Osmoregulation in tropical zoanthid Protopalythoa variabilis (Cnidaria: Anthozoa) / Osmorregulação no zoantídeo tropical Protopalythoa variabilis (Cnidaria: Anthozoa)

This study evaluated the physiological, morphological and ethological effects of salinity variations on the tropical zoanthid Protopalythoa variabilis. This zoanthid was submitted to different salinity levels to probe the hypothesis of osmoregulation. Specimens collected in beach rocks from Northeastern Brazil were taken alive to the laboratory in their original water. The osmoregulatory ability of P. variabilis can be determined by measuring the hemolymph osmolality under various salinity conditions and comparing with the osmolality of the medium. The zoanthid P. variabilis is a "weak regulator", as it only osmoregulates within a narrow range of external salinity values, and its hemolymph osmolality drops, approximately in parallel with the isosmotic line, when the medium salinity falls below a certain limit. Ethological and morphological modifications under different salinities are discussed. This experiment shows for the first time the importance of osmotic regulation in the tropical zoanthid P. variabilis.

Este estudo avaliou os efeitos fisiológicos, morfológicos e etológicos no zoantídeo tropical Protopalythoa variabilis em diferentes níveis de salinidade. Para testar a hipótese de osmorregulação, o zoantídeo foi submetido a diferentes variações de salinidade. Os indivíduos foram coletados em recifes de arenito no Nordeste brasileiro e foram levados vivos para o laboratório na água em que foram recolhidos. A capacidade osmorregulatória de P. variabilis foi determinada pela medição da osmolaridade da hemolinfa em diferentes condições de salinidade e comparadas com a osmolaridade do meio. O zoantídeo P. variabilis é um "regulador fraco" visto que osmorregula dentro de uma estreita faixa de valores de salinidade externa e quando a salinidade do meio cai abaixo de um certo limite, ocorre redução da osmolaridade da hemolinfa, aproximadamente em paralelo com a linha isosmótica. As mudanças etológicas e morfológicas em diferentes salinidades são discutidas. Este experimento demonstra pela primeira vez a importância da regulação osmótica no zoantídeo tropical P. variabilis.

Reclutamiento de corales pétreos en arrecifes coralinos a diferentes distancias de fuentes de contaminación en La Habana, Cuba / Stony coral recruitment in coral reefs at different distances from pollution sources in Habana, Cuba

The effect of pollution on coral recruitment has been insufficiently studied. This research deals with coral recruitment in coastal areas and aimed to determine the variations of density and dominant species of corals recruits in sites at different distances from pollution sources. The composition and structure of stony coral (scleractinian and milleporids) recruit associations were characterized in the fringing reef of Western Havana, Cuba. This reef is influenced by urban pollution from the Almendares River and a sewage outlet located at its mouth. Four sites were sampled on the upper fore reef escarpment at 10m deep every three months between July 2007 and May 2008. A 25cm side quadrat was used to determine the density and taxonomic composition of recruits smaller than 3cm in diameter. Sampling units were placed following a random-systematic pattern. The mean density of recruits was determined both at assemble and species level. Bifactoral ANOVA tests were applied to compare mean densities at both sampling sites and dates. Student-Newman-Keuls test was applied to compare pairs of means. Cluster and nMDS analyses were applied to evaluate between site similarities. The predominant species was Siderastrea siderea followed by S. radians and Porites astreoides. Recruit densities were similar among La Puntilla, Calle 16 and Acuario sites. Lower densities were always found in Malecón. Significant differences in mean stony recruit densities were found both between sites and sampling dates. The statistic analysis did not show significant spatial-temporal interactions. Malecón, the most polluted site, showed the lowest recruit density and the greater presence of species considered as indicators of organic pollution, sedimentation and abrasion. The density of recruit species was higher in October 2007 and lower in May 2008, and it was apparently influenced by reproduction and cold front seasons, respectively. The higher dominance and abundance of S. siderea, S. radians and P. astreoides recruits were apparently due to their high reproductive potential and resistance to disturbances. The identity of dominant species was apparently related to distance from major pollution sources. We highly recommended the replication of this research in other areas of the greater Caribbean region to test the generality of present results and to compare among areas. Future research should take into account the influence of other environmental factors, along with an appraisal of recruit species tolerance to these factors, to better ponder the effect of urban pollution on recruitment. Areas with well assessed pollution regimes are recommended for research.

