Long-term monitoring of crab Cardisoma guanhumi (Decapoda: Gecarcinidae) captures in Jobos Bay Estuary, Puerto Rico

The densities of the land crab Cardisoma guanhumi has been declining due to overfishing, habitat degradation and loss, and continued capture in Natural Protected Areas (NPA). Numerous management strategies and regulations have been developed to monitor and reduce population declines. In Puerto Rico, an administrative order of 1999, regulates a closed season, prohibited the capture of crabs through the year from NPA's and below a minimum size for capture (64 mm). The goal of this research was to monitor spatial-temporal dynamics of crab captures after the implementation of the administrative order. Crabs captured in the Jobos Bay Estuary (JBE) were studied over a 15-year period. The size (carapace width) (CW), sex, and color were documented for 1 531 crabs from 31 crab hunters. Significant temporal difference in crab size was observed (Kruskal Wallis = 46.82, P < 6.187e-9), the smallest crabs were captured in 2004 and the largest crabs were captured in 2013. Crab size varied by color (Kruskal Wallis = 86.54, P < 2.2e-16), larger crabs were blue, medium sized crabs were brown and smallest crabs were orange. Since color is related to development stage and market value, color can be used as an educational and enforcement tool. There was significant spatial difference in the size of crabs captured (Kruskal Wallis = 252.54, P < 2.2 e-16), smaller crabs were captured in smaller hunting areas. Only three percent of crabs captured from 2009 to 2018 were below the legal-size limit. Temperature had a weak significant positive relationship with crab size and in years when rainfall was lower smaller crabs were captured. Increases in crab size from 2004 to 2013 coincided with mangrove recovery and the current decrease of crab size coincides with droughts of 2015. Management plans in the Caribbean must include local actions to reduce hunting and climate variability impacts on crab habitat and food availability.

Las densidades del cangrejo terrestre Cardisoma guanhumi ha disminuido debido a la sobrepesca, la degradación y pérdida de hábitat y la captura continua en áreas naturales protegidas (ANP). Se han desarrollado numerosas estrategias y regulaciones de gestión para monitorear y reducir el declive de la población. En Puerto Rico, una orden administrativa de 1999 regula una temporada cerrada, prohibió la captura de cangrejos durante todo el año en las ANP y por debajo de un tamaño mínimo para la captura (64 mm). El objetivo de esta investigación fue monitorear la dinámica espacio-temporal de las capturas de cangrejo después de la implementación de la orden administrativa. Los cangrejos capturados en el estuario de la Bahía de Jobos (JBE) se estudiaron durante un período de 15 años. El tamaño (ancho del caparazón) (CW), el sexo y el color se documentaron para 1 531 cangrejos de 31 cazadores de cangrejos. Se observó una diferencia temporal significativa en el tamaño del cangrejo (Kruskal Wallis = 46.82, P < 6.187e-9), los cangrejos más pequeños se capturaron en 2004 y los cangrejos más grandes en 2013. El tamaño del cangrejo varió según el color (Kruskal Wallis = 86.54, P < 2.2e-16), los cangrejos más grandes eran azules, los cangrejos medianos eran marrones y los cangrejos más pequeños eran anaranjados. Dado que el color está relacionado con la etapa de desarrollo y el valor de mercado, el color se puede utilizar como herramienta educativa y de cumplimiento. Hubo una diferencia espacial en el tamaño de los cangrejos capturados (Kruskal Wallis = 252.54, P < 2.2e-16), se capturaron cangrejos más pequeños en áreas de caza pequeñas. Solo el tres por ciento de los cangrejos capturados de 2009 a 2018 estaban por debajo del límite de tamaño legal. La temperatura tuvo una relación positiva significativa con el tamaño del cangrejo, cuando la lluvia fue menor, se capturaron cangrejos pequeños. Los aumentos en el tamaño de los cangrejos de 2004 a 2013 coincidieron con la recuperación de los manglares y la disminución actual del tamaño de los cangrejos coincide con las sequías de 2015. Los planes de manejo en el Caribe deben incluir acciones locales para reducir la caza y los impactos de la variabilidad del clima en el hábitat del cangrejo y la disponibilidad de alimentos.

