recovery from injuries that emulated the bite... more In this study, the rates of tissue regeneration and recovery from injuries that emulated the bites of either butterfly or parrotfish on colonies of Montastraea annularis exposed to different sedimentation regimesp were determined. Two small reef patches were chosen close to key Dos Mosquises, north of the Venezuclan mainland. Sixteen colonies (8 treatments + a single replicate) were artificially damaged at each patch and their recovery was monitored for three months by photographic means. The lesions were inflicted using two different techniques: scratching the polyps with a hard-nylon brush to resemble parrotfish (Scaridae) damages (Lesions Type 1) or jetting out the tissue with a syringe to simulate butterflyfish (Chaetondontidae) bites (Lesions Type 2). The diameter of the wounds ranged from 5 (small lesion) to 8 cm (large lesions) and both kinds were inflicted on the top and bottom of the colonies, with a single replicate for each treatment. The main factors affecting the recove...

PeerJ

Estimating variability across spatial scales has been a major issue in ecology because the descri... more Estimating variability across spatial scales has been a major issue in ecology because the description of patterns in space is extremely valuable to propose specific hypotheses to unveil key processes behind these patterns. This paper aims to estimate the variability of the coral assemblage structure at different spatial scales in order to determine which scales explain the largest variability on β-diversity. For this, a fully-nested design including a series of hierarchical-random factors encompassing three spatial scales: (1) regions, (2) localities and (3) reefs sites across the Venezuelan territory. The variability among spatial scales was tested with a permutation-based analysis of variance (Permanova) based on Bray-Curtis index. Dispersion in species presence/absence across scales (i.e., β-diversity) was tested with a PermDisp analysis based on Jaccard’s index. We found the highest variability in the coral assemblage structure between sites within localities (Pseudo-F = 5.34; ...

Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roqu... more Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roques because the actual status of this species at Los Roques was unclear in this archipelago after its regional collapse. In that opportunity we aimed to produce a baseline study for this species in Los Roques combining population genetics with demographic data. At that time, our results suggested that this species had the potential to come back at least in 6 out of 10 surveyed sites. This conclusion was based upon high abundance, low disease prevalence, high genetic diversity and a dominance of sexual reproduction in these populations. However, we recognized that the potential of recovery could be hindered depending on local and regional threats. In 2014, the status of this species was re-evaluated by increasing the number of sites from 12 to 106 and by identifying and targeting local and global threats that may affect population recovery. The results from this new survey showed that A. p...

Coral disease research encompasses five decades of undeniable progress. Since the first descripti... more Coral disease research encompasses five decades of undeniable progress. Since the first descriptions of anomalous signs, we have come to understand multiple processes and environmental drivers that interact with coral pathologies. In order to gain a better insight into the knowledge we already have, we explored how key topics in coral disease research have been related to each other using network analysis. We reviewed 719 papers and conference proceedings published from 1965 to 2017. From each study, four elements determined our network nodes: 1) studied disease(s); 2) host genus; 3) marine ecoregion(s) associated with the study site; and 4) research objectives. Basic properties of this network confirmed that there is a set of specific topics comprising the majority of research. The top five diseases, genera, and ecoregions studied accounted for over 48% of the research effort in all cases. The community structure analysis identified 15 clusters of topics with different degrees of o...

PloS one, 2017

Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global ... more Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest monitoring program in the wider Caribbean, to evidence local-scale (decreases in water quality) and global-scale (increases in temperature) stressors across the basin. Trend analyses showed that visibility decreased at 42% of the stations, indicating that local-scale chronic stressors are widespread. On the other hand, only 18% of the stations showed increases in water temperature that would be expected from global warming, partially reflecting the limits in detecting trends due to inherent natural variability of temperature data. Decreases in visibility were associated with increased human density. However, this link can be decoupled by environmental factors, with conditions that increase the flush of water, dampening the effects of human influence. Besi...