El efecto de la contaminación sobre el reclutamiento ha sido insuficientemente estudiado. Este trabajo trata el tema del reclutamiento en sitios ubicados a diferentes distancias de dos importantes fuentes de contaminación. Se caracterizó la composición y estructura de las asociaciones de reclutas de corales pétreos (escleractinios y milepóridos) al oeste de la Ciudad de La Habana, Cuba. Esta área está influenciada por la contaminación urbana del río Almendares y del emisario submarino construido en su desembocadura. El objetivo de esta investigación fue determinar las variaciones en la densidad y predominio de las especies de reclutas, en sitios ubicados a diferentes distancias de fuentes de contaminación, en distintas épocas de un año. Se muestreó cada tres meses entre julio 2007- mayo 2008. Se escogieron cuatro sitios de muestreo cerca del borde superior del escarpe del arrecife frontal a 10m de profundidad. Se utilizó un marco cuadrado de 25cm de lado de forma aleatoria-sistémica para determinar la densidad y composición taxonómica de reclutas de corales pétreos (colonias menores de 3cm). Para comparar las densidades medias entre sitios y fechas de muestreo se aplicó un análisis de varianza bifactorial. Para comparar los pares de densidades medias se empleó la prueba de Student-Newman-Keuls. La aplicación de un análisis Clasificación Numérica Jerárquica Aglomerativa (Cluster Analysis) y uno de ordenamiento por Escalado Multidimensional no Métrico (nMDS) mostró una distribución en la que los sitios quedaron agrupados en función de sus distancias de las fuentes contaminantes. Predominó Siderastrea sidérea seguida por Siderastrea radians y Porites asteroides. Durante el año de muestreo, las densidades de reclutas fueron similares entre La Puntilla, Calle 16 y Acuario. Las menores densidades se observaron siempre en Malecón. Se encontraron diferencias significativas entre las densidades medias de los sitios, así como entre de las distintas fechas de muestreo. El análisis de variancia bifactorial no mostró interacción significativa espacio-tiemporal. Malecón, sitio más contaminado, presentó menor reclutamiento y mayor presencia de especies consideradas indicadoras de contaminación orgánica, sedimentación y abrasión. Las densidades fueron mayores en Octubre 2007 y menores en Mayo 2008, al parecer influenciados por las épocas de reproducción y la acción de los frentes fríos respectivamente. El mayor predominio y abundancia de reclutas de S. siderea, S. radians y P. astreoides parece responder a sus elevados potenciales reproductivos y altas resistencias a disturbios. La identidad de las especies dominantes estuvo relacionada aparentemente con las distancias de las principales fuentes de contaminación. Se recomienda replicar esta investigación en otros lugares de la región del Caribe para probar la generalidad de estos resultados. Estudios futuros debieran tener en cuenta la influencia de otros factores ambientales, junto con una valoración de la tolerancia de las especies de reclutas a estos factores, para ponderar mejor el efecto de la contaminación urbana sobre el reclutamiento.

Estructura y daños en las comunidades de octocorales (Octocorallia: Alcyonacea) de la Reserva Ecológica Siboney-Juticí, Santiago de Cuba, Cuba

Structure and injuries of octocoral communities (Octocorallia: Alcyonacea) of Ecological Reserve Siboney-Juticí, Santiago de Cuba, Cuba. In the spur-and-groove reefs of the Ecological Reserve Siboney-Juticí (Southeast Cuba) octocorals are one of the predominant components of the sessile fauna. Main objectives of the present paper are characterizing the composition, structure and conservation status of the octocoral communities and assessing on the prevailing environmental conditions in the study area. For data collection, six sampling sites were located every 2-3km ranging from 12m to 17m depth along the spur-and-groove reefs. In each site, 22-26 1m² quadrants were zigzag arranged every 2m. The density of colonies was determined per site. The severity degree and predictability of environmental conditions were inferred by using the Heterogeneity and Equitability indexes, respectively. Hydrodynamic stress and the Comparative Pollution Index were also assessed. Current affectations of the octocoral communities were also determined and classified into four main categories: mechanical damage, diseases, predation and invertebrate and macroalgae overgrowth. As a result, 25 species represented by 752 colonies were recorded and Eunicea flexuosa and Gorgonia ventalina were the most abundant. The occurrence of Eunicea succinea forma succinea constituted the first report for Eastern Cuba. Site densities ranged from 3.58±1.84 to 7.58±2.16 colonies/m² and considered from moderate to low. The biggest densities were reported at both sides of the San Juan River mouth. Despite of the composition and structure of the octocoral communities, low to high hydrodynamic stress and low and moderate levels of contamination were inferred, it is likely that these indexes could have been overestimated due to the sensitivity of the indicator species to other factors such as sedimentation. The environmental conditions were mostly favorable and stable. In general, the number of dead colonies was low and mostly caused by the detachment of the substrate and overgrowth of Millepora alcicornis. Injuries were mainly brought about by mechanical damage, followed by coenenchyme loss, predation by Cyphoma gibbosum and macroalgae overgrowth. On the other hand, negative effects by Hermodice carunculata predation, bleaching, Red Band and Black Band Disease were not observed. Among sampled species, G. ventalina colonies were the most severely damaged within the community. As a whole, octocoral communities of spur-and-groove reefs in the Ecological Reserve Siboney-Juticí showed a good conservation status. Rev. Biol. Trop. 58 (4): 1211-1221. Epub 2010 December 01.