Methodological approaches to assess passion fruit resistance (Passiflora spp. ) to passionfruit woodiness disease / Aspectos metodológicos para avaliação da resistência do maracujazeiro (Passiflora spp. ) à virose do endurecimento dos frutos

The passion fruit woodiness disease, induced by Cowpea aphid borne mosaic virus (CABMV), is considered the most economically important factor limiting passion fruit production in many countries. This study aimed to assess the progression of symptoms caused by CABMV in different Passiflora species. Eighty genotypes belonging 12 species were evaluated in experiments carried out in a completely randomized block design with treatments arranged in a factorial scheme (80 genotypes x 7 evaluation intervals) considering each inoculated plant as a repetition. The disease severity was estimated by the disease index (DI). The evaluations were performed at 20, 27, 34, 41, 48, 55 and 62 days after inoculation (DAI). The average DI values were used to describe the disease progress at each evaluation interval. The shortest time from evaluation to stabilization of CABMV progress was considered to cluster the genotypes by the Scott- Knott test (p0.05) and to classify the genotypes as resistant (R), moderately resistant (MR), moderately susceptible (MS), susceptible (S) or highly susceptible (HS). The mean severity gradually increased in the intervals from 20 to 55 DAI and reached a maximum at 62 DAI. The five classes (R, MR, MS, S and HS) contained about 19, 24, 36, 10 and 11% of the germplasm accessions, respectively. The disease temporal progress was quite variable within and among groups, although no difference in DI was observed in the genotypes after 55 DAI, indicating genotype symptom stabilization at this time, regardless of the genotype resistance level.

O endurecimento dos frutos causada pelo Cowpea aphid borne mosaic virus (CABMV) é considerada a doença mais importante economicamente limitando a produção de maracujazeiro em vários países. O objetivo deste trabalho foi avaliar o progresso dos sintomas causados pelo CABMV em espécies de Passiflora. O estudo foi realizado em delineamento em blocos casualizados, em esquema fatorial (80 genótipos x 7 períodos de avaliação) considerando cada planta como uma repetição, utilizando 80 genótipos pertencente a 12 espécies de maracujazeiro. A severidade foi estimada por meio do índice de doença (ID). As avaliações foram realizadas 20, 27, 34, 41, 48, 55 e 62 dias após a inoculação (DAI). As médias do ID foram utilizadas para verificar a evolução da doença em cada período de avaliação. O período mínimo para estabilização do progresso do CABMV foi utilizado para agrupar os genótipos pelo teste Scott-Knott (p0,05), bem como para classificar os genótipos em resistente (R), moderadamente resistente (MR), moderadamente suscetível (MS), suscetível (S), e altamente suscetível (AS). A severidade média da doença aumentou gradativamente nos intervalos de 20 a 55 DAI e atingiu seu máximo aos 62 DAI. Cerca de 19, 24, 36, 10 e 11% do germoplasma avaliado foi classificado como R, MR, MS, S e AS, respectivamente. O progresso temporal da doença foi bastante variável dentro e entre os grupos, embora não tenha sido observada diferença no ID dos genótipos a partir de 55 DAI, indicando a estabilização dos sintomas a partir deste período, independentemente do nível de resistência do genótipo.

Diet and trophic structure of the fish assemblage in the mid-course of the Teles Pires River, Tapajós River basin, Brazil

This study was carried out in a section of the middle course of the Teles Pires River, a clear water river that drains ancient and highly eroded geological formations, and where five hydropower plants are planned or in construction. In this study we tested the hypothesis that local fish fauna is mainly sustained by autochthonous food resources, with modest changes in the trophic structure of fish assemblages along the hydrometric cycle. Sampling was performed every three months between July 2008 and May 2009 at seven sites distributed along a 50-km section of the river. Piscivores was the most representative group in terms of biomass, abundance and species richness, followed by herbivores, insectivores and omnivores. The trophic structure did not change significantly during the hydrometric cycle, only omnivores showed significant temporal variation in abundance. The main food resources consumed by the ichthyofauna were of autochthonous origin, mainly immature aquatic insects and fish. Eight of 34 species showed temporal variations of the food resources consumed. Our results corroborate the hypothesis that the fish fauna of large, clear water rivers can be sustained by autochthonous resources. This contributes to understanding some determinants of fish production in large Neotropical rivers.(AU)