Marine Animal Forests, 2016

Octocorals (Cnidaria, Octocorallia) constitute a geographically widely distributed and common gro... more Octocorals (Cnidaria, Octocorallia) constitute a geographically widely distributed and common group of marine invertebrates commonly referred to as “soft-corals,” “sea fans,” “horny corals,” “sea feathers,” and “sea plumes.” They are found from shallow coastal habitats to mesophotic and abyssal depths. Octocorals are important members of most Atlantic-Caribbean, Indo-Pacific, and Mediterranean coastal and mesophotic reef communities; however, information about their susceptibility to diseases, predation, and competition, and their relationship with changing environmental conditions is limited. At least 19 diseases have been observed in at least 42 common octocoral species throughout their range. Twelve of these have been reported in the widerCaribbean (CA), one in Brazil (BR), two in the Mediterranean (ME), one in the Eastern Pacific (EP), and three in the western Pacific (WP). Pathogenic and/or environmental causes have been identified for eight diseases, including viruses, terrestrial fungi, protozoans, bacteria and cyanobacteria, filamentous algae, parasitic copepods, and high temperature. Only a few of the suspected pathogens have been tested with Koch’s postulates. At least eight disease outbreaks have led to extensive octocoral mortalities in the CA, ME, BR, and EP with detrimental ecological consequences. The fungal disease Aspergillosis has produced the highest mortalities in the CA and the EP. Other fungi, protozoans, and the bacterium Vibrio coralliilyticus were identified as potential causes of the death of millions of colonies in two Mediterranean disease outbreaks. Bacterial and fungal agents seemed to be responsible for the mass mortalities in Brazil and the WP. Most outbreaks in all regions were linked to high thermal anomalies associated with climate change, which seems to be the major driver. Other biological stressors such as predation and/or competition produce injuries that may contribute to the spread of infections and mortality. Overfishing of common predators could lead to population explosions of octocoral-feeding species that produced mass mortalities in some Caribbean localities. Our lack of knowledge of causes and pathogenesis of octocoral diseases parallels that of hard corals. New diseases are being described almost every year concomitant with increasing seawater temperatures. The ecological and economic consequences could be significant, with drastic changes in the seascape of shallow coral reefs and other coastal marine habitats and reduction of their ecological services. Given our limited knowledge, our best options for recovery of octocorals and coral reefs in general include sound management of coastal fisheries, development and tourism; reduction of landand sea-based pollution; and abating effects of climate change.

PeerJ, 2016

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitu... more Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms:Orbicella faveolata(massive-boulder),O. annularis(massive-columnar) andAcropora cervicornis(branching). We also compared mortality rates in colonies ofA. cervicornisbearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. InA. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI inA. cervicorniswas faster than in the massive speciesO. faveolata(0.5 ± 0.6 mm/day) andO. annularis(0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the morta...

PeerJ, 2016

This study evaluated pollution levels in water and sediments of Península de Paraguaná and relate... more This study evaluated pollution levels in water and sediments of Península de Paraguaná and related these levels with benthic macrofauna along a coastal area where the largest Venezuelan oil refineries have operated over the past 60 years. For this, the concentration of heavy metals, of hydrocarbon compounds and the community structure of the macrobenthos were examined at 20 sites distributed along 40 km of coastline for six consecutive years, which included windy and calm seasons. The spatial variability of organic and inorganic compounds showed considerably high coastal pollution along the study area, across both years and seasons. The southern sites, closest to the refineries, had consistently higher concentrations of heavy metals and organic compounds in water and sediments when compared to those in the north. The benthic community was dominated by polychaetes at all sites, seasons and years, and their abundance and distribution were significantly correlated with physical and che...

Interciencia, Sep 1, 2002

PeerJ, 2016

In the past decade, significant efforts have been made to describe fish-habitat associations. How... more In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies ofAcropora cervicornisto estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% o...

Marine Biodiversity Records, 2016

PeerJ, 2016

Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout... more Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recover...

Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout... more Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recover...

Caribbean Journal of Science, 2009

... Temporal variability and impact of coral diseases and bleaching in La Parguera, Puerto Rico f... more ... Temporal variability and impact of coral diseases and bleaching in La Parguera, Puerto Rico from 2003-2007 Ernesto Weil 1, Aldo Croquer and Isabel Urreiztieta ... 1998; Green and Bruckner 2000; Gil-Agudelo and Garzón-Ferreira 2001; Rodríguez-Martínez et al. 2001; Weil et al. ...