Se estudió la comunidad de octocorales del arrecife de macizos y canales de la Reserva Ecológica Siboney- Juticí (sur oriente de Cuba) con el objetivo de caracterizar su composición, estructura y estado de conservación, así como inferir a partir de estas las condiciones ambientales imperantes en el área. La investigación se realizó entre enero y junio de 2009, en seis localidades ubicadas entre 12m y 17m de profundidad. Como unidad de muestreo se empleó un marco de 1m², el cual fue puesto en zigzag cada 2m sobre la superficie del arrecife de macizos. Se determinó, por localidad, la densidad de colonias y se infirieron los grados de severidad, constancia ambiental, tensión hidrodinámica y el Índice Comparativo de Contaminación. Se determinaron, además, los daños en la comunidad de octocorales. Se analizaron 752 colonias e identificaron 25 especies de octocorales. Eunicea flexuosa y Gorgonia ventalina fueron las especies más abundantes. La densidad fluctuó entre 3.58±1.84 colonias/m² y 7.58±2.16 colonias/ m² (densidad de baja a moderada tendiendo a baja). En la zona se infirió una tensión hidrodinámica entre baja y alta, con niveles de contaminación bajos y moderados, y un ambiente generalmente favorable y constante. Los daños de tipo mecánico fueron los más frecuentes, siendo G. ventalina la especie con más colonias dañadas. La comunidad de octocorales del hábitat de macizos y canales de la Reserva Ecológica Siboney-Juticí presentó un buen estado de conservación.

The effects of a coral disease on the reproductive output of Montastraea faveolata (Scleractinia: Faviidae)

The direct impacts of coral diseases on coral populations have been assessed by quantifying coral tissue loss and colony mortality, but the determination of the indirect effects of diseases, such as disruptions in life history functions (e.g. reproduction, growth and maintenance), are more difficult to ascertain and have been scant. This study involved a comparison of various measures of reproductive output from histological slides of healthy tissue samples of Montastraea faveolata and tissue samples from colonies with white plague (WP) infections in Dominica (West Indies). Although the variability in the reproductive data was high, WP had significant negative impacts on the percentage of reproductive polyps per cm2, the percentage of reproductive mesenteries within a polyp, oocyte quantity per polyp, mean oocyte volume (mm3), and fecundity (oocyte volume per cm2 of tissue). However, these effects were only observed in the tissue directly impacted by the WP disease "band" and were not observed in tissue samples taken 20 cm away from the lesion. Therefore, the effects of a coral disease (WP) on reproductive output are localized and not expressed colony-wide. Rev. Biol. Trop. 58 (Suppl. 3): 99-110. Epub 2010 October 01.

Recent dynamics and condition of coral reefs in the Colombian Caribbean

Long-term monitoring data provide a basis to recognize changes in coral reef communities and to implement appropriate management strategies. Unfortunately, coral reef dynamics have been poorly documented at any temporal scale in the Southern Caribbean. Through the "National Monitoring System of Coral Reefs in Colombia" (Spanish acronym: SIMAC), we assessed 32 permanent plots at different depth levels in six reefs areas of the Colombian Caribbean from 1998 to 2004. Temporal trends in coral and algal cover were evaluated by repeated measures ANOVA. The model included the effect of depth levels (a fixed effect), monitoring plots (a random effect) as a nested factor within depths, and time (repeated factor). We found high spatial variability in major benthic components. Overall means indicated that algae were the most abundant biotic component in nearly all areas, ranging from 30.3% at Rosario to 53.3% at San Andrés. Live coral cover varied considerably from 10.1% at Santa Marta up to 43.5% at Urabá. Coral and algae cover per se are not always accurate reef indicators and therefore they need supplementary information. Temporal analyses suggested relative stability of coral and algal cover along the study but the causes for the observed trends were rarely identified. A significant decrease (p=0.042) in coral cover was only identified for some monitoring plots in Tayrona-time x plot (depth level) interaction, and importantly, few coral species explained this trend. Significant increase (p=0.005) in algal cover was observed over time for most plots in Rosario. Temporal trajectories in algal cover were influenced by depth-significant time x depth interaction-in San Andrés (increase, p=0.004) and Urabá (decrease, p=0.027). Algae trends were mainly explained by changes in algal turfs. Monitoring programs must focus on the mechanisms mediating the changes, in particular those concerning coral recovery and reef resilience in the current context of climate change. Rev. Biol. Trop. 58 (Suppl. 1): 107-131. Epub 2010 May 01.

Este trabajo contiene el primer análisis temporal de la información obtenida por el Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC). Entre 1998 y el 2004 se monitorearon un total de 32 parcelas permanentes ubicadas a diferentes niveles de profundidad en seis áreas arrecifales del Caribe colombiano. Los patrones temporales de algas y corales fueron evaluados mediante análisis de varianza de medidas repetidas. Los promedios generales indicaron que las algas dominaron en la mayoría de las áreas evaluadas, variando de 30.3% (Rosario) hasta 53.3% (San Andrés). La cobertura coralina fluctuó considerablemente entre 10.1% (Santa Marta) y 43.5% (Urabá). Los arrecifes estudiados han permanecido relativamente estables durante el periodo evaluado en términos de algas y corales. El único cambio significativo en la cobertura se detectó en algunas parcelas de monitoreo del Tayrona, y pocas especies coralinas explicaron la tendencia de disminución. En Rosario se detectó una tendencia significativa de incremento para las algas en la mayoría de las parcelas. En San Andrés y Urabá las tendencias temporales (aumento y disminución respectivamente) se presentaron en ciertos niveles de profundidad. En estas dos áreas las tendencias en la cobertura de las algas fueron explicadas principalmente por cambios en los tapetes algales. En general las causas de los patrones observados no pudieron identificarse. Los programas de monitoreo deben evaluar no solo las tendencias generales de algas y corales sino también las de sus componentes (especies de coral y grupos funcionales de algas). Así mismo, deben enfocarse en evaluar los mecanismos involucrados en los cambios, en especial aquellos relacionados con la recuperación coralina y la resiliencia arrecifal, de manera que se pueda enfrentar el deterioro arrecifal en el actual contexto de cambio climático.