Este estudo foi desenvolvido em um trecho do curso médio do rio Teles Pires, um rio de águas claras que drena regiões de terreno geologicamente antigos, e onde cinco usinas hidrelétricas estão previstas ou em construção. Dado a transparência da água e as características do terreno nos hipotetizamos que a fauna de peixes local é principalmente sustentada por recurso autóctone e com alterações pouco significativas na estrutura trófica ao longo de um ciclo hidrométrico. As amostragens foram realizadas trimestralmente entre julho/2008 e maio/2009 em sete pontos dispostos ao longo de um trecho de cerca de 50 km do rio. Piscívoros foram os mais representativos em biomassa, número de exemplares e riqueza de espécies, seguidos pelos herbívoros, insetívoros e onívoros. Não houve mudança significativa na estrutura trófica da assembleia ao longo do ciclo hidrométrico, apenas onívoros apresentaram significativa variação temporal na abundância. Os principais recursos alimentares utilizados pela ictiofauna foram de origem autóctone, sobretudo insetos imaturos e peixes. Oito de 34 espécies apresentaram variação temporal na dieta. Os resultados corroboram a hipótese de que grandes rios de água clara podem ser sustentados majoritariamente por recursos autóctone. Desta forma, este estudo contribui para a compreensão de alguns fatores determinantes da produção secundária em grandes rios Neotropicais.(AU)

Spatial and temporal distribution of stream macroalgae in a tropical river basin / Distribuição espacial e temporal de macroalgas de riachos em uma bacia tropical

Spatial and temporal distribution of stream macroalgae in streams from southeastern Brazil were assessed for one year. The fluctuations in macroalgal species composition and environmental factors were monitored monthly. The region exhibit a tropical climate, with defined rainy and dry seasons. Nineteen species were found, with a predominance of Chlorophyta (52.7% of the species), followed by Cyanobacteria (26.3%), Ochrophyta and Rhodophyta (10.5% each). Scytonema arcangeli had the highest number of records (63.6%), while Mougeotia capucina occurred in all sampling sites. Community structure had low similarity (20-26%) and the environmental factors showed a weak contribution to the distribution pattern observed. Despite this, the light availability at the stream-bed seems to be a major influence on the macroalgal seasonal dynamics. We suggest that macroalgae communities are predominantly composed of rare species, and this could explain the lack of a clear spatial and temporal variation pattern of these organisms.

A distribuição espacial e temporal das macroalgas lóticas em riachos do sudeste do Brasil foram avaliadas por um ano. As flutuações na composição de espécies de macroalgas e fatores ambientais foram monitorados mensalmente. A região apresenta um clima tropical, com estações chuvosas e secas definidas. Dezenove espécies foram encontradas, com predomínio de Chlorophyta (52,7% das espécies), seguido por Cianobactérias (26,3%), Ochrophyta e Rhodophyta (10,5% cada). Scytonema arcangeli teve o maior número de registros (63,6%), enquanto Mougeotia capucina ocorreu em todos os pontos de amostragem. A estrutura da comunidade teve baixa similaridade (20-26%) e os fatores ambientais mostraram uma fraca contribuição para o padrão de distribuição observado. Apesar disso, a disponibilidade de luz no leito do riacho parece ser de grande influência sobre a dinâmica sazonal de macroalgas. Nós sugerimos que as comunidades de macroalgas são predominantemente compostas por espécies raras, e isso poderia explicar a falta de um padrão claro de variação espacial e temporal desses organismos.

Studies on spatio-temporal dynamics of phytoplankton in El-Umum drain in west of Alexandria, Egypt.

Phytoplankton was assessed quantitatively and qualitatively in regard to their abundance in the northern part of El-Umum drain, west of Alexandria at four stations to study the spatial, temporal, dominance and abundance of the phytoplankton community. The samples were collected monthly from April 2003 to April 2004. A total of 152 phytoplankton taxa were identified belonging to Bacillariophyceae (60), Chlorophyceae (46), Cyanophyceae (20), Euglenophyceae (17) and Dinophyceae (9). A limited number of these were recorded throughout the year, and showed an indication of organic pollution. The total densities (333.8x103units l-1) were mainly a reflection of the trends in counts of Bacillariophyceae and Chlorophyceae (138.1 x 103 and 131.6 x 103 units l-1, respectively). Monthly differences in the quantitative (18 x 103 to 1645 x 103 units l-1) and qualitative composition ( 41 to 113 taxa) of the phytoplankton communities in the different stations were marked, with recurrent high abundance in spring (910.4 x103 units l-1), whereas lowest densities occurred in autumn (99.7x103 units l-1). Cyanophyceae was most abundant in July (67.5 x103 units l-1), whereas Euglenophyceae in December (32.0x103 units l-1). Species diversity (H’) gave a signal of the area is light to moderate polluted. The present study emphasized the need to use phytoplankton community as index of water quality.