Lesiones naturales y regeneración de tejido en ramets del coral Montastraea annularis (Scleractinia: Faviidae) en un arrecife degradado del Caribe Colombiano

Natural lesions and regeneration of ramets of Montastraea annularis (Scleractinia: Faviidae) in a degraded reef of the Colombian Caribbean. Currently, Montastraea annularis populations are suffering from high partial mortality rates; yet few studies have determined type, frequency and intensity of natural lesions in situ. During a year we followed natural lesions that appeared on healthy ramets of a population on a degraded reef within a Marine Protected Area in Colombia, to infer the effect on population size structure. From September 2003 to September 2004, 94% of the ramets presented lesions caused by bleaching, predation; or algae, sponge and borrower interactions. Predation caused 47% of the lesions and algae 36%; most lesions (85%) were small (<5cm²), although some were bigger than 60cm2 (0.3%). Lesion recovery was high (83%), but 11.2% did not recover or grow. On 2.5% algae invasion was seen. Bleaching lesions affected more ramet area (>60% of its live tissue) and were evident from September to November, yet total recovery was found in three months. In contrast, lesions by algae (36%), showed less recovery (6.7%), and a tendency to grow in time. In general, percentage of affected tissue area of a ramet in any month was lower than 10%. Nevertheless from May to September, the area affected was larger (10-50%) due to an increase in frequency and abundance of predation, bleaching and algal damage, and a decrease in recovery. At the end of the year, lesions that did not recover caused partial mortality in 25% of the ramets. Ramets with lesions shrunk throughout the year and by the end of year, 21% passed to a smaller class size. Rev. Biol. Trop. 57 (4): 939-954. Epub 2009 December 01.

Las poblaciones de Montastraea annularis muestran síntomas de declinamiento y sin embargo, pocos estudios se han realizado sobre tipos, frecuencias e intensidad de lesiones naturales in situ. Durante un año, septiembre 2003 a septiembre 2004, se hizo el seguimiento anual de lesiones naturales que aparecieron en ramets sanos de una población en un arrecife degradado dentro de un Área Marina Protegida, para inferir su efecto en la estructura de talla de la población. El 94% de los ramets presentaron lesiones causadas por blanqueamiento, depredación e interacciones con algas, esponjas y bioerodadores. La depredación causó el 47% y la interacción con algas el 36%. El 85% de las lesiones eran de tallas pequeñas (<5cm²) aunque algunas fueron mayores a 60 cm² (0.3%). La recuperación de las lesiones fue alta (83%), sin embargo 11.1% no se recuperaron y por el contrario aumentaron. En el 2.5% de las lesiones hubo invasión de algas. Las lesiones causadas por blanqueamiento afectaron mayor área de los ramets (>60% de su tejido vivo) en los meses de septiembre a noviembre, pero la recuperación fue del 100% a los tres meses. Por el contrario, las lesiones con algas (36%), mostraron menor recuperación (6.7%) y una tendencia a aumentar el área de lesión con el tiempo. En general, el porcentaje de área de tejido afectada por lesiones en un ramet durante cualquier mes fue menor a 10%. Sin embargo, de mayo a septiembre el porcentaje de tejido afectado fue mayor (10-50%) debido al incremento en la frecuencia y abundancia de depredación, blanqueamiento e interacción con algas, y a la menor tasa de recuperación. Al final de un año, las lesiones que no se recuperaron causaron mortalidad parcial en el 25% de los ramets. El efecto de las lesiones y la recuperación sobre el tamaño de los ramets evidenció disminución de talla a lo largo del año, y al final de este, significó que el 21% pasara a una clase de talla menor.

Influence of Palythoa caribaeorum (Anthozoa, Cnidaria) zonation on site-attached reef fishes

This work aimed to test the influence of Palythoa caribeorum, a widely distributed zoanthid in the Atlantic, on site-attached reef fish in a subtropical rocky shore. Density, richness and vertical distribution of reef fish inside (ID) and outside (OD) previously chosen P. caribaeorum dominance patches were compared through stationary visual censuses along three different periods. Fishes were grouped in different trophic guilds to evidence differences in resources uses in both treatments. A complexity index was estimated by the chain link method and percentage covering of benthic organisms was obtained analyzing random points from replicated photo-quadrats. We observed thirty-eight species of fishes, belonging to twenty-five families. Reef fish communities between studied patches were similar,both in terms of species composition and vertical distribution. Considering only the most site-attached fishes, which were the most frequent and abundant species, data showed that ID sustains higher diversity and abundance than OD. Results showed that benthic composition differ significantly among patches whereas complexity remained without differences. Otherwise, results indicated that these areas might play an important role in space limitation, structuring neighboring benthic community and consequently reef fish assemblages.

Este estudo visou testar a influência de Palythoa caribeorum, um zoantídeo amplamente distribuído no Atlântico, na estruturação da comunidade de peixes recifais associados a um costão rochoso de uma região subtropical. A densidade, a riqueza e a distribuição vertical de peixes recifais em áreas previamente selecionadas com e sem a dominância de Palythoa caribaeorum foram comparadas através de censos visuais estacionários em três períodos distintos de tempo. Os peixes foram agrupados em guildas tróficas a fim de evidenciar diferenças nos usos dos recursos nas diferentes áreas analisadas. Foram analisados também índices de complexidade estrutural através do método da corrente e os percentuais de cobertura bentônica através de fotos quadracts replicados. Foram registradas trinta e oito espécies de peixes recifais de vinte e cinco famílias diferentes. Acomunidade de peixes entre as áreas estudadas foi similar tanto em composição de espécies quanto em distribuição vertical. Considerando apenas as espécies mais associadas ao substrato, que foram as mais freqüentes e abundantes, os dados mostraram que as áreas com dominância de P. caribaeorum sustentam maior diversidade e abundância do que as áreas sem a dominância de P. caribaeorum. Foram encontradas ainda diferenças significativas na composição bentônica entre os diferentes tratamentos estudados, mas não foram verificadas diferenças entre a complexidade estrutural entre estas áreas. No entanto, os resultados sugerem que as áreas com dominância de P. caribaeorum podem desempenhar papel importante na limitação de espaços, estruturando as comunidades bentônicas e, conseqüentemente, afetando a comunidade de peixes recifais.

Efectos de un emisario submarino de aguas "residuales" urbanas sobre comunidades de octocorales (Octocorallia: Alcyonacea) en Cuba / Effects of a submarine discharge of urban waste on octocoral (Octocorallia: Alcyonacea) communities in Cuba

The composition and structure of octocoral communities on coral reefs close to a submarine outfall were studied at Reparto Flores, west of Havana City, Cuba. Octocoral community changes after the deployment of the submarine outfall in 2000 were monitored from June 2002 to September 2005, taking as baseline the data existing before its construction. The area also receives the influence of the polluted river Quibú that passes through a great part of the west side of the City. Sampling was done by means of SCUBA diving, counting and identifying colonies in situ within a 1 m2 frame that was randomly placed as many times as to warrant stabilized values of Shannon and Weaver's heterogeneity index H'. In agreement with the available hydrochemical information, changes in the diversity indexes (Shannon and Weaver's heterogeneity index H', Pielou's equitability index J', and Margalef's species richness index R1), the Herrera-Moreno's comparative pollution index (ICC), and density of some octocoral species at a depth of 10 m suggest a decrease in the influence of polluters from 1989 to 2005. Nevertheless, these indicators were affected in 2004 by a sudden intense but brief colonization of Briareum asbestinum, a species that is not typical of polluted places. At a depth of 20 m, a co-dominance of Plexaura kuekenthali and Eunicea clavigera (resistant and non resistant to pollution, respectively) and an increase of the comparative pollution index (ICC) was observed. The increase of P. kuekenthali, a pollution indicator, suggests a rise in the pollution effect 20 m in depth, because of the recent impact caused by the greater closeness of the outfall mouth 50 m deep. Results corroborate the hypothesis about the pollution indicator character of P. kuekenthali. However, this could not be explored for Eunicea flexuosa (also considered a pollution-indicator) due to an intensive illegal selective extraction for lucrative handicraft purposes, which...

Para profundizar en las respuestas de las comunidades de octocorales a la influencia de residuales urbanos se estudió su composición y estructura en sitios de arrecife cercanos a un emisario submarino urbano en el Reparto Flores, La Habana, Cuba. Desde junio del 2002 hasta septiembre del 2005, se efectuó el monitoreo de los cambios ocurridos en las comunidades después de la puesta en operación del emisario en el año 2000, tomando como línea base datos existentes antes del inicio de su construcción. El muestreo se realizó mediante buceo SCUBA, contando e identificando las colonias in situ dentro de cuadricula de 1 m2 de lado. Diversos índices sugieren una disminución de la influencia de la contaminación en la última década.El incremento de P. kuekenthali (indicadora de contaminación, , sugiere un aumento del efecto de la contaminación a 20 m de profundidad debido al impacto reciente de la mayor cercanía del desagüe del emisario que se encuentra a 50 m de profundidad. B. asbestinum y E. clavigera se perfilaron como poco resistentes a la contaminación.