Mid-term coral-algal dynamics and conservation status of a Gorgona Island (Tropical Eastern Pacific) coral reef

Colombian coral reefs, as other reefs worldwide, have deteriorated significantly during the last few decades due to both natural and anthropogenic disturbances. The National Monitoring System for Coral Reefs in Colombia (SIMAC) was established in 1998 to provide long-term data bases to assess the changes of Colombian coral reefs against perturbations and to identify the factors responsible for their decline or recovery. On the Pacific coast, data on coral and algal cover have been collected yearly during seven consecutive years (1998-2004) from 20 permanent transects in two sites at La Azufrada reef, Gorgona Island. Overall, coral cover was high (55.1%-65.7%) and algal cover low (28.8%-37.5%) and both exhibited significant changes among years, most notably on shallow areas. Differences between sites in both coral and algal cover were present since the study began and may be explained by differences in sedimentation stress derived from soil runoff. Differences between depths most likely stem from the effects of low tidal sub-aerial exposures. Particularly intense sub-aerial exposures occurred repeatedly during January-March, 2001 and accounted for a decrease in coral and an increase in algal cover on shallow depths observed later that year. Additionally, the shallow area on the Northern site seems to be negatively affected by the combined effect of sedimentation and low tidal exposure. However, a decrease in coral cover and an increase of algal cover since 2001 on deep areas at both sites remain unexplained. Comparisons with previous studies suggest that the reef at La Azufrada has been more resilient than other reefs in the Tropical Eastern Pacific (TEP), recovering pre-disturbance (1979) levels of coral cover within a 10 year period after the 1982-83 El Niño, which caused 85% mortality. Furthermore, the effects of the 1997-98 El Niño, indicated by the difference in overall live coral cover between 1998 and 1999, were minor (<6% reduction). Despite recurrent natural disturbances, live coral cover in 2004 was as high as that existing before 1982 at La Azufrada, and one of the highest observed on healthy coral reefs in the TEP region. Rev. Biol. Trop. 58 (Suppl. 1): 81-94. Epub 2010 May 01.

A través del Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC) se han colectado anualmente (1998-2004) datos de cobertura de corales y algas en 20 transectos de 10m localizados en dos profundidades de dos sitios del arrecife de La Azufrada, Isla Gorgona (costa Pacífica). En general, la cobertura coralina fue alta (55.1% - 65.7%) y la de algas baja (28.8% - 37.5%), con una significativa variación entre años, más notablemente en áreas someras. Las diferencias entre sitios tanto en cobertura de coral como de algas estuvieron presentes desde que comenzó el estudio y pueden ser explicadas por diferencias en estrés por sedimentación (escorrentía terrestre). Las diferencias entre las profundidades muy probablemente se deben a los efectos de exposiciones aéreas durante mareas bajas. Las exposiciones aéreas particularmente intensas y repetidas entre enero-marzo de 2001 explican la disminución de la cobertura de coral, y aumento de la de algas en áreas someras observadas más tarde ese año. Adicionalmente, el área somera del sitio norte parece ser negativamente afectada por el efecto combinado de la sedimentación y la exposición mareal. Sin embargo, una tendencia a la disminución de la cobertura coralina y aumento de la de algas desde 2001 en las áreas profundas de ambos sitios permanece sin explicación. Comparaciones con estudios previos indican que el arrecife de La Azufrada ha sido más elástico que otros arrecifes del Pacífico Oriental Tropical (POT). A pesar de las perturbaciones naturales recurrentes, la cobertura coralina en 2004 fue tan alta como la existente antes de 1982 en La Azufrada, y una de las más altas observadas en arrecifes coralinos saludables de la región del POT.