Bioerosion caused by the sea urchin Diadema Mexicanum (Echinodermata: Echinoidea) at Bahías de Huatulco, Western Mexico

Mexican Pacific sea urchin studies have been focused mainly on species distribution, ecology and fisheries. Reef degradation by sea urchin bioerosion has not been studied previously en these reefs. We investigate the importance of Diadema mexicanum as a bioerosive agent of coral carbonate at Bahias de Huatulco, and the relative magnitude of coral accretion and bioerosion. At each of five localities in Bahias de Huatulco, sea urchin density, feeding and mechanical (spine) erosion was determined for three size class intervals. In general, D. mexicanum do not exert any significant role on coral reef community structure (live coral, dead coral or algal coverage) at the Huatulco area, probably because they are generally small (2.9-4 cm test size) and few in number (1.0-6.8 ind.m-2). Mean bioerosion rates are consistent with those measured for other diadematoids, as well as other urchin species in various eastern Pacific localities. However, the degree of bioerosive impact depends on species, test size, and population density of urchins. Coral carbonate removal by D. mexicanum erosion varies from 0.17 to 3.28 kgCaCO3m(-2)yr(-1). This represents a carbonate loss of < 5% of the annual coral carbonate production at Jicaral Chachacual, San Agustín and Isla Cacaluta, but 16 and 27% at Isla Montosa and La Entrega. On balance, coral accretion exceeds sea urchin erosion at all sites examined at Huatulco. At Bahias de Huatulco coral reef communities are actively growing, though in the coming years, it might be necessary to investigate the local effects of the interaction among erosion, and environmental and human induced perturbations

Diversidad y abundancia de equinodermos en la laguna arrecifal del Parque Nacional Cahuita, Caribe de Costa Rica / Diversity and abundance of echinoderms from the reef lagoon at Cahuita National Park, Caribbean from Costa Rica

A total of 15 species of echinoderms (one asteroid, seven ophiuroids, five echinoids and two holothurians) were recorded at the Cahuita National Park reef lagoon, between September and October 2003, using a 1 m2 quadrant. The sites with coral substrate and algae were the most diverse, while those with seagrass and sand were the least. Ophiuroids were the most abundant group with 170 individuals, asteroids were the least abundant. Adding other studies and reports of echinoderms to this study, a total of 23 species have been found at Cahuita National Park, which is the most diverse area on the Caribbean of Costa Rica. We report nine new echinoderm records for Costa Rica's Caribbean.

Patterns of sexual recruitment of acroporid coral populations on the west fore reef at Discovery Bay, Jamaica

Coral recruitment was examined on terracotta tiles deployed for four six-month periods between March 2001 and April 2003 on the West Fore Reef at Discovery Bay, Jamaica. During each sampling period, four tiles were deployed on each of two arrays at six depths ranging from 3 m to 33 m. Only three Acropora spat recruited to the tiles over the sampling period. The Acropora spat recruited during only one of the four six-month sampling periods and at only one depth, 3m. That represents a density of 8 spat m(-2) at 3 m depth for one six-month sampling period. Acropora recruitment represented <1 % of the total spat recruiting to the tiles deployed at 3 m during the four sampling periods. Density of acroporids on the West Fore Reef is low. Only one Acropora colony (an A. palmata) was recorded during Point-Quarter surveys of coral cover and density at depths of 3 m, 9 m, 14 m and 19 m. Considering the paucity of acroporid colonies and the infrequent settlement of acroporid spat on the West Fore Reef, it is unlikely that the historic abundance of A. palmata and A. cervicornis will return soon.

Environmental education in Tobago's primary schools: a case study of coral reef education

Environmental education is a relatively new area on the primary school curriculum of Trinidad and Tobago. Because of the close relationship between human activities and the degradation of the natural environment in Tobago, environmental education will become increasingly important to the preservation and conservation of the island's fragile natural resources. Current teaching methods rely heavily on text books and utilise a lecture style that does not promote student interaction. Unfortunately, these methods are not very conducive to environmental education. As such, this paper examines a pilot program in which staff from the Buccoo Reef Trust taught students from 15 primary schools about coral reefs using interactive tools and hands-on methods as described in People & Corals: an Education Package for Primary Schools (People & Corals). The pilot program ran over an eight week period with prepared lessons being taught every two weeks and student evaluations taking place once before the first lesson and once after the last lesson. The lessons were supplemented with a field trip to a coral reef ecosystem. Despite several challenges that were faced in the implementation process, the overall outcome of the pilot program was successful. Teachers and students reacted positively to the information that was being shared, thereby reinforcing the effectiveness of using a dynamic, active method of teaching to advance environmental education

Reproductive biology of Palythoa caribaeorum and Protopalythoa variabilis (Cnidaria, Anthozoa, Zoanthidea) from the southeastern coast of Brazil

A biologia reprodutiva de Palythoa caribaeorum (Duchassaing & Michelotti 1860) e Protopalythoa variabilis (Duerden 1898) foi estudada por amostras mensais de colônias etiquetadas de junho de 1996 a junho de 1997, no canal de São Sebastião, São Paulo, Brasil (45º26'W, 23º50'S). A gametogênese apresentou-se semelhante à de outros zoantídeos, como evidenciado em preparações histológicas. O diâmetro dos oócitos e os estágios de maturação dos folículos testiculares foram avaliados por preparações do tipo "squash". Ambas as espécies mostraram hermafroditismo seqüencial protogínico, com alta freqüência de pólipos férteis (83% em P. variabilis e 72% em P. caribaeorum) e de colônias na condição sexual feminina (65,3% para P. variabilis e 41,7% para P. caribaeorum), e, aparentemente, gametogênese contínua. Em P. caribaeorum, a liberação de oócitos foi contínua e a liberação de espermatozóides ocorreu durante metade do período analisado. Para P. variabilis, a liberação de oócitos e de espermatozóides ocorreu em abril-maio e fevereiro-março de 1997, respectivamente.

El arrecife coralino de Punta Cocles, costa Caribe de Costa Rica / Punta Cocles coral reef, Caribbean Coast of Costa Rica

Este estudio describe al arrecife de Punta Cocles (Limón, Costa Rica). Los datos se obtienen por medio de un muestreo con nueve transectos, paralelos a la costa y por observaciones directas durante buceos a pulmón entre los meses de setiembre y noviembre del 2002. Este arrecife consta aproximadamente de 10.5 hectáreas, en las que se identifican 13 especies de corales, 39 de macroalgas, dos de pastos marinos, dos de zoántidos, una anémona, un coralimorfario y una esponja. Se observa un incremento en la cobertura de corales vivos (16%) con respecto a otros años (5% en 1985, y 13.2% en 1995), y una baja cobertura de coral muerto (0.2%). Las macroalgas presentan la cobertura más alta (59%), particularmente las algas pardas con una distribución en parches de Sargassum y Padina. Laurencia brongniartii (Rhodophyta) constituye una nueva adición para la flora ficológica de Costa Rica. El arrecife de Punta Cocles, funciona como un refugio para los organismos, debido a la ausencia de centros de población y desembocaduras de los ríos, además, del tipo de formación costera, lo que se ve favorecido por la conciencia ambiental que viven cerca del arrecife

This paper describes the Punta Cocles reef (Limón, Costa Rica). Data were obtained by sampling nine transects along the coast and observations done by skin diving between September and November of 2002. This reef consist of 10.5 hectares, where 13 species of corals, 39 of macroalgae, two of seagrasses, two of zoantids, one anemone, one corallimorpharian, and one sponge were identified. Life coral coverage (16%), was higher than in other years (5% for 1985, and 13.2% for 1995), and death coral coverage was very low (0.2%). Macroalgae have the highest coverage (59%), particularly brown algae with a patchy distribution of Sargassum and Padina. Laurencia brongniartii (Rhodophyta) is added to the list of marine flora of Costa Rica. The Punta Cocles reef works as a refuge for organisms, because there are no towns or river mouths nearby, and because of the coast formation. The refuge character is enhanced by the environmental conscience of the people that live close to the reef and help to protect the environment

Sexual reproduction of the reef-building coral Diploria labyrinthiformis (Scleractinia: Faviidae), in the Colombian Caribbean

Sexual reproduction of the coral Diploria labyrinthiformis was studied for the first time.Monthly histological analyses at the Corales del Rosario National Park (Colombian Caribbean) from May 1997 to April 1998 show that D.labyrinthiformis is a hermaphroditic broadcasting species.It presents an annual gametogenic cycle with a 10-11 month period for gonad investment,in which oogenesis begins in August and ends in May- June.Spermiogenesis is short because sperm cysts were only observed in May tissue samples.In histological collected in May,an average of four mature eggs and six spermatic cysts per fertile mesentery were found.The mean diameter of mature eggs was 297 µm (±97 SD)and 90 µm (±33)for spermatic cysts.Rapid maturation of eggs from stage II to stage III coincides with increases in air temperature,high number of solar hours per month,decreases in wind velocity and absence of rainfall.Reproductive effort for D.labyrinthiformis (14.07 mm3/cm2/year)was similar to other Faviidae species.Although gamete release was not observed in the field,the absence of gonads in histological samples in June suggests spawning between May 25 (five days after full moon) and June 24.This event coincides with high air temperature,low number of solar hours per month,low wind velocity,and initiation of the rainy season.The earlier spawning time of this species differs from other species of the same family known for the Caribbean region

La reproducción sexual del coral Diploria labyrinthiformis fue estudiada por primera vez.Análisis histológicos mensuales de muestras de D.labyrinthiformis extraídas en el Parque Nacional Natural Corales del Rosario (Caribe colombiano)entre mayo de 1997 a abril de 1998,muestran que es una especie hermafrodita,liberadora de gametos. Presenta un ciclo gametogénico anual de 10-11 meses para inversión en gónadas,en el cual la oogénesis comienza en agosto y termina en mayo-junio.La espermatogénesis es corta,ya que los paquetes espermáticos solo fueron observados en muestras de tejido del mes de mayo.En las muestras histológicas de mayo,un promedio de cuatro huevos maduros y seis paquetes espermáticos por mesenterio fértil fueron encontrados.El diámetro promedio de los huevos fue de 297 µm (±97 DS)y de 90 µm (±33) para los paquetes espermáticos.La rápida maduración de los huevos del estadío II al III coincidió con aumentos en la temperatura del aire,mayor número de horas de sol por mes,disminución en la velocidad del viento y ausencia de lluvias.El esfuerzo reproductivo de esta especie (14.07 mm3 /cm2/año)fue similar al de otras especies de Faviidae. Aunque la liberación de gametos no fue observada en el campo,la ausencia de gónadas en las muestras histológicas del mes de junio sugieren que la liberación ocurrió entre el 25 de mayo (cinco días después de luna llena)y el 24 de junio.Este evento coincidió con altas temperaturas del aire,bajas velocidades del viento y la iniciación de la época lluviosa.El tiempo de liberación de gametos en esta especie difiere de otras de la misma familia,conocidas para la región del Caribe