Temporal Changes of Direction and Spatial Frequency Tuning in Visual Cortex Areas 17 and 18 / 한국실험동물학회지

Spatial frequency and direction tuning to drifting sinusoidal gratings are intrinsic properties of neurons in visual cortex neurons in areas 17 and 18. To investigate the stability of these tuning properties during visual stimulation in anesthetized cats, the temporal dynamics of spatial frequency and direction tuning were analyzed in every 0.1 sec. The responses of cortical neurons (n=109) as a function of spatial frequency as well as direction at a particular velocity for 1 second were measured and plotted as a contour plot. Five parameters from this plot were extracted: optimum response, preferred direction (direction that showed the optimum response), optimum spatial frequency (spatial frequency that showed the optimum response), direction tuning width (the difference between the highest and lowest directions to which the cell was at least half as responsive as it was to its optimum direction) and spatial frequency bandwidth (the difference between the highest and lowest frequencies to which the cell was at least half as responsive as it was to its optimum frequency). Then, this contour plot was further analyzed in every 0.1 sec to investigate whether these five parameters were changed or not during the course of stimulation. These parameters were plotted along the time (0.1 sec step) and a line of fit was found. Both spatial frequency and direction tuning properties were not changed in most of the cells. This suggests that both direction and spatial frequency tuning properties are stable during drifting sinusoidal gratings' stimulation.

Growth dynamics and state of the seagrass Thalassia testudinum in the Gandoca-Manzanillo National Wildlife Refuge, Caribbean, Costa Rica / Dinámica de crecimiento y estado del pasto marino Thalassia testudinum en el Refugio Nacional de Vida Silvestre Gandoca-Manzanillo, Caribe, Costa Rica

Seagrass beds are highly productive and valuable habitats, which fulfill a key role in coastal ecosystems. Spatial distribution, biomass, density, productivity and leaf dynamics of the dominant seagrass species Thalassia testudinum were studied at five locations in the Gandoca-Manzanillo National Wildlife Refuge, Caribbean coast of Costa Rica, from November 2005 until March 2006. Seagrass beds within the study area cover approximately 16 ha. Spatial and temporal differences in ecological seagrass parameters were examined along gradients of riverine inputs and related to a range of environmental parameters (depth, grain size distribution, nutrient concentrations, salinity and temperature). Average canopy cover and above-ground biomass of T. testudinum inversely correlated with depth, but did not vary significantly between study sites when compared along depth ranges. Considerable spatio-temporal variations in shoot densities, areal productivity and leaf sizes seem to be related to riverine inputs and wave energy. It appeared that T. testudinum at exposed sites respond to increased environmental disturbance related to the offset of the rainy season with clonal recruitment, whereby shoot densities increase and average leaf sizes are reduced. Lower shoot densities and greater leaf sizes, in contrast, are characteristic for locations with rather consistent environmental conditions, where seagrasses are sheltered. T. testudinum in the refuge has higher shoot densities but shorter leaves and lower productivity compared to sites in 15 other Caribbean countries. The seagrass beds appear to be in a relatively healthy state, however, observations of temporal increased stocks of filamentous epiphytes and macroalgae indicate temporal environmental stress in the system. Rev. Biol. Trop. 57 (Suppl. 1): 187-201. Epub 2009 November 30.

Las praderas de pastos marinos son sitios altamente productivos y hábitats valiosos en los ecosistemas costeros. Se estudió los cambios espaciales y temporales en la distribución del pasto marino dominante Thalassia testudinum, en cinco localidades expuestas a un gradiente de influencia fluvial, en el Refugio Nacional de vida Silvestre Gandoca-Manzanillo, Costa Rica, entre noviembre 2005 y marzo 2006. El pasto cubre unas 16ha. Tanto cobertura como biomasa disminuyen al aumentar la profundidad, pero no hubo diferencia de cobertura y biomasa entre lugares. Las variaciones espacio-temporales en densidad de estolones, productividad y tamaño de hojas, probablemente están relacionadas con la entrada de agua del río y la energía de las olas. Al parecer T. testudinum responde a disturbios ambientales con reclutamiento clonal: la densidad de estolones aumenta y las hojas son más pequeñas. En Gandoca-Manzanillo la densidad de estolones es mayor, las hojas más cortas y la productividad inferior, en comparación con otros 15 sitios del Caribe. Según estos parámetros, los pastos marinos de Gandoca-Manzanillo están en muy buenas condiciones. Sin embargo, se observaron aumentos en algas filamentosas epífitas y de macroalgas, que indican un impacto temporal en el sistema.