Akumal's reefs: stony coral communities along the developing Mexican Caribbean coastline

Fringing coral reefs along coastlines experiencing rapid development and human population growth have declined worldwide because of human activity and of natural causes.The "Mayan Riviera "in Quintana Roo,México,attracts large numbers of tourists in part because it still retains some of the natural diversity and it is important to obtain baseline information to monitor changes over time in the area.In this paper,the condition of the stony corals in the developing coastline of the Akumal-area fore reefs is characterized at the start of the new millennium at two depths,and along an inferred sedimentation gradient.Transect surveys were conducted in five fringing reefs starting at haphazardly chosen points.with respect to species composition,live cover,colony density,relative exposure to TAS mats and,for one species (Diploria strigosa ,Dana,1848),tissue regression rates in the presence of TAS mats.Fish population density and herbivory rates are also assessed.Data from line intercept transects (n=74)show that live stony coral cover,density and relative peripheral exposure of colonies to turf algal/sediment (TAS)mats were inversely related to an inferred sediment stress gradient at 13m.In 2000, live stony coral cover had decreased by 40-50%at two sites studied in 1990 by Muñoz-Chagín and de la Cruz- Agüero (1993).About half of this loss apparently occurred between 1998 and 2000 during an outbreak of white plague disease that mostly affected Montastraea faveolata ,and M.annularis .At a 13 m site,where inferred sedimentation rates are relatively high,time series photography of tagged Diploria strigosa ,(n=38)showed an average loss of 70 cm 2 of live tissue/coral/year to encroachment by TAS mats during the same period.Whereas densities of carnivorous fishes and herbivores (echinoids,scarids,acanthurids and Microspathodon chrysurus )in 2000 were low in belt transects at 10-19 m (n=106),turf-algal gardening pomacentrids were relatively common on these reefs

Para conocer el estado de las comunidades coralinas a lo largo de una costa en desarrollo,se realizó inventarios de transectos en cinco arrecifes de borde cerca de Akumal, México,con transectos de intersección (n=74).La cobertura de corales rocosos,la densidad y la exposición periférica relativa de las colonias y masas de algas-sedimentos son inversamente proporcionales a la gradiente de estrés de sedimentación inferida a 13m.En el 2000,la cobertura de corales rocosos vivos había decrecido un 40%en dos de los sitios estudiados por Muñoz-Chagín y de la Cruz-Agüero (1993).Alrededor de la mitad de esta pérdida aparentemente ocurrió entre 1998 y 2000 durante la epidemia de "blanqueo" que afectó principalmente a Montastraea faveolata y a M. annularis .En el sitio de 13m,donde las tasas de sedimentación inferida son relativamente altas,las fotografías en serie temporal de Diploria strigosa marcados (n=38)mostraron un promedio de pérdida de 70 cm2 de tejido vivo/coral/año y el cerco creciente de masas de algas durante el mismo periodo.Aunque las densidades de peces carnívoros y de organismos herbívoros (equinoideos, escáridos,acantúridos y Microspathodon chrysurus )en el 2000 fueron bajas en la franja a 10-19 m (n=106),se vio con frecuencia pomacéntridos que se alimentan de masas de algas

Seawater temperature measured at the surface and at two depths (7 and 12 m) in one coral reef at Culebra Bay, Gulf of Papagayo, Costa Rica

Superficial seawater temperature (SST) and at two depths (7 and 12 m) were measured non-continuously during the study of the corals and coral reefs of Culebra Bay (1993-1996). SST showed seasonal variations of approximately 4 degrees C. The highest average temperatures (27.0 +/- 0.1, range 23-29 degrees C) were during the rainy season from May to November and the lowest (22.9 +/- 0.3 degrees C, 15.5-29 degrees C) during the dry season from December to April. Cold fronts with 2-3 degrees C differences in SST frequently pass into the bay and remain there for several hours according to the tidal cycles. Differences of approximately 3 degrees C between SST and the bottom (5-10 m depth) were usually found, particularly at locations where bottom topography and tidal circulation produced tidal bores. The average temperatures recorded by data loggers placed at 7 and 12 m depth on a coral reef at the outer shores of Culebra Bay, were 27.1 +/- 0.02 degrees C (20.5-31.6 degrees C) and 25.8 +/- 0.04 (9.9-31.5 degrees C) respectively. The seasonal pattern of higher and lower temperatures corresponds respectively to the rainy and dry season of the northern Pacific coast of Costa Rica. Water temperature at 12 m was < 14 degrees C for some hours during an upwelling event whilst minimum temperatures at 7 m were > or = 22 degrees C. Negative temperature anomalies coincided with an increase of the NE-E winds intensity and there is a lunar and tidal component which influence diumal variations of temperature. These results suggest that coral reefs built by branching species (e.g. Pocillopora spp.) in Culebra Bay could be limited by both the influence of cold fronts and by seasonal upwellings which affect negatively those coral species, as reported for other locations in the tropical eastern Pacific.